Copepod Family Research Articles

Ectoparasitism on deep-sea fishes in the western North Atlantic: In situ observations from ROV surveys.

A complete understanding of how parasites influence marine ecosystem functioning requires characterizing a broad range of parasite-host interactions while determining the effects of parasitism in a variety of habitats. In deep-sea fishes, the prevalence of parasitism remains poorly understood. Knowledge of ectoparasitism, in particular, is limited because collection methods often cause dislodgment of ectoparasites from their hosts. High-definition video collected during 43 remotely operated vehicle surveys (2013–2014) provided the opportunity to examine ectoparasitism on fishes across habitats (open slope, canyon, seamount, cold seep) and depths (494–4689 m) off the northeastern U.S., while providing high-resolution images and valuable observations of fish behavior. Only 9% (n = 125 individuals) of all observed fishes (25 species) were confirmed with ectoparasites, but higher percentages (∼33%) were observed for some of the most abundant fish species (e.g., Antimora rostrata). Ectoparasites included two copepod families (Lernaeopodidae, Sphyriidae) that infected four host species, two isopod families (Cymothoidae, Aegidae) that infected three host species, and one isopod family (Gnathiidae) that infected 19 host species. Hyperparasitism was also observed. As host diversity declined with depth, ectoparasite diversity declined; only gnathiids were observed at depths down to 3260 m. Thus, gnathiids appear to be the most successful group to infect a diversity of fishes across a broad depth range in the deep sea. For three dominant fishes (A. rostrata, Nezumia bairdii, Synaphobranchus spp.), the abundance and intensity of ectoparasitism peaked in different depths and habitats depending on the host species examined. Notably, gnathiid infections were most intense on A. rostrata, particularly in submarine canyons, suggesting that these habitats may increase ectoparasite infections. Although ectoparasitism is often overlooked in deep-sea benthic communities, our results demonstrate that it occurs widely across a variety of habitats, depths, and locations and is a significant component of deep-sea biodiversity.

A new genus of Asterocheridae (Copepoda: Siphonostomatoida) ectoassociate of the ascidian Eudistoma vannamei Millar, 1977 (Polycitoridae) from Brazil.

Asterocheres Boeck, 1860 is the largest genus of the siphonostomatoid copepod family Asterocheridae, containing 63 valid species. The genus is known for its symbiotic relationships with many marine invertebrate taxa, especially sponges, cnidarians, bryozoans, and echinoderms. Recent studies have restricted the diagnosis of this genus. Consequently, many species are now considered as species inquirendae. The present paper describes a new species living externally on the tunic of Eudistoma vannamei Millar, 1977, an endemic ascidian from Brazil. As the new species does not fit Asterocheres in the strict sense, a new genus is erected to accommodate it. Setacheres gen. nov. is characterized by its possession of two distal setae on the third endopodal segment of P3, thus differing from the distal seta and spine pattern that is deemed as diagnostic of Asterocheres. A revision and comparison of Asterocheres´ species inquirendae revealed eight species sharing the same generic characteristics and were thus reallocated as members of the new genus.

Molecular evidence on evolutionary switching from particle-feeding to sophisticated carnivory in the calanoid copepod family Heterorhabdidae: drastic and rapid changes in functions of homologues

ABSTRACTThe oceanic calanoid copepod family Heterorhabdidae is unique in that it comprises both particle-feeding and carnivorous genera with some intermediate taxa. Both morphological and molecular (nuclear 18S and 28S rRNA) phylogenetic analyses of the family suggest that an evolutionary switch in feeding strategy, from transitions of typical particle-feeding through some intermediate modes to sophisticated carnivory, might have occurred with the development of a specially designed ‘poison’ injection system. In view of the small amount of genetic differentiation among genera in this family, the switching of feeding modes and re-colonization from deep to shallow waters might have occurred over a short geological period since the Middle to Late Miocene.

Proposition of indicators of anthropogenic pressure in the Bay of Toulon (Mediterranean Sea) based on zooplankton time-series

Zooplankton present characteristics of high interest in the frame of investigation for organisms sensitive to environmental changes and/or anthropogenic pressures. Such indicators are particularly needed in the present context of European legislation (Marine Strategy Framework Directive). However, zooplankton have not been given the interest they should have in regards to these issues. The aim of the present study is to provide an attempt of proposition of indicators of good environmental status and associated thresholds based on zooplankton data. Zooplankton time-series (2002–2013) from the Toulon Bay in the Mediterranean was used. This time-series presents the great characteristics that the sampling has be done jointly in two areas of the Bay of Toulon known to differ in term of anthropogenic pressures. The study focus on the copepod assemblage and different potential indicators are tested: ratio of copepod families on total copepod and diversity index (Piélou's evenness). The indicators relevance was evaluated per season by looking at the importance of the overlapping region between density's distributions for each indicator in both bays. This methodology well-recognized is commonly used, particularly in the medical sector, for a long time. The results show that the Oithonidae relative abundance and the Piélou's evenness index are the best indicators of anthropogenic pollution for this case study. Thresholds related to the selected indicators are also proposed in order to characterize the degree of anthropogenic pressure for the Toulon Bay and to provide a first evaluation for potential environmental management. Applicability of the selected indicators and future development needed are also discussed. This study is a first step in the investigation for operational zooplankton indicators and should open the way for additional studies in coastal anthropized area such as the Mediterranean coast where it is more urgently needed.

Vertical distribution of Eucalanoid copepods within the Costa Rica Dome area of the Eastern Tropical Pacific.

A variety of ecological strategies for tolerance of low-oxygen conditions within the Costa Rica Dome (CRD) area of the Eastern Tropical Pacific are documented for the copepod family Eucalanidae. During the summer of 2010, we compared the ecological strategies used by the Eucalanidae inside and outside the central CRD region. We compared the vertical and horizontal distributions of five species, Eucalanus inermis, Subeucalanus subtenuis, Subeucalanus subcrassus, Subeucalanus pileatus and Pareucalanus attenuatus together with Rhincalanus species, in the epipelagic (upper 200 m) among four locations, which we grouped into a section roughly crossing the core CRD area (inside-outside core CRD). The coastal area outside the CRD supported the most diverse assemblage, whereas overall abundance of Eucalanidae in the central CRD was 2-fold greater than outside and dominated by E. inermis (>60%). Eucalanidae in the central CRD had a shallow depth distribution, closely associated with the shallow thermocline (10-20 m). There was no evidence of daily vertical migration in the central CRD, but E. inermis demonstrated vertical migration outside the CRD. The vertical abundance patterns of Eucalanidae in the CRD region reflect complex interactions between subtle physical-chemical differences and food resources.

Sea lice (Copepoda: Caligidae) parasitic on fishes reported from the Neotropical region

The Caligidae, also known as sea lice, is a family of parasitic copepods of fish that consists of 31 genera and more than 450 species, some of which have been deleterious to cultured fish. The goal of this paper was to structure a list of sea lice species known from the Neotropical region based on information from published records. A total of 115 sea lice species found on 217 fish species were listed, including 58 species of Caligus and 22 of Lepeophtheirus. It seems that the inventory of this group of parasites is far from complete. Considering the promotion of finfish sea-cage aquaculture throughout the coastal areas of Latin America, a better understanding of the sea lice biodiversity will support systematic work on parasitic copepods in the Neotropics and will provide fundamental information that could impact fish disease control and prevention strategies.

A new genus and species of cyclopoid (Crustacea, Copepoda, Cyclopinidae) from a coastal system in the Gulf of Mexico

A new, monotypic genus of the interstitial marine cyclopoid copepod family Cyclopinidae G.O. Sars, 1913 is described from male and female specimens collected at Laguna de Términos, a large coastal lagoon system in the southern Gulf of Mexico. Mexiclopina campechana gen. et sp. n. cannot be adequately placed in any extant genus within the family. It differs from other cyclopinid genera in having a unique combination of characters including: 1) absence of modified brush-like seta on the mandibular exopod; 2) maxillule exopod with stout setal elements and brush-like setae absent; 3) basis of mandible with one seta; 4) presence of a modified seta on endopod of fourth leg; 5) fifth leg exopod unsegmented, armed with three elements in the female and five in the male; 6) intercoxal sclerite of first swimming leg with two medial spiniform processes on distal margin. The new genus is monotypic and appears to be most closely related to Cyclopina Claus, 1863 and Heptnerina Ivanenko & Defaye, 2004; the new species was compared with species of Cyclopina and it resembles Cyclopina americana Herbst, 1982 and Cyclopina caissara Lotufo, 1994. This is the second record of a species of Cyclopinidae in Mexico and the first in the Gulf of Mexico; the number of cyclopinid species recorded from the Americas is now 13.

The gastropod-crustacean connection: towards the phylogeny and evolution of the parasitic copepod family Splanchnotrophida

The gastropod-crustacean connection: towards the phylogeny and evolution of the parasitic copepod family Splanchnotrophida

A new genus and family of copepods (Crustacea: Copepoda) parasitic <br />on polychaetes of the genus Jasmineira Langerhans, 1880 (family Sabellidae) in the northeastern Atlantic

A new genus and species of copepod, Jasmineiricola mackiei n. gen. et n. sp., parasitic on at least three species of the sabellid polychaete genus Jasmineira Langerhans, 1880 is described. The adult female is mesoparasitic, living with part of its body (the endosoma) embedded within the host and part (the ectosoma) protruding through the host's body wall. The endosoma consists of a well defined head region carried anteriorly on the trunk which has paired lateral lobes housing the ovaries. The head bears a rosette-like array of eight slender lobes, which are probably derived from the mouthparts. The only limbs present on the trunk are the subchelate maxillipeds positioned immediately posterior to the head. The ectosoma consists of a posterior genito-abdominal lobe bearing paired genital apertures. The male is unknown. The new genus cannot be placed in any of the five existing families of mesoparasitic copepods on polychaete hosts and is treated as the type of a new monotypic family, the Jasmineiricolidae. The new species occurs over a depth range from 19 to 279 m, and is widely distributed from UK coastal waters to Norwegian waters inside the Arctic Circle.

High Prevalence and Potential Impacts of Caligid Ectoparasites on Larval Atlantic Croaker (Micropogonias undulatus) in the Chesapeake Bay

Larvae of Atlantic croaker Micropogonias undulatus enter Mid-Atlantic Bight estuaries annually between September and February. A high prevalence of ectoparasitic crustacean infection of ingressing larval M. undulatus was observed in Chesapeake Bay; this ectoparasite was identified as a species of Lepeophtheirus within the copepod family Caligidae from analysis of cytochrome oxidase I sequences and scanning electron microscopy. Between 2007 and 2011, seasonal differences in prevalence were observed, with higher infection rates on fall ingressing larvae (20 % mean monthly infection rate) than in larvae entering the estuary in the winter (monthly infection rate of 6 %); the head region had the highest parasite attachment rate, being observed in 78 % of the infected fish. The potential effects of this ectoparasite on larval M. undulatus could include reductions in feeding (and thus growth) and increased susceptibility to predation.

Description of four new endoparasitic species of the family Splanchnotrophidae (Copepoda, Poecilostomatoida) from nudibranch and sacoglossan gastropod hosts

The Splanchnotrophidae are a worldwide-distributed family of endoparasitic copepods, utilising shell-less opisthobranch gastropod hosts. Using scanning electron microscopy, we describe three new Ismaila Bergh, 1867 species infesting nudibranch hosts from southern Chile. Ismaila volatilis spec. nov. infests the proctonotid Janolus sp. and differs from all congeners by the size and number of dorsal bulges, the number of processes on the maxilla, and the thickness of thoracic appendages. Ismaila chaihuiensis spec. nov. was found in the doridoidean Diaulula punctuolata (D’Orbigny, 1837) and is diagnosed by a pore situated on a prominent bulge above the labrum. Ismaila genalis spec. nov. from a polycerid Holoplocamus papposus Odhner, 1926 host differs from its congeners in the size and form of the ventral bulges present on the head. These discoveries further broaden the range of splanchnotrophid host taxa; they are in line with earlier hypotheses of strict host specificity of Ismaila species and support Chile as a hotspot for Ismaila radiation. Herein, we present a key to the identification of all 14 Ismaila species. In Sulawesi (tropical Indo-West Pacific), Arthurius gibbosa spec. nov. infests the sacoglossan Elysia macnaei Marcus, 1982. The new species differs from both congeners by the short and stubby dorsal bulges. Uniquely among splanchnotrophids, long thoracic appendages are absent. Arthurius Huys, 2001 thus is the morphologically most divergent genus of the Splanchnotrophidae, but it is well characterized by the loss of several mouthparts and the preference for sacoglossan hosts. Currently, the distribution of the genus is limited to the Indo-West Pacific.

Ecological characteristics of eucalanoid copepods of the eastern tropical North Pacific Ocean: Adaptations for life within a low oxygen system

The eastern tropical North Pacific Ocean (ETNP) is home to one of the largest and most severe mid-water oxygen minimum zones (OMZs). Members of the copepod family Eucalanidae are abundant in this region and display varied vertical distributions throughout the OMZ. This research assessed the diversity of ecological strategies used by these copepods to cope with the presence of the OMZ based on their biochemical, physiological, and behavioral characteristics. Five species of copepods (Eucalanus inermis, Pareucalanus attenuatus, Rhincalanus nasutus, Rhincalanus rostrifrons, and Subeucalanus subtenuis) were collected at the Costa Rica Dome (9°N, 90°W) and Tehuantepec Bowl (13°N, 105°W) during cruises in fall of 2007 and winter of 2008–2009. Adult females of all species were collected and analyzed for water, ash, carbon, nitrogen, hydrogen, phosphorus, protein and lipid content, lactate dehydrogenase (LDH) activity, and survivorship when exposed to prolonged low-oxygen conditions. Four distinct ecological strategies were observed for the five species based on genus. E. inermis, found throughout the OMZ and surface waters, had very high water content (94% of wet weight (WW)), leading to low organic content per unit WW. However, when corrected to ash-free dry weight (AFDW), protein and storage lipid contents of this species had intermediate (46 and 8% of AFDW, respectively) values compared to other species. E. inermis demonstrated high survivorship under low-oxygen conditions (>90%), and had detectable levels of LDH, indicating an ability to rely on anaerobic pathways. Rhincalanus spp., found primarily in the lower-oxygen subsurface waters, also had detectable LDH activity and high survivorship under low-oxygen conditions (>85%), but had much higher storage lipid levels (>37% of AFDW), very low protein levels (28–33% of AFDW), and low water content (87% of WW). S. subtenuis and P. attenuatus are both distributed primarily in surface waters, but showed distinct ecological strategies. S. subtenuis protein levels were very high (67% AFDW), storage lipid levels low (0%), and water content low (87% of WW). They also had very low survivorship under low-oxygen conditions (22%) and no detectable LDH activity. P. attenuatus also did not have detectable LDH activity or large lipid stores. P. attenuatus, however, had much lower protein content (30% AFDW) and higher water content (89% of WW), indicating a distinct ecological strategy. Comparisons of ETNP individuals with conspecifics or congeners from higher-oxygen environments suggest that low protein levels (indicative of lower overall activity) seen in some groups may be an adaptation for survival in lower-oxygen regions.

Identification guide to some Diaptomid species (Crustacea, Copepoda, Calanoida, Diaptomidae) of "de la Plata" River Basin (South America).

An identification guide is presented for species of calanoid copepod family Diaptomidae from “de la Plata” River Basin (Argentina, Brazil, Bolivia, Paraguay and Uruguay). It was based on material collected during the summer and winter of 2010 from 43 sites across the eastern part and the lower stretches of this basin, the second largest in South America and the fourth in the world. The guide contains identification keys and species diagnoses for males and females, richly supported by scanning electronic micrographs and/or line drawings of 19 species. It also includes some general remarks on the taxonomy and phylogenetic relationships of these species. The key was adjusted to be useful for these species only, with separate keys for each sex, and is the first for females of South America. One species classified herein as incertae sedis was not included in the analysis. At least ten other species have previously been recorded in the basin but were not present in our samples. This is the first attempt to compile comprehensive taxonomic information on this group of copepods in this region, and it is expected to become a useful tool for biologists and young taxonomists interested in the crustacean biota of the Neotropical region.

Miocene cyclopid copepod from a saline paleolake in Mojave, California

There are remarkably few direct fossil records of Copepoda, which implies that current estimates of the lineage divergence times and inferences on the historical biogeography remain highly dubious for these small-sized crustaceans. The Cyclopidae, a predominantly freshwater copepod family with 1000+ species and distributed worldwide, has no fossil record at all. Recent collections from the middle Miocene Barstow Formation in Southern California resulted in ample material of finely preserved cyclopid fossils, including both adult and larval stages. To document the antennulary setation pattern in the adult and copepodid instars we used a coding system that is coherent between sexes and developmental stages. The majority of the cyclopid fossils, coming from saline lake environment, represent the modern genus Apocyclops, a euryhaline, thermophilic group occurring both in the New World and Old World. A new species Apocyclops californicus is described, based on the short medial spine and spiny ornamentation of ...

Macroevolutionary patterns of sexual size dimorphism in copepods.

Major theories compete to explain the macroevolutionary trends observed in sexual size dimorphism (SSD) in animals. Quantitative genetic theory suggests that the sex under historically stronger directional selection will exhibit greater interspecific variance in size, with covariation between allometric slopes (male to female size) and the strength of SSD across clades. Rensch's rule (RR) also suggests a correlation, but one in which males are always the more size variant sex. Examining free-living pelagic and parasitic Copepoda, we test these competing predictions. Females are commonly the larger sex in copepod species. Comparing clades that vary by four orders of magnitude in their degree of dimorphism, we show that isometry is widespread. As such we find no support for either RR or for covariation between allometry and SSD. Our results suggest that selection on both sexes has been equally important. We next test the prediction that variation in the degree of SSD is related to the adult sex ratio. As males become relatively less abundant, it has been hypothesized that this will lead to a reduction in both inter-male competition and male size. However, the lack of such a correlation across diverse free-living pelagic families of copepods provides no support for this hypothesis. By comparison, in sea lice of the family Caligidae, there is some qualitative support of the hypothesis, males may suffer elevated mortality when they leave the host and rove for sedentary females, and their female-biased SSD is greater than in many free-living families. However, other parasitic copepods which do not appear to have obvious differences in sex-based mate searching risks also show similar or even more extreme SSD, therefore suggesting other factors can drive the observed extremes.

Seasonal variation of the neustonic zooplankton community in southern waters of Korea

We investigated the seasonal variation of the neustonic zooplankton community in the surface layer (above 30 cm in depth) of 16 stations in southern waters of Korea from April 2002 to April 2003. In the neustonic community, copepods accounted for 59% of total organisms, as the most predominant group, while other dominant groups were invertebrate larvae, cladocerans, tunicates and fish eggs. Pontellid copepods, a major group of neustonic zooplankton, showed a marked seasonal variation and displayed a significant positive correlation with temperature (P < 0.05). Fish eggs appeared from spring to early summer in the inshore waters while tunicates and oceanic copepods (Eucalanus spp. and Euchaeta spp.) were dominant in the offshore waters during high temperature periods. This suggests that the distribution pattern of the neustonic zooplankton is seasonally affected by the hydrological conditions of in- and offshore waters. The abundance of zooplankton was higher in the surface layer (< 15 cm) than in the subsurface layer (15–30 cm), and was also higher at night than during the daytime. Of the dominant copepod families, the density of acartiid and pontellid copepods was higher in the surface layer than the subsurface layer. The density of acartiid and corycaeid copepods was significantly higher during daytime than nighttime. This indicates that the surface layer in temperate regions may provide a favorable habitat for neustonic copepods despite the dynamic environmental fluctuations.

Community structure of mesozooplankton in coastal waters of Sundarban mangrove wetland, India: A multivariate approach

Spatial and temporal distribution of community structure and seasonal distribution of mesozooplankton (MZ; 20–200μm) in the context of environmental parameters were studied in the coastal waters of Indian Sundarban wetland formed at the confluence of Hugli (Ganges) River estuary, India. The work has been aimed for better understanding of its ecological characteristics in terms of the most dominant mesozooplankton group in a tropical mesomacrotidal setting. Samples were collected from four sampling sites of different hydrodynamic set up using a ring trawl net (Hydro-Bios No. 438 700, mesh size 200μm) equipped with a calibrated flowmeter and both water and plankton samples were analyzed by standard methods. Distribution of MZ showed bimodality with two peak periods, primary peak during April coinciding with maximum number of copepod species (974ind.m−3) and the secondary one during August. Copepod was the most dominant taxon where the calanoids formed bulk of the biomass representing 33 species of 7 genera, while cyclopoids formed the next dominant group comprising 4 species of 3 genera followed by 4 monogeneric harpacticoid species. Results of correlation matrix revealed that two copepod families Acartiidae and Pseudodiaptomidae maintain negative relationship with other six families indicating that they form a group by themselves. Results of multiple regression analysis reveal that salinity, chlorophyll-a and transparency are the potential hydrological factors in the distribution and existence of the dominant copepods and total chaetognaths. An overall high diversity index values (max. 3.21) was associated with high richness index (4.39) and high evenness index (0.96) at the site of the mouth of the estuary. In terms of feeding guild, the herbivore copepods were dominant followed by omnivores. Cluster analysis confirmed an overall dominance of the calanoid copepod Bestiolina similis as a solitary group for all the sites. The chaetognath Sagitta bedoti was perennial in distribution where the contribution of juvenile form (recognized as Stage I) was dominant. Among the other MZ, hydromedusae, ctenophore, sergestid and mysid were also encountered contributing insignificant part of the total density. A long-term decadal change in copepod community was pronounced which might be due to climate-induced environmental changes which also modulate the physicochemical characteristics of water.

Assessment of storage lipid accumulation patterns in eucalanoid copepods from the eastern tropical Pacific Ocean

Members of the copepod family Eucalanidae are widely distributed throughout the world׳s oceans and have been noted for their accumulation of storage lipids in high- and low-latitude environments. However, little is known about the lipid composition of eucalanoid copepods in low-latitude environments. The purpose of this study was to examine fatty acid and alcohol profiles in the storage lipids (wax esters and triacylglycerols) of Eucalanus inermis, Rhincalanus rostrifrons, R. nasutus, Pareucalanus attenuatus, and Subeucalanus subtenuis, collected primarily in the eastern tropical north Pacific near the Tehuantepec Bowl and Costa Rica Dome regions, noted for its oxygen minimum zone, during fall 2007 and winter 2008/2009. Adult copepods and particulate material were collected in the upper 50m and from 200 to 300m in the upper oxycline. Lipid profiles of particulate matter were generated to help ascertain information on ecological strategies of these species and on differential accumulation of dietary and modified fatty acids in the wax ester and triacylglycerol storage lipid components of these copepods in relation to their vertical distributions around the oxygen minimum zone. Additional data on phospholipid fatty acid and sterol/fatty alcohol fractions were also generated to obtain a comprehensive lipid data set for each sample. Rhincalanus spp. accumulated relatively large amounts of storage lipids (31–80% of dry mass (DM)), while E. inermis had moderate amounts (2–9% DM), and P. attenuatus and S. subtenuis had low quantities of storage lipid (0–1% DM). E. inermis and S. subtenuis primarily accumulated triacylglycerols (>90% of storage lipids), while P. attenuatus and Rhincalanus spp. primarily accumulated wax esters (>84% of storage lipids). Based on previously generated molecular phylogenies of the Eucalanidae family, these results appear to support genetic predisposition as a major factor explaining why a given species accumulates primarily triacylglycerols or wax esters, and also potentially dictating major fatty acid and alcohol accumulation patterns within the more highly modified wax ester fraction. Comparisons of fatty acid profiles between triacylglycerol and wax ester components in copepods with that in available prey suggested that copepod triacylglycerols were more reflective of dietary fatty acids, while wax esters contained a higher proportion of modified or de novo synthesized forms. Sterols and phospholipid fatty acids were similar between species, confirming high levels of regulation within these components. Similarities between triacylglycerol fatty acid profiles of E. inermis collected in surface waters and at >200m depth indicate little to no feeding during their ontogenetic migration to deeper, low-oxygen waters.

Resource utilization and trophic position of nematodes and harpacticoid copepods in and adjacent to &amp;lt;i&amp;gt;Zostera noltii&amp;lt;/i&amp;gt; beds

Abstract. This study examines the resource use and trophic position of nematodes and harpacticoid copepods at the genus/species level in an estuarine food web in Zostera noltii beds and in adjacent bare sediments using the natural abundance of stable carbon and nitrogen isotopes. Microphytobenthos and/or epiphytes are among the main resources of most taxa, but seagrass detritus and sediment particulate organic matter contribute as well to meiobenthos nutrition, which are also available in deeper sediment layers and in unvegetated patches close to seagrass beds. A predominant dependence on chemoautotrophic bacteria was demonstrated for the nematode genus Terschellingia and the copepod family Cletodidae. A predatory feeding mode is illustrated for Paracomesoma and other Comesomatidae, which were previously considered first-level consumers (deposit feeders) according to their buccal morphology. The considerable variation found in both resource use and trophic level among nematode genera from the same feeding type, and even among congeneric nematode species, shows that the interpretation of nematode feeding ecology based purely on mouth morphology should be avoided.

Revision of basal calanoid copepod families, with a description of a new species and genus of Pseudocyclopidae

Revision of basal calanoid copepod families, with a description of a new species and genus of Pseudocyclopidae