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Four ovigerous females of the parasitic copepod Pseudosarcotretes omorii gen. et sp. nov. (Siphonostomatoida: Pennellidae) were found on North Pacific lightfish Maurolicus japonicus Ishikawa, 1915, collected from Suruga Bay, eastern Japan. Pseudosarcotretes gen. nov. shares some features with pennellids parasitic on mesopelagic fish such as Cardiodectes Wilson, 1917, Protosarcotretes Ohtsuka, Lindsay, and Izawa, 2018, and Sarcotretes Jungersen, 1911. The morphological differences between the new genus and other related genera are having a pair of lateral cephalothoracic holdfast, the presence of distinct caudal rami, and the absence of leg 4. The hatching stage of the new genus is the copepodid. A molecular phylogenetic analysis suggested that the reduction in the number of developmental stages in pennellid life cycles had occurred at least in two cases. According to the molecular data, the new genus consists of a clade accommodating Cardiodectes, Lernaeenicus Lesueur, 1824 and Pennella Oken, 1815. All these genera have a distinct cephalothoracic holdfast embedded into the host’s muscle tissues, which seems to be advantageous for expanding the range of the hosts to small mesopelagic fish.

During a plankton sampling conducted off the northeastern Mediterranean coast of Türkiye, a single female copepod, Caligus minimus Otto, 1821 was collected from a marine plankton sample. C. minimus is a well-known species of the genus Caligus O.F. Müller, 1785 which has been previously reported as a parasite from nine marine fish species belonging to eight different families. To date, however, C. minimus has never been reported from plankton samples. In this study, the general morphology based on the key diagnostic characters of the planktonic C. minimus is presented using confocal laser scanning microscope (CLSM) images. This is the first report of C. minimus from plankton samples off Turkish waters and global marine environments. [ABSTRACT FROM AUTHOR]

Sesenta y una especies, una variedad y dos especies no identificados de copépodos asociados a invertebrados marinos se han registrado para el Golfo de México y el Mar Caribe. Estos copépodos se han encontrado asociados a especies de diferentes taxa como Porifera, Cnidaria y Echinodermata. Se presenta una lista que contiene información del invertebrado hospedador, localidad de colecta y la cita bibliográfica. Se añade además una lista del invertebrado con su copépodo asociado.

Stygiopontius senokuchiae is a hydrothermal-vent-specific copepod species (Dirivultidae, Siphonostomatoida) and abundantly distributes near vent orifices. This species is thought to have an early juvenile planktic stage, and previous studies using bulk tissue stable-isotope and radioisotope data suggest that adults ingest chemoautotrophic microbes growing on vent chimneys. However, ontogenetic changes in their diets have not been investigated. We analysed gut contents of copepodite I to adult stages of S. senokuchiae collected from a hydrothermal-vent chimney at the Izu-Ogasawara Arc to check for the presence of bacterial cells in oral tubes and guts. We compared these results with an unidentified co-occurring calanoid and a species of Ectinosoma (Harpacticoida) and to other Siphonostomatoid copepods, namely Hatschekia labracis (Hatschekiidae), which was attached to a scarbreast tuskfin (Choerodon azurio , Labridae), and Asterocheres sp. 1 (Asterocheridae), which was attached to a spirastrellid sponge. Carbon isotope ratios of S. senokuchiae at different stages and Ectinosoma were measured to complement the nutritional insights obtained from gut-content analysis. Our results clearly showed that most S. senokuchiae individuals possessed bacteria in the oral tube or gut regardless of growth stage, whereas the coexisting Ectinosoma and calanoid did not. The carbon isotopic compositions confirmed that S. senokuchiae gains its nutrition from chemoautotrophic bacteria that use the rTCA carbon-fixation pathway. Comparisons with other Siphonostomatoida copepods suggest that Dirivultidae are specifically adapted to feed on bacteria at hydrothermal-vent chimneys, allowing their high dominance and evolutionary success in these habitats. [ABSTRACT FROM AUTHOR]

Little information is available until now about the copepods infecting different fish species. Therefore, this study aimed to provide light on siphonostomatoids infecting Epinephelus chlorostigma. Twenty fish specimens were taken from the Red Sea coast (Jeddah, Saudi Arabia), and ectoparasitic copepods were investigated. Light microscopy and molecular tools were used to examine copepods isolated from fish. Parasitological indexes were calculated and showed that 60% of the examined fish were infected with a mean intensity of 12 parasite/fish. Morphological examination revealed that this copepod species is characterized by all unique features of the genus Hatschekia with special reference to Hatschekia sargi. The taxonomic position of the recovered species in the Hatschekiidae family within Siphonostomatoida was confirmed using phylogenetic analysis based on partial mitochondrial cytochrome c oxidase subunit I (mt COI) gene sequences. The mt COI gene query revealed that the recovered Hatschekia species is closely related to Hatschekia maculatus (gb| JQ664005.1). This study discovers a new host for Hatschekia species isolated from Saudi Arabia and conducts the first genomic investigation of the mt COI gene. [ABSTRACT FROM AUTHOR]

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Introduction: Copepods of the genus Hatschekia Poche, 1902 are parasitic on the gills of marine actinopterygians. Currently, about 151 species of this genus have been reported in marine ecosystems and only few occur in South Atlantic Ocean. Methods: Fifty specimens of A. virginicus from Angra dos Reis, off the State of Rio de Janeiro, Brazil, were parasitized by copepods on the gills. Parasites were fixed and preserved in 70% ethanol. Morphological observations were based on light and scanning electron microscopy. Results: Hatschekia nagasawain. sp. can be distinguished from all congeners by the combination of the following characters: (1) presence of two pointed processes on the proximal (first) segment of antennule, (2) cephalothorax octagonal to ovoid, (3) absence of processes on the intercoxal sclerite of legs 1 and 2, (4) trunk without lobes at the postero-lateral margins. Other species of Hatschekia and their hosts previously collected off Brazil were analysed and discussed. Conclusions: This is the first report of a representative of the family Hatschekiidae Kabata, 1979 parasitizing a species of Anisotremus. The number of species of Hatschekia reported in the South Atlantic Ocean was increased to five, including the new species; however, the diversity of hatschekiid copepods in this oceanographic region is still underestimated, most likely being higher than what is currently known. [ABSTRACT FROM AUTHOR]

Purpose: The parasitic diversity on the intertidal fish of the Southern American Cone is barely known. The present study describes two new parasitic copepod species, a Clavella and a Haemobaphes found on the nototheniid fish Patagonotothen cornucola. Methods: The fish were collected from the intertidal zone of the Strait of Magellan, Southern Chile. The copepods were found on the fins and in the gill chamber of the fish, which were morphologically analyzed using optical and electronic microscopy. Results: Clavella cornucola sp. nov. and Clavella bowmani are similar but differ in the number of setae found on the maxillule (two setae on the inner lobe vs. three on C. bowmani), and a pad of spinules on the dorsal margin as opposed to the outer lobe (no pad vs. one pad, respectively). Haemobaphes puntaarenensis sp. nov. is distinguished from its congeners based on the lobe shapes of the head and the clear separation between the pedigerous somites (first, second, and third). The maxilla on H. puntaarenensis sp. nov. lacks a pad of spinules on the second segment, but it is found in all the other congeneric species. Conclusion: Clavella cornucola sp. nov. is the 10th species of the genus in Chile, whereas Haemobaphes puntaarenensis sp. nov. is the first species of the genus recorded in Chile and the Southern Cone coasts. [ABSTRACT FROM AUTHOR]

The biology, including accompanying ectoparasitic fauna, remains unstudied for several elasmobranchs off the Canary Islands in spite of concerns over their conservation. Within this region, this is the first report of copepod associations with these fishes. Twenty smooth hammerhead sharks, Sphyrna zygaena, and one common stingray, Dasyatis pastinaca, were inspected for symbionts on their body surface. Symbiotic siphonostomatoids were collected from 18 S. zygaena hosts and represent two different species, i.e., Alebion crassus (Caligidae) and Pandarus cranchii (Pandaridae). A high prevalence of 90% and a mean infection of 8.3 individuals per infected host were exhibited by A. crassus, while only a single P. cranchii was collected. Both these findings represent new geographical records. Additionally, one free-ranging common stingray Dasyatis pastinaca was opportunistically inspected and 11 Pseudocharopinus pillaii (Lernaeopodidae) collected which constitutes a new host record and a new geographical record. A re-description with detail regarding the morphology of the appendages is provided for the first time. Due to the morphological similarity between P. pillaii and P. malleus, a molecular analysis of the partial mitochondrial DNA cytochrome oxidase I gene was done in an attempt to determine if there is molecular divergence between the two species. This provided an estimate of the phylogenetic relationships amongst four Pseudocharopinus species (P. bicaudatus, P. pteromylaei, P. malleus, and P. pillaii) with Charopinus dubius as an outgroup as an alternative hypothesis to compare with the previous morphological topology estimated for all Pseudocharopinus species. [ABSTRACT FROM AUTHOR]

The crustacean parasites are the most frequently encountered and cause significant economic loss in mariculture. These parasites infect fish fin, skin, gills, and buccal cavity. This study aims to describe copepod parasite in the buccal cavity of cultured groupers, Epinephelus spp., from Batam waters using morphological and molecular biology approaches. The tiger grouper, Epinephelus fuscoguttatus (Forsskal, 1775), and hybrid grouper, Epinephelus sp. showing lethargy and skin darkening were collected from sea cages. The parasite's morphology was observed using light and scanning electron microscopes. The genomic DNA was isolated from the parasites and used as a template for amplification of cytochrome oxidase subunit-1 (Cox1) gene and followed by sequencing. The fish exhibited red nodules in the mouth cavity, on the lips, and gill arch in varying numbers and size of nodules. The copepodid, chalimus, and adult copepod stages were found from the nodule. Based on the presence of the oral cone, this parasite belonged to Siphonostomatoida order of copepods. Based on the structure of the caudal ramus with four long and four short setae, the first and second pair legs as biramous, and the third pair leg as uniramous, this parasite belonged to Pennellidae family of copepods. Basic local alignment search tool analysis of this Cox1 showed low homology within 80%, indicating that the DNA sequences of the parasite species were not reported in the GenBank. The unweighted pair group method using arithmetic average phylogenetic trees supported that this parasite belonged to the family Pennellidae. This is the first report on the pennellid parasite infection in the buccal cavity and gill arch of cultured groupers in Batam, Indonesia. [ABSTRACT FROM AUTHOR]

Naobranchia cygniformis Hesse, 1863 is one of 21 accepted species of the genus Naobranchia, which is distinguished from other genera in the family Lernaeopodidae by the possession of ribbon-like maxillae. The original description of N. cygniformis lacked detail concerning the armature, and later reports have not included a redescription. Thus, a redescription with details regarding the armature will be valuable for future comparative purposes. Additionally, this report of this parasitic copepod on the seabream Pagellus natalensis from the east coast of South Africa constitutes a new host and geographic record, since the only other Naobranchia species reported from the Indian Ocean off South Africa are N. kabatana and N. pritchardae. [ABSTRACT FROM AUTHOR]

Sesenta y una especies, una variedad y dos especies no identificados de copépodos asociados a invertebrados marinos se han registrado para el Golfo de México y el Mar Caribe. Estos copépodos se han encontrado asociados a especies de diferentes taxa como Porifera, Cnidaria y Echinodermata. Se presenta una lista que contiene información del invertebrado hospedador, localidad de colecta y la cita bibliográfica. Se añade además una lista del invertebrado con su copépodo asociado. ABSTRACT Sixty one species, one variety and two not identified copepods associate with marine invertebrates are registered for the Gulf of Mexico and the Caribbean Sea. Copepods were found in hosts belonged to different taxa as Porifera, Cnidaria and Echinodermata. A checklist contained information about the host, locality of the collection and the bibliographical citation is presented. A list of host-associate copepod is also added.

A new species of the copepod genus Stygiopontius is described based on samples from a cold seep in northeastern South China Sea southwest to Taiwan, which were collected by the ROV FAXIAN with its mother vessel R/V KEXUE in September 2017. The copepods were obtained by washing Shinkaia crosnieri Baba & Williams, 1998 (Decapoda: Munidopsidae) caught at a depth of 1124 m. The new species can be distinguished from its congeners by the combination of the following characteristics: caudal rami about 3.5 times as long as wide; basis of maxilliped with plumose seta, endopodal claw of maxilliped stout, with a row of fine spinules on inner margin; coxa of leg 1 with one inner seta; basis of leg 1 with stout spine exceeding to end of first endopodal segment; second endopodal segment of female leg 4 with pointed process; third exopodal segment of leg 4 with three outer spines. This is the first record of a Stygiopontius species from a cold seep. Résumé: Une nouvelle espèce du genre de copépode Stygiopontius est décrite à partir d'échantillons provenant d'un suintement froid situé au nord-est de la mer de Chine du Sud, au sud-ouest de Taiwan, collectés par le ROV "Faxian" avec son navire-mère R/V "Kexue" en septembre 2017. Les copépodes ont été obtenus par lavage de Shinkaia crosnieri Baba & Williams, 1998 (Decapoda : Munidopsidae) capturés à une profondeur de 1124 m. La nouvelle espèce peut être distinguée de ses congénères par la combinaison des caractéristiques suivantes : rames caudales environ 3,5 fois aussi longues que larges ; basis du maxillipède avec une soie plumeuse, croc endopodal du maxillipède fort avec une rangée de fines spinules au bord interne ; coxa de la patte 1 avec une soie interne ; basis de la patte 1 avec une forte épine dépassant l'extrémité du premier segment de l'endopodite ; second segment de l'endopodite de la patte 4 femelle avec un processus pointu ; troisième segment de l'exopodite de la patte 4 avec trois soies externes. Cette espèce constitue le premier signalement d'une espèce de Stygiopontius d'un suintement froid. [ABSTRACT FROM AUTHOR]

Neoparmulella periperiensis gen. et sp. nov. is a new siphonostomatoid copepod found associated with an endemic octocoral Phyllogorgia dilatata (Esper) in Bahia State, northeastern region of Brazil. The new genus belongs to the subfamily Parmulodinae which is recorded for the first time in the South Atlantic Ocean. The new genus differs from all other entomolepidids once it shows the fourth leg biramous and 3-segmented. The third endopodal segment of leg 4 also bears reduced setation. Modifications on the family diagnosis are proposed in order to accommodate the new genus and recent species described. The validity of the subfamilies is also discussed. MS - Genus - species - [ABSTRACT FROM AUTHOR]

The siphonostomatoid copepod Caligus undulatus Shen & Li, 1959 has been widely reported from plankton samples obtained from neritic and oceanic waters off coasts of the Indo-West Pacific and Atlantic Oceans. Until now, its fish host has remained unknown. This copepod belongs to an intriguing group of congeners that, despite being part of a chiefly parasitic group, are consistently found as zooplankters. Quite unexpectedly, in October 2019, a fish host of C. undulatus was discovered in the Seto Inland Sea, Japan--namely, the Japanese sardinella Sardinella zunasi (Bleeker, 1854). Both juvenile (chalimus) and adult individuals of this caligid were observed as parasites of the fish host. The discovery suggests that the species has an alternative life cycle as previously proposed for other purportedly 'planktonic' congeners and might frequently switch hosts during the adult stage. Thus, the C. undulatus group is newly proposed as a species group in the genus, in which five species are known as planktonic. Some hypotheses on the modified life cycle of caligids also briefly discussed. [ABSTRACT FROM AUTHOR]

The present paper reports the first record of the parasite Eudactylina pusilla Cressey, 1967 from the gills of the pelagic thresher shark, Alopias pelagicus Nakamura, 1935 collected during a multifilament longline operation at a depth of 762 m from Indian EEZ around Andaman Islands. The occurrence of this copepod gill parasite on A. pelagicus in the Indian waters constitutes new host record and extends the parasite’s known geographical distribution, thus contributing to the knowledge of biodiversity of the parasitic copepods in Indian waters. Molecular marker based taxonomical annotation using Mitochondrial 18S r DNA sequencing also confirmed the identity of the E. pusilla specimen.

Between 2013 and 2015, 2092 chondrichthyan fish belonging to eight species were collected along the Tunisian coast and examined for parasitic copepods. Eleven different species of copepods representing five families, Caligidae, Eudactylinidae, Kroyeriidae, Lernaeopodidae and Pandaridae, were collected. Three of these species are reported for the first time in Tunisia (Pseudocharopinus malleus , Perissopus dentatus and Nesippus orientalis) and one new species of Kroyeria was found. In addition, we identified a number of new host records including: the presence of Eudactylinella alba on Bathytoshia centroura , Dasyatis pastinaca , Mustelus mustelus and Scyliorhinus canicula. This is the first record of Nemesis sp. on B. centroura in Tunisia. We report here for the first time the presence of Pseudocharopinus bicaudatus and Pseudocharopinus concavus on Bathytoshia centroura and Lernaeopoda galei on Raja clavata. [ABSTRACT FROM AUTHOR]

Pseudanuretes chaetodontis Yamaguti, 1936 is redescribed based on both sexes, from specimens recovered from the branchial lamellae of Chaetodontoplus septentrionalis (Temminck & Schlegel, 1844) (Pisces, Pomacanthidae) in Japan. In addition, both sexes of copepodid V are described, as well as the free-living phase composed of two naupliar stages and the infective copepodid I stage, all reared from eggs, for the first time. Sexually dimorphic features found in the adult are discussed and it is pointed out herein that P. parvulus (Wilson, 1913) was described based on a copepodid V female specimen by that original author. Both sexes of the copepodid V exhibit sexually dimorphic features of the male type, i.e., in the maxilliped and in leg 5. [ABSTRACT FROM AUTHOR]

Using light and scanning electron microscopy of male and female copepods, we herein describe a new species of Neoalbionella ¨Ozdikmen, 2008 (Copepoda: Lernaeopodidae), Neoalbionella benzipirata n. sp., infecting the skin of the gulper shark, Centrophorus granulosus (Bloch and Schneider, 1801), in the northern Gulf of Mexico. Females of the new species were assigned to Neoalbionella by having 3 setae on the maxillule lateral palp (vs. 2 setae in Lernaeopoda Nordmann, 1832) and a single accessory denticle on the maxilliped subchela claw (vs. ≥2 denticles in Lernaeopoda). Females of the new species resemble those of Neoalbionella longicaudata (Hansen, 1923) O¨ zdikmen, 2008 but can be differentiated from them and those of all congeners by having a unique configuration of 16 dorsocephalic sensilla; an antennule terminal segment having 6 apical setae comprising tubercles 1 and 3, digitiform seta 4, 2 subequal setae of complex 5, and flagelliform seta 6; an antenna exopod with a thickened dorsal ridge, smooth (convex) outer surface with 2 short papillae, and rugose (concave) inner surface plus a terminal endopodal segment having a large dorsal hook, medial spine, bifid distal tubercle, and spinulose ventral process; a mandible having the formula P1, S1, P1, S1, P1, S1, B5; and a single pair of anterolateral spines on the mouth cone labium. Males attached to the posteroventral surface of the females’ genital trunk were assigned to Neoalbionella by having tapered (not inflated) caudal rami directed posteroventrally. They were differentiated from previously reported congeneric males by having an antennule with the same number and configuration of apical setae as the female; an antenna with a spatulate exopod having minute spinules along its apex plus a terminal endopodal segment with components the same as the female; a mandible with formula P2, S1, P1, S1, B5; a labium with 1 pair of anterolateral spines like the female; and a conspicuous mediative process with bifid tip. Detail of the dorsocephalic shield (in females) and mouth cone labium (in both sexes) previously had not been used to diagnose Neoalbionella spp. We also dissected voucher specimens of ‘‘Neoalbionella longicaudata’’ (collected from gulper sharks in the western Pacific Ocean off Japan by Shiino in 1956), which we morphologically diagnosed as an innominate species, Neoalbionella sp. This is the first report of a species of Neoalbionella from the Gulf of Mexico and the second species of Neoalbionella reported from C. granulosus, a deepwater shark seldom encountered and surveyed for parasitology. [ABSTRACT FROM AUTHOR]

Sixty one species, one variety and two not identified copepods associate with marine invertebrates are registered for the Gulf of Mexico and the Caribbean Sea. Copepods were found in hosts belonged to different taxa as Porifera, Cnidaria and Echinodermata. A checklist contained information about the host, locality of the collection and the bibliographical citation is presented. A list of host-associate copepod is also added. [ABSTRACT FROM AUTHOR]

Lernaeenicus ramosus Kirtisinghe, 1956 is redescribed on the basis of metamorphosed females recovered from the body surface of Epinephelus akaara (Temminck & Schlegel, 1842) (Pisces, Serranidae). Also the male, copepodid I, both sexes of chalimus II and III, and chalimus IV male were recovered, together with the females, from the branchial lamellae of the same host and are herein described for the first time for the species. The developmental process of leg 4 in L. ramosus differs from that in L. sprattae (Sowerby, 1806). [ABSTRACT FROM AUTHOR]

Hatschekia laeopsi sp. nov., H. branchiostegi Yamaguti, 1939 and H. pagrosomi Yamaguti, 1939 are (re-)described based on specimens collected from the branchial lamellae of three Japanese fishes, Laeops kitaharae (Smith & Pope, 1906) (Pleuronectidae), Branchiostegus japonicus (Houttuyn, 1782) (Malacanthidae), and Dentex tumifrons (Temminck & Schlegel, 1843) (Sparidae), respectively. The free-living stages of H. branchiostegi are described for the species for the first time. [ABSTRACT FROM AUTHOR]

Two new species of siphonostomatoid copepods are described based on specimens collected off Tokara Islands located in the northern part of the Ryukyu Islands, Southern Japan. Cholomyzon multisetum sp. nov. (Coralliomyzontidae) found from the orange cup coral Tubastraea coccinea Lesson, 1829 (Hexacorallia: Scleractinia: Dendrophylliidae) has the following characters: armature formula of the antennule of the female; the outer lobe of the maxillule; and numbers of elements on the legs 1 to 3. Another species, Entomopsyllus takara sp. nov. (Entomolepididae), was found from both the Indo-Pacific blue coral Heliopora coerulea (Pallas, 1766) (Octocorallia: Helioporacea: Helioporidae) and the race coral Distichopora violacea (Pallas, 1766) (Hydrozoa: Anthoathecata: Stylasteridae). This new species of the male specimen is characterized by the antennule with shortest sixth segment, the endopod of leg 2 bearing two inner setae on the second segment and five setae on the third segment, the third exopodal and endopodal segments of leg 3 bearing three spines and three setae, respectively, and the third exopodal segment of leg 4 bearing four setae. These two species represented the first records of the families Coralliomyzontidae and Entomolepididae from Japanese waters. http://www.zoobank.org/urn:lsid:zoobank.org:pub:7C8DED0A-9CEB-405D-9BBF-FAF2043B0858 [ABSTRACT FROM AUTHOR]

The parasitic copepod, Lernanthropinus trachuri (Brian, 1903) (Copepoda, Siphonostomatoida, Lernanthropidae) was found on the Mediterranean horse mackerel, Trachurus mediterraneus in Bandırma Bay, Turkey. The aim of this study is to present female Lernanthropinus trachuri with morphological characters with photos from Turkey. The details unseen in photos were supported with drawings. All parasites were firmly attached to the gill filaments of the host. This parasite is also specific for the genus Trachurus (Costa et al 2017). Therefore, this parasite may use as biomonitor or tag species for fish stock studies in Turkey. [ABSTRACT FROM AUTHOR]

The article offers information about two species of monacanthid fishes or Tetraodontiformes such as black scraper, also known as Thamnaconus modestus, and threadsail filefish, also known as Stephanolepis cirrhifer, both are maricultured in Japan. Information on the species' metazoan parasites is presented.

Our knowledge is limited of the parasitic copepods of the arhipelago known as the Andaman and Nicobar Islands within the Indian Exclusive Economic Zone. Here we report first records of parasitic copepod species form large pelagic fishes caught during exploratory longline operations conducted in Andaman and Nicobar waters. Four species of copepod parasites from three families (Eudactylinidae, Caligidae and Pseudocycnidae) were recovered; 1) Nemesis aggregatus Cressey, 1967 from the gills of pelagic thresher Alopias pelagicus Nakamura, 1935 2) Gloiopotes huttoni (Thomson G.M., 1890) from the body surface of black marlin Istiompax indica (Cuvier, 1832) 3) Caligus lobodes (Wilson C.B., 1911) from the body surface of great barracuda Sphyraena barracuda (Edwards, 1771) and 4) Yseudocycnus appendiculatus Heller, 1865 from the gills of yellowfin tuna Thunnus albacares (Bonnaterre, 1788). Alopias pelagicus represents a new host record for N. aggregatus. [ABSTRACT FROM AUTHOR]

Adult females of Bathygordion cliffus new gen. and new sp. belonging to the family Ecbathyriontidae Humes, 1987 are described from the Gorda Ridge of the North Pacific Ocean. The copepods were found at depth of 2701 m on the margin of a hydrothermal vent field (Sea Cliff, GR-14) among invertebrates colonizing wood blocks deployed for 2 years. The new genus differs from the only monotypic genus Ecbathyrion Humes, 1987 reported from hydrothermal vents of the Galapagos Rift and the East Pacific Rise in a number of morphological features (such as three articulating abdominal somites, mandible with 1 palp bearing setae, base of leg 1 with inner seta, distal exopodal segment of leg 4 with four inner setae, leg 5 2-segmented), suggesting long evolutionary history of the deep-sea family endemic to hydrothermal vents of the East Pacific. The derived feature of the new genus is the presence of one terminal spine on the distal endopodal segment of leg 3 (instead of bearing two terminal setae in Ecbathyrion). The diagnosis of the family Ecbathyriontidae is emended. [ABSTRACT FROM AUTHOR]

We present a detailed morphological description and a DNA barcoding of Parabrachiella platensis n. sp. collected from Mugil liza Valenciennes in Samborombon Bay (Buenos Aires, Argentina). This new species was compared with two Parabrachiella species parasitic on mugilids: Parabrachiella exilis (Shiino, 1956) and Parabrachiella mugilis (Kabata, Raibaut et Ben Hassine, 1971). Parabrachiella platensis n. sp. differs from those species in the shape of posterior processes, the anal slit with two pairs of bipartite papillae, the size of cephalothorax, the trunk, the maxilla, the microhabitat on the host, and the lack of caudal rami. On the host, the new species was in the nostrils (a new site for a species of the genus Parabrachiella ) and in the fins base. Some minor morphological differences were observed in relation to the locations on the host. The molecular analysis conducted based on mtDNA-COI between specimens of the new species on the fins and nostrils showed a genetic similarity of 99.8%. This percentage supports that the specimens found in nostrils and fins base could represent a single species. New studies on P. platensis n. sp., including infection of the same fish with the two forms, could bring some new information. Anyway according to the genetic information provided and the minimal morphological differences spotted we conclude that the two forms are a single specie. The differences observed are possibly influenced by the place of the host where the two forms of copepods were found, nostrils and fins. The new species was also molecularly compared to other five species of Parabrachiella including P. exilis (parasitizing mugilid from Chile), Parabrachiella anisotremis , Parabrachiella auriculata, Parabrachiella merluccii , and P. hugu (the last two sequences were taken from the GenBank). The genetic distance of 9% among P. platensis n. sp. and P. exilis , which is the close morphological related species, allow to states that these two copepods on mugilids belong to different species and then validating the morphological differences found between them. [ABSTRACT FROM AUTHOR]