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Taxa of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphniidae) are ubiquitous in temperate and tropical lakes, and the taxonomy of the genus is confused. Moreover, present keys are often regional and insufficient for the taxonomic assignment of species at a global scale. This communication is aimed at improving our understanding of the C. dubia s.l. species group. We redescribe C. dubia s.l. from Northern Eurasia and describe a new species from Central Yakutia (Eastern Siberia, Russia). In contrast to typical members of the C. dubia group, C. nikolaii sp.nov. has the postabdomen of the parthenogenetic female with preanal margin slightly or strongly projecting and angulated. Moreover, adult males have a pronounced preanal angle and sensory seta of antenna I which is shorter than the longest easthetasc. Our finding challenges current definitions of species groups in Ceriodaphnia. Indeed, a postabdomen shape with a strongly projected preanal angle is characterstic of another group of this genus, namely the C. laticaudata-group. We found a taxon that combines the diagnostic morphological characters of two species groups. Further development of the genus taxonomy must be accompanied by redescriptions of all well-accepted and dubious taxa from their type localities and revisions of populations from other localities of the world.

Spinicaudatan clam shrimps are an evolutionarily ancient lineage restricted to temporary freshwater pools. Use of classical morpho-taxonomic approaches alone have led to some issues in the taxonomy of this group, which are now being resolved through integrative taxonomy. Here, we describe two new leptestherid spiny clam shrimps Leptestheria chalukyae sp. nov. and Leptestheria gomantaki sp. nov. from peninsular India based on their unique morphological characters and distinct phylogenetic position. We also re-describe Leptestheria nobilis and present an overview of the morphological characters of all the Indian leptestherids. Most of the conventional taxonomic characters appear to overlap among all the Indian species, although the combination of occipital condyle shape and the cercopod marginal spines arrangement in combination, appear to be useful in separating leptestherid species.

Santos, Arielly De S., Andrade, Daniel Da S., Sousa, Francisco Diogo Rocha, Mugnai, Riccardo (2023): Three new records of Cladocera (Crustacea: Branchiopoda) for the State of Maranhão, Northeastern Brazil. Zootaxa 5319 (2): 224-234, DOI: 10.11646/zootaxa.5319.2.4, URL: http://dx.doi.org/10.11646/zootaxa.5319.2.4

Simocephalus (Coronocephalus) serrulatus (Koch, 1841) (Figs. 2 A–C) Material examined. 10 specimens, collection number CINCAA 0090. Remarks. This species has a right or acute angled anterior margin of the head and is armed with small spines, the typical characteristic of the subgenus Coronocephalus. (Fig. 2B). Simocephalus serrulatus differs from Simocephalus semiserratus Sars, 1901 in the posterior-dorsal projection of the carapace, which in the former is larger and more marked (Orlova-Bienkowskaja 1998).

Dadaya macrops (Daday, 1898) (Figs. 4 A–C) Material examined. 10 specimens, collection number CINCAA 0052 Remarks. Described from the material from the Sri Lanka region by Daday (1898) as Alona macrops Sars (1901) named the genus Dadaya Sars, 1901. The genus is monospecific and Dadaya ocellata Bergamin (1931) is still considered synonymous with D. macrops (Smirnov 1974; Elmoor-Loureiro 1997). This suggestion still needs investigation involving the analysis of populations from different regions of the world (Elmoor-Loureiro 2010). The most striking morphological trait of the species is the oval body with a markedly large ocellus, pointed rostrum and a single cephalic pore (Fig. 4B) (Smirnov 1996; Elmoor-Loureiro 2000). In Table 1 we can find the distribution of Cladocera for the state of Maranh„o and in Table 2 the list of Cladocera of Maranh„o state (modified from Santos et al. 2021).

Leptestheria timmsi sp. nov. (Figs.2A–B; Figs.3A–E) Eoleptestheria ticinensis Timms (2009) Etymology. The new species is named after Dr. Brian Timms, an expert on large branchiopods who has contributed extensively to the taxonomy and systematics of Australian animals Type locality. Australia, Queensland, Bindegolly National Park, Lake Toomaroo; - 27° 58’ 47.604” N, 144° 12’ 3.708” E. Type material. Holotype. 1 hermaphrodite (collected by M. Handley on 01.02.2006) deposited at the Australian museum, Sydney (Registration number: P92974). Paratypes. 8 hermaphrodites deposited at the Australian museum, Sydney (Registration number: P80191). Other material examined. Slovakia (Trebišov District/Novosad; MNHN-IU-2007-1122 (= MNHN-Bp83)). Mali (Mopti region/Sanga (Sangha); MNHN-IU-2007-747 (= MNHN-Bp463). Description (Diagnosis) of putative hermaphrodite. Population from the type locality of this species has been thoroughly described by Timms (2009) and hence we focus only the diagnostic traits and the traits that were not elaborated earlier. Head (Fig. 2A) with a distinct ocular tubercle. Eyes moderate sized about 0.6–0.7 times the width of ocular tubercle. The ratio of RL/TL ranging from 0.7–0.8. Occipital condyle rounded with a straight dorso-posterior margin. The rostral spine long, arched and nearly 6–8 times as long as the width at its base. Carapace oval with maximum width to maximum length ratio ranging from 0.55–0.6. Trunk. Last 12–14 body segments, each bear group of stout setae, directed posteriorly with acute apices, longest setae ~ 6–8 times as long as wide at the base (Fig.3B), numbers and size of longest setae increasing initially and then both decreasing gradually. Telson marginal spines ~ 40–45 in number, gradually increasing in length posteriorly (Fig. 2B). Telson marginal spines broadly of two types based on their length and shape. Posterior 1/3 rd spines 1.5–2 times longer than the anterior 2/3 rd. Anterior spines as long as their width at the base while posterior 1/3 rd 2–3 times the width at their base (Figs. 2B, 3A, 3C). Distance between the spines is subequal, lesser in the bigger spines and increases anteriorly (Figs. 2B, 3A, 3C). Telson filaments located between the 1–3 rd marginal spines (Fig. 2B). Cercopod long, gently arched, slightly extending beyond the telson spiniform projection and nearly equal to the length of the telson dorsal margin (Fig. 2B). Cercopod marginal spines closely spaced, increasing in size posteriorly with the most posterior spines 3-4 times in length than the most anterior spines (Figs. 2B, 3E). Smallest spines 2 times in length as compared with their base while the longest spines nearly 4–5 times in length as compared to their base (Fig.2B). Most of the anterior spines aligned medially and therefore not directly visible (Fig. 3D). Distribution. Northern Australia. In addition to the Lake Toomaroo population, two other populations are known (but not studied in this work), namely the Kuranda population in Queensland and the Benmore Well clay pan population (Pilbara) in Western Australia (see Timms, 2009).

Padhye, Sameer M., Rabet, Nicolas (2023): Assigning the Australian clam shrimp Eoleptestheria (Branchiopoda: Spinicaudata: Leptestheriidae) to a new species status. Zootaxa 5318 (4): 563-570, DOI: 10.11646/zootaxa.5318.4.9, URL: http://dx.doi.org/10.11646/zootaxa.5318.4.9

Sinev, Artem Y., Sousa, Francisco Diogo Rocha, Elmoor-Loureiro, Lourdes M.A. (2023): Revision of the guttata-group of Alona s. lato leads to its translocation to Prendalona Sousa, Elmoor-Loureiro & Santos, 2018 (Cladocera: Anomopoda: Chydoridae). Zootaxa 5293 (1): 95-121, DOI: 10.11646/zootaxa.5293.1.4, URL: http://dx.doi.org/10.11646/zootaxa.5293.1.4

Prendalona arvensis (Sousa, Elmoor-Loureiro & Santos, 2016) (Fig.1) Sousa, Elmoor-Loureiro & Santos, 2016: 34–37, fig. 9–10, 11Q–R (Prenda) Type locality. A temporary pond located in a high-altitude field (aproximately 1200 m), Bom Jesus, Rio Grande do Sul, Brazil (28°36ʹ57ʺS, 50°22ʹ11ʺW). Type material. Holotype: Dissected parthenogenetic female deposited at the Museum of Zoology of the State University of Bahia, accession number UFBA2168. Paratypes: Four parthenogenetic females from type locality, deposited at Laboratório de Taxonomia Animal, Universidade Federal de Jataí, accession number FDRS216-219. Material examined earlier: see Sousa et al. (2016) for list of material from type locality. Diagnosis. Parthenogenetic female. General (Fig. 1A) oval in lateral view, strongly compressed laterally, of moderate height, maximum height at middle of body, in adults height/length ratio about 0.63. Dorsal margin uniformly curved; postero-dorsal and postero-ventral angles broadly rounded; posterior margin uniformly curved; ventral margin almost straight; antero-ventral angle rounded. Valve with a well-developed pattern of longitudinal lines. Ventral margin (Figs. 1B–C) with about 35 setae. Postero-ventral angle (Fig. 1C) bears about 60 short, thin, hair-like setulae. Head. Eye larger than ocellus. Head shield without sculpturing, posterior margin of head shield broadly rounded (Fig. 1D). Two major head pores. PP about 0.5 IP. Lateral head pores located at about 1.5 IP distance from midline, at the level between major head pores. Labral keel (Fig. 1E) with a blunt prominence in upper portion of anterior margin, without clusters of setulae on posterior margin. Postabdomen (Fig. 1F) short, of moderate width, narrowing distally, with a rounded, prominent distal angle; length about 2.8 height. Ventral margin straight. Distal margin convex. Dorsal margin with distal part 2 times longer than preanal one, anal and postanal portion of similar length. Postanal portion of dorsal margin straight to weakly concave, anal portion concave. Postanal margin with 6–7 well-developed composite marginal denticles, three distalmost denticles significantly larger than others, most bearing spinules on anterior margin; length of distal denticles equal to the width of the postabdominal claw base. Anal margin with 3 clusters of thick spinulae. Postanal margin with 8–10 lateral groups of setulae, six–seven distalmost groups narrow, consisting of 5–7 thin setulae decreasing in length anteriorly, posteriormost seta being longest, of same thickness as others. Postabdominal claw curved, of moderate length, as long as preanal portion of postabdomen. Basal spine short, weakly curved, about 0.2 of claw length. Morphology of antennule and antenna typical for the genus. Morphology of thoracic limbs typical for the genus. Thoracic limb I (Figs. 1G–H) with a rudimentary seta i on endite 1. Thoracic limb III with setae 4 and 5 of similar length, two times shorter than seta 6. Ephippial female and male unknown. Size: length of adult parthenogenetic female up to 0.37 mm. Differential diagnosis. P. arvensis clearly differs from all other species of the genus in (1) two main head pores, and (2) labrum with a blunt prominence at its anterior margin. Distribution and ecology. To date known from the type locality only, a temporary pond covered by Sphagnum at a high-altitude field, with acid water (pH, Published as part of Sinev, Artem Y., Sousa, Francisco Diogo Rocha & Elmoor-Loureiro, Lourdes M. A., 2023, Revision of the guttata-group of Alona s. lato leads to its translocation to Prendalona Sousa, Elmoor-Loureiro & Santos, 2018 (Cladocera: Anomopoda: Chydoridae), pp. 95-121 in Zootaxa 5293 (1) on page 99, DOI: 10.11646/zootaxa.5293.1.4, http://zenodo.org/record/7959789

Prendalona julietae Sousa, Elmoor-Loureiro & Santos sp. nov. Fig. 11–12. Sousa et al. (2016 a): 4–13, fig. 1–3, 11A–C (Alona cf. guttata ). Etymology. This new species is named in honor of Julieta Abdu El-moor, mother of Lourdes M. A. Elmoor-Loureiro. Type locality: Artificial pond at Fontes do Ipiranga State Park (23°38ʹ19.7ʺS, 46°37ʹ16.5ʺW), São Paulo, Brazil. Type matetrial. Holotype. Parthenogenetic female deposited at the Museum of Zoology of the S„o Paulo University, accession number MZUSP41593. Allotype. A male deposited at the Museum of Zoology of the S„o Paulo University, accession number MZUSP41594. Paratypes. A parthenogenetic female deposited at the Museum of Zoology of the S„o Paulo University, accession number MZUSP41595. Material studied earlier: see Sousa et al. (2016 a). Description. Parthenogenetic female. General Body (Fig. 11A), oval in lateral view, of a moderate height; maximum height at middle of the body, in adults height/length ratio about 0.67. Dorsal margin uniformly curved; posterodorsal and posteroventral angles broadly rounded; posterior margin uniformly curved; ventral margin almost straight; anteroventral angle rounded. Valves oblique. Ventral margin of valves with 32–35 setae, anterior setae very short (Fig. 11B). Posterodorsal angle with about 30 setulae (Fig. 11C). Head. Compound eye larger than ocellus. Head shield without any sculpture, with a broadly rounded posterior portion. Three main pores, posterior and anterior pores larger than median pore; PP about 0.3–0.5 IP; lateral head pores located at level between median and anterior pores, distance from midline slightly shorter than IP. Labrum. Labral keel without a prominence at anterior margin, posterior margin of keel with two clusters of setulae. Posterior part of labrum (Fig. 12A–C) in most specimens covered with epibiont bacteria. Postabdomen (Fig. 11D) short, about 2.4 times as long as wide; preanal angle evident, preanal margin longer than anal and postanal margin. Anal margin slightly concave, with 3–4 groups of denticles. Postanal margin with distal portion acute, truncated, 6–7 well-developed marginal denticles, each with several spinulae on the anterior margin. Postabdominal claw similar in length to the anal margin, with one group of short spinulae on the base; pecten armed with one row of inner and outer spinulae; outer row with spinulae of similar length; distal spinulae on inner row longer than others. Morphology of antennule and antenna typical for the genus. Morphology of thoracic limbs typical for the genus. Thoracic limb I without seta i on endite 1. Thoracic limb III with seta 4 longer than seta 5. Ephippial female unknown. Male. General. Body low oval (Fig. 11E), with maximum height at the middle, body height/length ratio about 0.62. Compound eye larger than ocellus. Postabdomen (Fig. 11F) short, moderately wide, evenly narrowing distally. Postanal margin of postabdomen evenly comes to the base of claws, no distinct distal margin and dorsodistal angle. Length about 2.5 height. Ventral margin straight or weakly convex. Sperm duct opens at the end of postabdomen, forming minute protrusion above the base of claws. Dorsal margin almost straight in postanal portion. Preanal and postanal angles not defined. Preanal margin weakly convex to straight. Distal portion of postabdomen 2.5 times longer than preanal one; anal and postanal portions of similar length. Postanal margin with clusters of setulae of even thickness. Lateral groups of setulae as in female. Postabdominal claw (Fig. 11G) weakly curved, shorter than in female, much shorter than preanal margin of postabdomen, with acute tip without cluster of setulae. Basal spine very short, with a long spinule, longer than basal spine, near it. Antennule (Fig.11H) with male seta located at 2/3 distance from the base, its length about 0.4 length of antennule. Thoracic limb I (Fig. 11I) of typical for the genus morphology, endite 1 without seta i. Size. Length of parthenogenetic females 0.23–0.35 mm; of males 0.25–0.26 mm. For full description see Sousa et al. (2016 a). Differential diagnosis: P. julietae sp. nov. differs from P. arvensis in three main head pores and in labral keel without a prominence on anterior margin, and from P. werestschagini in (1) a smaller size, (2) smaller IP/PP ratio, and (3) a shape of both male and female postabdomen. P. julietae sp. nov. differs from P. barbulata in (1) head shield with broadly rounded posterior portion, (2) female postabdomen with acute prominent distal angle and strongly prominent preanal angle, (3) absence of seta i on endite 1 of thoracic limb I, and (4) evenly narrowing distally male postabdomen. Parthenogenetic females of P. julietae sp. nov. have similar morphology with those of P. guttata. Male of P. julietae sp. nov. differs from that of P. guttata in presence of a very long setule near basal spine of the postabdominal claw (this setule is longer than basal spine). Distribution and ecology: P. juliate sp. nov. has a wide distribution in Brazil with occurrence in different types of aquatic ecosystems (Sousa et al. 2016 a). It might be considered one of the most common alonine species in Brazil., Published as part of Sinev, Artem Y., Sousa, Francisco Diogo Rocha & Elmoor-Loureiro, Lourdes M. A., 2023, Revision of the guttata-group of Alona s. lato leads to its translocation to Prendalona Sousa, Elmoor-Loureiro & Santos, 2018 (Cladocera: Anomopoda: Chydoridae), pp. 95-121 in Zootaxa 5293 (1) on pages 112-114, DOI: 10.11646/zootaxa.5293.1.4, http://zenodo.org/record/7959789, {"references":["Sousa, F. D. R., Elmoor-Loureiro, L. M. A. & Santos, S. (2016 a) New findings of Hexalona-branch representatives in Brazil, with a description of Prenda gen. nov. (Crustacea: Anomopoda: Aloninae). Journal of Natural History, 50 (43 - 44), 2727 - 2768. https: // doi. org / 10.1080 / 00222933.2016.1208302"]}

Prendalona barbulata (Megard, 1967) comb. nov. Megard, 1967: 37–57, Figs. 9 –19, pl. 2a–b (Alona); Smirnov, 1971: 382, Fig. 458 (Alona). Type locality Island Lake in the Wind River Mountains, about 20 km northeast of Pinedale, Wyoming, U.S.A. Type material. The holotype (parthenogenetic female) and several paratypes deposited in the British Museum (No. 1966. 3.21.4). Material examined. Six parthenogenetic females, over 20 ephippial females, 7 adult males, 2 juvenile males of instar II from Salmon Lake, Missoula County, Montana, U.S.A., 15.11.1977, coll. K. Brakke, sample DGF 4458 in collection of Prof. D. G. Frey at National Museum of Natural History (Washington DC, USA), general access number 403774. Description. Parthenogenetic female. General. In lateral view body (Figs. 2A, 3A–C) oval, of moderate height, maximum height at middle of body, in adults height/length ratio 0.65. Dorsal margin uniformly curved; postero-dorsal and postero-ventral angles broadly rounded; posterior margin uniformly curved; ventral margin almost straight; antero-ventral angle rounded. Body moderately compressed laterally. Valves. Ventral margin with 30–40 setae, anteriormost ten setae short (Fig. 2B), not forming a group separated from setae in middle of margin, distal setae of moderate length (Fig. 2C). Postero-dorsal angle (Fig. 2D) bears about 70 short, thin, hair-like setulae of similar length, not organized in groups. A row of about 80–100 thin setulae of variable length along posterior margin at inner side of valve. Valve looks smooth by optical microscopy, but SEM examination reveals a weakly developed linear sculpture. Head of moderate size, oblique, triangular-round in lateral view; rostrum short, pointing downward. Compound eye larger than ocellus. Distance from tip of rostrum to ocellus in adults 1.5 times greater than that between ocellus and eye. Head shield (Fig. 2E) with a maximum width behind mandibular articulation, without sculpturing; rostrum short, broadly rounded; posterior portion of head shield triangular with obtuse apex. Three connected major head pores of similar size, middle pore located closer to posterior pore, PP less than 0.5 IP (Figs. 2F – 4C). Lateral head pores minute, located at about 0.8 IP distance from midline, at the level of anterior major head pores. Labrum (Figs. 2G–H, 4A–B) of moderate size; labral keel narrow (height about 2 width), with a rounded apex; anterior margin of keel convex, posterior margin with two clusters of short setulae, setulae in anterior cluster pointing almost forward. Posterior portion of labrum under optical microscope appears to be covered by thin setulae, but SEM examination (Fig. 4A–B) reveal that these ‘structures’ are in reality epibiotic bacteria. Thorax twice longer than abdomen, dorsal surface of abdominal segments not saddle-shaped. Postabdomen (Figs. 4D – 5A) short, of moderate width, slightly narrowing distally, with a rounded, not prominent distal angle, length about 2.5 height. Ventral margin straight. Base of claws separated from distal margin by a weak incision. Distal margin straight to weakly convex, distal angle rounded, not protruding before the base of claw. Dorsal margin with distal part 1.8–27 times longer than preanal one, with postanal portion 1.3–1.5 times shorter than anal. Postanal portion of distal margin straight, anal portion weakly concave. Preanal angle well-defined, but not protruding, postanal angle weakly defined. Postanal margin (Figs. 5B–C) with 6–7 marginal denticles, decreasing in size basally, 2–3 distalmost denticles robust, others have broad bases, bearing long spinules anteriorly; length of distal denticles equal to the width of the postabdominal claw base. Anal margin with four groups of short setulae. Eight–nine lateral fascicles of setulae, six–seven distalmost fascicles wide, consisting of thin setulae, with longest setulae in the middle, slightly shorter than longest marginal denticles. Several additional fascicles above the main row in anal portion. Postabdominal claw of moderate length, as long as preanal portion of postabdomen. Basal spine short, curved, about 0.2 of length of claw. Antennule (Fig. 2I) of moderate size, length about 2.5 width, with four clusters of thin setulae at anterior face, setae of two central clusters long. Antennular sensory seta slender, three times shorter than antennule, arising almost at the middle of antennule. Nine terminal aesthetascs, two longest of them about 2/3 length of antennule. Antenna (Figs. 2J – 4E) relatively short. Antennal formula, setae 0–0–3/1–1–3, spines 1–0–1/0–0–1. Basipodite segment robust, branches of moderate length and width, proximal segments of both branches 1.5 times longer than others, middle segments slightly shorter than apical. Seta arising from basal segment of endopodite thin, not reaching the end of endopodite. Seta arising from middle segment of endopodite of similar size with shortest apical setae. Spine on basal segment of exopodite as long as middle segment. Apical spines slightly longer than apical segments. Thoracic limbs: Six pairs. Limb I (Figs. 6 A–B) of moderate size. Epipodite with long process 3–4 times longer than exopodite itself. Accessory seta about 1/3 length of ODL seta, unilaterally armed by thick setulae. IDL with three setae and two–three clusters of small setulae, setae 2 and 3 only slightly shorter than ODL seta, armed with thin setulae in distal part, seta 1 very short, located laterally. Endite 3 with four setae, inner seta (1) shorter than setae a-c. Endite 2 with three setae (d–f), setae e–f of similar length, 1.5 shorter than limb itself. Endite 1 with two 2-segmented setae (g-h), both setulated in distal part, and very small, rudimentary seta i. No inner setae on edites 1–2. Six-seven rows of thin long setulae on ventral face of limb. Two ejector hooks, one of them larger than the other. Maxillar process elongated, with a short seta. Limb II (Figs. 6 C–D). Exopodite elongated, with a setulated seta as long as exopodite. Eight scraping setae (1–8), armed with small spinules, increasing in length distally, scraper 3 thicker than neighbors and armed with thicker spinules. Distal armature of gnathobase with four elements. Filter plate with seven setae, the posteriormost three times shorter than others. Limb III. Epipodite oval, with a short process; exopodite trapezium-shaped, with seven setae (Fig. 6E). Seta 3 being longest; setae 4 and 6 about 1/2 length of seta 3; setae 1 and 7 about 1/3 length of seta 3; seta 5 about 1/4 length of seta 3; seta 2 short. Setae 6–7 armed with short setulae in distal portion, all other setae plumose. Distal endite (Fig. 6F) with three anterior setae (1–3), two distalmost members slender, sharp, with distal parts unilaterally armed with sharp denticles, seta 1 significantly longer than seta 2; basalmost seta (3) as long as seta 2, broad, bilaterally armed with setulae. Basal endite (Fig. 6G) with four anterior stiff setae, increasing in size toward the base; a small sensillum near the base of distalmost seta. Four soft posterior setae increasing in size basally (a–d). Gnathobase not clearly separated from basal endite. Distal armature of gnathobase (Figs. 6 G–H) with four elements: an elongated, cylindrical sensillum; thin, bent seta; others two represented by sharp spines. Filter plate III with seven setae. Limb IV (Figs. 6 I–J). Preepipodite setulated, epipodite with a process two times longer than exopodite itself. Exopodite subquadrangular, with six setae. Seta 3 longest, setae 1–2 slightly shorter than seta 3, setae 4, 5 and 6 of 1/3, 2/3 and 1/2 length of seta 3, respectively. Setae 1–4 plumose, setae 5–6 with short setulae in distal portion. Inner-distal portion of limb IV with four setae and a small cylindrical sensillum; seta 1 slender, sharp, first flaming-torch seta (2) broad, with 7–8 thick setulae; two other thin, slender, with thin hair-like setulae. Three soft setae of similar size. Gnathobase with a 2-segmented seta, and a small hillock distally. Filter plate with five setae. Limb V (Fig. 6K). Preepipodite setulated, epipodite with process 2–2.5 times longer than exopodite itself. Exopodite divided into two lobes, incursion between lobes very deep, with four plumose setae. Setae 1–3 long, subequal in length, slightly decreasing in size basally, seta 4 short, 2.5 times shorter than seta 1. Inner limb portion, il, (Fig. 6L) as a small oval lobe, with setulated inner margin.At inner face, two setae, first seta about 3/4 length of exopodite seta 1, other seta 1.5 times shorter. Filter plate with three setae, a large semicircular sensillum located near it. Limb VI (Fig. 6M) as a large, elongated, rounded lobe with a setulated margin, as long as exopodite V, length about 2 widths. Ephippial female (Figs. 2K, 3D–E) with body slightly higher than parthenogenetic female, dorsal margin without a depression between valves and head shield. Ephippium light yellow-brown in preserved specimens, with weakly developed egg locule, covered by weak polygonal sculpture, the latter slightly more pronounced than that on valves of parthenogenetic specimens. Male. General. Juvenile male of instar II (Fig. 2L) similar in shape to a juvenile female. In adult male, body (Figs 2N, 3F–G) low oval, with a maximum height at the middle, height/length ratio about 0.5. Postabdomen in juvenile males (Fig. 5D) similar to that of female, but shorter, gonopore located laterally near ventral margin, at 2/3 distance from the base. Postanal denticles same as in female. In adult male, postabdomen (Figs. 4F, 5E–F) short, moderately wide, weakly narrowing distally in anal portion, and strongly narrowing distally in postanal portion. Postanal margin of postabdomen evenly comes to the base of claws, no distinct distal margin and dorsodistal angle. Length about 2.5-2.7 heights. Ventral margin straight. A sperm duct opens at the end of postabdomen, forming small protrusion above the base of claws. Dorsal margin weakly convex in postanal portion and almost straight in anal one. Preanal and postanal angles not defined. Preanal margin almost straight. Distal portion of postabdomen two times longer than preanal one, anal and postanal portions of similar length. Postanal margin with clusters of setulae, in distalmost 4–5 clusters ditalmost setula thick, spine-like. Lateral fascicles of setulae as in female. Postabdominal claw weakly curved, shorter than in female, much shorter than preanal margin of postabdomen, with blunt tip, bearing cluster of setulae. Basal spine very short. Antennule in juvenile male of instar II (Fig. 2M) similar to that of female, with 9 terminal aesthetascs, with very short anlage of male seta. In adult male (Fig. 2P) antennule slightly broader than in female, with 12 long terminal aesthetascs, longest aesthetasc about 2/3 length of antennule. Male seta located at 2/3 distance from the base, about 1/3 length of antennule. Thoracic limb I. In juvenile male of instar II (Figs. 6 N–O) limb with a curved copulatory hook, about 2/3 length of limb itself, with anlage of copulatory brush seta and smaller triangular seta, absent in adult male, about it. IDL with an anlage of male seta, IDL setae 1–3 similar to these of female. Ventral limb face under the copulatory brush seta with 4 moderately long setulae. Inner seta (1) of endite 3 same as in female. In adult male (Figs. 6P–Q) limb with a U-shaped copulatory hook, 1.5 times shorter than limb itself. IDL seta 1 absent, IDL setae 2 and 3 of similar size, much thinner and shorter than in female; male seta almost straight, as long as setae 2–3. Copulatory brush seta about 1/2 length of IDL setae 2–3. Ventral face of the limb under the copulatory brush with a double row of about 30 long stiff setulae, decreasing in length distally. Inner seta (1) of endite 3 longer and thinner than in female, as long as seta c, unilaterally armed with long setulae in distal portion. Size. In studied material, adult female length 0.37–0.41 mm, height from 0.24–0.27 mm; according to Megard, length of adult female up to 0.43 mm.Adult male length 0.34–0.35 mm, height 0.2–0.21 mm; juvenile male of instar II length 0.3–0.31 mm, height about 0.18 mm. Differential diagnosis. P. barbulata differs from P. arvensis in: (1) three main head pores and (2) in labral keel without a prominence on anterior margin. From P. werestschagini in: (1) a smaller size, (2) smaller IP/PP ratio, and (3) shape of both male and female postabdomen. P. barbulata is habitually similar to P. guttata and P. julietae sp. nov., but differs from them in: (1) head shield with well-defined posterior angle, (2) female postabdomen with right, not prominent distal angle, (3) presence of rudimentary seta i on endite 1 of thoracic limb I, and (4) male postabdominal claw with a blunt apex armed with small denticles. Distribution and ecology. P. barbulata is known from North-West U.S.A. and South-West Canada. In U.S.A., it was recorded from Wyoming, Montana, and Minnesota (Megard, 1967; our data). In Canada, it was found predominantly in Alberta and British Columbia, and once in Ontario; the species is always encountered on rocky-sandy shores (Chengalath 1987). Ecology of the species is poorly studied. According to Williams (1982), in Itasca lake, Minnesota it is the only species of Chydoridae to attain a winter density greater than its summer peak density. According to Whiteside et al. (1980), it is a pioneer species in moraine lakes of Yukon, suggesting the species can inhabit cold ultra-oligotrophic lakes., Published as part of Sinev, Artem Y., Sousa, Francisco Diogo Rocha & Elmoor-Loureiro, Lourdes M. A., 2023, Revision of the guttata-group of Alona s. lato leads to its translocation to Prendalona Sousa, Elmoor-Loureiro & Santos, 2018 (Cladocera: Anomopoda: Chydoridae), pp. 95-121 in Zootaxa 5293 (1) on pages 99-107, DOI: 10.11646/zootaxa.5293.1.4, http://zenodo.org/record/7959789, {"references":["Megard, R. O. (1967) Three new species of Alona (Cladocera, Chydoridae) from the United States. Internationale Revue der gesamten Hydrobiologie, 52, 37 - 50. https: // doi. org / 10.1002 / iroh. 19670520103","Smirnov, N. N. (1971) Chydoridae fauny mira. Fauna USSR. Rakoobraznie. 1 (2). Nauka, Leningrad, 531 pp. [English translation: Chydoridae of the world. Israel Program for Scientific Translations, Jerusalem, 1974]","Sousa, F. D. R., Elmoor-Loureiro, L. M. A. & Santos, S. (2016 a) New findings of Hexalona-branch representatives in Brazil, with a description of Prenda gen. nov. (Crustacea: Anomopoda: Aloninae). Journal of Natural History, 50 (43 - 44), 2727 - 2768. https: // doi. org / 10.1080 / 00222933.2016.1208302","Chengalath, R. (1987) The distribution of chydorid Cladocera in Canada. Hydrobiologia, 145 (1), 151 - 157. https: // doi. org / 10.1007 / BF 02530275","Williams, J. B. (1982) Temporal and Spatial Patterns of Abundance of the Chydoridae (Cladocera) in Lake Itasca, Minnesota. Ecology, 63 (2), 345 - 353. https: // doi. org / 10.2307 / 1938952","Whiteside, M. C., Bradbury, J. P. & Tarapchak, S. J. (1980) Limnology of the Klutlan Moraines, Yukon Territory, Canada. Quaternary Research, 14 (01), 130 - 148. https: // doi. org / 10.1016 / 0033 - 5894 (80) 90010 - 1"]}

Genus Prendalona Sousa, Elmoor-Loureiro & Santos, 2018 emend. nov. Sousa, Elmoor-Loureiro & Santos, 2016a: 28–34 (Prenda); Sousa, Elmoor-Loureiro & Santos, 2018: 1–2. Type species: Prenda arvensis Sousa, Elmoor-Loureiro & Santos, 2016 Emended diagnosis. Parthenogenetic female. General. Small to medium-sized alonines, length of adult female up to 0.55. Body of the Alona -like habitus, of moderate height, moderately compressed laterally. Head and carapace without a dorsal keel. Valves. Ventral margins of valves in ventral view almost straight, valves can be closed without even a narrow gap between them. Dorsal margin of carapace convex, postero-dorsal and postero-ventral angles broadly rounded. Posterior margin weakly convex. Antero-ventral angle rounded. Ventral margin weakly convex to straight, with 30– 50 setae, anterior setae short, not forming separate group from central setae, posterior setae of moderate length, decreasing in length posteriorly. Posteroventral angle without denticles, with numerous thin setulae of similar length, not forming groups. Carapace ornamentation as weakly to well-developed longitudinal lines or as tubercules. Head relatively small, low, triangular-rounded in lateral view. In lateral view rostrum relatively narrow, protruding downwards. Ocellus and compound eye present. Head shield with a maximum width behind mandibular articulation. Rostrum short and rounded. Posterior part of head shield broadly rounded or triangular with defined tip. Three or two major head pores with a narrow connection between them. PP about 1 IP or less in adults. Lateral head pores minute. Labrum of moderate size. Labral keel moderately wide, with a rounded apex. Anterior margin of keel convex or with blunt prominence in upper portion, posterior margin with two clusters of short setulae. Thorax two times longer than abdomen. Dorsal surface of abdominal segments not saddle-shaped. Abdominal joint not developed. Postabdomen of moderate size, moderately high, length about 2.5 height. Basis of claws bordered from distal margin by a clear incision. Distal margin from straight to convex; distal angle obtuse, straight, or acute, prominent. Dorsal margin almost straight in postanal portion and concave in anal one, with distal part about 2 times longer than preanal one, with postanal and anal portion 2.5 of similar length. Preanal angle well-expressed, postanal angle weak to not defined. Preanal margin almost convex. Postanal margin with 5–8 well-developed, sharp composite denticles, most with spinules along anterior margin; size of denticles increasing distally. Length of longest denticles equal to the width of base of postabdominal claw. About 8–10 lateral groups of setulae in the main row, distalmost 5–8 groups with all setulae of similar thickness, in most species central setulae in the group being longest. Postabdominal claw of moderate length, similar in length to preanal portion of postabdomen. Basal spine short, about 0.15–0.2 length of the claw. Antennule of moderate size, length about 2.5–3 widths, with 3–4 clusters of setulae at anterior face. Antennular seta thin, about 1/3–1/2 length of antennule, arising at 1/3–1/2 distance from the end of antenna. Nine terminal aesthetascs of similar length, about 1/2–2/3 length of antennule. Antenna re latively short. Antennal formula, setae 0–0–3/1–1–3, spines 1–0–1/0–0–1. Basipodite robust, with very short seta between branches, branches relatively short. Proximal segments in both branches 1.5 times longer than two others. Seta arising from basal segment of endopodite thin, much shorter than other setae. Antennal spines well-developed, spine on basal segment of exopodite of same length or slightly shorter than middle segment, apical spines as long as apical segments. Thoracic limbs: six pairs. Limb I of moderate size. Accessory seta two times shorter than ODL seta. IDL with three setae, seta 1 very short, setae 2 and 3 long, with thin setulae in distal part. Endite 3 with four setae subequal in length. Endite 2 with two long distally setulated setae (e–f), a shorter seta near their base (d), without inner seta. Endite 1 with two 2-segmented setae, both setulated in distal part, with seta i rudimentary or absent, without inner seta. Limb II. Exopodite elongated, with a slender seta. Eight scraping spines, three basalmost spines (6–8) subequal in length, others increasing in length distally. Distal armature of gnathobase with four elements. Filter plate II with seven setae, the posteriormost member shorter than others. Limb III. Exopodite with seven setae. Seta 3 being longest, seta 6 second in length. Setae 1–5 plumose, setae 6–7 with short setulae in distal part. Morphology of inner portion typical of subfamily; scraping setae of distal endite moderately long. Filter plate III with seven setae. Limb IV. Exopodite with six setae. Setae 1–4 flat, plumose, setae 5–6 with short setulae. Inner portion of limb IV with four setae and a small sensillum. Scraping seta slender, distalmost flaming-torch seta (2) large, with broad base and robust setulae, two other two times narrower, armed with very thin, hair-like setulae. Three soft setae slightly increasing in size basally. Gnathobase with 2-segmented seta and a small hillock. Filter plate IV with five setae. Limb V. Exopodite divided into two lobes, with four plumose setae, setae 1–3 long, subequal in length; seta 4 shorter. Inner lobe narrow oval, with a setulated inner margin. At inner face, two setae densely setulated in distal part, one of them long; length similar to that of exopodite setae 1–3. Filter plate V with three setae. Limb VI as an oval lobe with setulated margin, as large as exopodite V. Male. General. Body low oval, with a maximum height at the middle or behind it. Postabdomen of variable shape, sperm ducts open on distal margin. Preanal and postanal angles not defined. Clusters of thin or robust setulae in place of female marginal denticles on postanal margin. Postabdominal claw much shorter than in female, basal spine very short or absent. Antennule broader than in female, with 12 terminal aesthetascs, male seta located laterally. Thoracic limb I with a copulatory hook of moderate size, half as long as limb itself. IDL without seta 1, IDL setae 2 and 3 much thinner and shorter than in female; male seta curved, long. Differential diagnosis: Prendalona clearly differs from its sister-group, genus Flavalona in: (1) minute lateral head pores without any pockets below, (2) absence of a genital process on male postabdomen and (3) absence of inner setae on endites 1–2 of thoracic limb I. From all other genera of Alona s. lato, Prendalona differs in: (1) differentiated flaming-torch setae of limb IV and (2) weakly-developed lateral fascicles of postabdominal setulae, with distalmost setula not being much thicker than the others. As a member of the Hexalona branch, Prendalona clearly differs from genera of the Coronatella branch, Coronatella, Anthalona, Karualona, Magnospina in: (1) presence of limb IV and (2) seven setae on exopodite III. Prendalona differs from Alona s. str. (the quadrangularis -group) and Ovalona in: (1) weakly developed IDL seta 1, (2) presence of a filter plate V and (3) presence of limb VI. It clearly differs from other groups of the Hexalona branch, such as Biapertura, Armatalona, and intermedia -groups in; (1) shape and armament of postabdomen, (2) absence of inner setae on endites 1–2 of thoracic limb I and (3) reduced or absent seta I on endite III of limb I. For summary of differences between the Hexalona genera see Table 1., Published as part of Sinev, Artem Y., Sousa, Francisco Diogo Rocha & Elmoor-Loureiro, Lourdes M. A., 2023, Revision of the guttata-group of Alona s. lato leads to its translocation to Prendalona Sousa, Elmoor-Loureiro & Santos, 2018 (Cladocera: Anomopoda: Chydoridae), pp. 95-121 in Zootaxa 5293 (1) on pages 97-98, DOI: 10.11646/zootaxa.5293.1.4, http://zenodo.org/record/7959789, {"references":["Sousa, F. D. R., Elmoor-Loureiro, L. M. A. & Santos, S. (2016 a) New findings of Hexalona-branch representatives in Brazil, with a description of Prenda gen. nov. (Crustacea: Anomopoda: Aloninae). Journal of Natural History, 50 (43 - 44), 2727 - 2768. https: // doi. org / 10.1080 / 00222933.2016.1208302"]}

Prendalona guttata (Sars, 1862) comb. nov. Figs. 7–10. Sars, 1862: 286–287 (Alona); Lilljeborg, 1901: Pl. 68: Fig. 16–19, 23, 24 (Lynceus guttatus); Smirnov, 1971: 379–382, Fig. 450, 454, 456 (Alona); Fl̂ssner, 1972: 296–299, Pl. 139 (Alona); Chiang, Du, 1979: 225–226, Fig. 154A–F (Alona); Negrea, 1983: 293–255, Fig. 119A–D (Alona); Alonso, 1996: 329– 331, Fig. 146 (Alona); Fl̂ssner, 2000: 313–315, Pl. 116 (Alona); Sinev, 1999: 29–30, Fig. 5 (Alona); Sinev, 2002: 934–935, Fig. 2 г, З, л, о, т (Alona); Hudec, 2010: 324–327, Fig. 79 (Alona); Kotov et al., 2010 (Alona): 247, Fig 138, 4, Fig 143, 1–3 (Alona); Sinev & Silva-Briano, 2012: 15–19, Fig. 8–9, 10 A–J (Alona); Korovchinsky et al. 2021: 286–288, Fig. 85, 1–9 (Alona). Type locality: Østensjøvannet lake, Oslo, Norway. Type material: non-existent, no material from type locality is present in G.O. Sars collection, deposited at Zoological Museum of Oslo University, Material examined. Norway: 20 parthenogenetic females from G.O. Sars collection, labeled just as “Norway”, Zoological Museum of Oslo University, sample F12411а; over 20 parthenogenetic females, 12 ephippial females, 8 adult males from Sagtjenn pond, Risør town, Agder county, coll. by J.–P. Nielssen. Russia: over 50 parthenogenetic females from littoral zone and coastal Sphagnum moss at Krugloe Lake (66.5426° N, 33.1393° E) in the vicinity of White Sea Biological Station of M. V. Lomonosov Moscow State University, Chupa District, Republic of Karelia, 07–08.2021, coll. A. Y. Sinev & I.A. Dadykin; 4 parthenogenetic females, 1 male from lake near Kur’ya Strelka, Yakutia Autonomous Republic (62.01857° N, 129.757° E) 09.2011 coll. E.I. Bekker, A.I. Klimovsky, AAK M-2290; China: 3 parthenogenic females from Liangzi lake, Hunan Prowince, (30.23894° N, 114.45440° E) 29.10.2018, coll. A. Y. Sinev & Y. Gu. Material examined previously. See Sinev (1999; 2002) for the list of material from Russia. Sinev & Silva-Briano (2012) for the list of material from Mexico. Morphology of parthenogenetic females of P. guttata, examined earlier during faunistic studies of Zeya River basin in the Amur Area of Russia (Kotov et al. 2011). Jeju-do Island in South Korea (Kotov et al. 2022). Yunnan Province (Sinev et al. 2020) and Hainan Island (Sinev et al. 2015) in China. All of this material not differ from that of examined specimens. Description. Parthenogenetic female. General. In lateral view body (Figs. 7A, 8A–E) oval of moderate height, maximum height at middle of body; in adults height/length ratio 0.65–0.70. Dorsal margin uniformly curved; postero-dorsal and postero-ventral angles broadly rounded; posterior margin uniformly curved; ventral margin almost straight; antero-ventral angle rounded. Body moderately compressed laterally. Valves with a weakly developed linear sculpture in posteroventral portion (Figs. 8A–D), or fully covered with tubercules (Figs. 8E–F). Ventral margin with about 35–40 setae, anterior ten setae short, not forming separate group from central setae, distal setae of moderate length (Fig. 7B). Posterodorsal angle (Fig. 7C) bears about 70 short, thin, hair-like setulae of similar length, not organized in groups. A row of about 80 thin setulae along the posterior margin on inner side of valve. Head of moderate size, triangle-round in lateral view, rostrum short, pointing downward. Compound eye larger than ocellus. Distance from tip of rostrum to ocellus in adults slightly greater than that between ocellus and eye. Head shield with a maximum width behind mandibular articulation, oblique in specimens with linear sculpture of valves, tuberculate in specimens with tuberculate valves; rostrum short, broadly rounded; posterior margin of head shield broadly rounded. Three connected major head pores (Figs. 7D – 9B), median pore located in the middle between two others and smaller than them, PP less than 0.5 IP. Lateral head pores minute, located about 1.0–1.2 IP distance from midline, at the level between anterior and middle major head pores. Labrum (Fig. 7E) of moderate size; labral keel narrow (height about 2 width), with a rounded apex; anterior margin of keel convex, irregular in some specimens (Fig. 7E), posterior margin with two clusters of short setulae. In some specimens, posterior portion of labrum overgrown with epibiotic bacteria. Thorax twice longer than abdomen, dorsal surface of abdominal segments not saddle-shaped. Postabdomen (Figs. 7G–H, 9C) short, of moderate width, narrowing distally, with a prominent acute distal angle, length about 2.5 height. Ventral margin straight. Base of claws separated from distal margin by a clear incision. Distal margin straight to weakly convex, distal angle prominent, protruding before the base of claw, acute with rounded tip. Dorsal margin with distal part 1.6–1.7 times longer than preanal one, with anal and postanal portions of similar length. Postanal portion of distal margin straight, anal portion concave. Preanal angle well-defined, strongly protruding, postanal angle weakly defined. Postabdomen with 5–6 well-developed narrow postanal marginal denticles, decreasing in size basally and with three–four groups of marginal setulae on anal margin. Most denticles with 1–6 spinules anteriorly; length of distal denticles exceed width of the postabdominal claw base. Eight–nine lateral groups of setulae, five–seven distalmost groups wide, with longest setulae in the middle, of similar length with longest marginal denticles. Several additional groups of short setae near preanal angle. Postabdominal claw of a moderate length, slightly shorter than preanal portion of postabdomen. Basal spine about 0.2 of length of claw. Antennule (Fig. 7I) of moderate size, length about 2.5 width, with three clusters of long thin setulae at anterior face. Antennular sensory seta slender, two times shorter than antennule, arising almost at the middle of antennule. Nine terminal aesthetascs, two longest of them about 2/3 length of antennule. Antenna (Figs. 7J, 9A–D) relatively short. Antennal formula, setae 0–0–3/1–1–3, spines 1–0–1/0–0–1. Basipodite robust, branches of moderate length and width, proximal segments of both branches 1.5 times longer than others. Seta arising from proximal segment of endopodite thin, not reaching the end of endopodite. Seta arising from middle segment of endopodite of similar size with shortest apical setae; in both branches one apical setae is much shorter than two others. Spine on proximal segment of exopodite significantly shorter than middle segment. Apical spines slightly longer than apical segments. Maxillule (Fig. 10A) very small, with two setae, setulated in distal portion. Thoracic limbs: Six pairs. Limb I (Figs. 10B–D) as in the previous species. but endite 1 without seta i. Limb II (Figs. 10E– F). Similar to that of previous species, but scraping seta 3 only slightly thicker than setae 2 and 4, with small spinules. Limb III (Figs. 10G–J). Epipodite oval, without process; exopodite trapezoid with seven setae. Seta 3 being longest, seta 6 of about 3/4 length of seta 3, setae 4 and 7 of about 1/2 length of seta 3, other setae short. Setae 6–7 with short setulae in distal portion, all other setae plumose. Inner portion as in the previous species. Limb IV (Figs. 10K–L). Preepipodite setulated, epipodite with process longer than exopodite itself. Exopodite rounded, with six setae. Seta 3 longest, setae 1, 2 and 5 slightly shorter than seta 3, setae 4 and 6 of 1/3 and 1/2 length of seta 3, respectively. Setae 1–4 plumose, setae 5–6 appear naked under the light microscope. Inner-distal portion of limb IV same as in the previous species. Limb V (Fig. 10M). As in the previous species. Limb VI (Fig. 10N) as in the previous species. Male. General. Body low oval, with maximum height at the middle, height/length ratio about 0.6. Head. Compound eye larger than ocellus. Postabdomen (Figs. 7M–N) short, moderately wide, evenly narrowing distally. Postanal margin of postabdomen evenly comes to the base of claws, no distinct distal margin and dorsodistal angle. Length about 2.5 height. Ventral margin straight or weakly convex. The sperm ducts open at the end of postabdomen, forming minute protrusion above the base of claws. Dorsal margin almost straight in postanal portion and clearly concave in anal one. Preanal and postanal angles not defined. Preanal margin weakly convex to straight. Distal portion of postabdomen 2.5 times longer than preanal one, anal and postanal portions of similar length. Postanal margin with clusters of setulae, in distalmost 4–5 clusters distalmost setula thick, spine-like (Fig. 9N). Lateral groups of setulae as in female. Postabdominal claw (Figs. 7M–N) weakly curved, shorter than in female, much shorter than preanal margin of postabdomen, with acute tip without cluster of setulae. Basal spine very short, with short spinule near it. Antennule (Fig. 7O ) slightly broader than in female, with 12 long terminal aesthetascs, longest aesthetascs about 2/3 length of antennule. Male seta located at 2/3 distance from the base, not reaching the end of antennule. Thoracic limb I (Fig. 10 O) same as in the previous species, Size. Adult female length 0.3–0.39 mm, height 0.19–0.25 mm. Adult male length 0.25–0.28 mm, height 0.14– 0.17 mm. Differential diagnosis. P. guttata differs from P. arvensis in; (1) three main head pores and (2) labral keel without a prominence on anterior margin; from P. werestschagini in: (1) a smaller size, (2) smaller IP/PP ratio, and (3) shape of both male and female postabdomen. P. guttata is habitually similar to P. barbulata but differs in: (1) head shield with broadly rounded posterior portion, (2) female postabdomen with acute prominent distal angle and strongly prominent preanal angle, (3) absence of seta i on endite 1 of thoracic limb I, and (4) evenly narrowing distally male postabdomen. P. guttata differs from P. julietae sp. nov. in: (1) shorter spine near basal spine on postabdominal claw of male and (2) proportion of male seta on the first limb. Distribution and ecology. The taxon is recorded worldwide, but probably it is represented by a complex of cryptic species. P. guttata s. str. is distributed in Palearctic. Taxonomic status of P. cf. guttata from Nearctic, Afrotropic, Indo-Malaysian and Australian regions is unclear. Records of P. guttata from the Neotropics probably all belong to P. julietae sp. nov. P. guttata s. str. in Palearctic is eurybiotic, eurythermic species, usually associated with shore vegetation, inhabiting littoral zone of lakes and ponds, floodplain water bodies, slow rivers, swamps and bogs, temporary water bodies, and also encountered in subterranean water. Encountered at pH> 3.8, at altitudes up to 5520 m a.s.l. (Korovchinsky et al. 2021). For detailed data on ecology see Duigan (1992) and Fryer (1993).

Prendalona barbulata (Megard, 1967) comb. nov. Megard, 1967: 37–57, Figs. 9 –19, pl. 2a–b (Alona); Smirnov, 1971: 382, Fig. 458 (Alona). Type locality Island Lake in the Wind River Mountains, about 20 km northeast of Pinedale, Wyoming, U.S.A. Type material. The holotype (parthenogenetic female) and several paratypes deposited in the British Museum (No. 1966. 3.21.4). Material examined. Six parthenogenetic females, over 20 ephippial females, 7 adult males, 2 juvenile males of instar II from Salmon Lake, Missoula County, Montana, U.S.A., 15.11.1977, coll. K. Brakke, sample DGF 4458 in collection of Prof. D. G. Frey at National Museum of Natural History (Washington DC, USA), general access number 403774. Description. Parthenogenetic female. General. In lateral view body (Figs. 2A, 3A–C) oval, of moderate height, maximum height at middle of body, in adults height/length ratio 0.65. Dorsal margin uniformly curved; postero-dorsal and postero-ventral angles broadly rounded; posterior margin uniformly curved; ventral margin almost straight; antero-ventral angle rounded. Body moderately compressed laterally. Valves. Ventral margin with 30–40 setae, anteriormost ten setae short (Fig. 2B), not forming a group separated from setae in middle of margin, distal setae of moderate length (Fig. 2C). Postero-dorsal angle (Fig. 2D) bears about 70 short, thin, hair-like setulae of similar length, not organized in groups. A row of about 80–100 thin setulae of variable length along posterior margin at inner side of valve. Valve looks smooth by optical microscopy, but SEM examination reveals a weakly developed linear sculpture. Head of moderate size, oblique, triangular-round in lateral view; rostrum short, pointing downward. Compound eye larger than ocellus. Distance from tip of rostrum to ocellus in adults 1.5 times greater than that between ocellus and eye. Head shield (Fig. 2E) with a maximum width behind mandibular articulation, without sculpturing; rostrum short, broadly rounded; posterior portion of head shield triangular with obtuse apex. Three connected major head pores of similar size, middle pore located closer to posterior pore, PP less than 0.5 IP (Figs. 2F – 4C). Lateral head pores minute, located at about 0.8 IP distance from midline, at the level of anterior major head pores. Labrum (Figs. 2G–H, 4A–B) of moderate size; labral keel narrow (height about 2 width), with a rounded apex; anterior margin of keel convex, posterior margin with two clusters of short setulae, setulae in anterior cluster pointing almost forward. Posterior portion of labrum under optical microscope appears to be covered by thin setulae, but SEM examination (Fig. 4A–B) reveal that these ‘structures’ are in reality epibiotic bacteria. Thorax twice longer than abdomen, dorsal surface of abdominal segments not saddle-shaped. Postabdomen (Figs. 4D – 5A) short, of moderate width, slightly narrowing distally, with a rounded, not prominent distal angle, length about 2.5 height. Ventral margin straight. Base of claws separated from distal margin by a weak incision. Distal margin straight to weakly convex, distal angle rounded, not protruding before the base of claw. Dorsal margin with distal part 1.8–27 times longer than preanal one, with postanal portion 1.3–1.5 times shorter than anal. Postanal portion of distal margin straight, anal portion weakly concave. Preanal angle well-defined, but not protruding, postanal angle weakly defined. Postanal margin (Figs. 5B–C) with 6–7 marginal denticles, decreasing in size basally, 2–3 distalmost denticles robust, others have broad bases, bearing long spinules anteriorly; length of distal denticles equal to the width of the postabdominal claw base. Anal margin with four groups of short setulae. Eight–nine lateral fascicles of setulae, six–seven distalmost fascicles wide, consisting of thin setulae, with longest setulae in the middle, slightly shorter than longest marginal denticles. Several additional fascicles above the main row in anal portion. Postabdominal claw of moderate length, as long as preanal portion of postabdomen. Basal spine short, curved, about 0.2 of length of claw. Antennule (Fig. 2I) of moderate size, length about 2.5 width, with four clusters of thin setulae at anterior face, setae of two central clusters long. Antennular sensory seta slender, three times shorter than antennule, arising almost at the middle of antennule. Nine terminal aesthetascs, two longest of them about 2/3 length of antennule. Antenna (Figs. 2J – 4E) relatively short. Antennal formula, setae 0–0–3/1–1–3, spines 1–0–1/0–0–1. Basipodite segment robust, branches of moderate length and width, proximal segments of both branches 1.5 times longer than others, middle segments slightly shorter than apical. Seta arising from basal segment of endopodite thin, not reaching the end of endopodite. Seta arising from middle segment of endopodite of similar size with shortest apical setae. Spine on basal segment of exopodite as long as middle segment. Apical spines slightly longer than apical segments. Thoracic limbs: Six pairs. Limb I (Figs. 6 A–B) of moderate size. Epipodite with long process 3–4 times longer than exopodite itself. Accessory seta about 1/3 length of ODL seta, unilaterally armed by thick setulae. IDL with three setae and two–three clusters of small setulae, setae 2 and 3 only slightly shorter than ODL seta, armed with thin setulae in distal part, seta 1 very short, located laterally. Endite 3 with four setae, inner seta (1) shorter than setae a-c. Endite 2 with three setae (d–f), setae e–f of similar length, 1.5 shorter than limb itself. Endite 1 with two 2-segmented setae (g-h), both setulated in distal part, and very small, rudimentary seta i. No inner setae on edites 1–2. Six-seven rows of thin long setulae on ventral face of limb. Two ejector hooks, one of them larger than the other. Maxillar process elongated, with a short seta. Limb II (Figs. 6 C–D). Exopodite elongated, with a setulated seta as long as exopodite. Eight scraping setae (1–8), armed with small spinules, increasing in length distally, scraper 3 thicker than neighbors and armed with thicker spinules. Distal armature of gnathobase with four elements. Filter plate with seven setae, the posteriormost three times shorter than others. Limb III. Epipodite oval, with a short process; exopodite trapezium-shaped, with seven setae (Fig. 6E). Seta 3 being longest; setae 4 and 6 about 1/2 length of seta 3; setae 1 and 7 about 1/3 length of seta 3; seta 5 about 1/4 length of seta 3; seta 2 short. Setae 6–7 armed with short setulae in distal portion, all other setae plumose. Distal endite (Fig. 6F) with three anterior setae (1–3), two distalmost members slender, sharp, with distal parts unilaterally armed with sharp denticles, seta 1 significantly longer than seta 2; basalmost seta (3) as long as seta 2, broad, bilaterally armed with setulae. Basal endite (Fig. 6G) with four anterior stiff setae, increasing in size toward the base; a small sensillum near the base of distalmost seta. Four soft posterior setae increasing in size basally (a–d). Gnathobase not clearly separated from basal endite. Distal armature of gnathobase (Figs. 6 G–H) with four elements: an elongated, cylindrical sensillum; thin, bent seta; others two represented by sharp spines. Filter plate III with seven setae. Limb IV (Figs. 6 I–J). Preepipodite setulated, epipodite with a process two times longer than exopodite itself. Exopodite subquadrangular, with six setae. Seta 3 longest, setae 1–2 slightly shorter than seta 3, setae 4, 5 and 6 of 1/3, 2/3 and 1/2 length of seta 3, respectively. Setae 1–4 plumose, setae 5–6 with short setulae in distal portion. Inner-distal portion of limb IV with four setae and a small cylindrical sensillum; seta 1 slender, sharp, first flaming-torch seta (2) broad, with 7–8 thick setulae; two other thin, slender, with thin hair-like setulae. Three soft setae of similar size. Gnathobase with a 2-segmented seta, and a small hillock distally. Filter plate with five setae. Limb V (Fig. 6K). Preepipodite setulated, epipodite with process 2–2.5 times longer than exopodite itself. Exopodite divided into two lobes, incursion between lobes very deep, with four plumose setae. Setae 1–3 long, subequal in length, slightly decreasing in size basally, seta 4 short, 2.5 times shorter than seta 1. Inner limb portion, il, (Fig. 6L) as a small oval lobe, with setulated inner margin.At inner face, two setae, first seta about 3/4 length of exopodite seta 1, other seta 1.5 times shorter. Filter plate with three setae, a large semicircular sensillum located near it. Limb VI (Fig. 6M) as a large, elongated, rounded lobe with a setulated margin, as long as exopodite V, length about 2 widths. Ephippial female (Figs. 2K, 3D–E) with body slightly higher than parthenogenetic female, dorsal margin without a depression between valves and head shield. Ephippium light yellow-brown in preserved specimens, with weakly developed egg locule, covered by weak polygonal sculpture, the latter slightly more pronounced than that on valves of parthenogenetic specimens. Male. General. Juvenile male of instar II (Fig. 2L) similar in shape to a juvenile female. In adult male, body (Figs 2N, 3F–G) low oval, with a maximum height at the middle, height/length ratio about 0.5. Postabdomen in juvenile males (Fig. 5D) similar to that of female, but shorter, gonopore located laterally near ventral margin, at 2/3 distance from the base. Postanal denticles same as in female. In adult male, postabdomen (Figs. 4F, 5E–F) short, moderately wide, weakly narrowing distally in anal portion, and strongly narrowing distally in postanal portion. Postanal margin of postabdomen evenly comes to the base of claws, no distinct distal margin and dorsodistal angle. Length about 2.5-2.7 heights. Ventral margin straight. A sperm duct opens at the end of postabdomen, forming small protrusion above the base of claws. Dorsal margin weakly convex in postanal portion and almost straight in anal one. Preanal and postanal angles not defined. Preanal margin almost straight. Distal portion of postabdomen two times longer than preanal one, anal and postanal portions of similar length. Postanal margin with clusters of setulae, in distalmost 4–5 clusters ditalmost setula thick, spine-like. Lateral fascicles of setulae as in female. Postabdominal claw weakly curved, shorter than in female, much shorter than preanal margin of postabdomen, with blunt tip, bearing cluster of setulae. Basal spine very short. Antennule in juvenile male of instar II (Fig. 2M) similar to that of female, with 9 terminal aesthetascs, with very short anlage of male seta. In adult male (Fig. 2P) antennule slightly broader than in female, with 12 long terminal aesthetascs, longest aesthetasc about 2/3 length of antennule. Male seta located at 2/3 distance from the base, about 1/3 length of antennule. Thoracic limb I. In juvenile male of instar II (Figs. 6 N–O) limb with a curved copulatory hook, about 2/3 length of limb itself, with anlage of copulatory brush seta and smaller triangular seta, absent in adult male, about it. IDL with an anlage of male seta, IDL setae 1–3 similar to these of female. Ventral limb face under the copulatory brush seta with 4 moderately long setulae. Inner seta (1) of endite 3 same as in female. In adult male (Figs. 6P–Q) limb with a U-shaped copulatory hook, 1.5 times shorter than limb itself. IDL seta 1 absent, IDL setae 2 and 3 of similar size, much thinner and shorter than in female; male seta almost straight, as long as setae 2–3. Copulatory brush seta about 1/2 length of IDL setae 2–3. Ventral face of the limb under the copulatory brush with a double row of about 30 long stiff setulae, decreasing in length distally. Inner seta (1) of endite 3 longer and thinner than in female, as long as seta c, unilaterally armed with long setulae in distal portion. Size. In studied material, adult female length 0.37–0.41 mm, height from 0.24–0.27 mm; according to Megard, length of adult female up to 0.43 mm.Adult male length 0.34–0.35 mm, height 0.2–0.21 mm; juvenile male of instar II length 0.3–0.31 mm, height about 0.18 mm. Differential diagnosis. P. barbulata differs from P. arvensis in: (1) three main head pores and (2) in labral keel without a prominence on anterior margin. From P. werestschagini in: (1) a smaller size, (2) smaller IP/PP ratio, and (3) shape of both male and female postabdomen. P. barbulata is habitually similar to P. guttata and P. julietae sp. nov., but differs from them in: (1) head shield with well-defined posterior angle, (2) female postabdomen with right, not prominent distal angle, (3) presence of rudimentary seta i on endite 1 of thoracic limb I, and (4) male postabdominal claw with a blunt apex armed with small denticles. Distribution and ecology. P. barbulata is known from North-West U.S.A. and South-West Canada. In U.S.A., it was recorded from Wyoming, Montana, and Minnesota (Megard, 1967; our data). In Canada, it was found predominantly in Alberta and British Columbia, and once in Ontario; the species is always encountered on rocky-sandy shores (Chengalath 1987). Ecology of the species is poorly studied. According to Williams (1982), in Itasca lake, Minnesota it is the only species of Chydoridae to attain a winter density greater than its summer peak density. According to Whiteside et al. (1980), it is a pioneer species in moraine lakes of Yukon, suggesting the species can inhabit cold ultra-oligotrophic lakes.

Prendalona guttata (Sars, 1862) comb. nov. Figs. 7–10. Sars, 1862: 286–287 (Alona); Lilljeborg, 1901: Pl. 68: Fig. 16–19, 23, 24 (Lynceus guttatus); Smirnov, 1971: 379–382, Fig. 450, 454, 456 (Alona); Fl̂ssner, 1972: 296–299, Pl. 139 (Alona); Chiang, Du, 1979: 225–226, Fig. 154A–F (Alona); Negrea, 1983: 293–255, Fig. 119A–D (Alona); Alonso, 1996: 329– 331, Fig. 146 (Alona); Fl̂ssner, 2000: 313–315, Pl. 116 (Alona); Sinev, 1999: 29–30, Fig. 5 (Alona); Sinev, 2002: 934–935, Fig. 2 г, З, л, о, т (Alona); Hudec, 2010: 324–327, Fig. 79 (Alona); Kotov et al., 2010 (Alona): 247, Fig 138, 4, Fig 143, 1–3 (Alona); Sinev & Silva-Briano, 2012: 15–19, Fig. 8–9, 10 A–J (Alona); Korovchinsky et al. 2021: 286–288, Fig. 85, 1–9 (Alona). Type locality: Østensjøvannet lake, Oslo, Norway. Type material: non-existent, no material from type locality is present in G.O. Sars collection, deposited at Zoological Museum of Oslo University, Material examined. Norway: 20 parthenogenetic females from G.O. Sars collection, labeled just as “Norway”, Zoological Museum of Oslo University, sample F12411а; over 20 parthenogenetic females, 12 ephippial females, 8 adult males from Sagtjenn pond, Risør town, Agder county, coll. by J.–P. Nielssen. Russia: over 50 parthenogenetic females from littoral zone and coastal Sphagnum moss at Krugloe Lake (66.5426° N, 33.1393° E) in the vicinity of White Sea Biological Station of M. V. Lomonosov Moscow State University, Chupa District, Republic of Karelia, 07–08.2021, coll. A. Y. Sinev & I.A. Dadykin; 4 parthenogenetic females, 1 male from lake near Kur’ya Strelka, Yakutia Autonomous Republic (62.01857° N, 129.757° E) 09.2011 coll. E.I. Bekker, A.I. Klimovsky, AAK M-2290; China: 3 parthenogenic females from Liangzi lake, Hunan Prowince, (30.23894° N, 114.45440° E) 29.10.2018, coll. A. Y. Sinev & Y. Gu. Material examined previously. See Sinev (1999; 2002) for the list of material from Russia. Sinev & Silva-Briano (2012) for the list of material from Mexico. Morphology of parthenogenetic females of P. guttata, examined earlier during faunistic studies of Zeya River basin in the Amur Area of Russia (Kotov et al. 2011). Jeju-do Island in South Korea (Kotov et al. 2022). Yunnan Province (Sinev et al. 2020) and Hainan Island (Sinev et al. 2015) in China. All of this material not differ from that of examined specimens. Description. Parthenogenetic female. General. In lateral view body (Figs. 7A, 8A–E) oval of moderate height, maximum height at middle of body; in adults height/length ratio 0.65–0.70. Dorsal margin uniformly curved; postero-dorsal and postero-ventral angles broadly rounded; posterior margin uniformly curved; ventral margin almost straight; antero-ventral angle rounded. Body moderately compressed laterally. Valves with a weakly developed linear sculpture in posteroventral portion (Figs. 8A–D), or fully covered with tubercules (Figs. 8E–F). Ventral margin with about 35–40 setae, anterior ten setae short, not forming separate group from central setae, distal setae of moderate length (Fig. 7B). Posterodorsal angle (Fig. 7C) bears about 70 short, thin, hair-like setulae of similar length, not organized in groups. A row of about 80 thin setulae along the posterior margin on inner side of valve. Head of moderate size, triangle-round in lateral view, rostrum short, pointing downward. Compound eye larger than ocellus. Distance from tip of rostrum to ocellus in adults slightly greater than that between ocellus and eye. Head shield with a maximum width behind mandibular articulation, oblique in specimens with linear sculpture of valves, tuberculate in specimens with tuberculate valves; rostrum short, broadly rounded; posterior margin of head shield broadly rounded. Three connected major head pores (Figs. 7D – 9B), median pore located in the middle between two others and smaller than them, PP less than 0.5 IP. Lateral head pores minute, located about 1.0–1.2 IP distance from midline, at the level between anterior and middle major head pores. Labrum (Fig. 7E) of moderate size; labral keel narrow (height about 2 width), with a rounded apex; anterior margin of keel convex, irregular in some specimens (Fig. 7E), posterior margin with two clusters of short setulae. In some specimens, posterior portion of labrum overgrown with epibiotic bacteria. Thorax twice longer than abdomen, dorsal surface of abdominal segments not saddle-shaped. Postabdomen (Figs. 7G–H, 9C) short, of moderate width, narrowing distally, with a prominent acute distal angle, length about 2.5 height. Ventral margin straight. Base of claws separated from distal margin by a clear incision. Distal margin straight to weakly convex, distal angle prominent, protruding before the base of claw, acute with rounded tip. Dorsal margin with distal part 1.6–1.7 times longer than preanal one, with anal and postanal portions of similar length. Postanal portion of distal margin straight, anal portion concave. Preanal angle well-defined, strongly protruding, postanal angle weakly defined. Postabdomen with 5–6 well-developed narrow postanal marginal denticles, decreasing in size basally and with three–four groups of marginal setulae on anal margin. Most denticles with 1–6 spinules anteriorly; length of distal denticles exceed width of the postabdominal claw base. Eight–nine lateral groups of setulae, five–seven distalmost groups wide, with longest setulae in the middle, of similar length with longest marginal denticles. Several additional groups of short setae near preanal angle. Postabdominal claw of a moderate length, slightly shorter than preanal portion of postabdomen. Basal spine about 0.2 of length of claw. Antennule (Fig. 7I) of moderate size, length about 2.5 width, with three clusters of long thin setulae at anterior face. Antennular sensory seta slender, two times shorter than antennule, arising almost at the middle of antennule. Nine terminal aesthetascs, two longest of them about 2/3 length of antennule. Antenna (Figs. 7J, 9A–D) relatively short. Antennal formula, setae 0–0–3/1–1–3, spines 1–0–1/0–0–1. Basipodite robust, branches of moderate length and width, proximal segments of both branches 1.5 times longer than others. Seta arising from proximal segment of endopodite thin, not reaching the end of endopodite. Seta arising from middle segment of endopodite of similar size with shortest apical setae; in both branches one apical setae is much shorter than two others. Spine on proximal segment of exopodite significantly shorter than middle segment. Apical spines slightly longer than apical segments. Maxillule (Fig. 10A) very small, with two setae, setulated in distal portion. Thoracic limbs: Six pairs. Limb I (Figs. 10B–D) as in the previous species. but endite 1 without seta i. Limb II (Figs. 10E– F). Similar to that of previous species, but scraping seta 3 only slightly thicker than setae 2 and 4, with small spinules. Limb III (Figs. 10G–J). Epipodite oval, without process; exopodite trapezoid with seven setae. Seta 3 being longest, seta 6 of about 3/4 length of seta 3, setae 4 and 7 of about 1/2 length of seta 3, other setae short. Setae 6–7 with short setulae in distal portion, all other setae plumose. Inner portion as in the previous species. Limb IV (Figs. 10K–L). Preepipodite setulated, epipodite with process longer than exopodite itself. Exopodite rounded, with six setae. Seta 3 longest, setae 1, 2 and 5 slightly shorter than seta 3, setae 4 and 6 of 1/3 and 1/2 length of seta 3, respectively. Setae 1–4 plumose, setae 5–6 appear naked under the light microscope. Inner-distal portion of limb IV same as in the previous species. Limb V (Fig. 10M). As in the previous species. Limb VI (Fig. 10N) as in the previous species. Male. General. Body low oval, with maximum height at the middle, height/length ratio about 0.6. Head. Compound eye larger than ocellus. Postabdomen (Figs. 7M–N) short, moderately wide, evenly narrowing distally. Postanal margin of postabdomen evenly comes to the base of claws, no distinct distal margin and dorsodistal angle. Length about 2.5 height. Ventral margin straight or weakly convex. The sperm ducts open at the end of postabdomen, forming minute protrusion above the base of claws. Dorsal margin almost straight in postanal portion and clearly concave in anal one. Preanal and postanal angles not defined. Preanal margin weakly convex to straight. Distal portion of postabdomen 2.5 times longer than preanal one, anal and postanal portions of similar length. Postanal margin with clusters of setulae, in distalmost 4–5 clusters distalmost setula thick, spine-like (Fig. 9N). Lateral groups of setulae as in female. Postabdominal claw (Figs. 7M–N) weakly curved, shorter than in female, much shorter than preanal margin of postabdomen, with acute tip without cluster of setulae. Basal spine very short, with short spinule near it. Antennule (Fig. 7O ) slightly broader than in female, with 12 long terminal aesthetascs, longest aesthetascs about 2/3 length of antennule. Male seta located at 2/3 distance from the base, not reaching the end of antennule. Thoracic limb I (Fig. 10 O) same as in the previous species, Size. Adult female length 0.3–0.39 mm, height 0.19–0.25 mm. Adult male length 0.25–0.28 mm, height 0.14– 0.17 mm. Differential diagnosis. P. guttata differs from P. arvensis in; (1) three main head pores and (2) labral keel without a prominence on anterior margin; from P. werestschagini in: (1) a smaller size, (2) smaller IP/PP ratio, and (3) shape of both male and female postabdomen. P. guttata is habitually similar to P. barbulata but differs in: (1) head shield with broadly rounded posterior portion, (2) female postabdomen with acute prominent distal angle and strongly prominent preanal angle, (3) absence of seta i on endite 1 of thoracic limb I, and (4) evenly narrowing distally male postabdomen. P. guttata differs from P. julietae sp. nov. in: (1) shorter spine near basal spine on postabdominal claw of male and (2) proportion of male seta on the first limb. Distribution and ecology. The taxon is recorded worldwide, but probably it is represented by a complex of cryptic species. P. guttata s. str. is distributed in Palearctic. Taxonomic status of P. cf. guttata from Nearctic, Afrotropic, Indo-Malaysian and Australian regions is unclear. Records of P. guttata from the Neotropics probably all belong to P. julietae sp. nov. P. guttata s. str. in Palearctic is eurybiotic, eurythermic species, usually associated with shore vegetation, inhabiting littoral zone of lakes and ponds, floodplain water bodies, slow rivers, swamps and bogs, temporary water bodies, and also encountered in subterranean water. Encountered at pH> 3.8, at altitudes up to 5520 m a.s.l. (Korovchinsky et al. 2021). For detailed data on ecology see Duigan (1992) and Fryer (1993)., Published as part of Sinev, Artem Y., Sousa, Francisco Diogo Rocha & Elmoor-Loureiro, Lourdes M. A., 2023, Revision of the guttata-group of Alona s. lato leads to its translocation to Prendalona Sousa, Elmoor-Loureiro & Santos, 2018 (Cladocera: Anomopoda: Chydoridae), pp. 95-121 in Zootaxa 5293 (1) on pages 107-112, DOI: 10.11646/zootaxa.5293.1.4, http://zenodo.org/record/7959789, {"references":["Sars, G. O. (1862) Hr. studios. Medic. G. O. Sars fortsatte sit Foredrag over de af ham i Omegnen af Christiania iagttagne Crustacea cladocera. Forhandlinger i Videnskabs - Selskabet i Christiania, 1861, 250 - 302.","Lilljeborg, W. (1901) Cladocera Sueciae. Nova acta regiae societatis scientatis scientiarum upsaleinsis, seriei tertiae, 19, 1 - 701.","Smirnov, N. N. (1971) Chydoridae fauny mira. Fauna USSR. Rakoobraznie. 1 (2). Nauka, Leningrad, 531 pp. [English translation: Chydoridae of the world. Israel Program for Scientific Translations, Jerusalem, 1974]","Chiang, S. & Du, N. (1979) Fauna Sinica. Crustacea. Freshwater Cladocera. Science Press, Academia Sinica, Peking, 297 pp. [in Chinese]","Negrea, S. (1983) Crustacea. Cladocera. In: Fauna of Romania. 4 (12). Editura Academiei Republicii Socialiste Romania, Bucuresti, pp. 1 - 399.","Alonso, M. (1996) Crustacea, Branchiopoda. Vol. 7. Fauna Iberica. Museo Nacional de Ciencias Natural. Consejo Superior de Investigationes Cientificas, Madrid, 486 pp.","Sinev, A. Y. (1999) Alona werestschagini sp. n., a species of the genus Alona Baird, 1843 related to A. guttata Sars, 1862 (Anomopoda: Chydoridae). Arthropoda Selecta, 8 (1), 23 - 30.","Sinev, A. Y. (2002) A key to identifying cladocerans of the genus Alona (Anomopoda, Chydoridae) from the Russian European part and Siberia. Zoologychesky Zhurnal, 81 (8), 926 - 939.","Hudec, I. (2010) Fauna Slovenska III. Anomopoda, Ctenopoda, Haplopoda, Onychopoda (Crustacea: Branchiopoda). Veda, Bratislava, 496 pp.","Kotov, A. A., Sinev, A. Y., Glagolev, S. M. & Smirnov, N. N. (2010) Water fleas (Cladocera). In: Alekseev, V. R. & Tsalolikhin, V. Y. (Eds.), Key book for zooplankton and zoobenthos of fresh waters of European Russia. Vol. 1. KMK Scientific Press, Moscow, pp. 151 - 276.","Sinev A. Y. & Silva-Briano, M. (2012) Cladocerans of genus Alona Baird, 1843 (Cladocera: Anomopoda: Chydoridae) and related genera from Aguascalientes State, Mexico. Zootaxa, 3569 (1), 1 - 24. https: // doi. org / 10.11646 / zootaxa. 3569.1.1","Korovchinsky, N. M., Kotov, A. A., Boikova, O. S & Smirnov, N. N. (2021 a) Water fleas (Crustacea: Cladocera) of Northern Eurasia. Vol. 1. KMK Scientific Press, Moscow, 482 pp.","Kotov, A. A., Korovchinsky, N. M., Sinev, A. Y. & Smirnov, N. N. (2011 a) Cladocera (Crustacea, Branchiopoda) of the Zeya basin (Amurskaya Area, Russian Federation). 3. Systematic-faunistic and zoogeographic analysis. Zoologichesky Zhurna l, 90, 402 - 411.","Kotov, A. A, Seleznev, D. G., Garibian, P. G., Korovchnsky, N. M., Neretina, A. N., Sinev, A. Y., Jeong, H. - G., Yang, H. - M. & Lee, W. (2022) History of Colonization of Jeju Island (Republic of Korea) by the Water Fleas (Crustacea: Cladocera) Is Reflected by the Seasonal Changes in Their Fauna and Species Associations. Water, 14, 3394. https: // doi. org / 10.3390 / w 14213394","Sinev, A. Y., Gu, Y. & Han, B. (2020) Winter-Spring fauna of Cladocera of Dali Bai Autonomous Prefecture, Yunnan Province, China. Limnetica, 39, 621 - 638. https: // doi. org / 10.23818 / limn. 39.40","Sinev, A. Y., Gu, Y. & Han, B. (2015) Cladocera of Hainan Island, China. Zootaxa, 4006 (3), 569 - 585. https: // doi. org / 10.11646 / zootaxa. 4006.3.9","Duigan, C. A. (1992) The ecology and distribution of the littoral freshwater Chydoridae (Branchiopoda, Anomopoda) of Ireland, with taxonomic comments on some species. Hydrobiologia, 241, 1 - 70. https: // doi. org / 10.1007 / BF 00007749","Fryer, G. (1993) The Freshwater Crustacea of Yorkshire: a faunistic and ecological survey. Yorkshire Naturalists' Union and Leeds Philosophical and Literary Society, Yorkshire, 312 pp."]}

Genus Prendalona Sousa, Elmoor-Loureiro & Santos, 2018 emend. nov. Sousa, Elmoor-Loureiro & Santos, 2016a: 28–34 (Prenda); Sousa, Elmoor-Loureiro & Santos, 2018: 1–2. Type species: Prenda arvensis Sousa, Elmoor-Loureiro & Santos, 2016 Emended diagnosis. Parthenogenetic female. General. Small to medium-sized alonines, length of adult female up to 0.55. Body of the Alona -like habitus, of moderate height, moderately compressed laterally. Head and carapace without a dorsal keel. Valves. Ventral margins of valves in ventral view almost straight, valves can be closed without even a narrow gap between them. Dorsal margin of carapace convex, postero-dorsal and postero-ventral angles broadly rounded. Posterior margin weakly convex. Antero-ventral angle rounded. Ventral margin weakly convex to straight, with 30– 50 setae, anterior setae short, not forming separate group from central setae, posterior setae of moderate length, decreasing in length posteriorly. Posteroventral angle without denticles, with numerous thin setulae of similar length, not forming groups. Carapace ornamentation as weakly to well-developed longitudinal lines or as tubercules. Head relatively small, low, triangular-rounded in lateral view. In lateral view rostrum relatively narrow, protruding downwards. Ocellus and compound eye present. Head shield with a maximum width behind mandibular articulation. Rostrum short and rounded. Posterior part of head shield broadly rounded or triangular with defined tip. Three or two major head pores with a narrow connection between them. PP about 1 IP or less in adults. Lateral head pores minute. Labrum of moderate size. Labral keel moderately wide, with a rounded apex. Anterior margin of keel convex or with blunt prominence in upper portion, posterior margin with two clusters of short setulae. Thorax two times longer than abdomen. Dorsal surface of abdominal segments not saddle-shaped. Abdominal joint not developed. Postabdomen of moderate size, moderately high, length about 2.5 height. Basis of claws bordered from distal margin by a clear incision. Distal margin from straight to convex; distal angle obtuse, straight, or acute, prominent. Dorsal margin almost straight in postanal portion and concave in anal one, with distal part about 2 times longer than preanal one, with postanal and anal portion 2.5 of similar length. Preanal angle well-expressed, postanal angle weak to not defined. Preanal margin almost convex. Postanal margin with 5–8 well-developed, sharp composite denticles, most with spinules along anterior margin; size of denticles increasing distally. Length of longest denticles equal to the width of base of postabdominal claw. About 8–10 lateral groups of setulae in the main row, distalmost 5–8 groups with all setulae of similar thickness, in most species central setulae in the group being longest. Postabdominal claw of moderate length, similar in length to preanal portion of postabdomen. Basal spine short, about 0.15–0.2 length of the claw. Antennule of moderate size, length about 2.5–3 widths, with 3–4 clusters of setulae at anterior face. Antennular seta thin, about 1/3–1/2 length of antennule, arising at 1/3–1/2 distance from the end of antenna. Nine terminal aesthetascs of similar length, about 1/2–2/3 length of antennule. Antenna re latively short. Antennal formula, setae 0–0–3/1–1–3, spines 1–0–1/0–0–1. Basipodite robust, with very short seta between branches, branches relatively short. Proximal segments in both branches 1.5 times longer than two others. Seta arising from basal segment of endopodite thin, much shorter than other setae. Antennal spines well-developed, spine on basal segment of exopodite of same length or slightly shorter than middle segment, apical spines as long as apical segments. Thoracic limbs: six pairs. Limb I of moderate size. Accessory seta two times shorter than ODL seta. IDL with three setae, seta 1 very short, setae 2 and 3 long, with thin setulae in distal part. Endite 3 with four setae subequal in length. Endite 2 with two long distally setulated setae (e–f), a shorter seta near their base (d), without inner seta. Endite 1 with two 2-segmented setae, both setulated in distal part, with seta i rudimentary or absent, without inner seta. Limb II. Exopodite elongated, with a slender seta. Eight scraping spines, three basalmost spines (6–8) subequal in length, others increasing in length distally. Distal armature of gnathobase with four elements. Filter plate II with seven setae, the posteriormost member shorter than others. Limb III. Exopodite with seven setae. Seta 3 being longest, seta 6 second in length. Setae 1–5 plumose, setae 6–7 with short setulae in distal part. Morphology of inner portion typical of subfamily; scraping setae of distal endite moderately long. Filter plate III with seven setae. Limb IV. Exopodite with six setae. Setae 1–4 flat, plumose, setae 5–6 with short setulae. Inner portion of limb IV with four setae and a small sensillum. Scraping seta slender, distalmost flaming-torch seta (2) large, with broad base and robust setulae, two other two times narrower, armed with very thin, hair-like setulae. Three soft setae slightly increasing in size basally. Gnathobase with 2-segmented seta and a small hillock. Filter plate IV with five setae. Limb V. Exopodite divided into two lobes, with four plumose setae, setae 1–3 long, subequal in length; seta 4 shorter. Inner lobe narrow oval, with a setulated inner margin. At inner face, two setae densely setulated in distal part, one of them long; length similar to that of exopodite setae 1–3. Filter plate V with three setae. Limb VI as an oval lobe with setulated margin, as large as exopodite V. Male. General. Body low oval, with a maximum height at the middle or behind it. Postabdomen of variable shape, sperm ducts open on distal margin. Preanal and postanal angles not defined. Clusters of thin or robust setulae in place of female marginal denticles on postanal margin. Postabdominal claw much shorter than in female, basal spine very short or absent. Antennule broader than in female, with 12 terminal aesthetascs, male seta located laterally. Thoracic limb I with a copulatory hook of moderate size, half as long as limb itself. IDL without seta 1, IDL setae 2 and 3 much thinner and shorter than in female; male seta curved, long. Differential diagnosis: Prendalona clearly differs from its sister-group, genus Flavalona in: (1) minute lateral head pores without any pockets below, (2) absence of a genital process on male postabdomen and (3) absence of inner setae on endites 1–2 of thoracic limb I. From all other genera of Alona s. lato, Prendalona differs in: (1) differentiated flaming-torch setae of limb IV and (2) weakly-developed lateral fascicles of postabdominal setulae, with distalmost setula not being much thicker than the others. As a member of the Hexalona branch, Prendalona clearly differs from genera of the Coronatella branch, Coronatella, Anthalona, Karualona, Magnospina in: (1) presence of limb IV and (2) seven setae on exopodite III. Prendalona differs from Alona s. str. (the quadrangularis -group) and Ovalona in: (1) weakly developed IDL seta 1, (2) presence of a filter plate V and (3) presence of limb VI. It clearly differs from other groups of the Hexalona branch, such as Biapertura, Armatalona, and intermedia -groups in; (1) shape and armament of postabdomen, (2) absence of inner setae on endites 1–2 of thoracic limb I and (3) reduced or absent seta I on endite III of limb I. For summary of differences between the Hexalona genera see Table 1.

Ceriodaphnia nikolaii sp. nov. (Figs. 9–16) Etymology. The taxon is named after our teacher, Prof. Nikolai N. Smirnov, who initiated great progress in the studies of cladocerans in Eurasia and in the world and collected the type series. Type locality. An un-named oxbow of the Lena River, City Yakutsk, Republic of Sakha (Yakutia), Russia (62.0˚N, 129.8˚E). Type material. Holotype. A parthenogenetic female, MGU Ml 266 at the Collection of Zoological Museum of M. V. Lomonosov Moscow State University, Moscow, Russia. Allotype. An adult male, MGU Ml 267. Paratypes. Ten parthenogenetic females, six ephippial female and seven adult males, MGU Ml 268. Several parthenogenetic, ephippial females and males, AAK 1999-045. Adult parthenogenetic female. General (Figs. 9b,c,e,f). Body subovoid in lateral view, with maximum height in middle of valves. Dorsal margin interrupted by a depression in posterior head portion. Dorsal and ventral portion ovoid, poster-dorsal angle present, with small caudal spine. Postero-dorsal angle well-developed, sometimes represented by a short caudal spine, valve margin from the former to anterior margin uniformly rounded. In dorsal view, body subovoid and elongated. Head (Figs. 10a–g) small, ovoid, without rostrum, with a strong depression in posterior head half; small dorsal head pore in this depression. Dorsal head pore round; supraocular dome surround relatively big compound eye; ocellus minute. Labrum (Fig. 10g) quadrangular, with a wide fleshy main body and large setulated labral plate. In dorsal view, fornices from rounded to slightly projected. Valve large and ovoid (Figs. 11a–f); ventral portion with long setae at inner margin (Figs. 11a–b); postero-ventral portion with a row of short setae, short series of setules between them (Fig. 11c); two relatively long setae in dorsal most portion (Fig. 11d–f). Abdomen (Figs. 12b, h, i) short consisting of four segments, first segment having a long abdominal projection. Postabdomen (Figs. 12a–i) elongated, tapering distally. Ventral portion straight. Preanal margin from slightly to strongly projected and angled, postanal angle rounded. Postanal and anal margin bearing 8–9 teeths of different size. Preanal, anal and postanal portion covered by short series of minute setules. Postabdominal seta as long as postabdomen. Postabdominal claw elongated, curved, with pointed tip (Figs. 13a–h). Outer portion of dorsal margin with three successive pectens. First pecten with thin setules, second pecten consisting of twelve to twenty six stout teeth with variable size, and third pecten bearing numerous minute setules, not reaching the tip of claw. Antenna I (Figs. 10g,h) short and cylindrical. Antennular seta longer than antenna I body, mostly same in size with longest aesthetascs. Antenna II (Figs. 11g –i) with a narrow coxal part bearing two sensory setae. Basal segment of antenna II cylindrical elongated and covered by rows of small setules. Antennular branches long, approximately same in size, exopodite with four setulated segments, endopodite consist of three setulated segments. Antennal formula: 0-0-1- 3/1-1-3, second segment of exopodite bearing one short spine, distal part of basal segment with one short spine. Limb I (Figs. 14a and 15a) with a bilaterally setulated accessory seta. Outer distal lobe (ODL) bearing a very long, naked seta and a short seta setulated in distal part. Inner distal portion (endite 4) with a single anterior and two posterior setae of different size. Endite 3 with a single, long anterior seta (1) and two posterior setae (a–b); endite 2 with a single anterior seta (2) and two posterior setae (c–d); endite 1 with a single, short anterior seta (3) and four posterior setae (f–h). Two ejectors hooks subequal in size (Figs. 14a and 15a). Maxillar process absent. Limb II (Figs. 14b and 15b–d) with an ovoid epipodite (epp) an elongated exopodite (ext) bearing two long bilaterally setulated setae. Endite 5 with a short anterior seta (1) and two long, bilaterally setulated posterior setae (a–b); endite 4 with a single long (longest one) stiff anterior setae (2) and a long posterior seta (c); endite 3 with a single short anterior seta (3) and no posterior setae; endite 2 with a short anterior seta modified into sensillum (4) and a single posterior seta (d). A seta on unclear homology near gnathobase. Endite 1(e1) = gnathobase with two rows of setae. Anterior row consists of four setae: setae 1 presented by a small sensillum; seta 2 very long and setulated; seta 3 shorter than seta 2; seta 4 short. Posterior row with eight setae of different morphology. Limb III (Figs. 14c and 15e–h) with a subovoid and elongated prepipodite (pep) and ovoid epipodite (epp). Exopodite (ext) with two lateral (5–6) and four distal setae (1–4); distal segment of seta 1 and seta 2 thin, proximal part of seta 2 with a row of strong setules. Limb inner distal portion represented by five endites: endite 4 with a single anterior (2) and a single posterior (b) seta; endite 3 with a short anterior seta (3); endite 2 with a very short anterior seta (4); endite 1 (gnathobases) represented by a large lobe with a long distal anterior seta (1) and two small, stiff anterior setae (2–3), posterior portion represented by numerous long posterior setae. Limb IV (Figs. 14d and 15i) with an elongated prepipodite (pep) and ovoid epipodite (epp). Exopodite (ext) bears two lateral setae (5–6) and four distal setae (1–4); distal segment of seta 1 thin. Inner limb portion with two setulated anterior setae (1–2); posterior portion bears numerous long posterior setae. Limb V (Figs. 14e and 15j) with elongated epipodite (epp), exopodite (exp) triangular, with two distal setae of different size (1–2) and a large lateral seta (3). Inner portion of limb V with a setulated margin and a large distal seta. Juvenile female (Fig. 9d). Body subovoid and elongated; dorsal margin slightly convex; postero-dorsal and ventral portion round. Head round, with large compound eye and small ocellus. Dorsal portion with great depression between head and body; dorsal part of headshield with protruding dorsal head pore. Ephippial female (Figs. 9a and 10a). Body subovoid, valves modified into ephippium with a single resting egg; in lateral view ephippium with expressed reticulation; ephippium without lateral projections. Adult male (Fig. 16a,c–i). Body subovoid and elongated, dorsal margin straight, postero-dorsal and ventral portion rounded. Postero-ventral angle rounded. Head (Fig. 16a,c) relatively small, without rostrum. Compound eye large and ocellus small. Dorsal portion of head shield in lateral view with high depression between head and body; dorsal head pore present. Labrum (Figure 16c) as in parthenogenetic female. Valve (Fig. 16a) as in parthenogenetic female. Abdomen (Fig. 16e) with four setulated segments lacking any process, covered by minute setules. Postabdomen (Fig.16e,f) elongated, subrectangular; ventral margin convex.Dorsal margin convex, preanal angle projected. Postanal and anal portion with about seven strong teeth. Gonopore opens subdistally on postabdomen. Postabdominal claw as in female. Antenna I (Fig. 16c,d) cylindrical, long, with nine short aesthetascs. Sensory seta relatively short (shorter than longest aesthetascs) located subdistally on anttenna I body. Flagellum located distally, longer than antenna I body. Antenna II (Fig. 16c) same as in parthenogenetic female. Limb I (Fig. 16g,h) with a cylindrical outer distal lobe bearing a long seta and a short setulated seta. Inner distal lobe with a copulatory hook and four seta of different size. Morphology of endites mostly same as in female, but endite 5 with an additional seta. Limb II (Fig. 16i) endite 4 with long modified anterior seta (distal part bilaterally setulated); endite 3 and endite 2 bearing anterior seta longer than female anterior seta. Juvenile male (Fig. 16b). Body subovoid, dorsal margin relatively straight, postero-dorsal and ventral portion round. Head round, without rostrum; antenna I cylindrical with a long thick sensory seta on the basal part and a relatively short flagellum (same in size as antenna I body). Size. Parthenogenetic female length 0.38–1.1 mm / height 0.23–0.8 mm; ephippial female length 0.88 mm / height 0.64 mm; male length 0.64–0.68 mm / height 0.35 mm. Differential diagnosis. This taxon belongs to the C. dubia s.lat. species group and has four diagnostic characters mentioned in the Introduction. The main diagnostic character is the presence of larger teeth on the postabdominal claw, but their length is c.a. half the claw diameter in C. dubia group, while c.a. a claw diameter in C. reticulata group. Presence of these teeth as well as rudimentary stiff (anterior) setae on the inner-distal portion of limb II differentiate well C. nikolaii sp.nov. from C. laticaudata-rotunda group lacking such teeth and having relatively long setae on limb II. In contrast to other taxa of the C. dubia group, parthenogenetic female of C. nikolaii sp.nov. has the preanal angle of postabdomen from slightly pronounced to greatly pronounced (similarly to that in Ceriodaphnia laticaudata), while in other members of C. dubia s.lat. the preanal angle is smoothed or slightly projected. In addition, male postabdomen in C. nikolaii sp.nov. has an expressed preanal angle in contrast to. dubia s.l. with a completely smoothed preanal angle; the shortest seta of IDL has a size similar to that of two other setae, while in the latter the shortest seta is clearly shorter than other setae of IDL. Distribution. C. nikolaii sp. nov. is known to date only from its type locality: an oxbow of the Lena River near city of Yakutsk. Perhaps it is an endemic species with a limited distribution (i.e. it is absent in any other numerous samples from Easter Siberia and Far East studied by the authors). Note that the majority of studied populations from Republic of Sakha (Yakutia) belonged to C. dubia s.l. instead of C. nikolaii sp. nov.

Ceriodaphnia dubia Richard, 1894 s.l. from Northern Palaearctic (Figs. 1–8) Richard 1894: 570–572, Fig. 6–8; Lilljeborg 1901: 202–205, Pl. 28: Fig. 19–28 (affinis); Wagler 1937: 35 (quadrangula var. affinis); Behning 1941: 148–149, Fig. 57 (affinis); Šrámek-Hušek R. et al. 1962: 238–240, Fig. 85 (affinis); Manujlova 1964: 165–166, Fig. 64 (affinis); Scourfield & Harding 1966: 24, Fig. 56–57; Flössner 1972: 171–173, Fig. 80; Chiang & Du 1979: 139–140, Fig. 93; Ibrasheva & Smirnova 1983: 44–45 (affinis); Negrea 1983 a: 163–164, Fig. 67; Margaritora 1983: 42, Fig. 22B, B’, 23B, 24C; Margaritora 1985: 71–73, Fig. 30; Røen 1995: 139–141, Fig. 93; Alonso 1996: 186, 188, Fig. 82–I; Flössner 2000: 210–212, Pl. 79a–k; Hudec 2010: 134–136, Fig. 24 (affinis); Kotov et al. 2010: 187, Fig. 1; Bledzki & Rybak 2016: 183 (affinis); Rogers et al. 2019: 669, Fig. 16.2.11 F; Korovchinsky et al. 2021: 69–71, Fig. 16: 1. Material examined (all samples from Russia). Many parthenogenetic females, ephippial females and males from an oxbow of the Don River near village of Stogovskoy, Rostov Area, (49.73784˚N, 41.22782˚E), AAK M-4308; many pathenogenetic females, ephippial female and males from a puddle in Mongun-Taiyginskyi District, Republic of Tuva (50.092805˚N, 90.079438˚E), AAK 2022-097; few parthenogenetic females from a water in a metallic tank, city of Yakutsk, Republic of Sakha (Yakutia) (61.96021˚N, 129.6543˚E), AAK 2011-026; few parthenogenetic females from a nameless lake near the Federal Highway “Kolyma”, Republic of Sakha (Yakutia) (62.15591˚N, 130.9231˚E), AAK M-1949; few parthenogenetic female from a puddle near Chyoroktai Reservoir, Republic of Sakha (Yakutia) (62.05379˚N, 132.7742˚E), AAK M-1955; a single parthenogenetic female from lake Atyrdiakh, oxbow of the Handyga River, Republic of Sakha (Yakutia) (63.08686˚N, 134.0543˚E); few parthenogenetic females from a laboratory culture in the Institute of Inland Water Biology, Borok, Russia, AAK M-2883. All samples are kept at the working collection of the Laboratory of Aquatic Ecology and Invasions, A.N. Severtsov Institute of Ecology and Evolution, Moscow, Russia. Redescription. Parthenogenetic female. General. In lateral view body ovoid, maximum height in middle of valves (Figs. 1b, d, e). Dorsal margin interrupted by a depression in posterior head portion. Postero-dorsal angle well-developed, sometimes represented by a short caudal spine, valve margin from the anterior to posterior margin uniformly rounded. In dorsal view, body subovoid and elongated. Head (Figs. 2a–d) relatively small and round, rostrum very short. A strong depression in posterior head half, small dorsal head pore in this depression. Compound eye large, ocellus small, located near compound eye. Labrum (Fig. 2d) with a main fleshy body and a large setulated distal lobe. In dorsal view, fornices from rounded to slightly projected (see also Alonso 1996: 187, Fig. 82; Hudec 2010: 135, Fig. 24 for illustrations of projected, sharp fornices). Valve large and ovoid (Figs. 3a–h), its ventral portion with long setae at inner margin (Figs. 3a–c), postero-ventral portion with a row of short setae, short series of setules between them (Figs. 3d–h); two or three relatively long setae in dorsal most portion (Figs. 3e–h). Abdomen (Figs. 4a–c, e) consists of four segments. First segment with a long process. Second, third and fourth segments setulated, lacking of processes. Postabdomen (Figs. 3i, 4a–e) elongated, with narrowing distal portion. Ventral margin straight. Preanal margin straight, preanal angle from fully smooth (Fig. 4a, see also Alonso, 1996: Fig. 82H) to little developed (Fig. 4b, see also Flössner, 1972: Fig. 80C) or even somewhat projected (Fig. 4d, See also Scourfield & Harding, 1966: Fig. 56), postanal angle rounded. Postanal margin straight, bearing nine to eleven pairs of teeths, their size continuously increasing distally, except for the most distal spine which is usually the shortest. Preanal, anal and postanal portions covered by short series of minute setules. Postabdominal setae long as postabdomen. Postabdominal claw (Figs. 4f–k) long, slightly curved, with pointed tip. On its outer side, three successive pectens along the dorsal margin. The first pecten consisting of thin setules; the second pecten composed of 10–22 stout teeth with different thickness among populations and even within a single population; the third pecten consists of minute fine setules, this row does not reach the tip of claw. Antenna I (Figs. 2d,e) cylindrical, relatively short (length c.a. 1.5 diameter); antennular seta slender, longer than antenna I body, arising distally. Nine aesthetascs of different size, the longest one longer than antenna I body. Antenna II with a narrow coxopodite bearing two sensory setae (Fig. 2f). Basal segment elongated, covered by rows of minute setules, its distal part having a posterior sensory seta and a short anterior spine (Fig. 2g). Antennal branches elongated, subequal in size, exopodite with four segments, endopodite with three segments. Each branch segment covered by series of minute setules. Antennal setae formula: 0-0-1-3/1-1-3. The second segment of exopodite with a small, slender spine. Each swimming seta with proximal and distal segments bilaterally setulated and a chitinous insertion in distal segment near its connection with the proximal segment. Limb I (Figs. 5a, c and 6a) with ovoid epipodite (epp) and a bilaterally setulated accessory seta (acs); outer distal lobe (ODL) bearing a long naked seta and a short seta setulated distally. Inner distal lobe (IDL) or endite 4 having three setae of different size: a single anterior and two posterior setae. Endite 3 having an anterior seta (1) and two posterior setae (a–b); endite 2 with a single anterior seta (2) and two posterior setae (c–d); endite 1 with a single anterior seta (3) and four posterior setae (e–h). Two ejectors hooks relatively small, subequal in size. Maxillar process absent. Limb II (Figs. 5b, d and 6b–d) with ovoid epipodite (epp), exopodite (ext) elongated, with two long setae of different size. Endite 5 (e5) with a short stiff anterior seta (1) and two soft, long posterior setae (a–b); endite 4 (e4) with one relatively long, stiff anterior seta (2) and a long posterior seta; endite 3 (e3) with one relatively short, stiff anterior seta (3) shorter than anterior seta of endite 3, but longer than anterior seta of endite 5, and a long posterior seta (c); endite 2 (e2) with a short anterior seta (3) and no posterior setae. A seta on unclear homology near gnathobase. Endite 1(e1) = gnathobase with two rows of setae. Anterior row with four setae; seta 1 represented by a small sensillum; seta 2 very long, with long setules; seta 3 long but shorter than seta 2; seta 4 short, naked. Posterior row of gnathobase with eight setae of different morphology (a–h). Limb III (Figs. 5e and 6e–g) with an elongated preepipodite (pep) and subovoid epipodite (epp). Exopodite (ext) subovoid and flat with two lateral setae (5–6) and four distal setae (1–4). Distal segments of seta 1 and seta 2 slender, seta 2 with a row of strong setules on proximal part of distal segment. Limb inner distal portion consist of five endites: endite 5 (Fig. 5e: e5) with a single anterior (Fig. 6e: 1) and a single posterior (a) seta; endite 4 with a single anterior (2) and a single posterior (b) seta; endite 3 with a short anterior seta (3); endite 2 with a very short anterior seta (4); endite 1 (gnathobases) represented by a large lobe with a long distal anterior seta (1) and two small, stiff anterior setae (2–3), posterior portion represented by numerous long posterior setae. Limb IV (Figs. 5f and 6h) with an elongated prepipodite (pep) and a subovoid epipodite (epp). Exopodite (ext) subovoid, flat, bearing two lateral setae (5–6) and four distal setae (1–4). Distal segment of seta 1 very thin, naked. Limb inner distal portion with two soft anterior setae (1–2); inner margin of a gnathobase represented by numerous posterior setae. Limb V (Figs. 5g and 6i) with elongated epipodite (epp), exopodite (exp) triangular, with two distal setae of different size (1–2) and a large lateral seta (3). Inner portion of limb V with a setulated margin and a large distal seta. Juvenile female (Figs. 1c,f). Body subovoid, relatively elongated. Dorsal margin almost straight, postero-dorsal margin with a small caudal spine, sometimes with few minute terminal denticles; ventral margin ovoid, postero-ventral angle smooth. Head rounded, compound eye relatively large, completely occupies distalmost body portion, ocellus minute. Head in lateral view with a strong depression, dorsal head pore protruded. Ephippial female (Fig. 1a). Body mostly same as in parthenogenetic female, dorsal portion of valves modified into ephippium with a single resting egg. Ephippium subovoid in lateral view, with a clear reticulation, without any lateral projections. Adult male(Figs. 7a,d). Body subovoid, dorsal margin straight; postero-dorsal angle well-developed, sometimes represented by a short caudal spine. Ventral margin ovoid, postero-dorsal angle rounded. Head (Figs. 7a–e) rounded large, rostrum absent; compound eye relatively large, occupies most part of the distal head extremity; ocellus present. In lateral view headshield having a strong depression with a minute dorsal head pore. In dorsal view, headshield with mostly triangular fornices (Fig. 7b). Labrum (Fig. 7c) same as in parthenogenetic female. Valve (Figs. 7a,d) similar to that in parthenogenetic female. Abdomen (Figs. 8c,e) with four setulated segments lacking any processes, covered by minute setules. Postabdomen (Figs. 8c,e) elongated, subrectangular; ventral margin convex. Dorsal margin from straight to slightly convex. Preanal angle not expressed or slightly projected; postanal portion with nine strong spines of different size. Gonopore opens subdistally on postabdomen. Postabdominal claw (Fig. 8d) long with three pectens, tip pointed; pectens as in parthenogenetic female. Antenna I (Figs. 7c,e and 8a,b) long, cylindrical, with nine short aesthetascs of different size. Sensory seta long (longer than the longest aesthetascs), located subdistally of antenna I body. Flagellum located distally, very long (longer than antenna I body). Antenna II (Fig. 7c) as in parthenogenetic female. Maxilla (Fig. 8f) bearing four stiff setulated setae of different size. Limb I (Figs. 8g –k) with outer distal lobe bearing a single, very long seta and a short setulated seta. Inner distal lobe (IDL) modified, bearing a copulatory hook and four seta of different size. Among them, two anterior seta: one seta as in female, and the second an additional seta. The rest of limb I as in female. Limb II (Fig. 8i) in general as in female, with few modifications: endite 4 with a long anterior seta 2 bilaterally armed by short setules; endite 3 with anterior seta 3 longer than in female; endite 2 with anterior seta 4 longer than in female. Size. Parthenogenetic female length 0.44–1.25 mm, height 0.24–0.84 mm; ephippial female length 0, 82 mm, height 0.55 mm; male length 0.69–0.81 mm, height 0.35–0.42 mm. Taxonomic comments. C. dubia s.str. was described from Lake Toba, Sumatra, Indonesia (Richard 1894). Unfortunately, its type material is lost (Kotov & Ferrari 2010). In this article we cannot relate the morphological identity of C. dubia s.l. from Northern Eurasia with that from Indonesian populations, which it is a task of further studies. But we did not find any morphological evidence for the existence of more than one species in northern Eurasia (except for a single Yakutian population, see below). Note that Ceriodaphnia affinis Lilljeborg, 1901 was described from Europe, but its validity could be checked only by a comparison with Indonesian populations. To resolve the issue of the exact species status, a redescription of the population from Lake Toba and a full-scale revision of all populations belonging to the C. dubia s.l. species complex should be carried out in the future. Distribution and ecology. To date, C. dubia s.l. needs to be regarded as a widely distributed (almost cosmopolitan) taxon (Korovchinsky et al. 2021)., Published as part of Garibian, Petr G., Andreeva, Lena V. & Kotov, Alexey A., 2023, A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups, pp. 247-270 in Zootaxa 5284 (2) on pages 249-258, DOI: 10.11646/zootaxa.5284.2.2, http://zenodo.org/record/7923314, {"references":["Richard, J. (1894) Entomostraces recueillis par M. E. Modigliani dans le lac Toba (Sumatra). Annali del Museo Civico di Storia Naturale di Genova, 14, 565 - 578.","Lilljeborg, W. (1901) Cladocera Sueciae. Nova acta regiae societatis scientatis scientiarum upsaleinsis, Seriei Tertiae, 19, 1 - 701.","Wagler, E. (1937) Klasse: Crustacea, Krebstiere. Die Tierwelt Mitteleuropas, II (2 a), 1 - 224.","Behning, A. L. (1941) Kladotsera Kavkaza - The Cladocerans of the Caucasus. Gruzmedgiz Publishing, Tbilisi, 384 pp.","Manujlova, E. F. (1964) The cladocerans of fauna of the USSR. Nauka, Moscow & Leningrad, 327 pp.","Scourfield, D. J. & Harding, J. P. (1966) A key to the British freshwater Cladocera. 3 rd edition. Freshwater British Association, Scientific Publication, 5, 1 - 55.","Flossner, D. (1972) Krebstiere, Crustacea (Kiemen- und Blattfusser, Branchiopoda, Fischlause, Branchiura). VEB Gustav Fischer Verlag, Jena, 501 pp.","Chiang, S. & Du, N. S. (1979) Crustacea: freshwater Cladocera. Science Press, Peking, 1 - 297.","Ibrasheva, S. I. & Smirnova, V. A. (1983) Cladocerans of Kazakhstan. Mektep Publishing, Alma-Ata, 136 pp.","Negrea, S. (1983) Cladocera. In: Fauna Republicii Populare [Socialiste] Romania. Crustacea. 4 (12). Editura Academiei Republicii Socialiste Romania, Bucuresti, pp. 1 - 399.","Margaritora, F. G. (1983) Cladoceri (Crustacea, Cladocera). Guide per il riconoscimento delle specie animali delle acque interne italiane. Vol. 22. Consiglio Nazionalle delle Ricerche, Verona, 169 pp.","Margaritora, F. G. (1985) Cladocera. Fauna d'ltalia 23. Edizioni Calderini, Bologna, 399 pp.","Roen, U. I. (1995) Gaellefodder (Branchiopoda) Ferejer, Damrokker, Muslingeskalkrebs & Dafnier samt Karpelus (Branchiura). Danmarks Fauna, KObenhavn, 85, 1 - 358.","Alonso, M. (1996) Crustacea: Branchiopoda. Consejo Superior de Investigaciones Cientificas, Madrid, 486 pp.","Flossner, D. (2000) Die Haplopoda und Cladocera (ohne Bosminidae) Mitteleuropas. Backhuys, Leyden, 428 pp.","Hudec, I. (2010) Anomopoda, Ctenopoda, Haplopoda, Onychopoda. (Crustacea Branchiopoda). VEDA vydavatel ̕ stvo Slovenskej akademie vied, Bratislava, 496 pp.","Bledzki, L. A. & Rybak, J. I. (2016) Freshwater Crustacean Zooplankton of Europe. Springer International Publishing, Cham, 918 pp. https: // doi. org / 10.1007 / 978 - 3 - 319 - 29871 - 9","Rogers, D. C., Kotov, A. A., Sinev, A. Y., Glagolev, S. M., Korovchinsky, N. M., Smirnov, N. N. & Bekker E. I. (2019) Chapter 16.2. Arthropoda: Class Branchiopoda. In: Rogers, C. D. & Thorp, J. H. (Eds.), Thorp and Covich's Freshwater Invertebrates. Vol. 4. Keys to Palaearctic Fauna. Academic Press, London, pp. 643 - 724. https: // doi. org / 10.1016 / B 978 - 0 - 12 - 385024 - 9.00018 - 6","Korovchinsky, N. M., Kotov, A. A., Sinev, A. Y., Neretina, A. N. & Garibian, P. G. (2021) Water fleas (Crustacea: Cladocera) of North Eurasia. Vol. 2. KMK Press, Moscow, 544 pp.","Kotov, A. A. & Ferrari, F. D. (2010) The taxonomic research of Jules Richard on Cladocera (Crustacea: Branchiopoda) and his collection at the National Museum of Natural History, USA. Zootaxa, 2551 (1), 37 - 64. https: // doi. org / 10.11646 / zootaxa. 2551.1.2"]}

Ceriodaphnia nikolaii sp. nov. (Figs. 9–16) Etymology. The taxon is named after our teacher, Prof. Nikolai N. Smirnov, who initiated great progress in the studies of cladocerans in Eurasia and in the world and collected the type series. Type locality. An un-named oxbow of the Lena River, City Yakutsk, Republic of Sakha (Yakutia), Russia (62.0˚N, 129.8˚E). Type material. Holotype. A parthenogenetic female, MGU Ml 266 at the Collection of Zoological Museum of M. V. Lomonosov Moscow State University, Moscow, Russia. Allotype. An adult male, MGU Ml 267. Paratypes. Ten parthenogenetic females, six ephippial female and seven adult males, MGU Ml 268. Several parthenogenetic, ephippial females and males, AAK 1999-045. Adult parthenogenetic female. General (Figs. 9b,c,e,f). Body subovoid in lateral view, with maximum height in middle of valves. Dorsal margin interrupted by a depression in posterior head portion. Dorsal and ventral portion ovoid, poster-dorsal angle present, with small caudal spine. Postero-dorsal angle well-developed, sometimes represented by a short caudal spine, valve margin from the former to anterior margin uniformly rounded. In dorsal view, body subovoid and elongated. Head (Figs. 10a–g) small, ovoid, without rostrum, with a strong depression in posterior head half; small dorsal head pore in this depression. Dorsal head pore round; supraocular dome surround relatively big compound eye; ocellus minute. Labrum (Fig. 10g) quadrangular, with a wide fleshy main body and large setulated labral plate. In dorsal view, fornices from rounded to slightly projected. Valve large and ovoid (Figs. 11a–f); ventral portion with long setae at inner margin (Figs. 11a–b); postero-ventral portion with a row of short setae, short series of setules between them (Fig. 11c); two relatively long setae in dorsal most portion (Fig. 11d–f). Abdomen (Figs. 12b, h, i) short consisting of four segments, first segment having a long abdominal projection. Postabdomen (Figs. 12a–i) elongated, tapering distally. Ventral portion straight. Preanal margin from slightly to strongly projected and angled, postanal angle rounded. Postanal and anal margin bearing 8–9 teeths of different size. Preanal, anal and postanal portion covered by short series of minute setules. Postabdominal seta as long as postabdomen. Postabdominal claw elongated, curved, with pointed tip (Figs. 13a–h). Outer portion of dorsal margin with three successive pectens. First pecten with thin setules, second pecten consisting of twelve to twenty six stout teeth with variable size, and third pecten bearing numerous minute setules, not reaching the tip of claw. Antenna I (Figs. 10g,h) short and cylindrical. Antennular seta longer than antenna I body, mostly same in size with longest aesthetascs. Antenna II (Figs. 11g –i) with a narrow coxal part bearing two sensory setae. Basal segment of antenna II cylindrical elongated and covered by rows of small setules. Antennular branches long, approximately same in size, exopodite with four setulated segments, endopodite consist of three setulated segments. Antennal formula: 0-0-1- 3/1-1-3, second segment of exopodite bearing one short spine, distal part of basal segment with one short spine. Limb I (Figs. 14a and 15a) with a bilaterally setulated accessory seta. Outer distal lobe (ODL) bearing a very long, naked seta and a short seta setulated in distal part. Inner distal portion (endite 4) with a single anterior and two posterior setae of different size. Endite 3 with a single, long anterior seta (1) and two posterior setae (a–b); endite 2 with a single anterior seta (2) and two posterior setae (c–d); endite 1 with a single, short anterior seta (3) and four posterior setae (f–h). Two ejectors hooks subequal in size (Figs. 14a and 15a). Maxillar process absent. Limb II (Figs. 14b and 15b–d) with an ovoid epipodite (epp) an elongated exopodite (ext) bearing two long bilaterally setulated setae. Endite 5 with a short anterior seta (1) and two long, bilaterally setulated posterior setae (a–b); endite 4 with a single long (longest one) stiff anterior setae (2) and a long posterior seta (c); endite 3 with a single short anterior seta (3) and no posterior setae; endite 2 with a short anterior seta modified into sensillum (4) and a single posterior seta (d). A seta on unclear homology near gnathobase. Endite 1(e1) = gnathobase with two rows of setae. Anterior row consists of four setae: setae 1 presented by a small sensillum; seta 2 very long and setulated; seta 3 shorter than seta 2; seta 4 short. Posterior row with eight setae of different morphology. Limb III (Figs. 14c and 15e–h) with a subovoid and elongated prepipodite (pep) and ovoid epipodite (epp). Exopodite (ext) with two lateral (5–6) and four distal setae (1–4); distal segment of seta 1 and seta 2 thin, proximal part of seta 2 with a row of strong setules. Limb inner distal portion represented by five endites: endite 4 with a single anterior (2) and a single posterior (b) seta; endite 3 with a short anterior seta (3); endite 2 with a very short anterior seta (4); endite 1 (gnathobases) represented by a large lobe with a long distal anterior seta (1) and two small, stiff anterior setae (2–3), posterior portion represented by numerous long posterior setae. Limb IV (Figs. 14d and 15i) with an elongated prepipodite (pep) and ovoid epipodite (epp). Exopodite (ext) bears two lateral setae (5–6) and four distal setae (1–4); distal segment of seta 1 thin. Inner limb portion with two setulated anterior setae (1–2); posterior portion bears numerous long posterior setae. Limb V (Figs. 14e and 15j) with elongated epipodite (epp), exopodite (exp) triangular, with two distal setae of different size (1–2) and a large lateral seta (3). Inner portion of limb V with a setulated margin and a large distal seta. Juvenile female (Fig. 9d). Body subovoid and elongated; dorsal margin slightly convex; postero-dorsal and ventral portion round. Head round, with large compound eye and small ocellus. Dorsal portion with great depression between head and body; dorsal part of headshield with protruding dorsal head pore. Ephippial female (Figs. 9a and 10a). Body subovoid, valves modified into ephippium with a single resting egg; in lateral view ephippium with expressed reticulation; ephippium without lateral projections. Adult male (Fig. 16a,c–i). Body subovoid and elongated, dorsal margin straight, postero-dorsal and ventral portion rounded. Postero-ventral angle rounded. Head (Fig. 16a,c) relatively small, without rostrum. Compound eye large and ocellus small. Dorsal portion of head shield in lateral view with high depression between head and body; dorsal head pore present. Labrum (Figure 16c) as in parthenogenetic female. Valve (Fig. 16a) as in parthenogenetic female. Abdomen (Fig. 16e) with four setulated segments lacking any process, covered by minute setules. Postabdomen (Fig.16e,f) elongated, subrectangular; ventral margin convex.Dorsal margin convex, preanal angle projected. Postanal and anal portion with about seven strong teeth. Gonopore opens subdistally on postabdomen. Postabdominal claw as in female. Antenna I (Fig. 16c,d) cylindrical, long, with nine short aesthetascs. Sensory seta relatively short (shorter than longest aesthetascs) located subdistally on anttenna I body. Flagellum located distally, longer than antenna I body. Antenna II (Fig. 16c) same as in parthenogenetic female. Limb I (Fig. 16g,h) with a cylindrical outer distal lobe bearing a long seta and a short setulated seta. Inner distal lobe with a copulatory hook and four seta of different size. Morphology of endites mostly same as in female, but endite 5 with an additional seta. Limb II (Fig. 16i) endite 4 with long modified anterior seta (distal part bilaterally setulated); endite 3 and endite 2 bearing anterior seta longer than female anterior seta. Juvenile male (Fig. 16b). Body subovoid, dorsal margin relatively straight, postero-dorsal and ventral portion round. Head round, without rostrum; antenna I cylindrical with a long thick sensory seta on the basal part and a relatively short flagellum (same in size as antenna I body). Size. Parthenogenetic female length 0.38–1.1 mm / height 0.23–0.8 mm; ephippial female length 0.88 mm / height 0.64 mm; male length 0.64–0.68 mm / height 0.35 mm. Differential diagnosis. This taxon belongs to the C. dubia s.lat. species group and has four diagnostic characters mentioned in the Introduction. The main diagnostic character is the presence of larger teeth on the postabdominal claw, but their length is c.a. half the claw diameter in C. dubia group, while c.a. a claw diameter in C. reticulata group. Presence of these teeth as well as rudimentary stiff (anterior) setae on the inner-distal portion of limb II differentiate well C. nikolaii sp.nov. from C. laticaudata-rotunda group lacking such teeth and having relatively long setae on limb II. In contrast to other taxa of the C. dubia group, parthenogenetic female of C. nikolaii sp.nov. has the preanal angle of postabdomen from slightly pronounced to greatly pronounced (similarly to that in Ceriodaphnia laticaudata), while in other members of C. dubia s.lat. the preanal angle is smoothed or slightly projected. In addition, male postabdomen in C. nikolaii sp.nov. has an expressed preanal angle in contrast to. dubia s.l. with a completely smoothed preanal angle; the shortest seta of IDL has a size similar to that of two other setae, while in the latter the shortest seta is clearly shorter than other setae of IDL. Distribution. C. nikolaii sp. nov. is known to date only from its type locality: an oxbow of the Lena River near city of Yakutsk. Perhaps it is an endemic species with a limited distribution (i.e. it is absent in any other numerous samples from Easter Siberia and Far East studied by the authors). Note that the majority of studied populations from Republic of Sakha (Yakutia) belonged to C. dubia s.l. instead of C. nikolaii sp. nov., Published as part of Garibian, Petr G., Andreeva, Lena V. & Kotov, Alexey A., 2023, A new species of the genus Ceriodaphnia Dana, 1853 (Cladocera: Daphnidae) from Eastern Siberia (Russia) that combines morphological features of two species groups, pp. 247-270 in Zootaxa 5284 (2) on pages 259-264, DOI: 10.11646/zootaxa.5284.2.2, http://zenodo.org/record/7923314

Leptestheria gomantaki sp. nov. (Figs. 5, 6B, 7B) Leptestheria sp. M089 (Schwentner et al. 2020) Etymology. The species is named after the Indian name for the Goa region, Gomantak. Type locality. A dried temporary pool in sand dunes in Benaulim, India: Goa (15°15′36″N, 73°55′13″E; Date of collection of sediment Oct 2016). The absence of typical aquatic vegetation suggests that water is only present for a short time. Type material. Holotype. One female (without carapace) (in 4% formalin + glycerin) deposited at the Western Regional Centre of Zoological Survey of India (ZSI), Pune (Registration number: ZSI-WRC C.2074) Other material estudied. One female. Description. Male. Males were not obtained in the rehydrated sediments. Description. Female (holotype). Head. Eyes large, noticeable ocular tubercle but ocular notch not very conspicuous, ocellus elongated with a crescent shape, projecting fornix, rostrum triangular, spine present at the tip of rostrum, spine ~5 times as long as wide and arched, occipital condyle projecting but not prolonged with a pointed apex directed perpendicularly to the dorsal margin, L/W ratio of ~0.6. (Fig. 5A). First antenna. Bulbous and prolonged, more than two times the length of base of second antenna, about 6–8 lobes present on dorsal margin, each lobe lined with several sensillae. Second antenna. Bi-ramous with 14 flagellomeres, each flagellomere bearing about 3–8 long posteriorly projecting spines with acute apices on posterior surface and plumose setae on the anterior face. Carapace. Length. 6.3 mm; Width 3.3 mm (holotype carapace damaged; not measured). Roughly rectangular, straight dorsal and ventral margins, umbone prominent located on the anterior 1/3 rd of the carapace, carapace with 15 + distinct carapace lines, brown in coloration. Trunk. Trunk consisting of 24 segments, each with a pair of thoracopods and decreasing in size posteriorly, the last 6 very small. Thoracopods. As per the genus without any fingerlike exopodite projections, thoracopods 9 and 10 with long epipodites for carrying eggs. Segments 13–24, each bearing bunch of stout posteriorly directed setae with acute apices, number increasing anteriorly first and then slightly decreasing, maximum of 5–7 setae seen per segment (Figs. 5B, 7B). Telson. Broadly rectangular; dorsal margin gently arched, the lateral edge ending with a big spine, ~0.3 times the length of the cercopod; dorsal margin lined with about 30 irregularly sized spines but largest at the posterior end, largest spines ~2 times the length of smallest spines (Figs. 6B, 7B). Cercopods. Long, about ~1.1 times the length of dorsal margin of telson, highly arched and tapering posteriorly; tip exceeding the posterior lateral projection of the telson; 2/3 rd of the anterior part of the dorsal margin gradually increasing posteriorly with largest spines densely packed, the last few (4–5) as long as the breadth of the thickest region of the telson spine (Figs. 5C, 6B). Remarks. The female specimen (holotype) described here was used for obtaining sequences (few limbs), which were subsequently used to generate the phylogeny by Schwentner et al. 2020 (coded M089; Fig. 2 in Schwentner et al. 2020). Males of this species could not be obtained in the sediment rehydration. This species was still recognized as a distinct species because the unique head/cercopod morphology of the female amongst all the other Indian species. The cercopod structure of L. gomantaki resembles the Chinese species Leptestheria kunmingensis Shu, Rogers, Chen & Yang, 2015 female (Shu et al. 2015). This species was seen to co-occur with Eulimnadia bondi, Padhye, Rabet, Kulkarni & Pagni, 2018., Published as part of Padhye, Sameer M., Kulkarni, Mihir R., Pagni, Marco & Rabet, Nicolas, 2023, New leptestherid clam shrimps (Pancrustacea: Branchiopoda: Spinicaudata Leptestheriidae) from peninsular India, pp. 205-220 in Zootaxa 5264 (2) on pages 210-212, DOI: 10.11646/zootaxa.5264.2.3, http://zenodo.org/record/7836432, {"references":["Schwentner, M., Rabet, N, Richter, S., Giribet, G., Padhye, S., Cart, J., Bonillo, C., Rogers, D. C. (2020). Phylogeny and biogeography of Spinicaudata (Crustacea: Branchiopoda). Zoological Studies, 59, 44. https: // doi. org / 10.6620 / ZS. 2020.59 - 44","Shu, S., Rogers, D. C., Chen, X. & Yang, J. (2015) Two new species of clam shrimp (Branchiopoda: Spinicaudata) from Yunnan Province, China. Journal of Crustacean Biology, 35, 454 - 460. https: // doi. org / 10.1163 / 1937240 X- 00002338","Padhye, S. M., Rabet, N., Kulkarni, M. R. & Pagni, M. (2018) A new species of genus Eulimnadia Packard, 1874 (Branchiopoda: Spinicaudata: Limnadiidae) from India with an updated key for some Indian species. Zootaxa, 4399 (3), 341 - 350. https: // doi. org / 10.11646 / zootaxa. 4399.3.4"]}

Leptestheria chalukyae sp. nov. (Figs.3, 4, 6A, 7A) Leptestheria sp. M128 (Schwentner et al. 2020) Etymology. The species is named after the great medieval Indian dynasty called Chalukyas (Badami Chalukyas) who ruled large parts of Southern/Central India and whose capital was Badami where these specimens were collected from. Type locality. A rock pool dug in red sandstone near Badami fort (India: Karnataka) (15°55′17″N, 75°41′3″E; Date of collection of sediment, Oct 2016). Type material. Holotype. One male (4% formalin + glycerin) deposited at the Western Regional Centre of Zoological Survey of India (ZSI), Pune (Registration number: ZSI-WRC C.2073). Other material studied. Two females. Description. Male (holotype). Head. Broadly rectangular. Eyes large, noticeable ocular tubercle. Ocellus elongated and irregularly shaped, located at middle of rostrum. Prominent fornix. Rostrum broad and spatulate, occipital condyle rounded, barely projecting, spine present at the tip of rostrum (Fig.3B), spine nearly three times as long as wide and gently arching. First antenna. Antenna long, bulbous, more than two times the length of base of second antenna; about 10–14 lobes present on dorsal margin, each lobe lined with several sensillae. Second antenna. Bi-ramous, endopod and exopod with 14 flagellomeres (Fig.3C), length nearly twice the head length, each flagellomere bearing about 3–8 long posteriorly projecting spines with acute apices and plumose setae on opposite sides, flagellomere size decreasing posteriorly. Carapace. Length 7.6 mm; Height 3.4 mm. Oblong, dorsal and ventral margin straight, umbone prominent located on the anterior 1/3 rd of the carapace. Carapace with 10 + distinct carapace lines, light brown in coloration (Fig.3A), ventral margin lined with fine setae. Trunk. Consisting of 26 segments (Fig.3C), each with a pair of thoracopods and decreasing in size posteriorly, the last eight being the smallest. Thoracopods I & II. Modified as claspers. Both claspers large. Movable finger (endopod) broad anteriorly but narrowing and hook like distally in both claspers. Large palp (endite 5) two segmented in both claspers, both segments nearly equal in length in first clasper; distal segment about 1.3 times in length than proximal segment in the second clasper. Small palp (endite 4 outgrowth) cylindrically shaped, 2.5x as long as broad, directed posteriorly in both claspers, palm (endite 4) rectangular, as long as broad in the first clasper, marginally longer than broad in the second clasper, triangular protrusion observed medially at base of palm in both claspers, gripping area of the palm with small tubercles (smallest as long as broad) anteriorly and increasing gradually in size posteriorly (Fig. 4A). Other thoracopods having similar structure with 5 endites as the other members of the genus, decreasing in size posteriorly, the last eigth very small. Segments 16–26, each bearing bunch of stout posteriorly directed setae with acute apices dorsally (Fig. 3D), number increasing anteriorly first and then gradually decreasing, maximum of 6–7 setae are seen per segment. Telson. Broadly rectangular in shape. Dorsal margin distinctly arched, the lateral edge ending with a big spine, ~0.4 times the length of the cercopod. Dorsal margin with ~30 irregularly sized spines, longest spines twice as long as broad and 2.5 times as long as the smallest spines. Telson filaments between 1 stand 3 rd marginal spines (Fig.4B). Cercopod. Long, about 0.8 times the length of dorsal margin of telson, tapering posteriorly; margin gently curved until 2/3 rd of the length, tips dorsally and gradually upturned, tip at the same level as the postero-lateral projection of the telson; 2/3 rd of the anterior part of the dorsal margin lined with about 30 similar sized spinules, equally spaced (Fig. 4B). Female. Similar to male morphology but with some variations. Carapace size. Length 6.7 & 6.3 mm; Height 3.4 & 3.2 mm. Rostrum triangular, rostral spine long, ~4 times as long as broad at the base; occipital condyle similar to male (Figs. 3E, 7A); Telson. Dorsal edge less convex than male lined with about 20 irregularly sized spines (Fig.6A). Cercopods highly arched, spines on the dorsal margin gradually increasing posteriorly with last 6–7 spines being about 0.7–0.8 times that of the breadth of the thickest region of the telson spine (Fig. 3F). Remarks. The female described here was used (few limbs) for obtaining sequence which were subsequently used to generate the phylogeny by Schwentner et al. 2020 (coded M128; Fig 2 in Schwentner et al. 2020). This species differs from the rest of Indian species based on the occipital condyle shape/length and the very big cercopod marginal spines in males. The rounded occipital condyle of L. chalukyae sp. nov. resembles with Eoleptestheria species (E. ticinensis (Balsamo-Crivelli, 1859)). It is also relatively similar to the Indian species L. sarsi described from Telangana (a southern state in India). The cercopod spine size and arrangement in the male differs in these species with L. sarsi having 6–8 very big spines (length of the biggest spine is nearly 0.7–0.8 times the thickest region of the cercopod) near the tip of the cercopod (Fig.3D in Padhye & Rabet, 2017) which is absent in L. chalukyae sp. nov.. The female condyle is relatively elongated in L. sarsi female (Fig. 3B in Padhye & Rabet, 2017). Remarkably, both L. chalukyae and L. sarsi were reported from rock pools suggesting potential local diversification of these temporary-water specialist organisms in peninsular India. Eulimnadia chaperi (Simon, 1886) was seen coexisting with L. chalukyae sp. nov., Published as part of Padhye, Sameer M., Kulkarni, Mihir R., Pagni, Marco & Rabet, Nicolas, 2023, New leptestherid clam shrimps (Pancrustacea: Branchiopoda: Spinicaudata Leptestheriidae) from peninsular India, pp. 205-220 in Zootaxa 5264 (2) on pages 208-210, DOI: 10.11646/zootaxa.5264.2.3, http://zenodo.org/record/7836432, {"references":["Schwentner, M., Rabet, N, Richter, S., Giribet, G., Padhye, S., Cart, J., Bonillo, C., Rogers, D. C. (2020). Phylogeny and biogeography of Spinicaudata (Crustacea: Branchiopoda). Zoological Studies, 59, 44. https: // doi. org / 10.6620 / ZS. 2020.59 - 44","Padhye, S. M. & Rabet N. (2017) Re-description of two spiny clam shrimps (Crustacea: Branchiopoda: Spinicaudata) of the Indian subcontinent from Daday de Dees's collection at MNHN with new insights on the validity of Eulimnadia compressa (Baird, 1860) and Eulimnadia chaperi (Simon, 1886). Zootaxa, 4294 (3), 349 - 360. https: // doi. org / 10.11646 / zootaxa. 4294.3.5"]}

Leptestheria chalukyae sp. nov. (Figs.3, 4, 6A, 7A) Leptestheria sp. M128 (Schwentner et al. 2020) Etymology. The species is named after the great medieval Indian dynasty called Chalukyas (Badami Chalukyas) who ruled large parts of Southern/Central India and whose capital was Badami where these specimens were collected from. Type locality. A rock pool dug in red sandstone near Badami fort (India: Karnataka) (15°55′17″N, 75°41′3″E; Date of collection of sediment, Oct 2016). Type material. Holotype. One male (4% formalin + glycerin) deposited at the Western Regional Centre of Zoological Survey of India (ZSI), Pune (Registration number: ZSI-WRC C.2073). Other material studied. Two females. Description. Male (holotype). Head. Broadly rectangular. Eyes large, noticeable ocular tubercle. Ocellus elongated and irregularly shaped, located at middle of rostrum. Prominent fornix. Rostrum broad and spatulate, occipital condyle rounded, barely projecting, spine present at the tip of rostrum (Fig.3B), spine nearly three times as long as wide and gently arching. First antenna. Antenna long, bulbous, more than two times the length of base of second antenna; about 10–14 lobes present on dorsal margin, each lobe lined with several sensillae. Second antenna. Bi-ramous, endopod and exopod with 14 flagellomeres (Fig.3C), length nearly twice the head length, each flagellomere bearing about 3–8 long posteriorly projecting spines with acute apices and plumose setae on opposite sides, flagellomere size decreasing posteriorly. Carapace. Length 7.6 mm; Height 3.4 mm. Oblong, dorsal and ventral margin straight, umbone prominent located on the anterior 1/3 rd of the carapace. Carapace with 10 + distinct carapace lines, light brown in coloration (Fig.3A), ventral margin lined with fine setae. Trunk. Consisting of 26 segments (Fig.3C), each with a pair of thoracopods and decreasing in size posteriorly, the last eight being the smallest. Thoracopods I & II. Modified as claspers. Both claspers large. Movable finger (endopod) broad anteriorly but narrowing and hook like distally in both claspers. Large palp (endite 5) two segmented in both claspers, both segments nearly equal in length in first clasper; distal segment about 1.3 times in length than proximal segment in the second clasper. Small palp (endite 4 outgrowth) cylindrically shaped, 2.5x as long as broad, directed posteriorly in both claspers, palm (endite 4) rectangular, as long as broad in the first clasper, marginally longer than broad in the second clasper, triangular protrusion observed medially at base of palm in both claspers, gripping area of the palm with small tubercles (smallest as long as broad) anteriorly and increasing gradually in size posteriorly (Fig. 4A). Other thoracopods having similar structure with 5 endites as the other members of the genus, decreasing in size posteriorly, the last eigth very small. Segments 16–26, each bearing bunch of stout posteriorly directed setae with acute apices dorsally (Fig. 3D), number increasing anteriorly first and then gradually decreasing, maximum of 6–7 setae are seen per segment. Telson. Broadly rectangular in shape. Dorsal margin distinctly arched, the lateral edge ending with a big spine, ~0.4 times the length of the cercopod. Dorsal margin with ~30 irregularly sized spines, longest spines twice as long as broad and 2.5 times as long as the smallest spines. Telson filaments between 1 stand 3 rd marginal spines (Fig.4B). Cercopod. Long, about 0.8 times the length of dorsal margin of telson, tapering posteriorly; margin gently curved until 2/3 rd of the length, tips dorsally and gradually upturned, tip at the same level as the postero-lateral projection of the telson; 2/3 rd of the anterior part of the dorsal margin lined with about 30 similar sized spinules, equally spaced (Fig. 4B). Female. Similar to male morphology but with some variations. Carapace size. Length 6.7 & 6.3 mm; Height 3.4 & 3.2 mm. Rostrum triangular, rostral spine long, ~4 times as long as broad at the base; occipital condyle similar to male (Figs. 3E, 7A); Telson. Dorsal edge less convex than male lined with about 20 irregularly sized spines (Fig.6A). Cercopods highly arched, spines on the dorsal margin gradually increasing posteriorly with last 6–7 spines being about 0.7–0.8 times that of the breadth of the thickest region of the telson spine (Fig. 3F). Remarks. The female described here was used (few limbs) for obtaining sequence which were subsequently used to generate the phylogeny by Schwentner et al. 2020 (coded M128; Fig 2 in Schwentner et al. 2020). This species differs from the rest of Indian species based on the occipital condyle shape/length and the very big cercopod marginal spines in males. The rounded occipital condyle of L. chalukyae sp. nov. resembles with Eoleptestheria species (E. ticinensis (Balsamo-Crivelli, 1859)). It is also relatively similar to the Indian species L. sarsi described from Telangana (a southern state in India). The cercopod spine size and arrangement in the male differs in these species with L. sarsi having 6–8 very big spines (length of the biggest spine is nearly 0.7–0.8 times the thickest region of the cercopod) near the tip of the cercopod (Fig.3D in Padhye & Rabet, 2017) which is absent in L. chalukyae sp. nov.. The female condyle is relatively elongated in L. sarsi female (Fig. 3B in Padhye & Rabet, 2017). Remarkably, both L. chalukyae and L. sarsi were reported from rock pools suggesting potential local diversification of these temporary-water specialist organisms in peninsular India. Eulimnadia chaperi (Simon, 1886) was seen coexisting with L. chalukyae sp. nov.

Leptestheria gomantaki sp. nov. (Figs. 5, 6B, 7B) Leptestheria sp. M089 (Schwentner et al. 2020) Etymology. The species is named after the Indian name for the Goa region, Gomantak. Type locality. A dried temporary pool in sand dunes in Benaulim, India: Goa (15°15′36″N, 73°55′13″E; Date of collection of sediment Oct 2016). The absence of typical aquatic vegetation suggests that water is only present for a short time. Type material. Holotype. One female (without carapace) (in 4% formalin + glycerin) deposited at the Western Regional Centre of Zoological Survey of India (ZSI), Pune (Registration number: ZSI-WRC C.2074) Other material estudied. One female. Description. Male. Males were not obtained in the rehydrated sediments. Description. Female (holotype). Head. Eyes large, noticeable ocular tubercle but ocular notch not very conspicuous, ocellus elongated with a crescent shape, projecting fornix, rostrum triangular, spine present at the tip of rostrum, spine ~5 times as long as wide and arched, occipital condyle projecting but not prolonged with a pointed apex directed perpendicularly to the dorsal margin, L/W ratio of ~0.6. (Fig. 5A). First antenna. Bulbous and prolonged, more than two times the length of base of second antenna, about 6–8 lobes present on dorsal margin, each lobe lined with several sensillae. Second antenna. Bi-ramous with 14 flagellomeres, each flagellomere bearing about 3–8 long posteriorly projecting spines with acute apices on posterior surface and plumose setae on the anterior face. Carapace. Length. 6.3 mm; Width 3.3 mm (holotype carapace damaged; not measured). Roughly rectangular, straight dorsal and ventral margins, umbone prominent located on the anterior 1/3 rd of the carapace, carapace with 15 + distinct carapace lines, brown in coloration. Trunk. Trunk consisting of 24 segments, each with a pair of thoracopods and decreasing in size posteriorly, the last 6 very small. Thoracopods. As per the genus without any fingerlike exopodite projections, thoracopods 9 and 10 with long epipodites for carrying eggs. Segments 13–24, each bearing bunch of stout posteriorly directed setae with acute apices, number increasing anteriorly first and then slightly decreasing, maximum of 5–7 setae seen per segment (Figs. 5B, 7B). Telson. Broadly rectangular; dorsal margin gently arched, the lateral edge ending with a big spine, ~0.3 times the length of the cercopod; dorsal margin lined with about 30 irregularly sized spines but largest at the posterior end, largest spines ~2 times the length of smallest spines (Figs. 6B, 7B). Cercopods. Long, about ~1.1 times the length of dorsal margin of telson, highly arched and tapering posteriorly; tip exceeding the posterior lateral projection of the telson; 2/3 rd of the anterior part of the dorsal margin gradually increasing posteriorly with largest spines densely packed, the last few (4–5) as long as the breadth of the thickest region of the telson spine (Figs. 5C, 6B). Remarks. The female specimen (holotype) described here was used for obtaining sequences (few limbs), which were subsequently used to generate the phylogeny by Schwentner et al. 2020 (coded M089; Fig. 2 in Schwentner et al. 2020). Males of this species could not be obtained in the sediment rehydration. This species was still recognized as a distinct species because the unique head/cercopod morphology of the female amongst all the other Indian species. The cercopod structure of L. gomantaki resembles the Chinese species Leptestheria kunmingensis Shu, Rogers, Chen & Yang, 2015 female (Shu et al. 2015). This species was seen to co-occur with Eulimnadia bondi, Padhye, Rabet, Kulkarni & Pagni, 2018.

Leptestheria nobilis (Sars, 1900) (Figs. 8, 9) Leptestheriella nobilis (Padhye et al. 2011) Material studied. Four females and three males from University of Pune Pond (UoP pond) (18˚33′17.62″ N & 73˚49′26.80″ E), Pune collected in June 2010 (collected by SMP). Redescription. Male. Head. Broadly rectangular; eyes moderately sized, ocular tubercle conspicuous, shape of ocellus varying but mostly triangular; rostrum dilated and spatulate; occipital condyle prolonged and projecting posteriorly; L/W ratio ~0.9–1.0 with a pointed apex; sharp stout spine present at the tip of rostrum, thrice as long as wide and arched (Fig.9A) First antenna. Long & bulbous, twice the length of the base of second antenna; about 5–8 lobes, each lobe lined with several sensillae. Second antenna. Bi-ramous with varying number of antennomeres, each antennomere bearing spiniform projections (5–8) anteriorly; spines long, slender with an acute tip; plumose setae on opposite sides (Fig. 8B) Carapace. Length. 6.7 ± 0.7 mm; Height. 3.6 ± 0.40 mm. Oblong, broadly rectangular, dorsal and anterior margin straight, umbone prominence varying between populations (prominent in ‘tableland’ specimens but not in UoP pond), number of growth lines highly varying, 10–20 easily visible, dark brown or pinkish in coloration when alive. Trunk. Consists of 23–25 segments, each with a pair of thoracopods and decreasing in size posteriorly. First two thoracopods modified into claspers (Fig. 8A). Thoracopods I & II. Broad, anterior portion of movable finger (endopod) wide but tapering and strongly arching distally (hooklike), apex of which is lined with numerous scales in both the claspers; large palp (endite 5) two segmented, nearly equal in length in the first clasper, distal segment 1.2 times in length than proximal segment in the second clasper; small palp (endite 4 outgrowth) cylindrical, ~2.5 times as long as the width of its base; palm (endite 4) roughly rectangular and projecting obtusely, a medial triangular protrusion observed at base of palm in both claspers gripping area of palm lined with spines which increase in size posteriorly. Other thoracopods having similar structure with 5 endites, an endopodite with digitiform lobes on the exopodites, decreasing in size posteriorly, the last 5–8 very small (Fig. 8C). Each of the 8–23 segments has a group of short, posteriorly directed setae with acute apices, the number first increases, and then gradually decreases, a maximum of 7–8 setae per segment is observed. Telson. Broadly rectangular in outline, dorsal margin arched; the postero-lateral edge ending with a big spine, nearly half the length of the cercopod, curved, without any serration; dorsal margin lined with 30–40 spines, unequal in size and bearing serrations; telson terminal setae originating before the telson spines (Fig. 9C) Cercopods. Long and stout, about 0.8–0.9 the length of telson, straight, gradually narrowing to an acute slightly upturned apex; tip reaching the postero-lateral projection of the telson; eighty percent of the dorsal margin lined with small similar sized serrated spinules about 30–45 in number (Fig. 9C). Redescription. Female. Similar to male morphology but with some variations. Rostrum triangular in shape, L/ W ratio of ~ 1.0 (Fig. 9B). Ninth and 10th thoracopods modified with extended epipodites for carrying eggs. Telson dorsal margin more gently arched than male and lined with 30–40 spines on the dorsal margin (Fig.9B), cercopod morphology as in male (Fig. 8D) Carapace. Length 6.2 mm ± 0.4 mm; height 4 mm ± 0.3 mm. Egg. Spherical and with no ornamentation (Figs.4C & D in Padhye et al, 2016) Remarks. The morphology of Leptestheria nobilis is highly variable (Simhachalam & Timms, 2012), although some of the characters observed in these populations, such as the shape of the occipital condyle and the structure of the cercopod, coincide with previous and original descriptions (Daday, 1923; Sars, 1900). Leptestheria dumonti Subash Babu & Bijoy Nandan, 2010 and Leptestheria simhadrii (Simhachalam & Timms, 2012) are very similar to L. nobilis in terms of their morphology and thus their species validity needs to be checked using integrative approaches. The studied population could also represent a distinct cryptic species, though, this cannot be confirmed unless topotypic information is obtained. This species was found in assemblages (see Padhye & Dahanukar, 2015 for all combinations of assemblages) or occurred alone., Published as part of Padhye, Sameer M., Kulkarni, Mihir R., Pagni, Marco & Rabet, Nicolas, 2023, New leptestherid clam shrimps (Pancrustacea: Branchiopoda: Spinicaudata Leptestheriidae) from peninsular India, pp. 205-220 in Zootaxa 5264 (2) on pages 213-216, DOI: 10.11646/zootaxa.5264.2.3, http://zenodo.org/record/7836432, {"references":["Sars, G. O. (1900) On some Indian Phyllopoda. Archiv for Mathematik og Naturvidenskab, 22, 3 - 30.","Padhye, S. M., Ghate, H. V. & Pai, K. (2011) New locality records and additional information on habitats of three species of clam shrimps (Crustacea: Branchiopoda) from a region in northern part of Western Ghats (Sahyadris), India. Journal of Threatened Taxa, 3, 1756 - 1763. https: // doi. org / 10.11609 / JoTT. o 2486.1756 - 63","Simhachalam, G. & Timms, B. V. (2012) Two new species of Spinicaudata (Crustacea: Branchiopoda) in south India with a key to Leptestheriella and Eocyzicus. Zootaxa, 3161 (1), 20 - 36. https: // doi. org / 10.11646 / zootaxa. 3161.1.2","Daday de Dees, E. (1923) Monographie systematique des Phyllopodes conchostraces. II. Leptestheriidae. Annales de Sciences Naturelles. Zoologie, 6, 255 - 390.","Padhye, S. M. & Dahanukar, N. (2015) Distribution and assemblages of large branchiopods (Crustacea: Branchiopoda) of Northern Western Ghats, India. Journal of Limnology, 74, 371 - 380. https: // doi. org / 10.4081 / jlimnol. 2015.1115"]}

Bythotrephes longimanus austriacus ssp. nov. ( Figs. 3, 4) B. longimanus Leydig: Steuer, 1897: p. 520 (Lake Millstättersee). B. longimanus v. carnica Ischreyt, 1939: 125–126, 128, Abb. 6. B. longimanus longimanus Leydig, 1860: Flössner, 1972: 405–406, Abb. 190A; 2000: 375 B. longimanus Leydig, 1960: Korovchinsky, 2015: 20, Figs. 8E, 8F, 8I, 8K, 8P, 8Q, 8R, 8X. Etymology. The name of the species denotes the occurrence of the taxon in Austrian subalpine lakes. Type locality. Lake Erlaufsee, Styria, Austria (47°48′51′′N; 15°17′43′′E), 827 m a.s.l. Holotype. A female with body length 2.08 mm deposited in Zoological Museum of Moscow State University (№ MGU Ml 264). Paratypes. Three females from the same sample deposited in the same museum (№ MGU Ml 265). Material examined. Austria: 1) Lake Erlaufsee (Styria), 18.9.2018, 20 ad, 5 juv, coll. R. Ptáčniková; 2) Lake Irrsee (Upper Austria), 27.8.2012, 7 ad, coll. R. Ptáčniková; 3) Lake Wolfgangsee (Upper Austria), 28.8.2012, 9 ad, coll. R. Ptáčniková; 4) Lake Grundlsee (Styria), 18.7.2007, 20 ad, leg. M. Luger; 5) Lake Millstättersee (Carinthia), 8.11.2011, 2 ad, 1 male, 1 juv. leg. G. Santner; 6) Lake Mondsee (Upper Austria), 7.1993, 5 ad, leg. H. Löffler and S. Gaviria-Melo. (specimens from the localities 4-6 were investigated earlier (see Korovchinsky 2015) but here after adding new individuals their diagnostic features were revised anew). Data on body and body parts measurements of specimens from Erlaufsee and Grundlsee are presented in Table 1 (see also Korovchinsky 2015: Table 2). Description. Female. The general body structure and its parts as in other representatives of the genus. Thoracic limbs: four pairs (Figs. 2, 3) First pair of limbs (tl I) are especially long and strong (Fig. 3A) (78.9–129.6 % of body length). The first segment of the endopodite is long and bears 4–8 (mostly 5–8) anterior lateral setae with rows of spines and fine setules. Distally, this segment bears shorter anterior seta of the same type and long posterior finely setulated seta (Figs. 3B–E). The second segment of the endopodite is conspicuously shorter and bears only two apical either short or rudimentary setae (Fig. 3F–R). The terminal third segment of the endopodite slightly varies in length, being either shorter or slightly longer than the proximal first endopodital segment (71.4–108.0 % of body length) and always bearing apically four long roughly spinulated setae, two of them terminally and two subterminally. Second pair of limbs (tl II) are considerably shorter, their protopodite, again externally, is conspicuously longer and bears a conical outgrowth. The first basal segment of their endopodite bears a row of 4–8 (mostly 5–8) rather long anterior lateral setae (their number can vary in one individual). There are 1–3 posterior lateral setae on this segment. Internally, this segment bears a stout cylindrical pseudognathobasic process, possessing some prominences of different size and one small, thin seta. The second segment of the endopodite is short with only two setae, the anterior one of which is similar to the anterior terminal seta of previous segment, whereas the posterior seta is longer and finely setulated. The distal, third segment of endopodite of the limb bears four setae, two terminal and two subterminal ones. Third pair of limbs (tl III) are generally similar to those of the previous ones, differing in some details. The external outgrowth of their protopodite is conspicuously larger and lateral anterior and posterior setae (if present) of first segment of endopodite are fewer (4–6 and 1–2, respectively). The pseudognathobasic process is also similar to that of tl II. Terminal and subterminal setae of the third segment are similar to those of tl II but slightly shorter and bear fewer denticles. Fourth pair of limbs (tl IV) are considerably reduced; their protopodite bears slightly spinulated seta sited on a short cylindrical base. The only segment of the endopodite has two rows of comparatively short spine-like setae. The external row (group) (Fig. 2C: as) always consists of two setae, and the internal row of 5–8 (mostly 6–7) setae, which differ in their appearance and armament. The “ postabdomen” actually consists of two parts: the last small abdominal segment and the postabdomen per se (see Korovchinsky (2015) for more details), which is comparatively small, with the anal opening situated between the postabdominal claws. These claws are comparatively small (2.9–7.8 % of body length) and clearly directed backwards (Fig. 4A–H). Caudal process is directly connected with the postabdomen and proceeds as a very long, proximally rather thick and curved, then straight spine-like structure, variable in its length (159.0–274.0 % of body length), thus exceeding the body length by about 1.6–2.7 times. Basally, the caudal process bears one pair of claws similar to those of the postabdomen but usually larger (3.8–9.5% of body length). Pairs of claws sit moderately distantly, interclaw distance usually constitutes 8.1–22.9%. Between the claws, the thickness of the structure constitutes 4.1–9.6 %. Borders separating old molted integuments of caudal process with claws either are conspicuous or invisible. Size. 1.41–2.42 mm. Gamogenetic females have not been detected. Males. The only male we found did not differ, as usual, from males of the nominotypical subspecies. Intrapopulation variability. According to Table 1, the length of claws of postabdomen and caudal process is especially variable (CV = 12.7–21.2 and 14.4–18.7, respectively), the interclaw distance and interclaw thickness follow them in this respect (CV = 13.1–14.4 and 11.5–16.5, respectively). Of other structures, the comparative length of thoracic limbs of the first pair and that of caudal process are also rather variable (CV = 6.9–7.2 and 9.9–12.9, respectively). Also, the apical setae armament of a second endopodital segment of tl I (Fig. 3) and shape of claws of postabdomen and caudal process (Fig. 4) are variable as well. Differential diagnosis. The representatives of Bythotrephes longimanus austriacus ssp. nov. have generally a relatively smaller body size (up to 2.42 mm vs. 3.1 mm in B. longimanus longimanus) but they mostly differ from those of the B. l. longimanus by relatively smaller claws of postabdomen and caudal process (Table 2) (p Remarks. The present study confirmed the past preliminary observation that “Small size of claws of postabdomen and caudal process was the most pronounced common feature of all Austrian specimens” of B. longimanus (Korovchinsky 2015: p. 20). B. longimanus v. carnica was described by Ischreyt (1939) from Lake Millstättersee (Carinthia) with indication of doubtful diagnostic features, why a taxon can be considered incertae sedis (ICZN 67.2.5). Morphological traits of specimens from this lake certainly do not differ from those of B. l. austriacus occurring in some other adjacent lakes. Geographical distribution. T he representatives of the new subspecies are known to occur in some deep subalpine lakes in the central part of Austria., Published as part of Korovchinsky, Nikolai M., 2023, Unexpected high species richness of Bythotrephes Leydig, 1860 (Branchiopoda: Cladocera: Cercopagididae) in subalpine Austrian lakes, with the description of new taxa, pp. 77-93 in Zootaxa 5264 (1) on pages 84-87, DOI: 10.11646/zootaxa.5264.1.5, http://zenodo.org/record/7836203, {"references":["Steuer, A. (1897) Ein Beitrag zur Kenntnis der Cladoceren- und Copepodenfauna Karntens. Verhandlungen der Zoologisch- Botanischen Gessellschaft in Wien, 47, 495 - 541.","Ischreyt, G. (1939) Uber den Bythotrephes subalpiner Seen. Archiv fur Hydrobiologie, 34, 105 - 129.","Leydig, F. (1860) Naturgeschichte der Daphniden. Laupp & Siebeck, Tubingen, 252 pp.","Flossner, D. (1972) Kiemen- und Blattfusser, Branchiopoda, Fishlause, Branchiura. Tierwelt Deutschlands 60. G. Fischer Verlag, Jena, 501 pp.","Korovchinsky, N. M. (2015) Redescription of Bythotrephes longimanus Leydig, 1860 and B. cederstromii Schodler, 1877 (Crustacea: Cladocera: Onychopoda), with notes on the morphology and systematics of the genus Bythotrephes Leydig, 1860. Zootaxa, 3955 (1), 1 - 44. https: // doi. org / 10.11646 / zootaxa. 3955.1.1"]}

Bythotrephes longimanus Leydig, 1860 (Figs. 2���9) Bythotrephes longimanus: Leydig 1860, pp. 244���246, Taf. 10, Fig. 73���75; Weismann 1876, pp. 12���14, Fig. 1; Ischreyt 1934 a, pp. 261, 277, Abb. 16 c.; 1935, p. 199; 1936, p. 361; 1937, p. 55; 1939, p. 110, 118, 119, 128, Abb. 1, 3, 4, 5; Margaritora 1985, pp. 338���341, Fig. 134, 135; Litvinchuk 2002, p. 128, Fig. 38; 2007, p. 192. B. longimanus longimanus: Fl��ssner 1972, pp. 405���406, Abb. 190 a; 2000, p. 375, Abb. 136 d. B. longimanus brigantinus Ischreyt, 1930, pp. 266, 302, 320 ��� 321, Fig. 6 b, 9 c, 12, 13a���c, 14���16. Bythotrephes lariano (B. longimanus lariano) Agnesotti, 1935, pp. 157���172, Fig. 1, 2. B. longimanus v. carnica Ischreyt, 1939, p. 110, 119, 125 ��� 126, 128, Abb. 6. B. Cederstr��mii Sch��dler: Beck 1883, pp. 780���782, pl. 12, figs 1���8. Non Bythotrephes longimanus Leydig: Lilljeborg 1861, p. 268, Taf. 8, Fig. 23���29; Sars 1861 [1993], p. 156, Plates 106���109; Sars 1890, p. 51; Lilljeborg 1901, pp. 604���617, Tab. 80, fig. 10���19; Tab. 81, fig. 1���2; Tab. 82, fig. 1���10; Ekman, 1904, pp. 28���29; Rylov 1935 a, pp. 152���155, figs 230���233; Behning 1941, pp. 352���356, Fig. 146; Manuilova 1964, pp. 291���293, Fig. 160; Fl��ssner 1972, pp. 403���408, Abb. 189, 190 b (partim); 2000, pp. 371���376, Abb. 136, a���c, e���g; Mordukhai- Boltovskoi & Rivier 1987, pp. 149���152, Fig. 44, 93; Vekhov 1987, pp. 28���29, Fig. 1, 2; R��en 1995, pp. 322���324, Fig. 146; Rivier 1998, pp. 169���173, Fig. 215, 216. Material examined. Germany: Boden See (type locality), leg. H.-B. Stich, having three main areas: 1) Zeller See, 0 4.05.2009, 4 ad.; 2) Fischbach-Uttwil, 0 7.09. 2009, numerous ad. and juv.; 3) Bregenzer Bucht, 0 7.09.2009, 10 ad., 1 juv.; 4) ��� Bythotrephes longimanus Leydig, Bodensee, 1892, Lampert G.���, 2 females of first generation, 5 ad., 1 juv., 1 male, (MNB, № 9596). Switzerland: 1) Lake Geneva (Lac Leman, Genfer See): a) ��� Bythotrephes longimanus, Lac Leman, Forel, 1879 ���, 11 ad., 2 juv. (deformed), ZIN (№ 1638), b) 2 ad., 3 juv., ��� B. longimanus s.str., Swit., Lac Leman, 0 7.1887, coll. P.T. Cleve���, MEUU (№ 2671), c) ��� B. longimanus, Genfer See, 24.10. 1899, H. Blanc S.���, 23 ad., MNB (N �� 18910), d) ��� B. longimanus, Genfer See, 28.7. 1900, Blanc G.���, numerous ad., MNB (N �� 18910), e) ��� B. longimanus, Genfer See, 9.10. 1900, Blanc S.G.���, 12 ad., 1 juv., MNB (N �� 18910); 2) Vierwaldst��ttersee, ��� B. longimanus, 7.11 ���, 8 ad., 3 juv. (deformed), coll. Verestchagin, ZIN (N �� 6855); 3) Lake Neuch��tel: a) ���Neuchateler See, Februar, Fuhrmann���, 22 ad., 4 juv., MNB (N �� 18910), b) ���Neuchateler See, July, Fuhrmann���, 5 ad., MNB (N �� 18910), c) ��� Bythotrephes longimanus Leydig, Schweiz, Neuchateler See, October, Blanc I Fuhrmann G.���, 13 ad., MNB (N �� 18910). Italy: 1) Lago di Como (Lago Lario, Comer See), ��� Bythotrephes longimanus Leydig, 1860, Comer See, bis 72 m tief, leg. Besana, 23.9. 1900, ded.Weltner���, some dried ad., MNB (N �� 18909); 2) Lago di Garda (Gardasee), ��� Bythotrephes longimanus Leydig, 1860, Gardasee, 0���70 m, leg. Bullemer, 8.1910, ded. Weltner, 1.1918 ���, numerous ad., MNB (N �� 18845). Austria: 1) Mondsee, 0 7.1993, 5 ad.., leg. H. L��ffler and S. Gaviria-Melo; 2) Millst��ttersee, 0 8.11.2011, 2 ad., 3 juv., 1 male, leg. G. Santner; 3) Grundlsee, 18.07.2007, 20 ad., 31.08.2007, 15 ad., leg. M. Luger and R. Schabetsberger. Great Britain: 1) bottle (MNB (N �� 18929)) with a label: ��� Bythotrephes longimanus Leydig, England, Scourfield G.��� and four tubes: a) ���Windermere, English Lake District, Scourfield G.���, 4 ad., b) ���Grasmere, English Lake District, Scourfield G.���, 1 ad., c) ���Llyn Quellyn, North Wales, Scourfield G.���, 1 ad., 1 male, d) ���Llyn Padarn, North Wales, Scourfield G.���, 1 ad., 1 male; 2) bottle (MNB (N �� 18913) with a label: ��� Bythotrephes longimanus Leydig, 1860, Schottland, ded. Thomas Scott and Scourfield / Weltner��� and two tubes: a) ���Loch Ness, Scotland, Scourfield G.���, 3 ad., b) ���Loch Lochy in Inversness, Scotland ���, 14 gam., 3 males. Data on body and body parts measurements of two populations are presented in Table 1. The main part of the description is based on a population from Bodensee. Data from other populations have been taken into consideration for comparison. Description. Female. General body appearance and segmentation. Body elongated and divided into four parts: head, thorax, abdomen, and postabdomen with long caudal process (Fig. 2 A). Its longitudinal axis is conspicuously incurved when head is located at almost right angle to the thorax. Also highly movable abdomen can be either at straight line with the thorax or stays at different angles to it. Head large with rounded anterior part filled by the enormously developed compound eye and bearing small antennules ventrally. Posterior part of head bears long swimming antennae and mouth parts consisting of mandibles, maxillules (mx I), and upper lip (labrum). Thorax with strongly developed muscular ventral side bearing four pairs of thoracic limbs of different size directed antero-ventrally. Dorsally, thorax bears sack-like carapace transformed into brood pouch sometimes reaching large size. Abdomen (metasome) is elongated, cylindrical, inconspicuously three-segmented and flexible, connected with small postabdomen, bearing ventrally a pair of straight claws and posteriorly very long straight caudal process with a pair of similar claws proximally. General body length of females (without caudal process) may reach 3.0 mm or slightly more (in the examined specimens it ranges from 1.62 to 2.66 mm) while the length of caudal process may surpass the body length considerably. Head. Comparatively very large (36.8���44.6 % of body length) and subdivided into two parts: rounded anterior part mostly filled by large compound eye (18.4���22.8 % of body length) and posterior part bearing dorsally a large saddle-shaped neck organ, swimming antennae and mouth parts. Eye contains numerous ommatidia (~ 300 or> 200 ommatidia according to Miltz (1899) and Martin & Cash-Clark (1995), respectively) and have large pigment spot which occupies about one-third or at most a half of the eye���s volume (see also Ekman 1904). Ocellus (naupliar eye) is absent (Elofsson 1966). Antennules. Small and situated on the ventral side of the anterior head part beneath the eye. They are bulbous (Fig. 2 C) and sit on the joined basis slightly split anteriorly. Terminally they bear five regular aesthetascs in two groups, in three and two in each one, and one shorter and thinner aesthetasc-like structure, situated in a group with two regular aesthetascs, and having slightly widened apical end with dark granular structure inside (���accessory simple seta��� according to Scourfield (1896)). Swimming antennae. Comparatively long (56.6���77.3 % of body length), with elongated cylindrical basipodite (43.7 % of body length) (Fig. 2 A) which has dorsal thin naked seta on its folded proximal part (Fig. 2 D) and tiny distal sharp outer denticle located closer to base of lower branch (Fig. 2 E, arrowed) (this denticle is not always well visible, possibly sometimes it may be absent). Of two antennal branches, the lower three-segmented one (endopodite), sitting on the apical basipodital prominence, is slightly longer than upper branch (33.3 % vs. 29.8 % of body length). The upper branch is four-segmented (length of segments from proximal to distal: 8.7 % (first rudimentary one + second segment), 9.1 %, and 12.3 % of body length, respectively) and lower branch is threesegmented (10.3 %, 7.9 % and 15.1 % of body length, respectively). Proximal most segment of the upper branch is rudimentary and clearly visible only externally, all other segments of both branches are much more developed. Internally, two proximal segments seem fused rather firmly while distally their junction probably is more flexible. Integument of antennal basipodite and branches are covered by tiny spinules, which are situated in rows (Fig 3 A). Small denticle with a saw-like row of surrounded minute prominences on the end of second segment of upper antennal branch (Fig. 3 A), similar prominences on the end of third segment of the same branch (Fig. 2 F), and small apical denticle on the distal segment of the same branch (Fig. 2 G). The distal segment of the lower branch is also armed by a small apical spine (Fig. 2 H). Small proximal-most segment of upper branch lacks setae, while other segments possess a row of two-segmented swimming setae of more or less similar size except distal of them which are shorter (the comparative lengths of setae of three segments of upper branch from proximal to distal ones are as follows: (32.1), (32.9, 35.3), (32.5, 32.5, 28.6, 23.4, 17.5) % of body length; the same for the four segments of lower branch: (31.3), (35.3), (34.5, 33.7, 32.1, 31.0, 22.6) % of body length. The length of basal setae segments are about 50���63 % of their total length. All setae are bilaterally armed with rows of uniform thin setules. General formula of antennal setae: 0���1 ��� 2���5 / 1 ��� 1���5. Mouth parts. They are represented by upper lip (labrum), mandibles, and maxillules (maxilla I). The upper lip (Fig. 3 E) is composed of two parts; the posterior thick and flattened slightly triangular lobe and anterior large proboscis-like outgrowth. The latter is separated from the former one by a deep indention of the cuticle. The triangular lobe bears numerous papillae (Fig. 3 F) along its posterior-internal (oral) margin while the outgrowth is armed with tiny spinules. Mandibles are bilobed and adapted for biting (Fig. 3 B), with a toothed, blade-like posterior lobe and small anterior lobe (mandibular process) armoured with a cluster of 12���15 long prominences, bearing some tiny spinules distally (Fig. 3 C). Posterior lobe is strongly sclerotized and divided in two tooth-shaped parts, the larger (posterior) of which has a small additional tooth about midway along its border (Fig. 3 B). The inner surface of the mandible bears a small field of about 10 tiny spines (Fig. 3 D). Maxillules (mx I) look like two cylindrical structures situated posterior to mandibles (Fig. 2 I). Distally, they bear short central seta and some papillae near it. Maxillae (mx II) are absent; the openings of maxillar glands are situated near the bases of tl I laterally (see Olesen et al. 2003). Carapace. It looks like a bag-like structure, strongly modified into closed brood pouch (Fig. 2 A). It is attached to the dorsal side of thorax and reaching sometimes rather big size, surpassing body length. The females of first generation possess the biggest brood pouch, containing up to 22 embryos which distend its walls greatly (Zozulja 1977). The postero-ventral region of the brood pouch near its junction with dorsal side of thorax always appears to be indented. Thoracic limbs. Four pairs of strongly chitinized, stenopodous limbs are densely situated along the muscular ventral side of thorax and directed antero-ventrally (Fig. 2 A). All of them have complex and variously setaceous armament along their inner side. Limbs of three anterior pairs are five-segmented and those of the last fourth pair are three-segmented. Protopodites of all of them, covered by comparatively softer cuticle, are inconspicuously delimited into two parts (segments), coxa and basis, (Fig. 4 B, 4 C) while the endopodites of limbs of three anterior pairs are composed of three well developed segments and those ones of the fourth pair are unisegmented (Figs. 2 J, 4 D, 4 G, 6 A, 6 B). Limbs of first pair (tl I) are especially long and strong, their length often surpasses body length (83.1���112.8 % of body length) (Fig. 2 A, 2 J). Terminally, the inner side of their protopodite bears a small triangular lobe, ���gnathobasic��� process (the nature and homology of this structure will be discussed below), armed laterally and distally with two denticles and numerous spinules (Figs. 2 K, 4 B). The external part of protopodite is longer than internal one and bears apically a small conical outgrowth, having at its tip a tiny spine (Fig. 4 B, arrowed, 4 C). The first segment of endopodite is long (30.7���35.4 % of tl I length) and bears 4���7 (mostly 5���6) anterior lateral setae (their number on limbs of one individual can vary) (Fig. 2 K) of type ���j��� with rough spine-like setules (Fig. 4 J, 5 A). Distally, this segment bears short thorn-like anterior seta of type ���j��� and long posterior finely setulated seta of type ���k��� (Figs. 2 M, 2 N, 4 K). The second segment of endopodite is conspicuously shorter and bears only two apical setae: very short anterior seta of type ���j��� (sometimes it may be reduced up to small prominence, see Fig. 2 P) and longer posterior one (Figs. 2 O��� 2 R); both of them often seem naked. The terminal third segment of endopodite is also long (27.2���35.3 % of tl I length), almost equal or even surpassing the length of first segment (79.1���114.3 % of the latter), and bears apically four long roughly spinulated setae, two of them terminally and two subterminally (Fig. 2 J, 2 L); the anterior subterminal of them is shorter than others. Basally, these setae are armed by a row of smaller spines (Fig. 4 F, 5 F), while distally���by larger lanceolate spines directed terminally (Fig. 5 B). The limbs of second pair (tl II) are considerably shorter, their protopodite, again externally, is conspicuously longer and bears a conical outgrowth (Fig. 4 A, 4 C). The first, basal segment of their endopodite, bears a row of 4��� 7 (mostly 5���6) rather long anterior lateral setae of type ���l��� (their number also can vary in one individual) (Table 2) (Fig. 4 D, 4 E, 4 L). Sometimes there is one posterior lateral seta of the same type on this segment (Table 2). The terminal setae of the segment are of the same type ���l��� but may be longer, especially posterior one. Internally, this segment bears stout cylindrical ���gnathobasic��� process, possessing some prominences of different size, one small, thin seta, and a pore apically (Figs. 4 D, 5 D). The second segment is short with only two setae, the anterior of which is of ���j���- type, but comparatively thicker with more rough setules than it was in respective setae of tl I (Fig. 4 D, 4 J). The distal, third segment of endopodite of the limb bears four setae, two terminal and two subterminal ones (Fig. 4 D). Of the latter, the anterior seta is of type ���m���; it is comparatively short, thick and armed with a number of thin lateral denticles, while its distal part is naked and slightly hooked apically (Fig. 4 D, 4 M). Its neighboring posterior subterminal seta is considerably longer and similar with subterminal and terminal setae of tl I, having sharp straight apex (Fig. 4 D). The anterior terminal seta is of type ���n���; thick and comparatively short with longitudinal ribs, few thin lateral denticles, and slightly hooked apically as well (Figs. 4 D, 4 N). The posterior terminal seta similar to the respective subterminal one but shorter, has fewer denticles and slightly hooked apical end (Fig. 4 D). The limbs of the third pair (tl III) are generally similar to those of the previous ones, differing in some details. The external outgrowth of their protopodite is conspicuously larger (Fig. 4 C) and lateral anterior setae of first segment of endopodite are fewer (3���4) while posterior ones were not observed at all (Table 2) (Fig. 4 G, 4 H). These setae bear fewer proximal spinules. The ���gnathobasic��� process is similar to that one of tl II (Fig. 5 E). Of setae of second segment, the anterior one is thinner, longer, and more finely setulated than the respective seta of tl II. Terminal and subterminal setae of third segment are similar to those of tl II but shorter and bear fewer denticles (Figs. 4 G, 4 I, 5 C). The limbs of the fourth pair (tl IV) are considerably reduced; their protopodite bears externally and posteriorly distally spinulated seta sited on a short cylindrical base (Figs. 5 G, 6 A, 6 B, 6 E). The only segment of endopodite has two rows of comparatively short spine-like setae. The external row always consists of two setae, and the internal row of 5���7 (usually 5���6) setae, which differ in their appearance. Most of them (both external setae and four internal setae, located closer to protopodital seta, are stronger and armed with few proximal spinules (Figs. 6 A, 6 B, 6 D), while two anteriormost setae are slightly thinner and more feathered (Fig. 6 C). Almost the whole internal part of the endopodital segment is occupied by the reduced ���gnathobasic��� process armed by some denticles and thin seta (Figs. 5 G, 5 H, 6 B). The apex of the process probably has a pore covered by membrane (Fig. 5 H). The bulbous structure is situated just after the tl IV (Fig. 2 A). Abdomen (metasome) (Fig. 2 A, 2 S) is often deformed, compressed and for this reason it may be hardly measured (approximately its length is about 15���20 % of body length). It is inconspicuously delimited in two parts (segments?), short proximal and longer distal with prominent fold in the middle dorsal side. Due to softness of the abdomen���s integument, some additional smaller folds disguise its ���segmentation���. Postabdomen is comparatively small (6.3���9.1 % of body length), the anal opening is situated between postabdominal claws. The latter are large and more or less straight, directed downwards or slightly curved posteriorly (6.6���10.9 % of body length) (Figs. 2 A, 2 S, 6 F, 6 G). Sometimes the line divided postabdomen in two longitudinal parts, proximal and distal ones, may be observed, to the latter of whose the claws are attached (Figs. 2 S, 6 G, arrowed). Caudal process is directly connected with postabdomen either invisibly (Fig. 6 F) or being separated from it by a conspicuous border (Fig. 6 G) and then proceeds as a very long and straight spine-like structure variable in its length (186.0���301.0 % of body length), thus surpassing the body length in 1.8 ���3.0 times (Fig. 2 A, 2 B). Basally it bears a pair of claws similar to those of postabdomen (6.0��� 13.2 % of body length) (Fig. 6 F, 6 G), and apically two minute setae arose from common base (Fig. 2 T). Two pairs of claws sit closely (distance between them 7.5���14.9 % of body length). Between them, the thickness of the structure is considerable, reaching 40.0���123.0 % of the interclaw distance (Table 1). The caudal process is strongly chitinized and its surface is covered by numerous minute spinules (Fig. 5 I). Female of first generation hatched from resting eggs. Three such specimens were found, one (deformed) in the sample from Bodensee taken in the beginning of May 2009 and other two in old sample from the same lake stored in MNB (N�� 9596). One of the latter had body, Published as part of Korovchinsky, Nikolai M., 2015, Redescription of Bythotrephes longimanus Leydig, 1860 and B. cederstr��mii Sch��dler, 1877 (Crustacea: Cladocera: Onychopoda), with notes on the morphology and systematics of the genus Bythotrephes Leydig, 1860, pp. 1-44 in Zootaxa 3955 (1) on pages 6-21, DOI: 10.11646/zootaxa.3955.1.1, http://zenodo.org/record/288438, {"references":["Leydig, F. (1860) Naturgeschichte der Daphniden. Laupp & Siebeck, Tubingen, 252 pp.","Weismann, A. (1876) Das Thierleben im Bodensee. Schriften des Vereinsfur Geschichte des Bodensee und seiner Umgebung, 7, 132 - 161.","Ischreyt, G. (1934 a) Beitrag zur vergleichenden Morphologie und Systematik der Polyphemiden. Zeitschrift fur","Margaritora, F. (1985) Cladocera. Fauna d'Italia, 23, 399 pp. [Bologna, in Italian]","Litvinchuk, L. F. (2002) Systematics and distribution of water fleas of the family Cercopagidae (Crustacea, Cladocera) in the north-west of Russia. PhD Thesis, Zoological Institute, St. - Petersburg, 258 pp. [in Russian]","Flossner, D. (1972) Kiemen- und Blattfusser, Branchiopoda, Fishlause, Branchiura. Tierwelt Deutschlands 60. G. Fischer Verlag, Jena, 501 pp.","Ischreyt, G. (1930) Uber Korperbau und Lebenweise des Bythotrephes longimanus Leydig. Archiv fur Hydrobiologie, 21, 241 - 323.","Agnesotti, A. (1935) I Bitotrefi del Lario. Atti della Societa Italiana di Scienze naturali e del Museo Civico di Storia Naturale in Milano, 74, 157 - 172. [in Italian]","Ischreyt, G. (1939) Uber den Bythotrephes subalpiner Seen. Archiv fur Hydrobiologie, 34, 105 - 129.","Beck, C. (1883) On some new Cladocera of the English lakes. Journal of the Royal Microscopic Society, Series 2, 3, 777 - 784.","Lilljeborg, W. (1861) Beskrifning ofver tvenne markliga Crustaceer afordningen Cladocera. Ofversigtaf Konglisch Vetenskaps- Akademiens Forhandlingar 1860, 17 (5), 265 - 271. [in Swedish]","Sars, G. O. (1861 [1993]) On the freshwater Crustacea occurring in the vicinity of Christiania. University Publ., Bergen, 197 pp.","Sars, G. O. (1890) Oversigt af Norges Crustaceer, med forelobige bemerkninger over de nye eller mindre bekjendte Arter. II. (Branchiopoda - Ostracoda - Cirripedia). Forhandlingar Vidensk Selskabet Kristiania, Aar 1890 (1), 1 - 80. [in Norvegian]","Lilljeborg, W. (1901) Cladocera Sueciae oder Beitrage sur Kenntnis der in Schwedenlebenden Krebstiere von der Ordnung der Branchiopoden und der Unterordnung der Cladoceren. Nova acta regiae societatis scientatis scientiarum upsaleinsis, Series 3, 19, 1 - 701.","Ekman, S. (1904) Die Phyllopoden, Cladoceren und freilebenden Copepoden der nord-Schwedischen Hochgebirge. Ein Beitrag zur Tiergeographie, Biologie und Systematik der arktischen, nord- und mittel-europaischen Arten. Zoologische Jahrbucher. Abteilung fur Systematik, Geographie und Biologie der Tiere, 21, 1 - 179. http: // dx. doi. org / 10.5962 / bhl. title. 59325","Rylov, V. M. (1935 a) Das Zooplankton der Binnengewasser. Die Binnengewasser 15, E. Schweizerbart'sche Verlag, Stuttgart, 272 pp.","Behning, A. L. (1941) Cladocera of the Caucasus. Gruzmedgiz, Tbilisi, 384 pp. [in Russian]","Manuilova, E. F. (1964) Cladocera of the USSR. Guide-books on the fauna of the USSR 88, Nauka, Moscow-Leningrad, 379 pp. [in Russian]","Mordukhai-Boltovskoi, Ph. D. & Rivier, I. K. (1987) Predatory Cladocera: Podonidae, Polyphemidae, Cercopagidae and Leptodoridae of the world fauna. Guide-books on the fauna of the USSR 148, 1 - 182. [in Russian]","Vekhov, N. V. (1987) Distribution, biology, and morphological variability of Bythotrephes longimanus (Leydig) s. lat. in the European Subarctic. Nauchnye doklady vysshey shkoly. Biologitcheskie nauki, 2, 27 - 35. [in Russian]","Roen, U. (1995) Gaellefodder (Branchiopoda). Ferejer, Damrokker, Muslingeskalkrebs & Dafniersamt Karpekus (Branchiura). Danmarks Fauna 85. Dansk Naturhistorisk Forening, Kobenhavn, 358 pp. [in Danish]","Rivier, I. K. (1998) The predatory Cladocera (Onychopoda: Podonidae, Polyphemidae, Cercopagidae) and Leptodoridae of the World. Guides to the identification of the microinvertebrates of the continental waters of the World 13. Backhuys Publishers, Leyden, 213 pp.","Miltz, O. (1899) Das Auge der Polyphemiden. Zoologica, 28, 1 - 58.","Martin, J. W. & Cash-Clark, C. E. (1995) The external morphology of the onychopod ' cladoceran' Genus Bythotrephes (Crustacea: Branchiopoda: Onychopoda: Cercopagididae), with notes on the morphology and phylogeny of the order Onychopoda. Zoologica Scripta, 24, 61 - 90. http: // dx. doi. org / 10.1111 / j. 1463 - 6409.1995. tb 00475. x","Elofsson, R. (1966) The nauplius eye and frontal organ of the non-malacostraca (Crustacea). Sarsia, 25, 1 - 128.","Scourfield, D. J. (1896) The olfactory setae of the Cladocera. Journal of the Quekett Microscopical Club, Series 2, 6, 280 - 288.","Olesen, J., Richter, S. & Scholtz, G. (2003) On the ontogeny of Leptodora kindtii (Crustacea, Branchiopoda, Cladocera), with notes on the phylogeny of the Cladocera. Journal of Morphology, 256, 235 - 259. http: // dx. doi. org / 10.1002 / jmor. 10043","Muller, P. E. (1870) Note sur les Cladoceres des grands lacs de la Suisse. Archives des Sciences physiques et naturelles, 37, 317 - 340.","Pengo, N. (1880) On Bythotrephes of the Azov Sea and on species features of this genus in general. Trudy obschestva ispytatelei prirody pri Imperatorskom Har'kovskom Universitete 1879, 13, 47 - 67. [in Russian]","Weltner, W. (1888) Uber das Vorkommen von Bythotrephes longimanus Leydig und Dendrocoelum punctatum Pall. in dem Werbellinsee bei Berlin. Sitzungs-Bericht Gessellschaft naturforscheinder Freunde zu Berlin, 9, 171 - 177.","Ischreyt, G. (1935) Zur Rassenforschung in der Limnologie. Mikrokosmos, 29, 197 - 200.","Flossner, D. (2000) Die Haplopoda und Cladocera (ohne Bosminidae) Mitteleuropas. Backhuys Publishers, Leiden, 428 pp."]}

Bythotrephes sp. (Figs. 5D–F, 5J, 5K) Material examined. Austria: Lake Wolfgangsee, 28.8.2012, 4 ad, coll. R. Ptáčniková. Brief description. The general body structure and its parts as in other representatives of the genus. Thoracic limbs of first pair (tl I) are comparatively not long, their length not surpasses body length (73.9–92.2 %). The first segment of endopodite is long and bears 5–6 anterior lateral setae. Distally, this segment bears shorter anterior seta of the same type and long posterior finely setulated seta (Fig. 5D). The second segment of endopodite is conspicuously shorter and bears two rather long apical setae (Fig. 5E, 5F). The terminal third segment of endopodite is shorter than the proximal first endopodital segment (80.0–86.2% of the latter one) and always bears apically four long roughly spinulated setae, two of them terminally and two subterminally. Postabdominal claws of moderate size (4.2–7.2% of body length) and directed backwards (Figs. 5G, 5K). Caudal process is of moderate length (192–253 % of body length), thus exceeding the body length in 1.9–2.5 times. Basally, caudal process bears two pairs of claws similar to those of postabdomen but slightly larger (proximal claws reach 5.9–6.7 % and distal ones 6.7–7.7% of body length, respectively). Pairs of claws sit quite closely (interclaw distance 8.0–11.1% and 8.0–10.6% of body length). Between the pairs of claws, the thickness of the structure is considerable, constituting 7.3–10.0 % and 6.3–7.8 % of body length. Borders separating old molted integuments of caudal process with claws are inconspicuous. Size. Body length 1.44–1.90 mm. Remarks. Of all species of the genus, the analyzed specimens seem closest to the representatives of the B. arcticus — B. transcaucasicus species group. They are especially similar to them due to comparatively short tl I, the presence of a long apical setae on the second segment of tl I, and thick base of caudal process always bearing two pairs of claws directed backwards (see Korovchinsky 2016). At the same time, the present specimens differ from both mentioned species in the relatively smaller body size and longer caudal process and from B. arcticus Lilljeborg, 1901 also in the presence of smaller claws of postabdomen and caudal process and smaller distance between their pairs. Regarding the two latter features, the Austrian specimens are closer to B. transcaucasicus. Due to a small number of specimens and the uncertainty of their diagnostic morphological features, it seems better to leave the problem of a more precise species definition of the specimens under consideration for the future, when more abundant material may be available., Published as part of Korovchinsky, Nikolai M., 2023, Unexpected high species richness of Bythotrephes Leydig, 1860 (Branchiopoda: Cladocera: Cercopagididae) in subalpine Austrian lakes, with the description of new taxa, pp. 77-93 in Zootaxa 5264 (1) on pages 89-90, DOI: 10.11646/zootaxa.5264.1.5, http://zenodo.org/record/7836203, {"references":["Lilljeborg, W. (1901) Cladocera Sueciae oder Beitrage sur Kenntnis der in Schweden lebenden Krebstiere von der Ordnung der Branchiopoden und der Unterordnung der Cladoceren. Nova acta regiae societatis scientatis scientiarum upsaleinsis, Series 3, 19, 1 - 701. https: // doi. org / 10.5962 / bhl. title. 13925","Korovchinsky, N. M. (2016) Redescription of Bythotrephes arcticus Lilljeborg, 1901 (Crustacea:"]}

The presence of four taxa at the species and subspecies level was revealed based on morphological investigation of a small collection of the representatives of the genus Bythotrephes Leydig, 1860 from Austrian subalpine lakes. The presence of a new species, B. inexpectatus sp. nov. was revealed in two lakes and the presence of a new subspecies, B. longimanus austriacus ssp. nov., in six lakes. Specimens of the population from the Lake Halstättersee, distinguished by the presence of peculiar features, are provisionally assigned to the species B. brevimanus Lilljeborg, 1901 of which the main range is confined to Circumbaltic region. Few morphologically specific specimens from Wolfgangsee could not be accurately identified and therefore assigned to the taxon Bythotrephes sp. requiring further investigation. Previously described taxa from the region, B. styriacus Ischreyt, 1939 and B. longimanus var. carnica Ischreyt, 1939, were considered either required further taxonomic evaluation or having an unclear taxonomic status, respectively. In one lake, the co-occurrence of two species was recorded, which is a rather rare case for the representatives of the genus. The potential reasons for the high species richness of spiny waterfleas in Austrian subalpine lakes and their possible origin are briefly discussed.

Bythotrephes longimanus longimanus Leydig, 1860 The detailed redescription of the taxon with the designation of a neotype has been done by Korovchinsky (2015). The specimens of nominotypical subspecies have generally larger body size (up to 3.06 mm) but their most pronounced diagnostic difference is the presence of large, directed more or less down, claws of postabdomen (6.6– 14.0% of body length) and caudal process (6.0–15% of body length) (Table 2). Geographical distribution. Deep subalpine lakes of Switzerland, Southern Germany, and Northern Italy. The occurrence of the taxon in Great Britain requires further confirmation., Published as part of Korovchinsky, Nikolai M., 2023, Unexpected high species richness of Bythotrephes Leydig, 1860 (Branchiopoda: Cladocera: Cercopagididae) in subalpine Austrian lakes, with the description of new taxa, pp. 77-93 in Zootaxa 5264 (1) on page 84, DOI: 10.11646/zootaxa.5264.1.5, http://zenodo.org/record/7836203, {"references":["Leydig, F. (1860) Naturgeschichte der Daphniden. Laupp & Siebeck, Tubingen, 252 pp.","Korovchinsky, N. M. (2015) Redescription of Bythotrephes longimanus Leydig, 1860 and B. cederstromii Schodler, 1877 (Crustacea: Cladocera: Onychopoda), with notes on the morphology and systematics of the genus Bythotrephes Leydig, 1860. Zootaxa, 3955 (1), 1 - 44. https: // doi. org / 10.11646 / zootaxa. 3955.1.1"]}

Bythotrephes inexpectatus sp. nov. ( Figs. 1–2) Etymology. The name of the species denotes the surprise of its discovery in Austrian lakes of Central Europe. Type locality. Lake Altaussee, Styria, Austria (47°36′36′′N; 13°46′58′′E), 712 m asl. Type material. Holotype. A female with body length 2.69 mm deposited in Zoological Museum of Moscow State University (№ MGU ML 262). Paratypes. Two females from the same sample deposited in the same museum (№ MGU ML 263). All other paratypes are deposited in author’s collection in the Institute of Ecology and Evolution. Material examined. Austria, Styria: 1) Lake Altaussee, 29.8.2012, 12 ad, 7 juv, coll. R. Ptáčniková; 2) Lake Toplitzsee, 29.8.2012, 9 ad, 4 males, 6 juv, coll. R. Ptáčniková. Data on body and body parts measurements of specimens are presented in Table 1. Description. Female. General body appearance and segmentation. Body elongated and divided into four parts: head, thorax, abdomen, and postabdomen with long caudal process (Figs. 1A, 1G). The longitudinal axis is conspicuously incurved when the head is located at almost right angle to the thorax. Highly movable abdomen can be either in a straight line with the thorax or stays at different angles to it. Head large with rounded anterior part filled by the enormously developed compound eye and bearing small antennules ventrally. Posterior part of head bears long swimming antennae and mouth parts consisting of mandibles, maxillules (mx I), and upper lip (labrum). Thorax with strongly developed muscular ventral side bearing four pairs of thoracic limbs of different sizes directed antero-ventrally. Dorsally, thorax bears a sack-like carapace transformed into a brood pouch, sometimes reaching large size. Abdomen (metasome) is elongated, cylindrical, inconspicuously three-segmented (see Korovchinsky 2015 for details) and flexible, connected with a small postabdomen, bearing ventrally a pair of claws and posteriorly a very long caudal process with a pair of similar claws proximally. General body length of females (without caudal process) may reach 2.8 mm or slightly more (in the examined specimens it ranges from 1.73 to 2.88 mm) while the length of caudal process may exceed the body length by 1.4–2.4 times (on average, about 1.8 times). Head. Comparatively very large (Fig. 1A) and subdivided into two parts: rounded anterior part mostly filled by large compound eye and posterior part bearing dorsally a large saddle-shaped neckorgan, swimming antennae and mouth parts. The large pigment spot occupies about one-third or at most half of the eye’s volume. Ocellus (naupliar eye) is absent. Antennules. Small and situated on the ventral side of the anterior head part beneath the eye. They are bulbous (Fig. 1B) and sit on the joined basis slightly split anteriorly. Terminally they bear five regular aesthetascs in two groups of two and three, and one shorter and thinner aesthetasc-like structure, situated in a group with two regular aesthetascs, and having slightly expanded apical end (“accessory simple seta” according to Scourfield (1896). Swimming antennae. Comparatively long, with elongated cylindrical basipodite (Fig. 1A). Of the two antennal branches, the lower three-segmented one, sitting on the apical basipodital prominence, is slightly longer than the upper branch. The upper branch (exopodite) is four-segmented and lower branch (endopodite) is three-segmented. Proximalmost segment of the upper branch is rudimentary and clearly visible only externally; all other segments of both branches are much more developed. Small spine with a row of neighboring minute prominences at the end of the distal segment of the superior antennal branch (Fig. 1F). Small proximalmost segment of upper branch lacks setae, while other segments possess two-segmented swimming setae of more or less similar size except distalmost of them which are shorter.All setae bilaterally armed with rows of uniform thin setules. General formula of antennal setae: 0‒1‒2‒5/1‒1‒5 (see Korovchinsky (2015) for more details). Mouth parts. They are represented by upper lip (labrum), mandibles, and maxillules (maxilla I). The upper lip is composed of two parts: the posterior thick and slightly flattened triangular lobe and anterior large proboscis-like outgrowth. Mandibles are bilobed and adapted for biting, with a toothed, blade-like posterior lobe and small anterior lobe (mandibular process). Posterior lobe is strongly sclerotized and divided in two tooth-shaped parts, the larger (posterior) of which has a small additional tooth about midway along its border. Maxillules (mx I) resemble two cylindrical structures situated posterior to the mandibles. Distally, they bear short central seta and some spinules near it. For details see description of mouth parts in other species of the genus which have the same structure (Korovchinsky 2015, 2018). Carapace. It resembles a bag-like structure, strongly modified into a closed brood pouch (Fig. 1A) widely connected in its base with the dorsal surface of the thorax. It may be often well developed and massive, when filled with large embryos. Thoracic limbs. Four pairs of strongly chitinized, stenopodous limbs, are densely situated along the muscular ventral side of thorax and directed antero-ventrally (Fig. 1A). All of them have complex and variously setaceous armament along their inner side. Limbs of the three anterior pairs are five-segmented, and those of the last fourth pair are three-segmented. Protopodites of all of them, covered by comparatively softer cuticle, are inconspicuously delimited into two parts (segments), coxa and basis, while the endopodites of limbs of the three anterior pairs are composed of three well developed segments and those ones of the fourth pair are single-segmented (Figs. 1C, 2A, 2B, 2C). First pair of limbs (tl I) are especially long and strong (Fig. 1C), though comparatively they are more or less short (63.8–92.6 %, av. 79.4% of body length). Terminally, the inner side of their protopodite bears a small triangular lobe, pseudognathobasic process (see the explanation of the term in Korovchinsky (2015)). The first segment of the endopodite is long and bears 5–6 anterior lateral setae with rows of spines and fine setules. Distally, this segment bears a shorter anterior seta of the same type and long posterior finely setulated seta (Figs. 1C, 1D). The second segment of the endopodite is conspicuously shorter and bears only two apical setae similar to those on the end of previous segment but shorter (Fig. 1E). The terminal third segment of the endopodite slightly varies in length, being shorter than the proximal first endopodital segment (72.2–95.4 %, av. 81% of the latter one) and always bearing apically four long roughly spinulated setae, two of them terminally and two subterminally. Second pair of limbs (tl II) are considerably shorter, their protopodite, again externally, is conspicuously longer and bears a conical outgrowth. The first basal segment of their endopodite bears a row of 5–7 rather long anterior lateral setae (their number can vary in one individual) (Fig. 2A: as). There are 1–2 posterior lateral setae (ps) on this segment. The terminal setae of the segment differ in that the anterior one is shorter and roughly armored, whereas the posterior one is longer and finely setulated. Internally, this segment bears a stout cylindrical pseudognathobasic process, possessing some prominences of different size and one small, thin seta (Fig. 2A). The second segment of the endopodite is short with only two setae, the anterior one of which is similar to the anterior terminal seta of previous segment, whereas the posterior seta is longer and finely setulated. The distal, third segment of endopodite of the limb bears four setae, two terminal and two subterminal ones (Fig. 2A). Third pair of limbs (tl III) are generally similar to those of the previous ones, differing in some details. The external outgrowth of their protopodite is conspicuously larger and lateral anterior and posterior setae (if present) of first segment of endopodite are fewer (4–5 and 1, respectively) (Fig. 2B). Distal setae of the segment are similar to other ones. The pseudognathobasic process is also similar to that of tl II. Of setae of the second segment, the anterior one is similar to the respective one of tl II. Terminal and subterminal setae of the third segment are similar to those of tl II but slightly shorter and bear fewer denticles. Fourth pair of limbs (tl IV) are considerably reduced (Fig. 2C); their protopodite bears slightly spinulated seta sited on a short cylindrical base. The only segment of the endopodite has two rows of comparatively short spine-like setae. The external row (group) (Fig. 2C: as) always consists of two setae, and the internal row of 6–7 setae, which differ in their appearance and armament. Almost the whole internal part of the endopodital segment is occupied by the reduced pseudognathobasic process, also armed by some denticles and thin seta. Abdomen (metasome) (Fig. 1A) is often deformed. It is inconspicuously delimited in two segments, short proximal and long distal with a prominent fold more or less in the middle dorsal side. “ Postabdomen” actually consists of two parts: the last small abdominal segment and the postabdomen per se (see Korovchinsky (2015) for more details), which is comparatively small, with the anal opening situated between the postabdominal claws. These claws are comparatively small (3.4–6.8 %, av. 4.7% of body length), more or less straight or slightly curved and directed slightly backwards (Figs. 2D–I). Caudal process is directly connected with the postabdomen and proceeds as a very long, proximally rather thick and curved, then straight spine-like structure (Figs. 1A, 1G), variable in its length (138.0–239.0 %, av. 184% of body length), thus exceeding the body length by about 1.4-2.4 times. Generally, the caudal process is strongly chitinized and its surface covered by numerous minute spinules. Basally, the caudal process bears one pair of claws similar to those of the postabdomen but usually larger (4.0–8.5%, av. 5.9% of body length), and apically two minute setae arise from a common base (Fig. 1H). Pairs of claws of postabdomen and caudal process sit closely, interclaw distance usually constitutes 5.8–8.4% (av. 7.0%). Between the claws, the thickness of the structure constitutes 4.4–7.9 % (av. 6.0%). Borders separating old molted integuments of caudal process with claws always are quite conspicuous. Gamogenetic females have not been detected. Males. The thoracic limbs of the first pair (tl I) are comparatively short (59.0–73.0 % of body length) as well as each segment of them, especially the distal one, which is slightly swollen proximally and bears on its inner side a small strongly chitinized hook with two inner denticles (Figs. 1I, 1J). The copulatory appendages are small and armed with numerous minute spinules terminally (Fig. 1K). Size. Adult females— 1.73–2.88 mm. in length. Males, on average, are smaller than females (body length— 1.86–2.08 mm.). Intrapopulation variability of females. According to Table 1, the length of claws of the postabdomen and caudal process is especially variable (CV = 21.3–22.5, respectively), the interclaw distance and interclaw thickness follow them in this respect (CV = 11.3–11.8). At the same time, the claw shape is more or less stable. Of other structures, the comparative length of thoracic limbs of the first pair (tl I) seems also rather variable (CV = 8.4). Differential diagnosis. Bythotrephes inexpectatus sp. nov. is close to B. longimanus s.l. and B. centralasiaticus Korovchinsky, 2020 in having, in adult specimens, only one pair of claws on caudal process. At the same time, it differs from the former species (Table 2) in a unique combination of morphological features: relatively smaller body length; presence of very closely situated pairs of claws, the borders of which separating old molted integument always are quite conspicuous; presence of shorter thoracic limbs of first pair (tl I) and shorter caudal process (for all parameters p vs. short or rudimental in B. longimanus s.l.) at the apical end of the second endopodital segment of tl I. Compared to B. centralasiaticus, the specimens of Bythotrephes inexpectatus sp. nov. have on average larger body length, shorter caudal process, smaller claws of the postabdomen and caudal process, larger thickness of caudal process between pairs of claws, and conspicuously smaller interclaw distance (for all parameters p Bythotrephes and those of widely distributed interspecies hybrids B. brevimanus x B. cederströmii possess one-two pairs of claws on caudal process. Besides that, the relatively closely distributed B. brevimanus s.str., possesses, compared to the new species, smaller claws of postabdomen and caudal process that sit more distant from each other (p Geographical distribution. So far, representatives of a new species are known to occur only in two deep subalpine lakes in the central part of Austria., Published as part of Korovchinsky, Nikolai M., 2023, Unexpected high species richness of Bythotrephes Leydig, 1860 (Branchiopoda: Cladocera: Cercopagididae) in subalpine Austrian lakes, with the description of new taxa, pp. 77-93 in Zootaxa 5264 (1) on pages 79-84, DOI: 10.11646/zootaxa.5264.1.5, http://zenodo.org/record/7836203, {"references":["Korovchinsky, N. M. (2015) Redescription of Bythotrephes longimanus Leydig, 1860 and B. cederstromii Schodler, 1877 (Crustacea: Cladocera: Onychopoda), with notes on the morphology and systematics of the genus Bythotrephes Leydig, 1860. Zootaxa, 3955 (1), 1 - 44. https: // doi. org / 10.11646 / zootaxa. 3955.1.1","Scourfield, D. J. (1896) The olfactory setae of the Cladocera. Journal of the Quekett Microscopical Club, Series 2, 6, 280 - 288.","Korovchinsky, N. M. (2018) Further revision of the genus Bythotrephes Leydig (Crustacea: Cladocera: Onychopoda): redescription of B. brevimanus Lilljeborg, reevaluation of B. cederstromii Schodler, and description of a new species of the genus. Zootaxa, 4379 (3), 347 - 387. https: // doi. org / 10.11646 / zootaxa. 4379.3.2","Korovchinsky, N. M. (2020) Description of a new species in the genus Bythotrephes Leydig, 1860 (Crustacea: Cladocera: Onychopoda), supplements to selected species, and concluding remarks on the genus. Zootaxa, 4789 (2), 441 - 465. https: // doi. org / 10.11646 / zootaxa. 4789.2.4"]}

Anthalona vandammei sp. nov. Maiphae, Pholpunthin & Dumont 2008: 34, fig. 2b (Alona verrucosa). Etymology. the species is named after our friend and colleague, prominent Belgian cladocerologist Kay Van Damme. Type locality. Lake Kud-Thing, Bueng Kan province, Thailand, 18° 18.548’ N, 103° 39.700’ E. The type series was collected on 30.01.2017 by A.Y. Sinev & S. Tiang-nga. Samples were collected at a depth of about 0.5 m, where there were dense standing and submerged macrophytes. Holotype. A parthenogenetic female from the type locality, deposited in the Zoological Museum of M. V. Lomonosov Moscow State University, Ml-260. Paratypes. Four parthenogenetic females from the type locality, deposited in the Zoological Museum of M. V. Lomonosov Moscow State University, Ml-261. Other material studied. Five specimens from the type locality were dissected for appendage analyses but not kept; three specimens were used for SEM studies. Description. Parthenogenetic female. In lateral view, body high, egg-shaped (Figs. 1A, 2A–E); maximum height after the middle of the body. Height-length ratio 0.65–0.7 in adults. Dorsal margin convex, posterodorsal and posteroventral angles broadly rounded. Posterior margin convex, ventral margin almost straight, anteroventral angle rounded. Ventral margin (Fig. 1B) with 35–40 setae. About 20 anterior setae short, thin, naked; posterior setae (Fig. 3A–B) long, plumose; distalmost setae located at posteroventral angle of valves. Posteroventral angle (Figs. 1C, 3B) with about 15 short setulae not organized into groups. Carapace and head shield covered by tubercles. Head relatively small, round triangle in side view. In lateral view, rostrum protruding downwards. Ocellus smaller than eye. Distance from tip of rostrum to ocellus slightly greater than that between ocellus and eye. Head shield of typical for genus shape (Figs. 2F, 3D–E), covered by tubercles. Rostrum short, with almost straight anterior margin. Posterior margin rounded. Two main head pores with a narrow connection between them; anterior pore somewhat larger than posterior (Figs. 1D, 3F); PP up to 1 IP. Lateral head pores with bilobed asymmetric cosmaria, located at about 1 IP distance from midline, at level of anterior main head pore. Single posterior dorsal pore (Fig. 3G); minute aperture revealed by SEM examination, located behind posterior margin of head shield. Labrum of moderate size, without lateral projections (Figs. 1E, 3C). Labral keel wide, height only slightly exceeding width, with lateral indentations. Anterior margin of keel convex, with small blunt denticle in the upper third; apex rounded; posterior margin convex, without setulae. Thorax two times longer than abdomen. Dorsal surface of abdominal segments not saddle-shaped. Postabdomen (Figs. 1F–G, 4A–D) short and wide; maximum height at postanal angle. Length about 2.1–2.2 height. Ventral margin straight. Basis of claws separated from distal margin by clear incision. Distal margin weakly convex to straight, distal angle broadly rounded. Dorsal margin weakly convex in postanal portion and unevenly concave in anal one, distal part 1.5–1.7 times longer than preanal one, postanal portion 1.5 times shorter than anal one. Preanal angle well-defined, postanal angle weakly defined. Preanal margin almost straight. Postanal margin with 5–6 narrow denticles, length of denticles decreases posteriorly, length of longest denticles about the width of postabdominal claw base. Anal margin with 3–4 groups of marginal spinules and setulae. Eight–ten lateral groups of setulae. In postanal portion fascicles narrow, composed of 3–8 setulae each, distance fascicles between them about width of fascicle; posteriormost setula very long, thick, with length about 2–2.5 widths of postabdominal claw base. In anal portion fascicles wider and spaced more closely, with shorter distalmost setula. Postabdominal claw slender, of moderate length, shorter than preanal portion of postabdomen. Basal spine short and slender, about 0.25 of the claw length. A long spinule located near the base of basal spine. Antennule (Figs. 1H, 3D) of moderate size, length about 2.5widths, with 3 clusters of short setulae at anterior face. Antennular seta of about 2/3 length of antennule, arising at 1/4 distance from the end. Nine terminal aestetascs, longest of them about half length of antennule. Antenna (Figs. 1I, 3H) with antennal formula: setae 0-0-3/1-1-3 and spines 1-0-1/0-0-1. Basal segment robust, with short seta between branches, branches relatively short, basal segments in both branches 1.5 times longer and thicker than others. Basal and middle segment of endopodite with clusters of short setulae. Seta arising from basal segment of endopodite reaching after the end of endopodite. Seta arising from middle segment of endopodite of similar size to shortest apical setae. One of apical setae on both branches significantly shorter and thinner than two others. Spine on basal segment of exopodite slightly longer than middle segment. Spines on apical segments as long as apical segments. Thoracic limbs: five pairs. Limb I (Figs. 4F, 4G, 5A–C). Epipodite oval, with process two times longer than epipodite itself. Accessory seta 2 times shorter than ODL seta. ODL seta with short setulae in distal portion. IDL with two setae, seta 1 absent, seta 3 thick, curved, as long as ODL seta, ending in one thick and two–three slender long spines, seta 2 short, more thin, bearing 2–3 thick spines; in both setae basalmost spine longer and thicker than two others. Endite 3 with four very short setae, setae 1 and с thick, robust, setae a–b thin. Endite 2 with short seta d, setae e–f of similar length, moderately short, 2.5 times shorter than limb itself. Endite 1 with two long 2-segmented setae of similar size (g–i), setulated in distal part, long flat seta (j) pointed to the limb base. No inner setae found on endites 1–2. Ventral face of limb with 5–6 clusters of long setulae. Two ejector hooks, one of them much larger than other. Limb II subtriangular (Figs. 4G, 5D–E). Exopodite elongated, no exopodite seta found. Eight scraping spines, spines 1–3 largest, armed with thin spinules, setae 4–5 much shorter than setae 1–3, all armed with thin spinules. Spines 6–8 short, with wide bases and short distal part, spine 7 smaller than two others, short denticles observed only on spines 6–7. Distal armature of gnathobase with four elements. Filter plate II with seven setae, three distalmost setae much shorter than others. Limb III. (Fig. 5F–G) Epipodite rounded, with short process. Exopodite narrow, with six setae. Seta 3 longest, setae 4, and 5 about 1/2, 2/3 and 1/5 length of seta 3, setae 1–2 very short. Setae 1–4 plumose, seta 5 armed bilaterally with short hard setulae, seta 6 naked. Distal endite with 3 setae, two distalmost members slender, with blunt tips, without denticles in distal part, short bottle-shaped sensillum located between their bases, seta 3 much shorter, with long setulae. Basal endite with four outer setae (a–d) slightly increasing in length basally. Gnathobase not clearly separated from basal endite. Four inner setae (4–7) very short, slightly increasing in size basally; a sensillum near the base of distalmost seta. Distal armature of gnathobase with four elements, the first one an elongated, cylindrical sensillum; the second a geniculated seta; two others are very short short spines with fused bases. Filter plate with seven setae. Limb IV (Fig. 5H–I). Pre-epipodite setulated. Epipodite with finger-like process two times longer than epipodite itself. Exopodite rounded, with six setae. Seta 1–3 long, of similar length, setae 4–6 about two times shorter. Setae 1–4 flat, plumose, setae 5–6 thin, unilaterally armed with short setulae in distal portion. Inner portion of limb IV with three setae and small sensilla. Scraping seta (1) slender, without denticles in distal portion, first flaming-torch seta (2) wider and longer than other (3). Three soft setae, basalmost seta significantly larger than others. Gnathobase with two-segmented seta and a small hillock distally. Filter plate IV with five setae. Limb V (Fig. 5J). Pre-epipodite setulated, epipodite oval, with process longer than epipodite itself. Exopodite bilobed, with four plumose setae. Seta 1 very long, slightly longer than exopodite body, setae 2, 3 and 4 of about 2/3, 1/2 and 1/3 length of seta 1, respectively. Inner lobe moderately wide, with straight outer margin. At inner face, two short setae, distal seta 1.5 times longer than basal. Filter plate V absent. Ephippial female and male unknown. Size: length of adult female in studied material was 0.31–0.38 mm, height 0.25–0.28 mm. Differential diagnosis. Anthalona vandammei sp. nov. differs from the most species of the genus in IDL setae armed with 3–4 very long spines and in limb II with very shortened distal portion spines 6–8; these characters are shared only by Neotropical A. brandorffi (Sinev & Hollwedel, 2002) and South-East Asian A. spinifera. A. vandammei sp. nov. clearly differs from both A. brandorffi and A. spinifera in IDL seta 3 with basal spine being much thicker and much longer than others, while in spines of IDL seta 3 are of similar thickness and length. A. vandammei sp. nov. differs from A. spinifera in the shape of postabdomen, which is narrowing basally in anal portion, in much longer posterior setae of valves, in posteroventral angle of valves armed with about 15 setulae only, and in having only two flaming-torch setae on limb IV. A. vandammei sp. nov. differs from A. brandorffi in longer setae e–f of limb I and in scraper 7 of limb II being only slightly smaller than scraper 6. Other differences between these two species are summarized in Table 1. Distribution. So far, the new species has been recorded in Lake Kud-Thing in Bueng Kan Province, North-East Thailand, and in Thungtong swamp in Surat Thani Province, Southern Thailand (Maiphae et al. 2008).

Key for Anthalona species of South-East Asia 1a. IDL seta 3 with long distal portion, armed with thin setules of equal thickness.................................................................................................. Anthalona sanoamuangae Sinev & Kotov, 2012. 1b. IDL seta 3 with thick spine at the middle and shortened distal portion armed with thin setulae, or IDL seta 3 armed with several long spines.......................................................................................... 2 2a. IDL seta 3 with thick spine at the middle and shortened distal portion armed with thin setulae......................... 3 2b. IDL seta 3 armed with several long spines.................................................................. 5 3a. Cosmaria of lateral pores flower-like............................................. Anthalona milleri (Kiser, 1948) 3b. Cosmaria of lateral pores bilobed......................................................................... 4 4a. IDL setae 2-3 thick, curved, claw-like; distal portion of seta 3 shorter than its basal spine. Anterior margin of labral keel with a blunt denticle bearing a spinule.......................... Anthalona harti harti Van Damme, Sinev & Dumont, 2011. 4b. IDL setae 2-3 moderately thick, weakly curved; distal portion of seta 3 longer than its basal spine. Anterior margin of labral keel with a blunt denticle lacking a spinule........................ Anthalona obtusa Van Damme, Sinev & Dumont, 2011. 5a. Posterior setae of valves short, posteriormost setae located before posteroventral angle of valves. IDL setae 2-3 armed with spines of similar thickness and length................... Anthalona spinifera Tiang-nga, Sinev & Sanoamuang, 2016. 5b. Posterior setae of valves long, posteriormost setae located at posteroventral angle of valves. IDL setae 2-3 with basal spine much thicker and longer than others............................................. Anthalona vandammei sp. nov., Published as part of Sinev, Artem Y., Tiang-Nga, Supatra & Sanoamuang, Laorsri, 2023, Anthalona vandammei sp. nov. from Thailand, a sibling species of Neotropical Anthalona brandorffi (Sinev & Holwedell, 2002) (Cladocera: Anomopoda: Chydoridae), pp. 67-78 in Zootaxa 5230 (1) on page 76, DOI: 10.11646/zootaxa.5230.1.4, http://zenodo.org/record/7550516, {"references":["Sinev, A. Y. & Kotov, A. A. (2012) New and rare Aloninae (Cladocera: Anomopoda: Chydoridae) from Indochina. Zootaxa, 3334 (1), 1 - 28. https: // doi. org / 10.11646 / zootaxa. 3334.1.1","Van Damme, K., Sinev, A. Y. & Dumont, H. J. (2011) Separation of Anthalona gen. n. from Alona Baird, 1843 (Branchiopoda: Cladocera: Anomopoda): morphology and evolution of scraping stenothermic alonines. Zootaxa, 2875 (1), 1 - 64. https: // doi. org / 10.11646 / zootaxa. 2875.1.1","Tiang-nga, S., Sinev, A. Y. & Sanoamuang, L. (2016) A new species of the genus Anthalona Van Damme, Sinev and Dumont, 2011 (Cladocera: Anomopoda: Chydoridae) from North-East Thailand. Zootaxa, 4150 (1), 93 - 100. https: // doi. org / 10.11646 / zootaxa. 4150.1.6"]}

Sinev, Artem Y., Tiang-Nga, Supatra, Sanoamuang, Laorsri (2023): Anthalona vandammei sp. nov. from Thailand, a sibling species of Neotropical Anthalona brandorffi (Sinev & Holwedell, 2002) (Cladocera: Anomopoda: Chydoridae). Zootaxa 5230 (1): 67-78, DOI: https://doi.org/10.11646/zootaxa.5230.1.4

Key for Anthalona species of South-East Asia 1a. IDL seta 3 with long distal portion, armed with thin setules of equal thickness.................................................................................................. Anthalona sanoamuangae Sinev & Kotov, 2012. 1b. IDL seta 3 with thick spine at the middle and shortened distal portion armed with thin setulae, or IDL seta 3 armed with several long spines.......................................................................................... 2 2a. IDL seta 3 with thick spine at the middle and shortened distal portion armed with thin setulae......................... 3 2b. IDL seta 3 armed with several long spines.................................................................. 5 3a. Cosmaria of lateral pores flower-like............................................. Anthalona milleri (Kiser, 1948) 3b. Cosmaria of lateral pores bilobed......................................................................... 4 4a. IDL setae 2-3 thick, curved, claw-like; distal portion of seta 3 shorter than its basal spine. Anterior margin of labral keel with a blunt denticle bearing a spinule.......................... Anthalona harti harti Van Damme, Sinev & Dumont, 2011. 4b. IDL setae 2-3 moderately thick, weakly curved; distal portion of seta 3 longer than its basal spine. Anterior margin of labral keel with a blunt denticle lacking a spinule........................ Anthalona obtusa Van Damme, Sinev & Dumont, 2011. 5a. Posterior setae of valves short, posteriormost setae located before posteroventral angle of valves. IDL setae 2-3 armed with spines of similar thickness and length................... Anthalona spinifera Tiang-nga, Sinev & Sanoamuang, 2016. 5b. Posterior setae of valves long, posteriormost setae located at posteroventral angle of valves. IDL setae 2-3 with basal spine much thicker and longer than others............................................. Anthalona vandammei sp. nov.

Murray-Darling Freshwater Research CentreMDFRC item.1. The hypothesis is tested that large daphnids are able to suppress their own and other species' feeding and reproduction by means of excreting an inhibitory chemical (or chemicals).2. In laboratory experiments with an Australian species, Daphnia carinata, water preconditioned with 3–67 daphnids 1-−1 for 30 h had the effect of reducing feeding rates of D. carinata and D. lumholtzi provided with Selenastrum capricornutum.3. For the two Daphnia species, there were highly significant negative correlations between feeding rate and the preconditioning density of D. carinata.4. Water preconditioned with 20–30 daphnids 1-−1 for 1–2 weeks reduced the grazing rates of Daphnia, Moina, and Diaphanosoma 2–3-fold.5. Moina kept in such water for 2 days stopped feeding. Conditioned water kept for 3 days without animals still inhibited grazing by Moina. Hearing to 100°C removed the inhibitory effect.6. Given excess food, and in non-renewed water, a gradient of D. carinata densities developed a strong negative correlation between clutch size and daphnid density after a 6-day time lag. This result may help explain the direct density-dependent regulation of cladoceran reproduction observed earlier in a subtropical lake.

The fairy shrimp genus Parartemiopsis Rogers, 2005 currently contains a single species reported from Russia and Mongolia. In 2013, an unidentified Parartemiopsis population was reported from the eastern margin of the Tibetan Plateau in China's Yunnan Province, from Patatson National Park in Shangri-La County. Here, we describe the Chinese populations as a new species, Parartemiopsis shangrilaensis sp. nov. This new species is distinguished from its congener, P. longicornis (Smirnov, 1930), by the form of the male second antennae and the gonopod. The discovery of P. shangrilaensis sp. nov. extends the known distribution of the genus, and more Parartemiopsis species may be found in the future. We present a key to the genera and species of Chirocephalidae in China as an aid to future research.

Pleistocene glaciations had a tremendous impact on the biota across the Palaearctic, resulting in strong phylogeographic signals of range contraction and rapid postglacial recolonization of the deglaciated areas. Here, we explore the diversity patterns and history of two sibling species of passively dispersing taxa typical of temporary ponds, fairy shrimps (Anostraca). We combine mitochondrial (COI) and nuclear (ITS2 and 18S) markers to conduct a range-wide phylogeographic study including 56 populations of Branchinecta ferox and Branchinecta orientalis in the Palaearctic. Specifically, we investigate whether their largely overlapping ranges in Europe resulted from allopatric differentiation in separate glacial refugia followed by a secondary contact and reconstruct their postglacial recolonization from the inhabited refugia. Our results suggest the existence of distinct refugia for the two species, with genetic divergence among intraspecific lineages consistent with late Pleistocene glacial cycles. While B. ferox lineages originated from Mediterranean refugia, the origin of B. orientalis lineages was possibly located on the Pannonian Plain. We showed that most dispersal events predominantly happened within 100 km, coupled with several recent long-distance events (> 1000 km). Hence the regional habitat density of suitable habitats in Central Europe is possibly a key to the co-existence of the two species. Overall, our study illustrates how isolation in combination with stochastic effects linked to glacial periods are important drivers of the allopatric differentiation of Palaearctic taxa.

Analysis of Cladocera (Crustacea: Branchiopoda) subfossil remains in lake sediments features prominently in paleolimnological studies. It is well known, however, that species composition in a taphocoenosis (assemblage of subfossil remains in sediments) does not represent perfectly that of the original living community (biocoenosis) from which it came. We analyzed the representation of different Cladocera skeletal components in sediments of 27 Russian water bodies to compare two methods of enumerating relative abundances of cladoceran remains: (1) recording the number of most abundant fragments of each taxon to represent the number of individuals, and (2) recording each fragment of a taxon as belonging to an individual specimen. Overall, for all cladoceran taxa and all water bodies sampled, proportions of different skeletal components differed from what would be expected based on those in live individuals. Carapaces were the most abundant component in 23 of 27 water bodies. Head shields were common, but predominated in only four samples, whereas postabdomens were rare, accounting for

It is widely accepted among the Cladocera (Crustacea) taxonomists that almost all “cosmopolitan” taxa are represented by some un-revised complexes of cryptic species. But many macro taxa of the cladocerans are still unrevised. The aim of this work is to analyze the taxonomic status of Oriental populations of the genus Bosminopsis Richard, 1895 (Anomopoda: Bosminidae) based on morphological characters. We have studied populations from India, Myanmar, Cambodia, Thailand, Laos, Vietnam, Philippines, Malaysia and Papua New Guinea and concluded that Oriental populations belong to a single species, Bosminopsis africanus (Daday, 1908), initially described from Africa. Analysis of literature data confirms that is widely distributed through whole Oriental zone. A single large mucro, or the mucro accompanied by an additional small spine in both sexes, is the main trait which differentiates B. africanus from B. zernowi Linko, 1901 distributed in more northern regions of Eurasia.

A new species of the genus Pseudochydorus Fryer, 1968 is described from Central Mexico. P. margaritalfonsorum sp. nov. differs from the Old World species of the genus, P. globosus (Baird, 1843) and P. bopingi Sinev, Garibian & Gu, 2016 in the morphology of thoracic limbs I–III. Analysis of existing literature data on distribution and morphology of Pseudochydorus in America suggest than P. margaritalfonsorum sp. nov. is an endemic of Central Mexican Plateau, and at least two more species of the genus are present in other regions of America.

Streptocephalus wolof sp. nov. (Figs. 6–9) Etymology. The name wolof refers to the ethnic group native to Senegal, Gambia, and in a lesser extent, to Mauritania. Most of the known geographic range of the newly described species overlaps with the Wolof ethnic distribution. The name is a noun in genitive case. Type material. Holotype. Male: Senegal, Tambacounda, 6 km west of Koutenabe, 93 m, 14 º 15′34.38″N, 12 º 35′42.38″W, 16-VIII-2015 (white label, printed); MNCN 20.04 /20321 (white label, printed); Holotypus, Streptocephalus wolof Sainz-Escudero, Alonso & Sánchez-Vialas, des. 2022 (white label printed). Paratypes. 20males, 15 females: Senegal, Saint-Louis, 2 km north of Podor, 9 m, 16 º 40′17.43″N, 14 º 57′55.29″W, 18-VIII-2015 (white label, printed); MNCN 20.04 /20269–20.04/20289 and 20.04/20327–20.04/20340 (white label, printed). Twenty-six males, 50 females: Senegal, Ziguinchor, Diembéreng, 9 m, 12 º 28′00.61″N, 16 º 47′02.16″W, 13-VIII-2015 (white label, printed); MNCN 20.04 /20290–20.04/20302 and 20.04/20341–20.04/20403 (white label, printed). Thirteen males, 22 females: Senegal, Matam, 1.9 km south-east of Bokiladji, 30 m, 15 º 02′48.91″N, 12 º 43′49.78″W, 17-VIII-2015 (white label, printed); MNCN 20.04 /20303–20.04/20320 and 20.04/20404- 20.04/20420(white label,printed). Five males: Senegal, Tambacounda, 6km west of Koutenabe, 93 m, 14 º 15′34.38″N, 12 º 35′42.38″W, 16-VIII-2015 (white label, printed); MNCN 20.04 /20321–20.04/20326 (white label, printed). All paratypes labelled: “ Paratypus, Streptocephalus wolof Sainz-Escudero, Alonso & Sánchez-Vialas, des. 2022 (white label printed) (Table 2). Description. Male. Head (Fig. 6A) round. Nuchal organ visible. Eyes spherical with diameter as long as its corresponding eyestalk. First antennae filiform, 2 times longer than basal joint of second antenna (Fig. 6A). Distal end with 3 subdistal setae, approximately 2–2.5 times longer than antennular thickness (Fig. 6B). Frontal appendage (Fig. 6C) consisting of 2 slightly curved long and pointed branches, reaching half-length of distal antennomere, with 2 small tips at inner margin, one close to base and other approximately in its half. Single acute basal projection in its ventral surface, whose length is about one-third of the latter. Second antennae (Fig. 6D) reaching thoracopod IX or X when extending backwards. Proximal and distal antennomeres subcylindrical, similar in length, 2 times as long as broad. Inner longitudinal row of 12 or 13 small papillae (sp) from medial part of proximal antennomere to medial part of distal antennomere. Medial part of distal antennomere with transversal row of 5–7 small papillae. Small papillae consist of a conical base with 1 apical small sensory seta. Apical joint (aj) oriented ventrolaterally, at distal end of basal joint, approximately as long as distal antennomere. Hand (according to Maeda-Martínez et al. 1995b) with 2 sharp and smooth rami. Longest ramus (anterior primary ramus, “thumb) 2 times longer than distal antennomere, slightly curved at end of proximal third; small subtriangular blunt (spur) present in its proximal part. Shorter ramus (posterior ramus, “finger) 0.6 times of anterior primary ramus length, and dorsally bent; proximal part with a small rounded protruding structure followed by short thickening. Labrum (Fig. 6E) subtrapezoidal, without distal protuberances; terminal fleshy process straight, tapering distally. Two setulose pads placed ventrally midway and in the base of fleshy process. Phyllopodia with gross structure, typical of the genus (Figs. 7A–E). Eleven pairs of thoracopods. First thoracopod (Fig. 7A) 2 times shorter than seventh thoracopod (Fig. 7C); eleventh thoracopod (Fig. 7E) 0.8 times longer than seventh thoracopod; rest of thoracopods subsimilar in size. Praepipodite (PE) oval, with serrated outline in all thoracopods. Epipodite (EP) wide, with undulated margin (Figs. 7A, C) in the tenth anterior thoracopod; eleventh thoracopod epipodite elongated, with serrated extreme (Fig. 7E). Exopodite (EX) oval, bordered by plumose marginal setae; first thoracopod small (Fig. 7A), not sticking out from endopodite; rest of thoracopods (Figs. 7C, E) of similar size to endopodite. Endopodite (EN) broad, covered by short plumose setae in its outer margin, and provided with a more or less marked depression in the middle (Figs. 7A, C, E). Endites from first to tenth thoracopods: first endite with 2 submarginal spine-like setae on anterior surface, proximal one long and thin, provided with denticles, and distal one shorter, spiniform, with a basal tiny spine-like seta (Figs. 7A, C); second endite with a long spiniform proximal seta, submarginal on anterior surface, with a basal tiny seta (Figs. 7A, C); third endite with 2 unequal submarginal spinelike seta on anterior surface and three plumose setae on posterior surface (Figs. 7B, D); 4 endite with 2 unequal submarginal spinelike seta on anterior surface and 2 plumose setae on posterior surface (Figs. 7B, D); fifth endite with 3 unequal submarginal spinelike seta on anterior surface and 2 plumose setae on posterior surface (Figs. 7B, D). Endites to eleventh thoracopod (Fig. 7E): first endite with submarginal spine-like setae very reduced; second endite with 2 small spines on anterior surface and 3 plumose setae on posterior surface; third and fourth endites with 2 small spines in anterior surface and 2 plumose setae on posterior surface; fifth endite with 1 small spine in anterior surface and 2 plumose setae on posterior surface. Abdominal segments (Fig. 8A) typical of the genus. First, second, and third segments with 2 small cuticle projections, one at each side, close to posterior margin (pointed with arrow in Fig. 8A). Genital segments (Fig. 8B) slightly expanded and partially fused. First segment ventrally smooth. Second segment with linguiform outgrowths 2 times shorter than basal part of gonopods, placed posterolaterally on ventral surface. Basal part of gonopods non-retractile, reaching the end of third abdominal segment; spinulated appendix located in its basal inner side and 2 rounded expansions in its distal end. Everted part of gonopods twice longer than basal part, provided with longitudinal rows of spines. Cercopods (Fig. 8C) of the type “spinose cercopods sensu Maeda-Martínez (1995b), sclerotized, with short spine-like setae replacing the marginal plumose setae on the distal half. Cercopods as long as the last 4 abdominal segments. Anus terminal. Female. First antennae (Fig. 9A) filiform 4 times longer than eye diameter, and 2 and a half longer than second antenna. Distal end as in male. Second antennae (Fig. 9A) broad with rounded end, little longer than eye plus stalk. Distal surface and margins bearing short setae. One small marginal beak on anterior edge close to distal end. Thoracopods as in male. Abdominal segments (Fig. 9C) with smooth surface. Some of them bearing warty outgrowths provided with sensillae (in fourth and sixth segments in the figure). Genital segments (Fig. 9C) completely fused. Brood pouch elongate, fusiform extending to middle of fourth abdominal segment; end provided with an angular flat expansion directed posteriorly (Fig. 9D). Eggs subspherical; surface covered by wide protruding keeled ribs delimiting polygonal fields (Fig. 3A). Diameter around 200 µm. Cercopods (Fig. 9E) broad in the base, margined on both sides by feathery setae gradually shortening to their acute end. Length as last four abdominal segments plus telson. Size. Total body length of the holotype (MNCN 20.04/20321), (including cercopods setae): 7.48 mm. Largest female specimen recorded: 10.56 mm. Geographic distribution. Streptocephalus wolof is known from the following localities in Senegal: 2 km north of Podor, Diembéreng, 1.9 km south-east of Bokiladji, 6 km east of Koutenable and Diabal (Table 2). Future studies could likely extend its distribution to the neighboring countries Mauritania, Gambia, Mali, Guinea, and Guinea-Bissau. The previous recorded populations identified as S. zeltneri in Senegal [Lingure and Palagu (Monod 1969; Hamer et al. 1994b; Maeda-Martínez et al. 1995b)] require revision as they were not examined by us, and therefore, we were unable to confirm its taxonomic identity. However, we tentatively treated these records as S. zeltneri until additional studies confirm its identity (Fig. 1). Remarks. The new species is closely related to Streptocephalus zeltneri. Both species cannot be distinguished based on adult morphological characters, and consequently they can be considered as cryptic species (Marrone et al. 2017). However, they differ on the basis of the eggs macrosculpture. Eggs of S. wolof present their surface covered with carinated ribs, delimiting polygons of variable number of sides (Fig. 3A). This trait was consistent in each revised population that contained mature females. Streptocephalus wolof is the most commonly found and widespread Anostraca species in Senegal, occurring in several ecoregions (including the Sahelian and Sudanian savannas, and the Guinean forest savanna close to the Guinean forest) (Fig. 1). The studied specimens of S. wolof were found during the rainy season in temporary ponds, both with transparent and turbid waters, often in syntopy with amphibian larvae, as Sclerophrys xeros (Tandy, Tandy, Keith & Duff-MacKay, 1976), Kassina senegalensis (Duméril & Bibron, 1841), K. fusca Schiøtz, 1967, Ptychadena bibroni (Hallowell, 1845), and Phrynobatrachus francisci Boulenger, 1912 (Fig. 5).

Branchinella (Branchinellites) chudeaui (Daday, 1910) Branchinellites chudeaui Daday, 1910b: 256 [Terra typica: Bassin du Moyen Niger, Simbidissi. Syntypes at the Muséum National d’Histoire Naturelle, Paris (Linder, 1941) and D1912-93, I/A-73 at the Hungarian Natural History Museum, Budapest; Belk & Brtek 1995]. Branchinella chudeaui (Daday, 1910): Linder 1941: 270. Material examined. Seven males, 23 females, from Senegal: Matam, Tilagne Tokkosel, 31 m, 15 º 58′13.40″N 13 º 36′48.42″W, 17-VIII-2015; MNCN 20.04 /20454–20.04/20483. Five males, from Senegal: Matam, Tilagne Tokkosel, 31 m, 15 º 58′12.13″N 13 º 36′39.27″W, 17-VIII-2015; MNCN 20.04 /20484–20.04/20488. Fifty-seven individuals, not sexed, Senegal: Matam, Tilagne Tokkosel, 31 m, 15 º 58′13.40″N 13 º 36′48.42″W, 17-VIII-2015; MNCN 20.04 /20489–20.04/20545 (Table 2). Published records. Chad: “Guelta de Koub Basso, mountain massif of Ennedi (Monod 1969). Mali-Niger: Bassin du Moyen-Niger, Simbidissi (Daday1910b). Senegal: Ndilla, close to Linguère (Monod 1969); Tambacounda, Poull Koz, 40 or 50 km northeast from the oriental edge of British Gambia (Gauthier 1951); Tambacounda, Poull Bourgou, in the forest savanna that extends to southwest of Tambacounda (Gauthier 1951). Geographic distribution. Reported from Chad, Gambia, Mali-Niger and Senegal (Daday 1910b; Gauthier 1951; Monod 1969; Belk & Brtek 1995, 1997; Rogers et al. 2013). Remarks. The type locality of this species is currently dubious, as “Bassin du Moyen-Niger, Simbidissi could be either in Mali or Niger. Branchinella chudeaui was described within Branchinellites on the basis of gonopodal traits, which are lacking in Branchinella s. str (Daday 1910b; Rogers 2006; Rogers et al. 2013)., Published as part of Sainz-Escudero, Lucía, Alonso, Miguel & Sánchez-Vialas, Alberto, 2022, Diversity and distribution of Anostraca in temporary ponds in Western Africa with description of a new species of Streptocephalus Baird, 1852 (Pancrustacea: Branchiopoda: Streptocephalidae), pp. 388-412 in Zootaxa 5213 (4) on pages 405-406, DOI: 10.11646/zootaxa.5213.4.4, http://zenodo.org/record/7381453, {"references":["Daday, E. V. (1910 b) Quelques Phyllopodes Anostraces. Nouveaux. Appendice a la Monographie Systematique des Phyllopodes Anostraces avec 5 figures dans le texte. Annales des Sciences Naturelles, Zoologie, Series 9, 12, 241 - 264.","Linder, F. (1941) Contributions to the morphology and the taxonomy of the Branchiopoda Anostraca. Zoologiska Bidrag fran Uppsala, 20, 101 - 303.","Belk, D. & Brtek, J. (1995) Checklist of the Anostraca. Hydrobiologia, 298, 315 - 353. https: // doi. org / 10.1007 / BF 00033826","Monod, T. (1969) Contribution a l'etude des eaux douces de l'Ennedi IV. Crustaces Phyllopodes. Bulletin de l'Institut Francais d'Afrique Noire, 31, 500 - 523.","Gauthier, H. (1951) Contribution l'etude de la faune des eaux douces au Senegal (Entomostraces). Imprimerie Minerva, Alger, 169 pp.","Belk, D. & Brtek, J. (1997) Supplement to \" Checklist of the Anostraca \". Hydrobiologia, 359 (1 - 3), 243 - 245. https: // doi. org / 10.1023 / A: 1003172516989","Rogers, D. C., Shu, S. & Yang, J. (2013) The identity of Branchinella yunnanensis Shen, 1949, with a brief review of the subgenus Branchinellites (Branchiopoda: Anostraca: Thamnocephalidae). Journal of Crustacean Biology, 33 (4), 576 - 581. https: // doi. org / 10.1163 / 1937240 X- 00002155","Rogers, D. C. (2006) A genus level revision of the Thamnocephalidae (Crustacea: Branchiopoda: Anostraca). Zootaxa, 1260 (1), 1 - 25. https: // doi. org / 10.11646 / zootaxa. 1260.1.1"]}

Streptocephalus wolof sp. nov. (Figs. 6–9) Etymology. The name wolof refers to the ethnic group native to Senegal, Gambia, and in a lesser extent, to Mauritania. Most of the known geographic range of the newly described species overlaps with the Wolof ethnic distribution. The name is a noun in genitive case. Type material. Holotype. Male: Senegal, Tambacounda, 6 km west of Koutenabe, 93 m, 14 º 15′34.38″N, 12 º 35′42.38″W, 16-VIII-2015 (white label, printed); MNCN 20.04 /20321 (white label, printed); Holotypus, Streptocephalus wolof Sainz-Escudero, Alonso & Sánchez-Vialas, des. 2022 (white label printed). Paratypes. 20males, 15 females: Senegal, Saint-Louis, 2 km north of Podor, 9 m, 16 º 40′17.43″N, 14 º 57′55.29″W, 18-VIII-2015 (white label, printed); MNCN 20.04 /20269–20.04/20289 and 20.04/20327–20.04/20340 (white label, printed). Twenty-six males, 50 females: Senegal, Ziguinchor, Diembéreng, 9 m, 12 º 28′00.61″N, 16 º 47′02.16″W, 13-VIII-2015 (white label, printed); MNCN 20.04 /20290–20.04/20302 and 20.04/20341–20.04/20403 (white label, printed). Thirteen males, 22 females: Senegal, Matam, 1.9 km south-east of Bokiladji, 30 m, 15 º 02′48.91″N, 12 º 43′49.78″W, 17-VIII-2015 (white label, printed); MNCN 20.04 /20303–20.04/20320 and 20.04/20404- 20.04/20420(white label,printed). Five males: Senegal, Tambacounda, 6km west of Koutenabe, 93 m, 14 º 15′34.38″N, 12 º 35′42.38″W, 16-VIII-2015 (white label, printed); MNCN 20.04 /20321–20.04/20326 (white label, printed). All paratypes labelled: “ Paratypus, Streptocephalus wolof Sainz-Escudero, Alonso & Sánchez-Vialas, des. 2022 (white label printed) (Table 2). Description. Male. Head (Fig. 6A) round. Nuchal organ visible. Eyes spherical with diameter as long as its corresponding eyestalk. First antennae filiform, 2 times longer than basal joint of second antenna (Fig. 6A). Distal end with 3 subdistal setae, approximately 2–2.5 times longer than antennular thickness (Fig. 6B). Frontal appendage (Fig. 6C) consisting of 2 slightly curved long and pointed branches, reaching half-length of distal antennomere, with 2 small tips at inner margin, one close to base and other approximately in its half. Single acute basal projection in its ventral surface, whose length is about one-third of the latter. Second antennae (Fig. 6D) reaching thoracopod IX or X when extending backwards. Proximal and distal antennomeres subcylindrical, similar in length, 2 times as long as broad. Inner longitudinal row of 12 or 13 small papillae (sp) from medial part of proximal antennomere to medial part of distal antennomere. Medial part of distal antennomere with transversal row of 5–7 small papillae. Small papillae consist of a conical base with 1 apical small sensory seta. Apical joint (aj) oriented ventrolaterally, at distal end of basal joint, approximately as long as distal antennomere. Hand (according to Maeda-Martínez et al. 1995b) with 2 sharp and smooth rami. Longest ramus (anterior primary ramus, “thumb) 2 times longer than distal antennomere, slightly curved at end of proximal third; small subtriangular blunt (spur) present in its proximal part. Shorter ramus (posterior ramus, “finger) 0.6 times of anterior primary ramus length, and dorsally bent; proximal part with a small rounded protruding structure followed by short thickening. Labrum (Fig. 6E) subtrapezoidal, without distal protuberances; terminal fleshy process straight, tapering distally. Two setulose pads placed ventrally midway and in the base of fleshy process. Phyllopodia with gross structure, typical of the genus (Figs. 7A–E). Eleven pairs of thoracopods. First thoracopod (Fig. 7A) 2 times shorter than seventh thoracopod (Fig. 7C); eleventh thoracopod (Fig. 7E) 0.8 times longer than seventh thoracopod; rest of thoracopods subsimilar in size. Praepipodite (PE) oval, with serrated outline in all thoracopods. Epipodite (EP) wide, with undulated margin (Figs. 7A, C) in the tenth anterior thoracopod; eleventh thoracopod epipodite elongated, with serrated extreme (Fig. 7E). Exopodite (EX) oval, bordered by plumose marginal setae; first thoracopod small (Fig. 7A), not sticking out from endopodite; rest of thoracopods (Figs. 7C, E) of similar size to endopodite. Endopodite (EN) broad, covered by short plumose setae in its outer margin, and provided with a more or less marked depression in the middle (Figs. 7A, C, E). Endites from first to tenth thoracopods: first endite with 2 submarginal spine-like setae on anterior surface, proximal one long and thin, provided with denticles, and distal one shorter, spiniform, with a basal tiny spine-like seta (Figs. 7A, C); second endite with a long spiniform proximal seta, submarginal on anterior surface, with a basal tiny seta (Figs. 7A, C); third endite with 2 unequal submarginal spinelike seta on anterior surface and three plumose setae on posterior surface (Figs. 7B, D); 4 endite with 2 unequal submarginal spinelike seta on anterior surface and 2 plumose setae on posterior surface (Figs. 7B, D); fifth endite with 3 unequal submarginal spinelike seta on anterior surface and 2 plumose setae on posterior surface (Figs. 7B, D). Endites to eleventh thoracopod (Fig. 7E): first endite with submarginal spine-like setae very reduced; second endite with 2 small spines on anterior surface and 3 plumose setae on posterior surface; third and fourth endites with 2 small spines in anterior surface and 2 plumose setae on posterior surface; fifth endite with 1 small spine in anterior surface and 2 plumose setae on posterior surface. Abdominal segments (Fig. 8A) typical of the genus. First, second, and third segments with 2 small cuticle projections, one at each side, close to posterior margin (pointed with arrow in Fig. 8A). Genital segments (Fig. 8B) slightly expanded and partially fused. First segment ventrally smooth. Second segment with linguiform outgrowths 2 times shorter than basal part of gonopods, placed posterolaterally on ventral surface. Basal part of gonopods non-retractile, reaching the end of third abdominal segment; spinulated appendix located in its basal inner side and 2 rounded expansions in its distal end. Everted part of gonopods twice longer than basal part, provided with longitudinal rows of spines. Cercopods (Fig. 8C) of the type “spinose cercopods sensu Maeda-Martínez (1995b), sclerotized, with short spine-like setae replacing the marginal plumose setae on the distal half. Cercopods as long as the last 4 abdominal segments. Anus terminal. Female. First antennae (Fig. 9A) filiform 4 times longer than eye diameter, and 2 and a half longer than second antenna. Distal end as in male. Second antennae (Fig. 9A) broad with rounded end, little longer than eye plus stalk. Distal surface and margins bearing short setae. One small marginal beak on anterior edge close to distal end. Thoracopods as in male. Abdominal segments (Fig. 9C) with smooth surface. Some of them bearing warty outgrowths provided with sensillae (in fourth and sixth segments in the figure). Genital segments (Fig. 9C) completely fused. Brood pouch elongate, fusiform extending to middle of fourth abdominal segment; end provided with an angular flat expansion directed posteriorly (Fig. 9D). Eggs subspherical; surface covered by wide protruding keeled ribs delimiting polygonal fields (Fig. 3A). Diameter around 200 µm. Cercopods (Fig. 9E) broad in the base, margined on both sides by feathery setae gradually shortening to their acute end. Length as last four abdominal segments plus telson. Size. Total body length of the holotype (MNCN 20.04/20321), (including cercopods setae): 7.48 mm. Largest female specimen recorded: 10.56 mm. Geographic distribution. Streptocephalus wolof is known from the following localities in Senegal: 2 km north of Podor, Diembéreng, 1.9 km south-east of Bokiladji, 6 km east of Koutenable and Diabal (Table 2). Future studies could likely extend its distribution to the neighboring countries Mauritania, Gambia, Mali, Guinea, and Guinea-Bissau. The previous recorded populations identified as S. zeltneri in Senegal [Lingure and Palagu (Monod 1969; Hamer et al. 1994b; Maeda-Martínez et al. 1995b)] require revision as they were not examined by us, and therefore, we were unable to confirm its taxonomic identity. However, we tentatively treated these records as S. zeltneri until additional studies confirm its identity (Fig. 1). Remarks. The new species is closely related to Streptocephalus zeltneri. Both species cannot be distinguished based on adult morphological characters, and consequently they can be considered as cryptic species (Marrone et al. 2017). However, they differ on the basis of the eggs macrosculpture. Eggs of S. wolof present their surface covered with carinated ribs, delimiting polygons of variable number of sides (Fig. 3A). This trait was consistent in each revised population that contained mature females. Streptocephalus wolof is the most commonly found and widespread Anostraca species in Senegal, occurring in several ecoregions (including the Sahelian and Sudanian savannas, and the Guinean forest savanna close to the Guinean forest) (Fig. 1). The studied specimens of S. wolof were found during the rainy season in temporary ponds, both with transparent and turbid waters, often in syntopy with amphibian larvae, as Sclerophrys xeros (Tandy, Tandy, Keith & Duff-MacKay, 1976), Kassina senegalensis (Duméril & Bibron, 1841), K. fusca Schiøtz, 1967, Ptychadena bibroni (Hallowell, 1845), and Phrynobatrachus francisci Boulenger, 1912 (Fig. 5)., Published as part of Sainz-Escudero, Lucía, Alonso, Miguel & Sánchez-Vialas, Alberto, 2022, Diversity and distribution of Anostraca in temporary ponds in Western Africa with description of a new species of Streptocephalus Baird, 1852 (Pancrustacea: Branchiopoda: Streptocephalidae), pp. 388-412 in Zootaxa 5213 (4) on pages 397-399, DOI: 10.11646/zootaxa.5213.4.4, http://zenodo.org/record/7381453, {"references":["Maeda-Martinez, A. M., Belk, D., Obregon-Barboza, H. & Dumont, H. J. (1995 b) A contribution to the systematics of the Streptocephalidae (Branchiopoda: Anostraca). Hydrobiologia, 298, 203 - 232. https: // doi. org / 10.1007 / 978 - 94 - 011 - 0291 - 9 _ 19","Monod, T. (1969) Contribution a l'etude des eaux douces de l'Ennedi IV. Crustaces Phyllopodes. Bulletin de l'Institut Francais d'Afrique Noire, 31, 500 - 523.","Hamer, M., Brendonck, L., Coomans, A. & Appleton, C. (1994 b) A review of the African Streptocephalidae (Crustacea: Branchiopoda: Anostraca) Part 2: north of Zambezi and Kunene rivers. Archiv fur Hydrobiologie, 99, 279 - 311.","Marrone, F., Rogers, D. C., Zarattini, P. & Naselli-Flores, L. (2017) New challenges in anistracan research: old issues, new perspectives and hot topics. Hydrobiologia, 801, 179 - 185. https: // doi. org / 10.1007 / s 10750 - 017 - 3345 - 6","Tandy, M., Tandy, J., Keith R. & Duff-MacKay, A. (1976) A new species of Bufo (Anura: Bufonidae) from Africa's dry savannas. Pearce-Sellards Series, Texas Memorial Museum, Austin, 24, 1 - 20.","Dumeril, A. M. C. & Bibron G. (1841) Erpetologie Generale ou Histoire Naturelle Complete des Reptiles. Vol. 8. Enclyclopdique Roret, Paris, 792 pp.","Schiotz, A. (1967) The treefrogs (Rhacophoridae) of West Africa. Spolia Zoologica Musei Hauniensis, KObenhavn, 25, 1 - 346.","Hallowell, E. (1845) Descriptions of new species of African reptiles. Proceedings of the Academy of Natural Sciences of Philadelphia, 2, 247 - 250.","Boulenger, G. A. (1912) Descriptions of new African batrachians preserved in the British Museum. Annals and Magazine of Natural History, Series 8, 10, 140 - 142. https: // doi. org / 10.1080 / 00222931208693207"]}

Streptocephalus zeltneri Daday, 1910 Streptocephalus (Streptocephalopsis) zeltneri Daday, 1910a: 396 [Terra typica: Africa centralis, Sudan, Yéliman]. Material examined. Two specimens of Type material (syntypes), one male with broken cercopods and one female, labelled as follows: Yeliman, 1907, F. de Zeltner leg., Muséum National d’Histoire Naturelle, Paris; MNHN-Bp 225 (MNHN-IU-2007-483). Additional examined specimens. All from Senegal. Two males and 13 females from Kédougou, 2.3 km east of Bandafassi, 141 m, 13 º 46′36.66″N 13 º 44′13.02″W, 07-VIII-2015; MNCN 20.04 /20421–20.04/20435. One male and two females also from Kédougou, 2.3 km east of Bandafassi, 161 m, 12 º 32′3.38′′N 12 º 18′32.59′′W, 10-VIII- 2015; MNCN 20.04 /20436–20.04/20438. One individual from Kédougou, Bandafassi, 141 m, 12 º 32′21.13″N 12 º 17′20.89″W, 10-VIII-2015; MNCN 20.04 /20439 (Table 2). Published records. Mali: Goumbou (Hamer et al. 1994b; Maeda-Martínez et al. 1995b); Yéliman (Hamer et al. 1994b; Belk & Brtek 1997). Senegal: pool at Ndilla dam, close to Linguère (Monod 1969; Hamer et al. 1994b); Palagu (Maeda-Martínez et al. 1995b). Geographic distribution. This species is only known from Mali and Senegal (Monod 1969; Hamer et al. 1994b; Maeda-Martínez et al. 1995b; Belk & Brtek 1997). Records from Sudan (Hamer et al. 1994b; MaedaMartínez et al. 1995b) are currently located in Mali. The previously recorded populations of S. zeltneri in Senegal need revision (see comments on the geographic distribution account of S. wolof). Remarks. According to the literature, Streptocephalus zeltneri is morphologically similar to S. trifidus Hartland-Rowe, 1969 and S. bouvieri Daday 1910 (Daday 1910a; Hartland-Rowe 1969; Hamer et al. 1994b). In their revision, Maeda-Martínez et al. (1995b) included S. zeltneri in a species group formed by S. bouvieri, S. gauthieri, S. rothschildi and S. spinifer. A more detailed study including morphological and molecular characters would be desirable to unveil the evolutionary relationships among the species of the bouvieri species group sensu Maeda-Martínez et al. (1995b). Brendonck & Coomans (1994) provided a description and a picture of the eggs of the holotype of S. zeltneri, stating that the eggs have simple and more or less regular polygons, and that their ribs are unkeeled. Similarly, the eggs from our samples of S. zeltneri of southeastern Senegal, have unkeeled ribs (Fig. 3B). This trait was consistent in the revised populations of S. zeltneri with mature females (two out of the three populations). Specimens were found in small and transparent pools with clam shrimps. Live specimens present the cercopods and the brood pouch with a strong red coloration., Published as part of Sainz-Escudero, Lucía, Alonso, Miguel & Sánchez-Vialas, Alberto, 2022, Diversity and distribution of Anostraca in temporary ponds in Western Africa with description of a new species of Streptocephalus Baird, 1852 (Pancrustacea: Branchiopoda: Streptocephalidae), pp. 388-412 in Zootaxa 5213 (4) on pages 404-405, DOI: 10.11646/zootaxa.5213.4.4, http://zenodo.org/record/7381453, {"references":["Daday, E. V. (1910 a) Monographie systematique des Phyllopodes Anostraces. Annales des Sciences Naturelles, Zoologie, Series 9, 11, 91 - 489.","Hamer, M., Brendonck, L., Coomans, A. & Appleton, C. (1994 b) A review of the African Streptocephalidae (Crustacea: Branchiopoda: Anostraca) Part 2: north of Zambezi and Kunene rivers. Archiv fur Hydrobiologie, 99, 279 - 311.","Maeda-Martinez, A. M., Belk, D., Obregon-Barboza, H. & Dumont, H. J. (1995 b) A contribution to the systematics of the Streptocephalidae (Branchiopoda: Anostraca). Hydrobiologia, 298, 203 - 232. https: // doi. org / 10.1007 / 978 - 94 - 011 - 0291 - 9 _ 19","Belk, D. & Brtek, J. (1997) Supplement to \" Checklist of the Anostraca \". Hydrobiologia, 359 (1 - 3), 243 - 245. https: // doi. org / 10.1023 / A: 1003172516989","Monod, T. (1969) Contribution a l'etude des eaux douces de l'Ennedi IV. Crustaces Phyllopodes. Bulletin de l'Institut Francais d'Afrique Noire, 31, 500 - 523.","Hartland-Rowe, R. (1969) A new species of Streptocephalus (Anostraca) from Rhodesia. Crustaceana, 16 (1), 78 - 80. https: // doi. org / 10.1163 / 156854068 X 00205","Brendonck, L. & Coomans, A. (1994) Egg morphology in African Streptocephalidae (Crustacea: Branchiopoda: Anostraca) Part 2: North of Zambezi and Kunene rivers, and Madagascar. Archiv fur Hydrobiologie, 99 (3), 335 - 356."]}

Streptocephalus sudanicus Daday, 1910 Streptocephalus sudanicus Daday, 1910b: 261 [Terra typica: Sudan, Nioro. Types at the Museum National d’Histoire Naturelle, Paris, and (6942) at the Zoological Institute of the Academy of Sciences (Saint Petersburg, Russia); Belk & Brtek 1995]. Material examined. Six males, seven females from Senegal: Tambacounda, Gourel Yoba, 39 m, 13º25′04.62″N 13 º 24′30.23″W, 11-VIII-2015; MNCN 20.04 /20440–20.04/20452. One male from Senegal: Tambacounda, Diabal, 56 m, 14 º 45′37.66″N 12 º 26′06.66″W, 16-VIII-2015; MNCN 20.04 /20453 (Table 2). Published records. Burkina Fasso: Arbolle, Nion (Maeda-Martínez et al. 1995b). Mali: Nioro du Sahel (Brendock et al. 1992; Belk & Brtek 1997); Yéliman (Belk & Brtek 1997); Goumbou (Belk & Brtek 1997). Niger: Chad-Niger región; Margdi (Brendock et al. 1992). Nigeria: Tofa E of Kabo (Maeda-Martínez et al. 1995b). Senegal: pond in Ndilla, close to Linguère (Monod 1969; Brendock et al. 1992); Palagu (Maeda-Martínez et al. 1995b). Sudan: Kas, E Nyalal lake (Maeda-Martínez et al. 1995b); Geographic distribution. Burkina Faso, Mali, Niger, Senegal, Sudan. Some localities reported from Sudan (Brendock et al. 1992) are actually located in Mali. Remarks. Brendock et al. (1992) noted the singularities of Streptocephalus sudanicus based on the presence of spinules on the finger dorsal side and the existence of tetrahedral eggs (Fig. 3C). They also created a new taxon, the subgenus Parastreptocephalus, based on these characters. Other species included in this taxon are S. lamellifer Thiele, 1900, S. kaokoensis Barnard, 1929, and S. zuluensis Brendonck & Hamer, 1992 (Brendock et al. 1992). The studied pecimens of S. sudanicus were found in pools with turbid water. Live specimens present the cercopods with a marked red coloration., Published as part of Sainz-Escudero, Lucía, Alonso, Miguel & Sánchez-Vialas, Alberto, 2022, Diversity and distribution of Anostraca in temporary ponds in Western Africa with description of a new species of Streptocephalus Baird, 1852 (Pancrustacea: Branchiopoda: Streptocephalidae), pp. 388-412 in Zootaxa 5213 (4) on page 405, DOI: 10.11646/zootaxa.5213.4.4, http://zenodo.org/record/7381453, {"references":["Daday, E. V. (1910 b) Quelques Phyllopodes Anostraces. Nouveaux. Appendice a la Monographie Systematique des Phyllopodes Anostraces avec 5 figures dans le texte. Annales des Sciences Naturelles, Zoologie, Series 9, 12, 241 - 264.","Belk, D. & Brtek, J. (1995) Checklist of the Anostraca. Hydrobiologia, 298, 315 - 353. https: // doi. org / 10.1007 / BF 00033826","Maeda-Martinez, A. M., Belk, D., Obregon-Barboza, H. & Dumont, H. J. (1995 b) A contribution to the systematics of the Streptocephalidae (Branchiopoda: Anostraca). Hydrobiologia, 298, 203 - 232. https: // doi. org / 10.1007 / 978 - 94 - 011 - 0291 - 9 _ 19","Belk, D. & Brtek, J. (1997) Supplement to \" Checklist of the Anostraca \". Hydrobiologia, 359 (1 - 3), 243 - 245. https: // doi. org / 10.1023 / A: 1003172516989","Monod, T. (1969) Contribution a l'etude des eaux douces de l'Ennedi IV. Crustaces Phyllopodes. Bulletin de l'Institut Francais d'Afrique Noire, 31, 500 - 523.","Thiele, J. (1900) Uber eine von Herrn O. Neumann gefundene Phyllopoden-art. Zoologischen Jahrbuchen: Abtheilung fur Systematik Geographie und Biologie der Thiere, 20, 371 - 374.","Barnard, K. H. (1929) Contributions to the Crustacean fauna of South Africa. 10. A revision of Branchiopoda (Phyllopoda). Annals of the South African Museum, 29, 181 - 270.","Brendonck, L., Hamer, M. & Thiery, A. (1992) Occurrence of tetrahedral eggs in the Streptocephalidae Daday (Branchiopoda: Anostraca) with descriptions of a new subgenus, Parastreptocephalus, and a new species, Streptocephalus (Parastreptocephalus) zuluensis Brendonck and Hamer. Journal of Crustacean Biology, 12 (2), 282 - 297. https: // doi. org / 10.2307 / 1549081"]}

Three genera of Anostraca have been recorded so far in Senegal: Streptocephalus Baird, 1852, Branchinella Sayce, 1903 and Artemia Leach, 1819. The occurrence of the previously recorded freshwater species in Senegal have been confirmed in this work, namely Streptocephalus zeltneri Daday, 1910, S. sudanicus Daday, 1910 and Branchinella (Branchinellites) chudeaui (Daday, 1910). New records and the description of a new species are given. The new species, Streptocephalus wolof sp. nov., has been recognized through molecular (mitochondrial and nuclear markers) and morphological (egg shape) data. The adult stage of this new species is morphologically indistinguishable to its closely related species Streptocephalus zeltneri, suggesting the existence of two cryptic species in Senegal. Finally, some taxonomic comments on the genus Streptocephalus are presented.

Sinev, Artem Y., Dadykin, Ivan A. (2022): Notes on morphology and ecology of an elusive water flea Rhynchotalona latens (Sarmaja-Korjonen, Hakojärvi & Korhola, 2000) (Crustacea: Cladocera). Zootaxa 5200 (3): 260-270, DOI: https://doi.org/10.11646/zootaxa.5200.3.4

Here we report the complete mitochondrial genome of the Arctic fairy shrimp, Branchinecta paludosa (Müller, 1788) (Anostraca, Branchinectidae), which was collected in the High Arctic of North Greenland. A complete 16,059 bp mitochondrion of B. paludosa was sequenced and assembled with the Illumina next generation sequencing platform. The B. paludosa mitogenome contains 13 PCGs, 22 tRNAs and 2 rRNA genes that are commonly observed in most metazoans and shows the conserved gene arrangement pattern of Anostraca. Our results of the phylogenomic analysis are consistent with the previous phylogenetic relationship, based on nuclear 18S ribosomal DNA. The B. paludosa mitogenome will be useful for understanding the geographical distribution and phylogenetic relationship of anostracans.

Rhynchotalona latens (Sarmaja-Korjonen, Hakojärvi et Korhola, 2000) Sarmaja-Korjonen et al., 2000: 166–167, Fig. 2 (Unapertura); Van Damme & Nevalainen, 2019: 465–466, Fig. 1–3; Korovchinsky et al., 2021: 386, Fig. 117:10–13. Description. Parthenogentic female. Body oval in lateral view, low in juveniles (Figs. 1A,B), of moderate height in adults (Figs. 1C,D, 2A–F); maximum height at body middle or behind it; body moderately compressed laterally. Height-length ratio about 0.6 in adults. Dorsal margin strongly convex, postero-dorsal and postero-ventral angles broadly rounded. Posterior margin strongly convex, ventral margin almost straight, antero-ventral angle rounded. Ventral margin (Fig. 1E) with about 40 setae; about 10–15 anterior setae moderately long, 5–7 middle setae very short, posterior 20 setae (Figs. 3E–F) very long, longer than setae of anterior group, posteriormost setae in the group being longest, located at postero-ventral angle. Postero-ventral angle (Fig. 1F) without denticles, with 15–20 moderately long setulae not reaching to the margin of the valves. A row of about 100 very short setulae along posterior margin on inner side of carapace. Sculpture of valves variable, with well or weakly developed longitudinal lines (Figs. 2A–C, F), or with tubercles (Figs. 2D,E). Unlike most Aloninae, adult female always bears a single parthenogenetic egg in the brood chamber; length of the egg slightly less than half-length of specimen. Head relatively small, triangular in lateral view. In lateral view rostrum moderately long, about two lengths of antennule, weakly curved posteriorly. Ocellus smaller than eye. Distance from tip of rostrum to ocellus about 2–2.5 times of that between ocellus and eye. Head shield with shape typical for the alonines, with maximum width behind maxillar articulation, smooth in specimens with linear sculpture of valves, tuberculated in specimens with tuberculated valves. Rostrum elongated, narrow triangular in dorsal view, with rounded tip (Figs. 1G, 3A). Posterior margin of head shield rounded (Figs. 4A,B). Main head pore (Figs. 4A,B) as oval rimmed field; distance from pore to the posterior end of head shield slightly greater than pore length. Lateral head pores minute, located at about two lengths of main head pore from midline, at the level of anterior margin of main head pore. Labrum (Figs. 1H–J) small, without lateral projections. Labral keel of narrow, height about 2 times width. Anterior margin of keel evenly convex, apex broadly rounded, posterior margin weakly convex, without clusters of setules. Thorax two times longer than abdomen. Dorsal surface of abdominal segments not saddle-shaped. Postabdomen short and narrow, with almost parallel margins (Figs. 1K, 4C–E). Distal angle obtuse, rounded. Dorsal margin with anal portion longer than postanal one. Preanal and postanal angles weakly defined. Preanal margin without notches. Postanal margin with 5–6 large single marginal denticles, length of largest of them 1.5 greater than width of postabdominal claw base. Anal margin with 2–3 groups of small spinules. Postanal part with about 3–4 well-developed lateral fascicles of 3–6 thick setules, shorter than marginal denticles; in anal portion 4–5 groups of 7–15 thinner, shorter setulae. Postabdominal claw (Figs. 1L, 4F) weakly curved, shorter than preanal portion of postabdomen. Basal spine short, slightly curved, about 0.15–0.2 length of claw. Antennule long, truncated at the end (Figs. 1M, 3B). Antennular sensory seta slender, about half length of antennule, arising at 2/3 distance from the base. Nine terminal aesthetascs, two longest only slightly shorter than antennule. Antenna of moderate length (Figs. 3C,D, 5A), antennal formula: setae 0-0-3/0-0-2; spines 1-0-1/0-0-1. Basipodite robust, with small seta between branches. Branches with segments of similar length. Spine on basal segment of exopodite about 1/3 length of middle segment. Spine on apical segment of endopodite significantly longer than apical segment. Spine on apical segment of exopodite as long as apical segment. One seta on apical segment of exopodite two times shorter and thinner than two others; longer setae on apical segment of exopodite of similar length and thickness than apical setae of endopodite. Thoracic limbs: six pairs. Limb I (Figs. 5B–C). Epipodite rounded, with a process 2–2.5 times longer than epipodite itself. Accessory seta moderately long, two times shorter than ODL single seta. IDL with two setae, seta 1 not found, setae 2 and 3 moderately thick, armed distally with thin setules, seta 2 slightly shorter than ODL seta, seta 3 slightly longer than ODL seta. Setae of endite 3 increasing in length from behind; seta c of same morphology as setae e–f of endite 2. Inner seta (2) on endite 2 not found; seta b much shorter than setae e–f; setae e and f of similar length, two times shorter than limb itself. Endite 1 with short inner seta (3), two two-segmented setae (g–h) and a short flat seta (i). Ventral face of limb with 5–6 clusters of setae. Maxillar process short, with a single seta. Limb II (Figs. 5D,E). Exopodite elongated, with a long seta. Eight scraping spines decreasing in length proximally, armed with thin setules. Distal armature of gnathobase with four elements. Filter plate with seven setae, posteriormost seta remarkably shorter than others. Limb III (Figs. 5F,G). Epipodite without a process. Exopodite subquadrangular, with seven setae. Setae 1–5 plumose, setae 6–7 slender, thin, without long setules. Seta 3 being longest, seta 6 slightly shorter than seta 3, setae 1, 4 and 7 about half length of seta 3, setae 2 and 5 of 1/4 and 1/3 length of seta 3 respectively. Distal endite with three long setae, two distal setae (1–2) long and thin adapted for scraping, small sensillum (s) located between their bases, seta 3 flattened, with long setules. Basal endite with four stiff setae (a–d) of similar size. Four soft setae increasing in size proximally, small sensillum near the base of distalmost seta. Distal armature of gnathobase with four elements: an elongated, cylindrical sensillum; large geniculated seta; and two spines with fused bases. Filter plate of seven setae. Limb IV (Figs. 5H,I). Pre-epipodite setulated; epipodite with a process longer than epipodite itself. Exopodite subrectangular, with six setae Setae 1–4 flattened, plumose, setae 5–6 slender, thin, naked. Seta 1 being longest, setae 2–3 slightly shorter thans seta 1, seta 4 about 1/3 length of seta 1, setae 5–6 about 2/3 length of seta 1. Inner portion of limb IV with four setae and small elongated sensillum (s) (see Fig. 5I). Scraping seta (1) moderately long, three flaming-torch setae elongated, of similar length, first of them (2) armed with long, thick setulae, two other—with short thin setulae. Three soft setae (a–c) increasing in length basally. Gnathobase with two-segmented seta and a small hillock distally. Filter plate with five setae. Limb V (Figs. 5J,K). Pre-epipodite setulated. Epipodite with a process longer than epipodite itself. Exopodite clearly bilobed of moderate size, with four plumose setae decreasing in length basally; seta 4 about half length of seta 1. Inner limb portion as elongated oval lobe with setulated inner margin. At inner face, two short setae of similar length. Filter plate with three small setae and a large triangular sensillum (s). Limb VI as oval setulated lobe (Fig. 5L). Ephippial female and male unknown. Size. Single found juvenile female of instar I length 0.21 mm, height 0.11 mm Juvenile females of instar II length 0.26–0.27 mm, height 0.14–0.15 mm. Adult parthenogenetic female length 0.27–0.33 mm, height 0.17–0.2 mm. Differential diаgnosis. Rhynchotalona latens differs from all other species of the genus in shape of head shield, which has a broadly rounded posterior angle, and in lateral pores located at significant distance from midline. All other species of the genus (see Røen 1973; Sinev & Kotov 2014) have the posterior portion of the head shield as a broad elongated protrusion with rounded tip, and lateral head pores located very close to the main pore. Habitually, R. latens is most similar to Greenland endemic R. kistarae Røen, 1973, these species differ in shape of the main head pores, which is elongated in R. kistarae. R. latens clearly differs from species of falcata -clade (R. falcata (Sars. 1862), R. weiri Sinev & Kotov, 2014, and R. longiseta Sinev & Kotov, 2014) in rounded anteroventral corner of valves and armament of the postabdomen. In species of the falcata -clade the anteroventral corner of the valves forms an elongated protrusion with rounded tip (Sinev & Kotov 2014). Other differences between R. latens, R. kistarae and species of the falcata -clade are summarized in Table 1. Distribution and ecology. Recent findings belong to Finland, North Karelia and Pechora River Delta. This is an interstitial species, dwelling within patches of the waterlogged Sphagnum mosses at lakes shores; some specimens are accidentally found in littoral zone of such lakes. Water conditions measurements, taken on 26 June 2022 at Krugloe Lake, reveal significant differences between littoral zone of the lake and the patches of Sphagnum mosses. Water squeezed from Sphagnum had a temperature 24.9°C, pH 3.4, oxygen concentration 3.4 mg /l (saturation 41%) and conductivity 34.1 µS/cm, while littoral lake water at 10–15 cm from the coast had temperature 22.1°C, pH 5.3, oxygen concentration 8.8 mg /l (saturation 100%), and conductivity 24 µS/cm. In the studied material, only parthenogenetic females were present from late June to the middle of September. R. latens seems to be a slow and rather reluctant swimmer; observed specimens swim rather slow, unsteady, and for short periods, usually less than 10–15 seconds, preferring crawling on substrate using antennae and postabdomen., Published as part of Sinev, Artem Y. & Dadykin, Ivan A., 2022, Notes on morphology and ecology of an elusive water flea Rhynchotalona latens (Sarmaja-Korjonen, Hakojärvi & Korhola, 2000) (Crustacea: Cladocera), pp. 260-270 in Zootaxa 5200 (3) on pages 261-267, DOI: 10.11646/zootaxa.5200.3.4, http://zenodo.org/record/7260518, {"references":["Sarmaja-Korjonen, K., Hakojarvi, M. & Korhola, A. (2000) Subfossil remains of an unknown chydorid (Anomopoda: Chydoridae) from Finland. Hydrobiologia, 436, 165 - 169. https: // doi. org / 10.1023 / A: 1026502219867","Van Damme, K. & Nevalainen, R. L. (2019) The most latent cladoceran in the Holarctic revealed - sinking Unapertura Sarmaja-Korjonen, Hakojarvi & Korhola, 2000 into the genus Rhynchotalona Norman, 1903 (Branchiopoda: Cladocera: Chydoridae). Zootaxa, 4613 (3), 463 - 476. https: // doi. org / 10.11646 / zootaxa. 4613.3.3","Korovchinsky, N. M., Kotov, A. A., Sinev, A. Y., Neretina, A. N. & Garibian, P. G. (2021) Water fleas (Crustacea: Cladocera) of North Eurasia. Vol. 2. KMK Press, Moscow, 544 pp.","Roen, U. (1973) Rhynchotalona kistarae sp. n. from South Greenland (Crustacea, Cladocera, Chydoridae, Aloninae). Steenstrupia, 3, 89 - 92.","Sinev, A. Y. & Kotov, A. A. (2014) Revision of the Holarctic genus Rhynchotalona Norman, 1903 (Anomopoda: Chydoridae). Zootaxa, 3841 (2), 188 - 210. https: // doi. org / 10.11646 / zootaxa. 3841.2.2"]}

The complete mitochondrial genome of Antarctic fairy shrimp Branchinecta gaini Daday, 1910 was sequenced, assembled and annotated using next-generation sequencing technology. The mitogenome of B. gaini is circular at 15,536 bp in length, consisting of 13 protein-coding genes, 23 tRNAs, two rRNAs and two major non-coding regions. In particular, there are two tRNAGly genes and one non-coding region between these two tRNAGly genes. A phylogenetic tree was constructed using concatenated amino acid sequences of 13 protein-coding genes. It reveals that B. gaini is clustered with the Anostraca group within the Branchiopoda clade. This study helps us understand the evolution of Anostraca.