Brazil has the richest biodiversity of Ergasilidae on Earth, with 76 species in 19 genera. However, several authors suggested that there is still great potential for discoveries, especially regarding genetic data that are still scarce for ergasilids from this region. To expand our knowledge of this taxon, we conducted an integrative study involving morphological (light and scanning electron microscopy) and molecular analyses of ergasilids from fishes sampled in the Pardo River, São Paulo State, Brazil. Two ergasilid species were found, Gamispatulus schizodontis and Rhinergasilus piranhus parasitizing the nostrils of 5 fish species (native and exotic): (i) R. piranhus from Astyanax lacustris; Cyphocharax modestus; Coptodon rendalli; Psalidodon bockmanni; and (ii) G. schizodontis from Serrasalmus maculatus. Additionally, we redescribed R. piranhus herein based on novelties and discrepancies found in the antennules, antennae, body segments and ornamentation of the swimming legs. Novel molecular data of ribosomal (18S and 28S rDNA) and/or mitochondrial (cox 1) genes were provided for both species and the phylogenetic relationships among the ergasilids were tested. Relationships between species/genera are still uncertain in Ergasilidae, but it was possible to verify the formation of 5 well-supported terminal clades – i.e. including a clade formed only by Neotropical species. More molecular data are needed to test this hypothesis, but the clades observed here represent good targets for future taxonomic revisions. The occurrence of R. piranhus specimens in the introduced fish, Co. rendalli can indicate (for the first time) host switching in this parasite species and spillback from native to introduced hosts.

Nine hundred and ninety-two (992) specimens of Pseudocyclops lerneri Fosshagen, 1968 (Copepoda: Pseudocyclopidae) were collected from the largest South Atlantic coral reef, Abrolhos bank (17°20′–18°10′S; 38°35′–39°20′W). Specimens were distinguished from other Pseudocyclops spp. by a close examination of the female and male fifth leg. This is the first record of the family Pseudocyclopidae in the South Atlantic. We further indicate that the low number of studies on this species, and as a consequence, the poorly understood ecology of Pseudocyclopidae may be caused by the use of inadequate sampling methods, indicating the use of demersal-focused samplers, such as emergence traps as an alternative to the sampling of these bottom-dwelling copepods.

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.

The Splanchnotrophidae is a family of highly modified endoparasitic copepods known to infest nudibranch or sacoglossan sea slug hosts. Most splanchnotrophid species appear to be specific to a single host, but some were reported from up to nine different host species. However, splanchnotrophid taxonomy thus far is based on external morphology, and taxonomic descriptions are, mostly, old and lack detail. They are usually based on few specimens, with intraspecific variability rarely reported. The present study used molecular data for the first time to test (1) the current taxonomic hypotheses, (2) the apparently strict host specificity of the genus Ismaila and (3) the low host specificity of the genus Splanchnotrophus with regard to the potential presence of cryptic species. Phylogenetic analyses herein used sequences of the barcoding region of the cytochrome oxidase I (COI) gene from 40 specimens representing 13 species of five genera. Species delimitation approaches include distance and barcoding gap analyses, haplotype networks and diagnostic nucleotides. Molecular results are largely compatible with the commonly accepted, morphology-based taxonomy of the Splanchnotrophidae. Strict host specificity could be confirmed for two Ismaila species. COI analyses also supported the idea that Splanchnotrophus angulatus is host-promiscuous. In Ismaila, morphology seems more suitable than barcoding to display speciation events via host switches in a recent Chilean radiation. In Splanchnotrophus, some genetic structure suggests ongoing diversification, which should be investigated further given the inadequate morphology-based taxonomy. The present study thus supports the presence of two different life history strategies in splanchnotrophids, which should be explored integratively.

The Indian Western continental shelf (IWCS) is amongst the most productive regions of the world, being noteworthy for upwelling (south-west monsoon) and downwelling (north-east monsoon) that tunes the water biogeochemistry. The present study provides baseline information on temporal variation of in situ copepod gut pigments from IWCS. The copepods were collected between November 2011 and October 2013 and gut pigment contents and composition were estimated using the gut fluorescence method. Results revealed that copepods procured high gut pigment content in monsoon that coincided with ambient water pigment credited to discrete upwelling. Fluorometric analyses of copepod orders revealed presence of gut chlorophyll a (Chl a) throughout the study with highest gut Chl a (0.31 ± 0.25 ng copepod−1; N = 21) and total gut pigments (2.01 ± 2.15 ng copepod−1; N = 21) recorded in Calanoida. Consecutively, Calanoida and Poecilostomatoida chiefly consumed autotrophic biomass that was evident from presence of canthaxanthin and astaxanthin as dominant gut pigments. Interestingly, the marker pigment of Cryptophyceae was present only in Calanoida during monsoon and post-monsoon. Collectively these results conclude that copepods predominantly showed omnivory with discrete temporal variability by grazing upon autotrophic biomass that in turn probably supports the fishery.

A new species of stephid calanoids copepod Stephos grieveae sp. nov. was collected from an anchialine cave on Mljet Island (Croatia). The new species can be distinguished from other Stephos spp. by a combination of the following features: last pedigerous somite slightly asymmetrical, female genital double-somite symmetrical in ventral view, about as long as wide, single operculum; antennules of both sexes are symmetrical, 24-segmented and very long, reaching almost to end of anal somite; antennal exopod 7-segmented; maxillule displays 13 armature elements on praecoxal arthrite; female fifth legs symmetrical, uniramous and 3-segmented, terminal segment very long armed with spinules distally along inner and outer margins, single small spine on anterior surface and spiniform process laterally; male fifth legs are uniramous and asymmetrically, right leg 4-segmented and left 5-segmented, segment 4 not swollen and segment 5 simple, crescent shaped and is connected to segment 4 at approximately one quarter of its length. The shorter part of segment 5 tapers into a heavy process, while the longer part forms a club-shaped, curved extension.

A male of the new species Stygiopontius senckenbergi belonging to the family Dirivultidae Humes & Dojiri, 1980 (Copepoda: Siphonostomatoida) and endemic to deep-sea hydrothermal vents, is described from a raised fault block structure south of Edison seamount of the New Ireland Fore-Arc system (Papua New Guinea). The copepods were collected in by box-corer during cruise SO-133 of the RV ‘Sonne’ at a depth of 1610–1625 m, 3°19′S 152°35′E. The new species belongs to a group of eight species that are separate from 21 congeners on the basis of setation of legs 1 and 4: the coxa of leg 1 has an inner seta (absent on the others) and the third exopodal segment of leg 4 has three outer spines (instead of two spines). The new species shares with S. pectinatus Humes, 1987 a pectinate maxilliped but differs from it in lacking two pectinate, terminal claw-like setae on the endopod of the antenna.

Three species of Asterocheres, including two new species, are reported as associates of sponges in shallow Antarctic water. Asterocheres spinosus sp. nov. has a combination of diagnostic features: mandibular palp is one-segmented, caudal ramus is 1.88 times as long as wide, antennule is 20-segmented in the female and 18-segmented in the male, urosome is spinulose, and legs 1 and 2 display weak sexual dimorphsims. In A. rai sp. nov., the body is large, 1.66 mm long in the female, the lateral margin of genital double-somite is smooth without setules or spinules, the exopod of antenna bears only a single seta, with two mucilaginous substances transformed from setae, and the third endopodal segment of leg 1 bears a prolonged distal process. A supplementary description is given for A. hirsutus Bandera, Conradi and López-González, 2005, recorded previously from the Antarctic.

A new species of the genus Dahmsopottekina is described from the Mediterranean Sea. Dahmsopottekina guilvardi sp. nov. was collected from abyssal habitats at a depth range of 2340–2850 m. Like its congeners, the new species has a vermiform habitus, a highly transformed P1 in both sexes and a plough-like rostrum in the female. Dahmsopottekina guilvardi sp. nov. can be distinguished from its congeneric species by the combination of a fused basis and endopodite in P1 of both sexes and the absence of an endopodite in P2–P4 of the female. Dahmsopottekina guilvardi sp. nov. is the second record of a harpacticoid species after its congener D. peruana in which the basis and endopodite of a leg other than the P5, namely the P1, are fused. Furthermore, the new species is the only one among Dahmsopottekina species with a 1-segmented P1 exopodite in the male. Similar to its congeners, D. guilvardi sp. nov. is strongly sexually dimorphic. This is evident through the morphology of most of the cephalic appendages and the reduction of P2–P6 in the female. The results of the present study support the observation that Dahmsopottekina species are sparsely distributed and highly endemic. Nevertheless, our results do not agree with the statement of considerably larger females as the length variability between females is greater than between the two sexes. Despite the morphological characters of the species commensurate with a burrowing mode of life, its presence in sediment traps suggests that D. guilvardi sp. nov. is an active ‘swimmer’.

We provide a review on scientific contributions concerned with Leptocaris (Harpacticoida: Copepoda) that includes the zoogeography, ecology, biology, and morphology of this genus. A tabular key is given to aid in the identification of the ignavus-group. Leptocaris ryukyuensis sp. nov. is included on the basis of specimens collected from Akeijima sandy beach of the Ryukyu Islands in Japan. The new species can be distinguished from its congeners by an abexopodal seta and 3 exopodal setae on A2, a barbed inner seta on the proximal, endopodal segment of female P1 to P3, setae of the caudal ramus (setae I and II are very small, and the basal seta is transformed to a big spine), and modified inner setules of P2 enp-2 and P3 enp-2 in the males. The new species belongs to the ignavus-group established by Kunz (1994) and is the third species of the genus Leptocaris in East Asia.

Females of the new species Exrima walteri sp. nov. were found in sediment trap samples deployed over different sites of the East Pacific Rise (13°N) at 2600 m depth. Four traps were deposited during the HOPE99 cruise (1999) and recovered during the AMISTAD (1999) cruise on the research vessel ‘L'Atalante’. The new species is distinguished from congeners, E. singula Humes, 1987 and E. dolichopus Humes, 1987, by the following derived characters: first somite of the urosome with 3 (one dorsal and two lateral) stout conical extensions; distal endopodal segment on the swimming leg 4 broad. In addition, many specimens of copepodids I and lecithotrophic nauplii, identified as belonging to Dirivultidae gen. sp., were found in the samples of all sediment traps. This is the first record of copepodids I and of a nauplius of dirivultids from the Pacific Ocean. Study of type and additional material collected during different Ifremer cruises at different vent sites (HERO91, EXOMAR, PHARE and MoMARETO) required synonymy of four species of Aphotopontius Humes, 1987, Stygiopontius Humes, 1987 and Rhogobius Humes, 1987. Aphotopontius rapunculus Humes and Segonzac, 1998 is transferred to the genus Rhogobius because it possesses all presumed derived attributes of this genus: last abdominal somite with lobes at sides of anal operculum; second segment of antennal endopod elongate and slender. A new study of the type material suggests that: Aphotopontius temperatus Humes, 1997 is a synonym of A. atlanteus Humes, 1996; Stygiopontius lumiger Humes, 1989 is a synonym of S. sentifer Humes, 1987 while S. bulbisetiger Humes, 1996 is a synonym of S. pectinatus Humes, 1987. Females of the three synonymized species were found to be sub-adult females at copepodid V. Leg 6 on these specimens is one seta located dorsolaterally on the posterior part of the genital somite. This position for leg 6 is unknown for copepodid V of other siphonostomatoids whose leg 6 is located ventrally at copepodid V; the dorsolateral position is presumed derived and shared by the dirivultid genera Aphotopontius Humes, 1987 and Stygiopontius Humes, 1987. A new key to the Dirivultidae genera is presented.

Community structure and vertical distribution of oncaeid copepods were investigated at an offshore site in Tosa Bay, southern Japan. Samples were collected with a 0.063 mm closing type net from eight discrete layers between the surface and 500 m depth in August and November 2005. A total of 45 species and three form variants belonging to the genera Triconia, Oncaea, Spinoncaea, Conaea and Epicalymma were identified. The greatest number of species was consistently found in the lower epipelagic zone, at 50–100 m. The vertical distribution patterns of oncaeid copepods were similar between August and November, with the highest abundances in the upper epipelagic zone above the thermocline. The oncaeid maxima corresponded with the depth where appendicularians occurred in high numbers. Dominant species in the water column (0–500 m) were O. venusta small form, O. media, O. scottodicarloi, O. waldemari, O. zernovi, O. tregoubovi, S. ivlevi, S. tenuis and T. conifera. The vertical succession of species composition was almost the same between August and November, although several species showed a downward shift of their depth-range to some extent in November. The oncaeid copepod community could be differentiated into three distinct groups according to the depth layers, each corresponding to different hydrographic conditions in the water column.

Burrowing depth may affect predation rate, feeding ability and reproduction in bivalve clams. We studied the effect of burrowing depth on the abundance of the ergasilid Paraergasilus rylovi in the freshwater bivalve clam Anodonta piscinalis. We transplanted uninfected clams to a lake where they were allowed to choose their preferred burrowing depth, and were exposed naturally to copepodids of the parasite. There was a significant positive correlation between proportionate burrowing depth (PBD) and the abundance of P. rylovi at the end of the 17-day experiment, the deeper-burrowed clams harbouring more P. rylovi. Original PBD (0%, 50%, 100%) did not influence the final PBD or parasite abundance. Clam length affected PBD, smaller clams burrowing deeper, but it did not affect parasite abundance. Infected experimental clams and naturally-burrowed uninfected clams, both originating from the same lake, did not differ in their mean PBD. This indicated that burrowing of the experimental clams affected parasitism rather than the parasites altering burrowing of the clams. In line with the experimental result, we observed a significant positive correlation between PBD and the abundance of P. rylovi also among clams collected from 2 natural A. piscinalis populations.

The assemblage patterns of pelagic Cladocera species were investigated in a meso-eutrophic reservoir from January 2000 to December 2002. Trends of environmental factors (water temperature, conductivity, pH, and nutrient concentrations), as well as of biotic factors (availability of potentially edible phytoplankton and densities of herbivorous and carnivorous copepods) were assessed. Zooplankton community was dominated by Cladocera and Copepoda. Assemblage patterns for Cladocera were identified by performing a cluster analysis on abundance data of the dominant species: Daphnia longispina, Ceriodaphnia pulchella, Bosmina longirostris and Diaphanosoma brachyurum. In winter and spring, Daphnia was dominant. In early summer and end of autumn, Ceriodaphnia and Daphnia coexisted. During summer, Ceriodaphnia was dominant and coexisted with Diaphanosoma. Bosmina was present in low densities during the whole study period. Cladoceran populations exhibited non-synchronous peaks of abundance, evidencing different ecological optima. Temperature seemed to be the main structuring factor of this assemblage. The way biotic interactions influenced pelagic cladoceran assemblage in this reservoir was not clear and needs further research.

Zooplankton was sampled intensively with an RMT 1+8M system in the fjord of Cumberland East Bay, South Georgia during late winter 1983 and summer 1987. In summer, biomass was highest in the surface 20 m, reaching 142 g dw/1000 m3. Copepods dominated the zooplankton comprising 96–99% by numbers, of which 80–90% occurred in the top 100 m of the 265-m water column. The small clausocalanid Drepanopus forcipatus was particulary abundant. With increasing depth the proportion of non-copepod biomass, principally Mysidacea and Amphipoda increased significantly. Biomass throughout the water column in winter was generally 4–5 times lower than in summer although again copepods, and in particular D. forcipatus and members of the Metridinidae, still numerically dominated the plankton. Biomass levels were some 2–3 times greater than those found in Antarctic oceanic regions but were comparable with estimates from some boreal fjords. The mixture of neritic and oceanic species encountered, and the seasonal presence of some gelatinous zooplankton, particularly ctenophores, appears typical of the community structure of many fjord ecosystems.

Composition, abundance, and distribution of suprabenthos from a depth between 1 and 1.33 m above the seafloor were analysed. The samples were taken during ANT XV/3 with RV Polarstern in February and March 1998 by means of the supranet of an epibenthic sledge along two transects in the southern Weddell Sea (Vestkapp and Halley Bay) and one east of King George Island. At each of these three transects, five to six stations were taken in water depth between 200 and 2000 m. In total, 34 057 specimens were sampled at 16 stations, yielding 1 205 050 individuals for all stations standardized to 1000 m3 hauls. Of these, copepods were usually the most abundant group in the supranet (805 822 ind 1000 m−3. The suprabenthic fauna of the southwest of Vestkapp (Weddell Sea) transect was dominated by planktonic taxa in terms of individual numbers especially at the deeper stations (938–1983 m). At Halley Bay the total abundance of plankton was lower but its relative abundance (> 80%) was also high, whilst off King George Island peracarid crustaceans were an important fraction.

Rangabradya n. gen. and Rangabradya indica n. sp. from the subterranean freshwaters of India axe described. The new genusbelongs to a group of genera in the family Ectinosomatidae Sars, 1904 possessing fusiform body shape and it is very similar tothe genus Halectinosoma Lang, 1944. The new genus has the exopodite and basiendopodite of the fifth leg completely fused,without surface seta, as well as a characteristic appearance of the antennula, antenna and maxilla. The position of the genusRangabradya n.gen. within the family Ectinosomatidae is discussed.

Le cyclopoïde Mesocyclops ogunnus Onabamiro, 1957 a été identifié dans la retenue de Sidi Salem (Tunisie). C'est la premièreobservation d'une espèce du genre Mesocyclops en Tunisie. Déjà signalé en Algérie, cette nouvelle observation permet deconfirmer le lien entre les aires de répartition africaine intertropicale et euro-asiatique de M. ogunnus (Israël, Ouzbékistan,Bangladesh, Sri Lanka, Laos).

After examination of 44 populations of Attheyella (Brehmiella) wulmeri (Kerhervé, 1914) (Copepoda : Harpacticoida) from Montenegro (SE Europe), its taxonomic status is revised. Three new synonyms of this species are established : A. (B.) osmana Kiefer, 1955, A. (B.) naphtalica Por, 1983, and A. (B.) paranaphtalica Pesce & Galassi, 1988. Detailed description, map of distribution, as well as a review of all important variable characteristics are presented.

Fratia gaditana, n. gen., n. sp., is described based on the specimens obtained from the atrium of the ascidian, Clavelina dellavallei (Zirpolo), collected at Tarifa Island in Cádiz, Spain. The new species belongs to a new family of Cyclopoida. Cladistic analysis revealed that phylogenetically it is closer to the Ascidicolidae than to the two other ascidicolous families, Archinotodelphyidae and Notodelphyidae.