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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.

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.

Sound is the most effective means of communication in marine and freshwater ecosystems. However, no data about acoustic emissions from non-malacostracan crustaceans are currently available, so their ability to produce sounds is unknown. For the first time, this study investigated the sound produced by 2 tadpole shrimp species,Triops cancriformisandLepidurus lubbocki.L. lubbockiindividuals were collected from a natural temporary pond in Sicily (Italy), whereasT. cancriformisindividuals were obtained from eggs contained in sediment from a rock pool in Sardinia (Italy). In the laboratory, experimental tanks with the animals (one species at a time) were acoustically monitored. Both species produced high-frequency, wideband pulses distinguishable by their sound pressure level, which was higher inL. lubbocki(146 dB) than inT. cancriformis(130 dB), and by their first and second peak frequencies, which were higher inL. lubbocki(65 and 86 kHz) than inT. cancriformis(63 and 71 kHz). The energy distributions in the power density spectra showed different shapes, as revealed by the 3 dB bandwidth and centre frequency. The pulse durations were 88 and 97 µs inL. lubbockiandT. cancriformis, respectively.L. lubbockipresented a higher emission rate thanT. cancriformisand a marked circadian pattern, with a higher abundance of sounds during the night. This study reports the first evidence of sound emissions from non-malacostracan crustaceans and reveals the high potential of passive acoustic monitoring to detect the presence, abundance, and life cycle of these elusive keystone species of temporary water bodies.

In time of global climate changes, astatic inland water reservoirs that contribute to water retention and alleviation of adverse effects of periodic river floods, are getting more and more important. Small, periodically drying off water reservoirs are also rich hubs of biodiversity. Animals especially connected to such ecosystems are primitive but unique crustaceans called tadpole shrimps (order Notostraca). Those animals seem to have universal significance – both ecological and economic. Though their primitive morphology and small size, they can radically affect the nature of their habitats, sometimes even helping us fight with noxious pests. Unfortunately, due to progressing global warming, intensification in agriculture, and urbanisation, habitats of notostracans are disappearing rapidly. Simultaneously, because of their rare occurences and taxonomic difficulties, tadpole shrimps have been insufficiently studied. However, protection of these crustaceans is inseparably connected with conservation of once numerous, periodically drying reservoirs as tadpole shrimps are referred as keystone species of such habitats. Thus, the aim of this review article is to sum up and disseminate current state of knowledge about Notostraca by a general overview of available international literature. This might help to engage more scientists into research and conservation of these little known, yet interesting crustaceans and their unique habitats.

We investigated the presence and ecology of Chirocephalus croaticus (Steuer, 1899) during three successive seasons (spring and autumn 2018, spring 2019) at Lake Petelinje (SW Slovenia). Although the presence (duration, abundance) of this fairy shrimp strongly differs among different seasons and both years, we showed that in a season with favourable conditions (spring 2018) its abundance increases rapidly at the end of the season as the shrimps persist in small pools until the water dries out. The species may appear again during the autumn, however, its abundance and persistence seem to be much lower and shorter than during the spring, respectively. Nevertheless, persistence and abundance may also differ strongly among the two successive spring seasons (less shrimps found during the shorter season of 2019 than in 2018). Larvae appear first, and are most abundant at the beginning of the season, and are followed by adult males (protandry) and females, which become most abundant at the end of the season. Also, larvae seem to be more abundant on exposed bottom (gravel path), while adults are much more abundant in the shelter of a submerged meadow. Ovigerous females had 9-37 cysts (fertilized eggs) in their brood pouch, and the position of differently developed eggs changed during the season; the presence of females without eggs during mid- and at the end of season indicates the production of thin-shelled summer, and thick-shelled winter cysts, respectively. In contrast with the water decrease that is in strongly negative association with the abundance of the fairy shrimps (lake size — abundance: , ), no other environmental parameters were highly associated () with species abundance. Although the local population (one of only two currently known) seems to be in good condition, appropriate conservation action should be taken to prevent the decrease of this population in the future.

Fairy shrimp are the most divergent taxon of large branchiopod crustaceans and have a worldwide distribution. Yet the diversity and distribution of fairy shrimps in the “Roof of the World” remain poorly known. Here, based on morphology, we identified three species of fairy shrimp (Branchinecta orientalis, Chirocephalus graziellae and Branchipodopsis affinis), among 14 fairy-shrimp populations from the Tibetan Plateau, China. Their phylogenetic relationships were verified based on mitochondrial DNA sequences (cytochrome c oxidase subunit I gene) and two nuclear markers (18S ribosomal RNA gene and internal transcribed spacer 2). Syntopy of different species of fairy shrimp was observed. Some haplotypes were shared among populations, and sequences from B. affinis exhibited a star-like pattern in haplotype networks, suggesting a recent rapid expansion. Finally, a high genetic diversity of fairy shrimp was detected on the Tibetan Plateau. Obtained results contribute to a better knowledge of the diversity of high-altitude fairy shrimps.

Abnormal trunk morphology is observed in two populations of Bosmina longirostris. One population is from a trout cultivation pond, the other from a pond with a very high angling pressure. The length and shape of the first antenna (trunk) of part of the population are abnormal. No abnormalities were observed at three locations, with low or no angling pressure. The observations are considered in the context of the described variation in the first antenna of this species. Possible causes of the abnormalities are discussed.

In Yellowknife (Northwest Territories, Canada), roaster stack emissions from historic gold mining activities, particularly Giant Mine (1948–2004), have left a legacy of arsenic contamination in lakes. We examined Cladocera (Branchiopoda, Crustacea) subfossil remains in the recent and pre-industrial sediments of 23 lakes (arsenic gradient of 1.5–750 µg/l) within a 40 km radius of Giant Mine to provide a snapshot of regional change in Cladocera since pre-1850. We found that littoral and benthic taxa dominated the recent assemblages in high-[As] lakes (surface water [As] > 100 µg/l), while pelagic Bosmina was dominant in lakes with lower [As]. Cladocera richness and diversity were positively correlated with [As] (P = 0.004, R2 = 0.39; and P = 0.002, R2 = 0.46, respectively), except for four lakes with [As] > 100 µg/l. The lakes that showed the most pronounced changes in Cladocera since pre-1850 were those affected by both metal(loid) pollution and urban development, where complete shifts in the dominant taxa occurred. Lakes that were most heavily impacted by arsenic emissions did not experience notable shifts in Cladocera assemblages. Our study suggests that changes in Cladocera assemblages in mining-impacted subarctic lakes are modulated by local, lake-specific limnological conditions and the interaction of multiple stressors.

The class Branchiopoda (Crustacea) shows great diversity in morphology and lifestyle among its constituent higher-level taxa: Anostraca, Notostraca, Laevicaudata, Spinicaudata, Cyclestherida and Cladocera. The phylogenetic relationships among these taxa have long been controversial. We sequenced three orthologous nuclear genes that encode the catalytic subunit of DNA polymerase delta and the largest and second-largest subunits of RNA polymerase II in the expectation that the amino acid sequences encoded by these genes might be effective in clarifying branchiopod phylogeny and estimating the times of divergence of the major branchiopodan taxa. The results of phylogenetic analyses based on these amino acid sequences support the monophyly of Branchiopoda and provide strong molecular evidence in support of the following phylogenetic relationships: (Anostraca, (Notostraca, (Laevicaudata, (Spinicaudata, (Cyclestherida, Cladocera))))). Within Cladocera, comparison of the nucleotide sequences of these same genes shows Ctenopoda to be the sister group of Haplopoda + Anomopoda. Three statistical tests based on the present amino acid sequence data-the approximately unbiased test, Kishino-Hasegawa test and weighted Shimodaira-Hasegawa test-tend to refute most of the previous molecular phylogenetic studies on Branchiopoda, which have placed Notostraca differently than here; however, our results corroborate those of one recent phylogenomic study, thus confirming the effectiveness of these three genes to investigate relationships among branchiopod higher taxa. Divergence time estimates calibrated on the basis of fossil evidence suggest that the first divergence of extant branchiopods occurred about 534 Ma during the early Cambrian period and that diversification within the extant branchiopod lineages started in or after the late Permian.

Clam shrimp (Spinicaudata) are worldwide distributed branchiopod crustaceans specialised in ephemeral freshwater habitats. The Carboniferous is an important period for the early evolution and diversification of clam shrimp. Compared with the rare and geographically confined fossil record of the Devonian, clam shrimp in the Carboniferous have a much wider geographical distribution and higher biodiversity. Over 20 genera of clam shrimp have been recorded in the Carboniferous all over the world, but they are sparse in China. To date, five records of Carboniferous clam shrimp have been reported from China (Pruvost, 1927; Zhang et al., 1976; Wang, 1987; Zheng et al., 1988; Liu & Fan, 1995; Liao et al., 2019). Among them, four species Lioestheria? mathieui Pruvost, 1927, Protomonocarina huixianensis Wang, 1987, Retrofractus lingyuanensis Liu & Fan, 1995, and Pemphilimnadiopsis cheni Liao, Shen & Huang, 2019, are found in the Pennsylvanian Benxi Formation in North China (Pruvost, 1927; Zhang et al., 1976; Wang, 1987; Liu & Fan, 1995; Liao et al., 2019).

In 2018, the water flea, Ilyocryptus spinifer Herrick 1882 (Cladocera, Ilyocryptidae), was found for the first time in the Vetluga River, Nizhny Novgorod Region, European Russia. This species with a benthic phytophilic mode of life belongs to the southern thermophilous complex of cladocerans and shows a circumtropical distribution pattern. So far, I. spinifer has never been found in Europe, sporadic records of this species were known only from few southern regions in the Asian part of Russia. The invasion of I. spinifer to relatively high latitudes may be related to a natural distribution range expansion due to global climate warming, to transfers via migratory birds, and/or with ballast waters in ships. In any case, further monitoring of the revealed populations is very important to control the water ecosystem conditions in Russia and other countries.

Broad-scale assessment of biodiversity is needed for detection of future changes across substantial regions of the Arctic. Presently, there are large data and information gaps in species composition and richness of the freshwater planktonic and meiobenthos communities of the Russian Arctic. Analysis of these data is very important for identifying the spatial distribution and temporal changes in species richness and diversity of rotifers, cladocerans, and copepods in the continental Russian Arctic. We investigated biogeographic patterns of freshwater plankton and meiobenthos fromc. 67 degrees to 73 degrees N by analysing data over the period 1960-2017. These data include information on the composition of rotifers, cladocerans, and copepods obtained from planktonic and meiobenthic samples, as well as from subfossil remains in bottom sediments of seven regions from the Kola Peninsula in the west, to the Indigirka River Basin (east Siberia) in the east. Total richness included 175 species comprised of 49 rotifer genera, 81 species from 40 cladoceran genera, and 101 species from 42 genera of calanoid, cyclopoid, and harpacticoid copepods. Longitudinal trends in rotifer and micro-crustacean diversity were revealed by change in species composition from Europe to eastern Siberia. The most common and widespread species were 19 ubiquitous taxa that includedKellicottia longispina(Rotifera),Chydorus sphaericuss. lat. (Cladocera),Heterocope borealis,Acanthocyclops vernalis, andMoraria duthiei(Copepoda). The highest number of rare species was recorded in the well-studied region of the Bolshezemelskaya tundra and in the Putorana Plateau. The total number of copepod and rotifer species in both Arctic lakes and ponds tended to increase with latitude. Relative species richness of copepods was positively associated with waterbody area, elevation, and precipitation, while relative species richness of cladocerans was positively related to temperature. This result is consistent with known thermophilic characteristics of cladocerans and the cold tolerance properties of copepods, with the former being dominant in shallow, warmer waterbodies of some western regions, and the latter being dominant in large cold lakes and waterbodies of eastern regions. Rotifers showed a negative association with these factors. Alpha- and beta-diversity of zooplankton in the Russian Arctic were strongly related to waterbody type. Lake zooplankton communities were more diverse than those in pond and pool systems. Moreover, the highest beta-diversity values were observed in regions that showed a greater breadth in latitude and highly heterogeneous environmental conditions and waterbody types (Bolshezemelskaya tundra and Putorana Plateau). Redistribution of freshwater micro-fauna caused by human activities occurred in the 1990s and 2000s. As a result of climate warming, a few cladoceran species appear to have extended their range northward. Nevertheless, the rotifer and micro-crustacean fauna composition and diversity of the majority of Arctic regions generally remain temporally conservative, and spatial differences in composition and species richness are chiefly associated with the differences between the warmer European and colder east Siberian climates.

We describe Phallocryptus fahimii sp. n., the fifth species in the genus, based on combined morphological and molecular genetic analyses. It is endemic to Iran and known only from its type locality...

The brine shrimp Artemia is of considerable economic importance in fish and shellfish larviculture. The quality of the Artemia product, differs, in terms of hatching and biometric characteristics, from strain to strain and from location to location. The same applies for their nutritional value which is not constant but varies among strains and within batches of each strain, causing unreliable outputs in marine larviculture. In the present paper we report and compare the fatty acid profiles of decapsulated Artemia cysts of thirteen Artemia populations from different species and geographical origins. Results showed that palmitic acid (16:0) was found in relatively constant proportions from 11.4 to 20.6% of total fatty acids in the cysts of all populations, while proportions of palmitoleic acid (16:1n-7) were higher in marine-type populations (18.6 to 19.1%) than in freshwater-type population (4.3 to 8.3%). In contrast, linoleic acid (18:2n-6) was observed in higher quantity in freshwater-type populations (4.0 to 8.1%) than in marine-type populations (3.1 to 3.3%). Furthermore, a higher n-3/n-6 HUFA ratio was observed in the marine-type population (>1) than in the freshwater-type population (

The branchiopod Eurycercus lamellatus is widely distributed in Norwegian lakes, ranging from coastal to alpine areas. On the Hardangervidda mountain plateau in southern Norway, E. lamellatus was searched for in 144 lakes in 11 catchments in the western and 16 catchments in the central and eastern areas. The occurrence of E. lamellatus is mainly based on the diet of brown trout Salmo trutta. Eurycercus lamellatus was recorded in 25% and 70% of the lakes in these two areas, respectively. This may be due to striking differences in the environmental conditions, with more dilute water and lower water temperatures in western areas, and hence shorter growing seasons. The occurrence of E. lamellatus in central and eastern catchments increased with lake size, being found in 65% and 85% of lakes with a surface area of 400 mm). However, under high predation pressure, E. lamellatus also contributed significantly to the diet of larger fish. The abundance of E. lamellatus seems to vary highly on a yearly basis in one of the lakes (Sandvatn). Even though E. lamellatus is described as a typical littoral species, it was commonly found down to depths of 15 m.

A new extinct genus and species of Anostraca (Crustacea, Branchiopoda), Daohugounaias cheni gen. et sp. nov. is described based on a well-preserved specimen from the Middle Jurassic of Daohugou, Inner Mongolia, China. The new genus differs from other Anostraca by the short, forward-pointing spines at the joint of the abdomen and brood pouch. Scanning electron microscopy (SEM) shows that eggs are preserved in three-dimension and some ridges and spines remain on their surfaces. Energy dispersive X-ray (EDS) demonstrates that the relatively abundance or depletion of elements vary between different parts of the body. The new discovery fills a stratigraphical gap in the Anostraca and supports the previous palaeoenvironmental reconstruction of the Daohugou area.

The embryological development of Ceriodaphnia reticulataDumont & Pensaert, 1983 and Scapholeberis rammneriJurine, 1820 were investigated using scanning electron microscopy. A carapace spine did not develop and there was no fusion of the first antennae. These are apparent apomorphies of DaphniaMüller, 1785, which suggests that the common ancestor of Daphniidae Straus, 1820 did not have a carapace spine during its embryological development, and its first antennae were short and separated during embryogenesis. Morphological evidence thus appears congruent with molecular interpretations showing that ScapholeberisSchoedler, 1858 is basal to other genera of Daphniidae, Ceriodaphnia being a sister taxon to Daphnia.

Daphnia pulex is a freshwater microcrustacean that is known for its cyclical parthenogenesis. In D. pulex, parthenogenetic reproduction switches to sexual reproduction when the living conditions worsen. However, this transformation also occurs over age under favourable living conditions. Thus, there might be a relationship between aging and reproductive conversion. We performed Illumina RNA sequencing, generating 51 712 680 and 59 854 588 raw reads from 1 day-old D. pulex and 25 day-old D. pulex, respectively. From these reads, 60 776 transcripts were assembled and 36 569 (60.15%) unigenes were annotated. A number of significantly differentially expressed genes associated with growth, aging, and reproduction were identified and Quantitative real-time PCR for six genes confirmed the transcriptome data. RNA interference (RNAi) of the caspase-3 gene (casp3) that is a key gene for growth, development, aging, and reproduction, was conducted, which achieved an 80% reduction in casp3 mRNA expression. Meanwhile, the mRNA expression of upstream genes jnk and akt, and sir2 (encoding a substrate of casp3) were also detected. The change of jnk mRNA expression before and after RNAi was not significant () and the mRNA levels of sir2 decreased, while akt increased after casp3 RNAi (). The results indicated the interrelationships of some genes in the senescence pathway and helped to identify the molecular mechanism of the aging progress in D. pulex. Overall, the difference in mRNA expression profile during aging of D. pulex forms a basis for further studies aimed at understanding the role of the transcriptional level in regulating aging and reproductive transformation.

—The effect of gamma radiation doses of 2.5, 5.5, and 7.5 Gy received by Artemia cysts on hatching of nauplii and postnauplial survival of crustaceans has been studied at salinities of 0, 9, 18, 36, 54, 62, 78, and 88 g/L. Under the same salinities, the above parameters are estimated without irradiation. It has been found that the rate of nauplii hatching from cysts depends primarily on the salinity, the coefficient of determination being equal to 90%. The radiation dose does not affect nauplii hatching at any salinity, except 54 g/L, when a significant negative relationship is found between the proportion of hatched nauplii and the radiation dose. The survival of crustaceans appearing from irradiated cysts depends on the salinity. In the salinity range of 9–52 g/L, it is significantly less than in the range of 62–88 g/L (2.5 and 5.5 Gy). The crustaceans emerged from cysts which received 7.5 Gy do not survive to day 12 at the salinity of 88 g/L. The minimum post-nauplial survival of crustaceans is recorded at a salinity of 54 g/L under all irradiation doses; such salinity may be considered critical for Artemia at which the osmoregulation mechanism reconfigures. Ecological effects in Artemia populations can occur starting from a dose of 2.5 Gy. The studied radiation doses may have remote consequences for Artemia populations in hypersaline water bodies. To quantify the effect of these doses on Artemia populations correctly, it is necessary to study not only the generation of crustaceans immediately hatched from irradiated cysts but also 2–3 subsequent generations.

The purpose of this study is to analyze the taxonomic composition of the branchiopod crustaceans (Crustacea: Branchiopoda) from the assemblage of animal and plant remains recovered from fossil mammoth hair found in the Allaikha River basin, Sakha Republic, Russian Federation. We studied the hair structure. AMS radiocarbon dating of both the hair itself and the remains demonstrated their different ages. We found different animal and plant remains in the hair taphocoenosis. The most diverse and numerous remains belong to branchiopod crustaceans: resting eggs and distal portions of the mandibles of Anostraca, distal portions of the mandibles of Notostraca, filtering limbs of some Anostraca or Daphniidae, ephippia of Daphnia (Daphnia) curvirostris, Daphnia (Ctenodaphnia) atkinsoni, and D. (C.) magna. No representatives of D. (Ctenodaphnia) now occur in northeastern Eurasia, but our findings of numerous ephippia in the fossil hair of two mammoths, one from the Allaikha River and the other, studied previously, from the Bol’shaya Chukochya River basin (see Kirillova et al., 2016), show that Daphnia (Ctenodaphnia) taxa occurred in the region at least in the past and were probably common and widely distributed there. The reasons for the extinction of Daphnia (Ctenodaphnia) in northeastern Eurasia require additional special study. We also emphasize the need for further studies of the morphology of ephippia, resting eggs, and mandibles of recent Branchiopoda, which would be essential for adequate identification of Pleistocene remains.

Use of subfossil cladoceran remains for paleolimnological studies in Mesoamerica, especially in Central America, is constrained by the poorly known composition of cladoceran communities. We examined sediments from 56 waterbodies in Central America (Guatemala, El Salvador, Honduras) and the Yucatan Peninsula (Mexico), and provide illustrations and descriptions of the remains of Chydoridae from the region, emphasizing their diagnostic traits. In total, 36 Chydoridae taxa, representing 24 genera, were recognized. The illustrations and descriptions of chydorid subfossils included here will enable paleolimnologists to recognize and identify such remains in lake sediment cores, thereby facilitating paleoenvironmental inferences from lake sites in Mesoamerica. Furthermore, data included here expand knowledge about the geographic distributions of Neotropical chydorids.

Until now, Pumilibranchipus deserti was known from only one locality in Namibia. This paper reports the first record of this species from South Africa in Hakskeen Pan, Northern Cape, which represen...

The dynamics of sea water self-purification processes in the water area of the Karadag Nature Reserve during five years after the emergency discharges of sulfur and oil products to the Black Sea has been studied. The toxicity of aquatic environment was estimated by the biotesting method based on using saltwater crustaceans: Artemia salina species from the Branchiopoda order. The rate of self-purification processes in surface and deep levels of sea water was established. The ecological significance of self-purification for restoring the quality of marine aquatic environment was specified. The sea water self-purification mechanisms occurring as a result of mechanical, physicochemical and biological processes are studied. It has been revealed that the incoming pollutants are diluted by marine water of the Black Sea, suspended substances gradually settle down to the bottom, while the organic substances are subjected to oxidation at the expense of oxygen dissolved in water. These processes result in organic substances gradually being mineralized by their disintegration into simpler substances. It must be underlined that a complex of biocenoses formed by different hydrobionts takes part in self-purification processes. The majority of them are also directly involved in decontamination of sea from bacterial contaminants, including pathogenic microbes. The mechanism of antibacterial action of hydrobionts is sufficiently diversified. Some of them absorb bacteria for feeding, others cause the cell lysis, and the third release the antibacterial agents into environment. Different type relationships are formed between the bacterial population and other hydrobionts. The predominant types, besides trophic, are metabiosis and antagonism. The biochemical activity of hydrobionts is a dominant process in self-purification of marine ecosystem. The conclusions are made about the need of monitoring the sea water quality by using the methods of biotesting on animal and plant test-organisms of different trophic levels.

The phylogenetic relationships of branchiopod crustaceans have been in the focus of a number of recent morphological and molecular systematic studies. Although agreeing in some respects, major differences remain. We analyzed molecular sequences and morphological characters for 43 branchiopods and two outgroups. The branchiopod terminals comprise all eight ‘‘orders’’. The molecular data include six loci: two nuclear ribosomal genes (18S rRNA, 28S rRNA), two mitochondrial ribosomal genes (12S rRNA, 16S rRNA), one nuclear protein coding gene (elongation factor 1a), and one mitochondrial protein coding gene (cytochrome c oxidase subunit I). A total of 65 morphological characters were analyzed dealing with different aspects of branchiopod morphology, including internal anatomy and larval characters. The morphological analysis resulted in a monophyletic Phyllopoda, with Notostraca as the sister group to the remaining taxa supporting the Diplostraca concept (‘‘Conchostraca’’ + Cladocera). ‘‘Conchostraca’’ is not supported but Cyclestheria hislopi is the sister group to Cladocera (constituting together Cladoceromorpha) and Spinicaudata is closer to Cladoceromorpha than to Laevicaudata. Cladocera is supported as monophyletic. The combined analysis under equal weighting gave results in some respects similar to the morphological analysis. Within Phyllopoda, Cladocera, Cladoceromorpha and Spinicaudata + Cladoceromorpha are monophyletic. The combined analysis is different from the morphological analysis with respect to the position of Notostraca and Laevicaudata. Here, Laevicaudata is the sister group to the remaining Phyllopoda and Notostraca is sister group to Spinicaudata and Cladoceromorpha. A sensitivity analysis using 20 different parameter sets (different insertion–deletion [indel] ⁄ substitution and transversion ⁄ transition ratios) show the monophyly of Anostraca, Notostraca, Laevicaudata, Spinicaudata, Cladoceromorpha, Cladocera, and within Cladocera, of Onychopoda and Gymnomera under all or almost all (i.e., 19 of 20) parameter sets. Analyses with an indel-to-transversion ratio up to 2 result in monophyletic Phyllopoda, with Laevicaudata as sister group to the remaining Phyllopoda and with Spinicaudata and Cladoceromorpha as sister groups. Almost all analyses (including those with higher indel weights) result in the same topology when only ingroup taxa are considered. � The Willi Hennig Society 2007.

Detailed study of morphology of Alona werestschagini Sinev, 1999 (Crustacea: Cladocera) confirms its affinities with Alona guttata Sars, 1862. A. werestschagini is the only Arcto-Alpine species among the family Chydoridae, distributed along Arctic coast of Eurasia and in mountains of Central Asia, newer recorded in temperate lowlands of the continent. In our opinion, the species evolved in mountainous regions of Central Asia, while its spreading to Arctic regions took place in Pleistocene.

Spinicaudatan clam shrimp are a widespread and diverse group of branchiopod crustaceans, yet few mitochondrial genomes have been published for this taxonomic group. Here, we present the mitogenome ...

A detailed study of morphology of the rare phytophilous cladoceran Camptocercus lilljeborgi Schoedler, 1862 revealed that populations from Eastern Siberia and Far East of Russia belong to a new species. C. smirnovi sp. nov. differs from C. lilljeborgi in body shape, morphology of ventral margin of valves, morphology of postabdomen, and length of IDL seta 1 of the thoracic limb I. C. lilljeborgi s. str. is distributed in Europe and Western Siberia, therefore, the lilljeborgi-group provides an example of the western-eastern differentiation in Northern Eurasia. Some characters of taxa from the lilljeborgi-group are convergently similar to the characters of the species of genus Graptoleberis Sars, 1862; both groups are adapted to a snail-like crawling on the surface of water macrophytes.

Using literature and field sampling data, we found that Brazilian fauna of the order Ctenopoda (Cladocera, Branchiopoda) was composed of twelve species, including the locally endemic Holopedium amazonicum and Sarsilantona behningi. In Brazil, Diapahanosoma (Neodiaphanosoma) bergamini was reported out of its type locality for the first time. Ctenopoda species were reported in all Hydrographic Regions in Brazil, however, the sampling effort was clearly distinct between many areas. These findings suggest the necessity of new faunal surveys in several parts of Brazil.

International audience; Global change transforms processes regulating carbon dioxide (CO2) concentrations in lakes, yet our understanding of the broad-scale responses of lake CO2 to global and local human perturbation across heterogeneous landscapes and multidecadal time scales is limited. We examined decadal variability in the carbon isotope (delta C-13) composition of subfossil zooplankton (Branchiopoda: Cladocera) in seven large clear perialpine lakes, including three previously studied sites, to decipher different patterns in summer surface CO2 concentrations. Generalized additive models were used to examine whether and how these patterns connect to changing nutrient regimes and anthropogenic warming over the past century. In all but one of the lakes shifts in cladoceran delta C-13 values coincided with turning points in the eutrophication history, broadly implying decreasing summer surface CO2 concentrations driven by phosphorus fertilization of pelagic primary production. Yet where nutrient concentrations remained below mesotrophic levels, the positive relationship between delta C-13 and phosphorus diminished indicating that the strong biotic control of CO2 concentrations was overwritten, probably by catchment inorganic carbon inputs and internal biochemical processes. Even under extensive nutrient loading, the connection was further weakened in lakes with high catchment to lake area ratio attributable to increased catchment interference and shorter water residence times. Warming of the perialpine region was also imprinted in the isotope records, yet the temperature effects appeared modest and were restricted to three smaller lakes with lower drainage ratios. In these lakes, warming contributed to declining cladoceran delta C-13 values likely partially driven by epilimnetic deepening increasing CO2 in surface waters. Overall, our results manifest the broad heterogeneity of lake responses to global change and point to the importance of hydrogeomorphic context in shaping the sensitivity and responses of lake CO2 to changing nutrient regimes and warming at the regional scale.

Insufficient attention has been recently paid by the taxonomists to the family Bosminidae Baird (Crustacea: Cladocera). Here we describe a new species of Bosmina (Liederobosmina) Brték from high mountain water bodies of Colombia which is unique among all bosminids having heavily striated valves. Most probably, this taxon has a narrow distribution area in the Andean high mountains. It is obvious that the Andean highlands must be studied in detail, i.e. using molecular methods, and more new taxa might be detected in the future.

The behavioral responses of Branchipus schaefferi Fisher, 1834 males and females to short-term thermal stress in six different rearing conditions are studied. The swimming performance was tested in pure tap water and water collected from both male and female culture mediums. The animal's behavior was recorded using a high-definition digital video camera mounted approximately 30 cm above the experimental containers. The swimming track and the thoracopod beating rates were recorded manually for each animal at different temperatures. The results indicate that in most cases, a significant increase in active swimming and limb beating rate occurred with increasing temperature. However, the animals tested in the different male and female culture medium were significantly less active compared to those in tap water, under similar thermal stress. Animals seem to produce substances in the culture media that influence their locomotor behavior under thermal stress.

We present the first records of Leptestheria brevirostris since its discovery in Namibia by Barnard in 1924. Our records come from Botswana and South Africa, and present significant range extensions. We redescribe L. brevirostris according to modern standards and present the first description of the male. We also discovered that L. brevirostris is likely a rock pool specialist, specific to sandstone and gneiss outcrops; this is the first record of a rock pool specialist clam shrimp from Africa and the second rock pool specialist described for Leptestheriidae. Finally, we depict and discuss the validity and usefulness of diagnostic characters for Leptestheria species in southern Africa, especially the usefulness of carapace interval ornamentation.

Este artículo contiene 46 páginas, 15 figuras, 2 tablas., Species of the genus Ceriodaphnia Dana, 1853 (Crustacea: Cladocera: Daphniidae) are present in the plankton of many freshwater bodies all around the World. However, the taxonomy of the genus is still poorly developed. Most species have been described in the nineteenth century and data on their morphology and distribution should be revised according to current standards. Currently, due to lack of reliable morphological and genetic data, almost all nominal species of Ceriodaphnia are considered as species groups rather than separate biological species, complicating the detection and description of new species of the genus. Here, we redescribe the morphology of Ceriodaphnia quadrangula (O.F. Müller, 1785) based on material close to the type locality in Denmark, and describe a new species of Ceriodaphnia from the Mediterranean region. Also, we provide a phylogenetic analysis using existing and novel sequences of mitochondrial DNA of the commonest species of the genus. Ceriodaphnia smirnovi sp. nov. can be easily distinguished from C. quadrangula via presence of the head pore and the structure of the second thoracic limb, the postabdomen and the ephippium. From other species of Ceriodaphnia known to date C. smirnovi sp. nov. can also be separated on ephippium structure and some other fine morphological features. Although distribution range of C. smirnovi sp. nov. must be clarified in the future based on analysis of more sampling points, most likely, it is restricted to the Mediterranean region. The phylogenetic analyses showed high divergence among 16 different clades (mean clade separation of 13±2.3 % (mean ± SD) and 20.7±2.1% for 16S and COI respectively). These clades belonged to 11 described species and 5 undescribed. The high intraspecific variability of some species indicates the possible existence of more undescribed species within present species groups., Morphological and genetic parts, manuscript writing and correction for ANN was carried out within the frame of work under the grant of the President of the Russian Federation for the state support of young Russian Ph.D researchers (project № MK-525.2020.4). MV was partially supported by the Spanish Government projects FUNBIO (RTI2018-096217-B-I00) and BIOOCULT (2413/2017).

Recently, Lara et al. (2020a, b) described a new fossil taxon, Duraznovis gallegoi, based on two specimens from the Upper Triassic Potrerillos Formation at Quebrada del Durazno, Cuyana Basin of Argentina. This fossil is considered to be an enigmatic arthropod closely resembling the living and fossil representatives of xiphosurans (Chelicerata) and notostracans (Branchiopoda), two completely different arthropod groups with convergent body plans. Some distinctive combination of features, however, makes the systematic position of these specimens indeterminate (Lara et al., 2020a, b).

Clam shrimps (Spinicaudata) are a widespread and diverse crustacean group that frequent temporary aquatic habitats, but few complete mitochondrial genomes have been published for this group. Here, ...

Fairy shrimps (Anostraca) constitute an important component of seasonally aquatic habitats, but few complete mitochondrial genomes have been published for this group. Here, we report the mitogenome of a common southern African species, Streptocephalus cafer, from Botswana (accession number: MN720104). Low-coverage shotgun sequencing recovered two contigs 15653 bp and 1347 bp in length that are separated by a repetitive region of unknown length within the non-coding control region. The mitogenome’s GC content is 31.80%. Phylogenetic analysis using protein-coding genes confirms the sister taxon relationship of S. cafer with the only other congener whose mitogenome has been reconstructed to date, the Asian S. sirindhornae.