Search Results (20)

A new genus of Ectinosomatidae is recorded in association with an Ascidia from a permanent submerged coral community in Barra Beach, Salvador City, Bahia State (Brazil). The new taxon belongs to a smaller group of genera in the family Ectinosomatidae based on the geniculate maxilla and the prehensile first swimming leg. This group is composed of Bradiellopsis, Chaulionyx, Halophytophilus, and Sigmatidium. The new genus differs from the others due to distinct aspects of the mandible gnathobasis, which features sharp processes on the pars incisiva and pars molaris followed by a short spinulated area and a serrulated seta; the presence of a two-segmented endopod of the first swimming leg, with the first endopodal segment longer than all exopodites combined; and a short, quadratic second endopodal segment with two strong curved claws. In addition, it differs from other genera due to the distinct armature of the first to fourth swimming legs and the presence of fused exopod and baseoendopod on the fifth swimming leg. Cruscollatus gen.nov. lives specifically within the digestive tract of Eudistoma vannamei Millar, 1977, an Ascidia species endemic to northeastern Brazil. This study reports the first documented association between a harpacticoid copepod of the family Ectinosomatidae (order Harpacticoida) and ascidian hosts (Ascidia). Full article

The diet of the invasive ctenophore Mnemiopsis leidyi in the Gulf of Trieste was examined during its peak occurrence in the summer and early-autumn months (July to October) from 2017 to 2019, through the analysis of stomach contents. Altogether 506 specimens were individually caught for the analysis. A total of 3215 prey items were isolated and identified. Copepods emerged as the primary prey (relative abundance 66.7%), followed by cladocerans (7.7%), and bivalve larvae (6%). Notably, specimens of M. leidyi constituted a significant portion of the diet (5.4.%), providing further evidence of cannibalism within this species. Copepods were also the most commonly occurring prey items in the diet of M. leidyi. Most of them were represented by calanoid and cyclopoid nauplii (48.2%), followed by a harpacticoid M. norvegica (28.3%), and calanoids (26.8%). Other frequently occurring taxa were bivalve larvae (19.3%), M. leidyi (18.7%), and cladoceran Penilia avirostris (16.1%). The rate of cannibalism peaked in July, coinciding with a period of limited food availability. Additionally, the study revealed that fish eggs and larvae were infrequently found in the stomachs of M. leidyi. However, the presence of massive aggregations of M. leidyi may impact microzooplankton populations in late summer or autumn, potentially leading to competition with small pelagic fish. Full article

Quinquelaophonte is a genus of laophontid harpacticoid, including 13 valid species around the world. Many of them are known to possess inter- and/or intra-individual variations in their swimming legs. During a survey of the meiofaunal biodiversity of Jeju Island in Korea, specimens of Quinquelaophonte were collected from an intertidal zone off the west coast of Jeju Island. This study examined the morphological characteristics and amplified partial sequence of four genes (18S rRNA, 28S rRNA, COX1, and CYTB). As with other Quinquelaophonte species, specimens of this new species showed variability in the chaetotaxy of their swimming legs in both sexes. There was a setal arrangement pattern in females that could be considered a standard, whereas male individuals showed two sets of the chaetotaxy on the fourth swimming legs. The molecular data confirmed that individuals belonged to a single species, regardless of morphological variations. The result of the morphological comparison showed that the new Quinquelaohponte species shared some characteristics with congeneric species but included some specific morphological characters different from its congeners. The new species was named Quinquelaophonte sominer sp. nov. and was presented with detailed descriptions, illustrations, and confocal micrographs. Furthermore, phylogenetic analyses were conducted using newly obtained data plus the sequences of other copepods and two Quinquelaophonte species. The result suggested that Q. sominer sp. nov. and two congeners were classified as branched lineages. This discovery brings the total number of species to three in the Northwest Pacific region. Full article

Diuron, an additive biocide in antifouling paints, is widely employed to curtail the attachment of organisms on submerged surfaces in aquatic structures. Despite the detection of diuron in aquatic ecosystems, information regarding its acute and chronic impacts on aquatic invertebrates, particularly planktonic crustaceans, remains limited. In this study, we analyzed the acute (24 h) and chronic (12 days exposure across three generations) effects of different concentrations of diuron (1/10 of the no observed effect concentration (NOEC), the NOEC, and 1/10 of the lethal concentration 50% (LC50), derived from the 24 h acute toxicity value of 1152 μg L⁻¹) on the harpacticoid copepod Tigriopus japonicus. The acute exposure experiment indicated that the 1/10 LC50 value of diuron significantly reduced the copepod’s feeding rate and acetylcholinesterase activity. In response to the 1/10 LC50 value, the intracellular reactive oxygen species were elevated alongside increased malondialdehyde levels, while the glutathione content was depleted. The enzymatic activities of glutathione S-transferase, catalase, and superoxide dismutase were significantly enhanced by the 1/10 LC50 value, suggesting a proactive role of the antioxidant defense system against oxidative stress. Conversely, the activities of glutathione peroxidase and glutathione reductase enzymes were increased at the NOEC value, while their values were reduced by the 1/10 LC50 value. Chronic exposure to 1/10 NOEC and NOEC values revealed the adverse multigenerational effects of diuron. The second generation exhibited the most sensitivity to diuron, with the NOEC value notably reducing survival rate, body length, nauplius-to-adult development, neonates per brood count, and extending the reproduction period. Taken together, our findings underscore that even sublethal diuron levels can adversely impact copepod populations across generations through intergenerational toxicity. Full article

Copepods are the dominant crustacean group in groundwater, where they perform valuable ecosystem services related to carbon recycling. The life-history traits of stygobitic (groundwater-obligate dweller) copepods, however, have only been casually studied in the past. In addition, next to nothing is known about the responses of stygobitic copepods to climate change. In this study, we investigated the life-history traits and respiratory metabolism of a species of harpacticoid copepods, Moraria sp., endemic to the Corchia Cave in the Apuan Alps (Italy). We collected the specimens of Moraria sp. from the dripping waters of the cave and observed their development, survival, and reproduction rates in the laboratory for one year. We also evaluated the acclimation ability of adult females of Moraria sp. by measuring their oxygen consumption in a temperature range from 8 °C (average annual temperature of the dripping water in the Stalactites Gallery of the Corchia Cave) to 12.5 °C (maximum temperature of the dripping water of the cave expected according to climate change scenarios in 2100). Our results indicate that Moraria sp. Is a stenothermal species showing remarkable stygobitic traits (long life span, low metabolic rates). We noted that the metabolism of this species is significantly affected by small (+1.5 °C) thermal changes. Our results showed no metabolic compensation occurring in this species over two weeks of exposure to temperatures higher than 8 °C. The outcomes of this study suggest that Moraria sp. May not be able to tolerate thermal changes brought on by climate change. Full article

Thirty-one nominal species of the benthic harpacticoid family Zosimeidae Seifried, 2003 are known from several coastal systems less than 200 m depth and the deep sea. Several copepods of the family Zosimeidae were found in deep-sea sediment samples from the Gulf of Mexico and the Gulf of California (Mexico). The Mexican material represents new species of the genera Zosime Boeck, 1873, Peresime Dinet, 1974, Heterozosime Kim and Lee, 2021, and Acritozosime Kim and Lee, 2021. Standardized and complete descriptions for these new species are provided. Previous studies have shown that the genus Zosime can be subdivided into two species groups. We performed phylogenetic analyses (88 characters and 42 taxa) to test the naturalness of such subdivision, to subdivide these groupings further, and to shed some light on the phylogenetic relationships among the zosimeid genera and their species. Our results confirmed (i) the monophyly of previous subdivisions of the genus Zosime, and (ii) that the genus Zosime can be further subdivided into two major subgroups composed of several subordinate clades. Additionally, some comments on the phylogenetic hypotheses amongst the species of each genus reported here, are provided. Full article

Lake Baikal (LB) is the only freshwater ancient lake on Earth where animals inhabit all bathymetric zones down to the deepest sites (approximately 1640 m). However, there is very little data on the composition of their abyssal harpacticoid fauna. On the basis of the samples collected in LB in 2010–2017 at a depth of 270–1632 m, analysis of the fauna composition and species diversity of harpacticoids in the deep-water zone is presented. Studies were conducted in all parts of the lake, including areas of a hydrothermal, oil–methane seeps, and mud volcanoes. Nineteen Baikal endemic morphological species of the genera Bryocamptus, Attheyella, and Moraria (Baikalomoraria) were found. A brief description of the taxa morphology is presented. The genus Bryocamptus was the richest by species number at the studied sites, and Bryocamptus smirnovi Borutzky was the most frequent. The most diverse (8 species) was the fauna of the Saint Petersburg methane seep. Studies have shown that the taxonomic diversity of harpacticoid copepods in the deep-water zone of LB is lower than in its littoral zone. According to two non-parametric species estimators (Chao 2 and Jackknife 1), a 1.5-fold increase of species richness of harpacticoids of the LB abyssal is expected. Full article

The Gulf of Gabès, located on the south-east Tunisian coast, is an important maritime area, with great influence on the local economy and human welfare. The aim of the current study was to assess the response of meiobenthic copepod populations from this gulf to anthropogenic disturbances. Nine sampling sites, situated along the shores of the gulf were surveyed seasonally from winter of 2004 to autumn of 2005. Interestingly, this biotope has one of the highest semi-diurnal tides in the Mediterranean Sea. Despite the fact that the data being presented here are not that new, such a high maximum amplitude of tides reaching 2 m makes any information available on animals with diurnal dispersal cycles such as copepods extremely precious. Furthermore, the lack of knowledge on these crustaceans is obvious and lags behind that of numerous other meiobenthic taxa and planktonic calanoids. Actually, most publications do not reach the species level and are limited to determining densities. This is mainly due to the modest size of harpacticoids, and the lack of qualified taxonomic experts and global taxonomic databases. Sediment samples were analyzed for fluorine, carbohydrates and trace metals (i.e., Fe, Zn and Cd) content. A pollution index, based on the eigenvalues of the main ordination axis of a Principal Component Analysis, was applied. The highest values of chemicals were detected at the sites situated near an industrial complex, along with significant variations among seasons. The copepod community comprised 38 species, including five species new to science. Species richness, density and biomass of copepod communities varied among sites and seasons. These community-based indices were also analyzed separately for each season with conditional autoregressive models, revealing a significant negative response with the level of pollution. However, the results of partial Mantel tests showed positive correlations between species richness and pollution level, after controlling for the effect of geographic proximity in-between pairs of sites (winter: r = 0.927, p < 0.0001; spring: r = 0.935, p < 0.0001; summer: r = 0.918, p < 0.0001; autumn: r = 0.937, p < 0.0001). The overall pattern was that nearby sites were characterized by similar pollution levels and inhabited by similar species of copepods. Moreover, the copepod communities were significantly influenced by pollutants, mainly by trace metals. The results of the current survey emphasize the usefulness of meiobenthic copepods in biomonitoring programs not only for the gulf of Gabès, but also for other coastal areas from the Mediterranean Sea region. Full article

The locally isolated harpacticoid copepods Tigriopus sp. and Tisbe holothuriae were subjected to salinity tolerance experimentation at salinities under and above of 40 ppt, and presented high halotolerances in Tigriopus LC50 (24 h) of 1 ± 4.43 ppt and 132 ± 5.35 ppt, respectively, and in Tisbe of 15 ± 2.41 ppt and 93 ± 3.23 ppt, respectively. Tetraselmis suecica, among other microalgal feeds (Asteromonas gracilis, Rhodomonas salina, Dunaliella salina and Isochrysis galbana), resulted in the higher production of nauplii in Tigriopus and R. salina and D. salina in Tisbe (also close to T. suecica in Tigriopus). The demographics (number of nauplii, egg sacs, completion of hatching) of both copepods, using combinations of salinities in the range of 22–60 ppt and D. salina and R. salina as feeds, exhibited almost the same preference for microalgae but were negatively affected by the salinity of 60 ppt. The present experiments showed that these local copepods that have extreme salinity tolerance and a wide preference for easily cultured microalgae can be used in ecological studies and for mass production as live feed in marine fish hatcheries. Full article

As a part of ongoing efforts for monitoring benthic ecosystem in the Gulf of Mexico, Harpacticoid copepods were collected from the southwestern Gulf of Mexico. Among them we report three new species of Zosime, and a new species of Peresime for the study area. Zosime is the most specious-rich genus in the family. Three species of Zosime were morphologically similar to Z. paratypica Becker and Schriever, 1979, Z. atlantica Bodin, 1968, and Z. destituta Kim J.G., Jung and Yoon, 2016, respectively. However, all three species have unique characteristics that distinguish them from similar species such as setal formulae and shape of female P5 and caudal rami. The new species of Peresime has similar morphological characters with P. reducta (Becker and Schriever, 1979). These two species can be distinguished by differences in mouth parts and the length of the setae on P2. This is the first report on the genera Zosime and Peresime from the Gulf of Mexico. We also discuss the global diversity and distribution of Zosimeidae and provide a key to the genera of the family and species of each genus, including the four new species from the Gulf of Mexico. Full article

Benthic harpacticoids were collected from Korean waters. Two species were identified as members of the genus Longipedia Claus, 1863, because they have an extremely elongated distal segment of the P2 endopod. Longipedia koreana sp. nov. is morphologically most closely related to L. nichollsi Wells, 1980 and L. scotti Sars, 1903, but it can clearly be distinguished from both species based on the following morphological characteristics: P1 coxa with strong spinules near the outer margin and the distal element being much bigger than the proximal elements, P2 coxa with a small inner seta on the anterior surface, P4 exopod first segment without an inner element, and the P5 with a rectangular exopod (more than 3.5 times as long as wide). L. ulleungensis sp. nov. is similar to L. brevispinosa Gurney, 1927, L. spinulosa Itô, 1981, and L. weberi Scott A., 1909. However, L. ulleungensis sp. nov. is characterized by the P2 coxa with a reduced inner seta, the P4 exopod second segment without an inner seta, and the anal operculum with a long median projection, a single spine, and a group of outer spines on each side. In a molecular analysis using the mitochondrial cytochrome c oxidase subunit I (COI) and 18S ribosomal RNA (18S rRNA) genes, the inter-specific variation was 22.525–23.102% and 1.325–1.382% of COI and 18S rRNA between the two new species, respectively. A key to the family Longipediidae is provided herein. Full article

Comparative phylogeography has become a powerful approach in exploring hidden or cryptic diversity within widespread species and understanding how historical and biogeographical factors shape the modern patterns of their distribution. Most comparative phylogeographic studies so far focus on terrestrial and vertebrate taxa, while aquatic invertebrates (and especially freshwater invertebrates) remain unstudied. In this article, we explore and compare the patterns of molecular diversity and phylogeographic structure of four widespread freshwater copepod crustaceans in European water bodies: the harpacticoids Attheyella crassa, Canthocamptus staphylinus and Nitokra hibernica, and the cyclopoid Eucyclops serrulatus, using sequence data from mtDNA COI and nuclear ITS/18S rRNA genes. The three taxa A. crassa, C. staphylinus and E. serrulatus each consist of deeply diverged clusters and are deemed to represent complexes of species with largely (but not completely) non-overlapping distributions, while in N. hibernica only little differentiation was found, which may however reflect the geographically more restricted sampling. However, the geographical patterns of subdivision differ. The divisions in A. crassa and E. serrulatus follow an east–west pattern in Northern Europe whereas that in C. staphylinus has more of a north–south pattern, with a distinct Fennoscandian clade. The deep mitochondrial splits among populations of A. crassa, C. staphylinus and E. serrulatus (model-corrected distances 26–36%) suggest that divergence of the lineages predate the Pleistocene glaciations. This study provides an insight into cryptic diversity and biogeographic distribution of freshwater copepods. Full article

To understand the environmental factors affecting the spatiotemporal distribution of copepods, sampling was conducted seasonally in a small mesotidal inlet and estuary located in Doam Bay of southwestern Korea. The study area was divided seasonally into two or three station groups (estuarine, mixed, and coastal) by a cluster analysis and non-metric multidimensional scaling based on copepod abundance. Acartia forticrusa, A. hudsonica, A. ohtsukai, Paracalanus parvus s. l., Pseudodiaptomus marinus, Tortanus derjugini, T. dextrilobatus, T. forcipatus, Oithona spp., and harpacticoids were important species for grouping the stations. The spatiotemporal distribution of the first two species was restricted to the estuarine area in summer and significantly correlated with temperature, salinity, and chlorophyll-a concentration. The distribution of other brackish species, such as T. derjugini and T. dextrilobatus, significantly correlated with temperature, salinity, and chlorophyll-a concentration. In contrast, A. hudsonica significantly correlated with dinoflagellate density and turbidity in winter, in addition to the abovementioned environmental factors. Acartia hudsonica also maintained a large population in the estuarine area in fall and winter, and its distribution extended across the entire bay in spring. Other coastal species occurred in all areas and did not significantly correlate with environmental factors. Therefore, brackish species in the study area may have developed seasonally different behaviors to sustain their populations. Full article

Information about invertebrates in the low-flow water bodies of northeastern Siberia is far from complete. In particular, little is known about crustaceans—one of the main components of meiobenthic and zooplanktonic communities. An open question is which environmental factors significantly affect the crustaceans in different taxonomic and ecological groups? Based on the data collected on the zooplankton and meiobenthos in the tundra ponds in the southern part of the Lena River Delta, analysis of the crustacean taxocene structure was performed. In total, 59 crustacean species and taxa were found. Five of these are new for the region. The species richness was higher in the large thermokarst lakes than in the small water bodies, and the abundance was higher in small polygonal ponds than in the other water bodies. Variations in the Cladocera assemblages were mainly affected by the annual differences in the water temperature; non-harpacticoid copepods were generally determined by hydrochemical factors; and for Harpacticoida, the macrophyte composition was significant. Three types of the crustacean assemblages characteristic of different stages of tundra lake development were distinguished. The hypothesis that the formation of crustacean taxocenes in the Lena River Delta is mainly determined by two types of ecological filters, temperature and local features of the water body, was confirmed. Full article

In rocky shore systems, sessile macrobenthic assemblages may act as “ecosystem engineers” for many smaller benthic organisms. Thus, the influence of macrobenthic coverage on the diversity and assemblage structure of the harpacticoid copepod fauna was investigated in the rocky shores of a Marine Protect Area (MPA) in the Ligurian Sea (NW, Mediterranean Sea). Two sampling sites were investigated in two seasons at three different depths on both sub-vertical and inclined reefs. A total of 61 species of copepods mainly represented by Miraciidae, Laophontidae, Longipediidae and Thalestridae were found. The complex micro-topography of these substrata provided a wide variety of niches for many species with different lifestyles that suggests the important role of rocky shores to ensure the functioning of coastal ecosystems. The harpacticoid assemblage structure seemed mainly influenced by season and depth. The temporal spread observed is likely one of the underlying mechanisms of niche segregation that allows many species to co-occur in this specific environment along with a subordinate spatial segregation corresponding to the depth gradient. The results seem to support the hypothesis that the different species composition of the “ecosystem engineer” (and consequently its structure changes) are relevant in structuring the copepod assemblages. The comparison with previous data on general meiofauna underlines that higher surrogacy of the taxonomic identification could be used to study rocky shore communities, but the rich diversity that these systems host can only be understood at the lower taxonomic levels. The same holds for future evaluations of impact of environmental changes (including MPA regulations) on meiofaunal assemblages. Full article