Haloschizopera cheni sp. n., was recognized from our latest collections from the East China Sea. The new species is similar to H. abyssi Becher, 1974 but differs from it by the following combined ...features: baseoendopodal lobe of female P5 with five setae, P2 and P3 enp-3 both longer than enp-1-2 combined, and caudal rami longer than broad. Comparison of all the known species of Haloschizopera was performed. Species in the genus can be divided into four groups by the setal formulae of P3 and P4. The main diagnostic characters of each species are listed and a key to all known species of Haloschizopera is also provided.
Aquatic invertebrates contribute significantly to environmental impact assessment of contaminants in aquatic ecosystems. Much effort has been made to identify viable and ecologically relevant ...invertebrate test organisms to meet rigorous regulatory requirements. Copepods, which are ecologically important and widely distributed in aquatic organisms, offer a huge opportunity as test organisms for aquatic toxicity testing. They have a major role not only in the transfer of energy in aquatic food chains, but also as a medium of transfer of aquatic pollutants across the tropic levels. In this regard, a supratidal and benthic harpacticoid copepod Tigriopus japonicus Mori (order Harpacticoida) has shown promising characteristics as a test organism in the field of ecotoxicology. Because there is a need to standardize a battery of test organisms from species in different phylogenetic and critical ecosystem positions, it is important to identify another unrelated planktonic species for wider application and comparison. In this regard, the cyclopoid copepod Paracyclopina nana Smirnov (order Cyclopoida) has emerged as a potential test organism to meet such requirements. Like T. japonicus, it has a number of features that make it a candidate worth consideration in such efforts. Recently, the genomics of P. nana has been unraveled. Data on biochemical and molecular responses of P. nana against exposure to environmental chemicals and other stressors have been collected. Recently, sequences and expression profiles of a number of genes in P. nana encoding for heat shock proteins, xenobiotic-metabolizing enzymes, and antioxidants have been reported. These genes serve as potential biomarkers in biomonitoring of environmental pollutants. Moreover, the application of gene expression techniques and the use of its whole transcriptome have allowed evaluation of transcriptional changes in P. nana with the ultimate aim of understanding the mechanisms of action of environmental stressors. Whole-animal bioassays and gene expression studies indicate that P. nana may serve as an excellent tool to evaluate the impact of diverse disturbances in the marine environment. With a better understanding of toxicological mechanisms, ecotoxicologists will be able to understand defense mechanisms against toxicants in copepods. In this review, we illustrate the potential of P. nana as an alternative as well as a complementary invertebrate model organism for risk assessment of aquatic pollutants.
1. With few exceptions, copepods dominate over other crustacean and non-crustacean invertebrate groups in ground water. They have colonised a vast array of habitats in continental ground waters, ...where they are represented by over 1000 species in six orders: Platycopioida, Misophrioida, Calanoida, Cyclopoida, Harpacticoida, Gelyelloida. However, members of only the last four orders entered genuine fresh ground water. 2. Stygobiotic copepods show a wide range of morphological and physiological adaptations to different groundwater habitats. They frequently exhibit simplifications in body plans, including reductions in appendage morphology, which is regarded as a result of paedomorphic heterochronic events. 3. Copepod distributions at small spatial scales are most strongly affected by habitat type and heterogeneity, with sediment grain size and availability of organic matter being important habitat characteristics. Large-scale spatial distributions (biogeographical) are mainly related to past geological, climatic and geographical processes which occurred over medium to long time scales. 4. Such processes have affected colonisation patterns and diversification of copepods in ground water, leading to a number of phylogenetic and distributional relicts and a high degree of endemism at different taxonomic levels. This is reflected in the composition of groundwater copepod communities characterised by distantly related species in the phylogenetic tree. 5. Copepods dominate the species richness of groundwater fauna in all regions and on all continents where more than cursory surveys have been carried out, i.e. in Europe, North and Latin America as well as in Australia. 6. Species-specific microhabitat preferences, high proportions of local endemics, high proportions of phylogenetic and distributional relicts, and higher-level taxonomic diversity are all factors suggesting that copepods are a useful indicator group of overall species richness for defining conservation priorities in ground water.
It is assumed that the south‐eastern Europe and especially the Romanian Carpathians were important regions for surface and underground invertebrates survival during glacial periods and acted as a ...source of post‐glacial colonization processes. We analyzed data from 233 georeferenced records for 164 species of groundwater copepods and ostracods from Romania and used a comparative approach to recognize the determinants of the regional‐scale richness, endemism, and distribution patterns, with a primary focus on species from the Carpathian Mountains. In addition, we examined the driving forces for the observed pattern of distribution and richness linked to contemporary (groundwater habitat fragmentation and heterogeneity, climate, vegetation) and historical (past climate and vegetation) environmental conditions. Our analyses showed that: (1) species richness was high, irrespective of habitat heterogeneity, in karst and non‐karst areas; (2) the main driver accounting for high species richness in the karst landscape was the rainfall regime (> 1350 mm per year), whereas, in non‐karst areas, it was woodland vegetation; and (3) there was significant species richness and richness of phyletic lineages in hypothetical forest glacial refugia of the Carpathian arc. The combination of the distribution pattern, diversification, and evolution of stygobite lineages provides reliable evidence for species persistence in the Romanian groundwater during Pleistocene.
The effects of compacted algal mats growing attached to sediments on the abundance and community structure of intertidal sediment meiofauna and harpacticoid copepod assemblages were evaluated on a ...tropical estuarine mudflat. Differences in fauna based on the presence of algae (within vs. outside the algal patches) and the physiological stages of the algae (live vs. decomposing algal patches) were compared. In general, lower densities occurred within algal patches for most meiofaunal groups, except for harpacticoids, which showed an increase in number in the live algal patches (LAP). Non-metric MDS analysis clearly distinguished both meiofauna community and harpacticoid assemblage in relation to the presence of algae and the physiological stage. Organic matter, carbohydrates, proteins and photosynthetic pigments were higher within algal patches and highly correlated with meiofauna variables. One species of harpacticoid (Cletocamptus sp.1) dominated the LAP samples and thus reduced species richness and diversity of harpacticoids in these samples. The species Robertsonia mourei occurred exclusively in decomposing algal patches (DAP) and probably is an opportunistic species within the DAP samples. Strong differences regarding live and decomposing algae samples highlighted the importance of physiological stage in understanding meiofaunal responses to algal mats.
•Most meiofauna major taxa and Harpacticoida species were very sensitive to compact algal mats•Harpacticoid diversity and richness were reduced within live algal patches•Strong differences of community structure highlights the importance of algal physiological stage•Sediment biogeochemistry and benthic animals changes will affect system productivity and energy flow
The author reports 19 harpacticoid species (Crustacea, Copepoda) sampled from the marine coastal and brackish waters on the Icelandic shore of the Atlantic Ocean in June and July 2004.
Two new species,
Cerviniella bisegmenta
sp. nov.
and
C. permixta
sp. nov.
, are described in detail with illustrations based on females from the Korean Yellow Sea. These species lacking the fourth ...leg endopod belong to the
mirabilipes
group, one of two species groups within the genus
Cerviniella
Smirnov, 1946. Both species can be distinguished from each other by the surface ornamentation of the cephalothorax, shape of the rostrum tip, antennule segments, armature formula of thoracic legs 1–4, and length ratio of the caudal rami.
Cerviniella bisegmenta
sp. nov.
is characterized by a short caudal ramus and a two-segmented antennary exopod, which are unique within the genus.
Cerviniella permixta
sp. nov.
differs from other congeners of the
mirabilipes
group by the seven-segmented antennule, the armature formulae of the exopod of the antenna and thoracic legs 1–4, and the modified apical inner element of the second endopodal segment of the second leg. The present study is the first to identify the genus
Cerviniella
in Korean waters, resulting in extension of its distribution area to East Asia.
A new species of
closely related to
was found in sediment samples taken from a polluted estuarine system in north-western Mexico. The genus
was relegated to
in 1986, and this finding prompted us to ...evaluate the current taxonomic position of the genus within the Canthocamptidae. The latter has been subdivided in several, seemingly unnatural subfamilies in the past to better understand the relationships between its constituent taxa. In this study we propose a new subfamily, the Cletocamptinae
for
,
, and
gen. nov., defined by the synapomorphic subdistal ventral spinules on the rostrum. The genus
is proposed for
,
, and
, and is supported by the 'cletodid' shape of the body and the reduced one-segmented endopod of the fourth swimming leg.
includes all the other species with long slender spinules on the posterior margin of prosomites and with the sexually modified inner spine on the second endopodal segment of the second swimming leg in the males.
retained the primitive female fifth leg with exopod and baseoendopod separated, and the primitive prehensile endopod of the first leg, but is defined by the loss of the antennary exopod. Other (syn)apomorphies are given, and the evolution of the mandibular palp is briefly discussed. Additionally, a diagnosis for the new subfamily,
, an amended narrower diagnosis for
, the diagnosis for
, and a phylogenetic analysis supporting the proposal of these new taxa, are given.
Declining oxygen concentrations in aquatic habitats represent extreme conditions that threaten benthic life. Hypoxia has recently become an important research topic, as areas affected by these ...phenomena are spreading globally. Omura Bay is one of the most highly enclosed seas in Japan, and severely hypoxic conditions occur at the bottom every summer. We conducted a preliminary study in the center of the bay to evaluate how seasonal hypoxia affects the abundance and community composition of benthic meiofauna, with particular reference to copepods. The copepod densities and their nauplii differed significantly among seasonal categories (before, during, and after hypoxia). Furthermore, the degree of the seasonal decline in copepods during hypoxia seemed much more severe than that in nematodes, the most abundant meiofauna. The assemblages of adult copepods had the simplest composition during hypoxia, when harpacticoid copepods in the family Cletodidae, which have smaller and slender bodies, occurred at significantly higher frequencies (a contribution of 84% to the mean similarity among seasons). After hypoxia, the relative abundance of copepods in the families Ectinosomatidae and Longipediidae increased, which may likely be attributed to their higher swimming abilities and rapid recruitment via specific planktonic nauplius stages, respectively. High frequencies of copepods in the Cletodidae family have also been observed under hypoxic conditions in the Mediterranean Sea, suggesting that similar processes affect benthic copepod communities, which work to the advantage of cletodid species with small and slender forms in the subtidal sediment bottom under severe hypoxia in Omura Bay and other regions.
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