Isolated posterior gills from the Chinese crab Eriocheir sinensis acclimated to freshwater (FW) were used for perfusion. Dopamine and dibutyryl cAMP (db-cAMP) induced a significant increase of ³⁶Cl^– influx. When amiloride, a specific sodium selective channels blocker, was added to the incubation saline, it induced a dramatic decrease of ²²Na influx, and such an effect could be reversed by dopamine or db-cAMP. In the same experimental condition, we observed that ouabain added to the serosal side induced a marked decrease of the stimulating effect of db-cAMP on ²²Na uptake across the epithelium to the hemolymph, suggesting that dopamine stimulates Na and Cl^– influxes via cAMP and Na /K -ATPase pathways.

Larvae of Chinochthamalus scutelliformis (Darwin, 1854) (Cirripedia: Chthamalidae) from Hong Kong were cultured in the laboratory. Larval development includes six naupliar stages and a nonfeeding cypris stage following the ground patterns of Cirripedes. Larvae reached the cypris stage in 20 days at ∼21°C compared to 13 days at ∼28°C. Morphological features including the cephalic shield, frontal horns, labrum, hind body, antennules, antennae, and mandibles in all nauplius and cypris stages were described and illustrated using a combination of light microscopy and scanning electron microscopy. Attempts were made to compare morphological differences between the nauplii and cyprid of C. scutelliformis with those of Chthamalus malayensis and Chamaesipho species. Observations of the nauplii of Chinochthamalus scutelliformis supported Foster's suggestion to move this species from the genus Chamaesipho to the genus Chinochthamalus.

Nauplius larvae (Stages I–VI) and cyprids of Tetraclita squamosa (Brugiére, 1789) and Tetraclita japonica (Pilsbry, 1916) were cultured and their morphologies compared using light microscopy and scanning electron microscopy (SEM). Using a mixture of Skeletonema costatum Greville, 1866, Isochrysis galbana Parke, 1938, and Tetraselmis Stein, 1878, sp. as food, the larvae of both species completed naupliar development and metamorphosed to cyprids in ∼14 days at 20°C. The body shape and size of the larvae of both species are similar. The major diagnostic morphological difference is the setation of the antennulae and mandibulae. From Stage V to VI, the antennulae of T. japonica bear one more preaxial seta than T. squamosa. From Stage IV to VI, the mandibulae of T. japonica also bear one more simple seta on the endopodite than T. squamosa. The size, shape, antennular morphology, and surface sculpturing of the cyprids of the two species are similar when observed under SEM. The morphology of T. squamosa and of T. japonica is compared with those of the larvae of other Tetraclita species, and taxonomic relationships within the possibly monophyletic Tetraclitidae are discussed.

The Rhizocephala is a group of extremely reduced parasitic crustaceans, that exclusively parasitize other Crustacea. In the family Sacculinidae, the external sac-like part (externa) of the adult parasite contains the reproductive apparatus and is attached beneath the abdomen of the host crab. Hosts with more than one externa may occur and are in most cases believed to have arisen from multiple cyprid larvae. However, in three species of the genus Sacculina, multiple externae have been shown to originate by asexual reproduction from a single parasitic cypris larva. We present a phylogenetic analysis of ten species of Sacculina and outgroups based on partial sequences from the cytochrome oxidase 1 (CO1) and the entire 18s rDNA gene. A separate parsimony analysis from the 18s rDNA and CO1 genes resulted in two trees with almost identical topologies. Both genes strongly support a monophyletic, asexually reproducing clade and fail to support a monophyletic Sacculina genus. As a consequence we have established a new genus, Polyascus, to accommodate three members of this clade which also share a number of common morphological features.

Five juvenile copepodids of Critomolgus anthopleurus Kim, 1996, were obtained by rearing the copepod and its actiniarian host for 10 days within a laboratory aquarium. Copepodid I of C. anthopleurus shows significant morphological differences from previous records. At this stage of C. anthopleurus, the antennule is 4-segmented, with 3 setae on the first segment; the antenna has a rudimentary exopod; the mandible has 2 armature elements in addition to distal lash; and the maxilliped is 4-segmented, with an armature formula 1, 2, 1, and 3. Sexual dimorphism first occurs at copepodid V of the maxilliped, which differs between sexes. A comparison of the maxillipeds of copepodid I between C. anthopleurus and other lichomolgoid copepods resulted in a conclusion that the maxillipedal endopod of the lichomolgoid copepodid I is fundamentally 2-segmented, with 1 seta on the first segment, and 3 setae and a setiform process on the second segment.

Two new species of the Family Clausiidae, Likroclausia namhaensis n. gen. and n. sp. and Rhodinicola laticauda n. sp., were described from washings of polychaetes collected from an intertidal mud flat on Namhae Island in the Korea Strait and from an intertidal sandstone in Kyokpo in the Yellow Sea, respectively. The host of the former species is Dasybranchus caudatus Grube, but that of the latter is unidentified. Cladistic analysis of the family indicated that the 20 clausiid species should be kept in six groups, with Pontoclausia-group containing five species (antiqua, lobata, prima, tomis, wilsoni); Likroclausia-group, one species (namhaensis); Rhodinicola-group, three species (gibbosa, elongata, laticauda); Mesnilia-group, two species (cluthae, martinensis); Clausia-group, seven species (bacescui, curticaudatum, lubbocki, mirabilis, rugosum, thomassini, uniseta); and Pseudoclausia-group, two species (giesbrechti, longiseta). Each group is a monophyletic entity identified with one or more synapomorphies. Whilst the taxonomical status of the genera Indoclausia, Megaclausia, Pherma, and Seridium are unclear, it is unequivocal that the following four genera should be treated as valid taxa in the Clausiidae in addition to Clausia: Mesnilia, Pontoclausia, Pseudoclausia, and Rhodinicola. Also, both Doviella prima Rocha, 1986, and Clausia wilsoni Gooding, 1963, are transferred to Pontoclausia. Rhodinicola thomassini Laubier, 1970, should be transferred to Clausia for the time being.

A new species of thaumatopsyllid copepod, Caribeopsyllus amphiodiae, is described based on adult specimens reared from nauplii inhabiting the stomach of a burrowing, amphiurid brittle star, Amphiodia urtica (Lütken), collected in California, U.S.A. It is the first member of the family to be reported from the eastern Pacific Ocean. Caribeopsyllus chawayi, its only known congener, inhabits the Caribbean Sea. All other thaumatopsyllid species occur in the eastern hemisphere. Caribeopsyllus amphiodiae is only the second thaumatopsyllid of which both sexes and sexual dimorphism have been described and for which a host species has been identified. Caribeopsyllus differs from confamilial genera by the presence of a 1-segmented leg 4 exopod. The new species is distinguished from C. chawayi by its general habitus, and by the absence of spiniform processes at the base of each exopodal spine of leg 1 and the first three exopodal spines of leg 2. Analysis of the phylogenetic relationships of Thaumatopsyllidae shows that it is not a member of any of the other previously established orders of Copepoda. Accordingly, a new order, Thaumatopsylloida, is proposed to accommodate the five species of thaumatopsyllids thus far reported and is shown to be a member of a Thaumatopsylloida-Monstrilloida-Siphonostomatoida clade.

Among several other cases of taxonomic indefinition within the cyclopoid copepod genus Mesocyclops, we selected and examined in detail two neotropical species with overlapping distributional ranges: M. meridianus (Kiefer, 1926) and M. brasilianus Kiefer, 1933. The latter has long been considered as a synonym of M. meridianus by some authors, while other specialists recognize both forms as valid. The available descriptions were not detailed enough to determine the taxonomic status of the two. Upgraded descriptive standards, including SEM analysis, were used in order to provide morphological data for both species, emphasizing microcharacters. After examination and comparison of both male and female specimens collected in several neotropical areas (Mexico, Peru, Brazil, Venezuela), we confirmed that M. brasilianus and M. meridianus are in fact valid, separate taxa. This statement was based on previously undetected differences in the ornamentation of the antennules, antennal basis, maxillulae, maxillae, and swimming legs 3 and 4, among other structures. A detailed complementary description and depiction of both species is provided herein. Males of both species are described in full for the first time. This kind of analysis is expected to mark new standards and to become a major tool in re-defining the species limits of the neotropical Mesocyclops.

Individuals of the brackish water ostracod species Ishizakiella ryukyuensis are found sympatrically with those of the closely related species I. miurensis at the Kii Peninsula, western Japan, and possess a projection on the male copulatory duct. By contrast, individuals of this species recovered from the Nansei Islands, southern Japan, do not have such a projection. Molecular phylogenetic trees based on mitochondrial COI sequences consistently indicated that the populations at the Nansei Islands formed a paraphyletic group outside of a cluster consisting of the population at the Kii Peninsula. Thus, the development of the projection in the male copulatory organ is considered as a derived character for the individuals at the Kii Peninsula, and this feature may have been brought about by the sympatric distribution and a process of character displacement.

Two new stegocephalid (Amphipoda) species of the subfamily Andaniexinae are described: Glorandaniotes vemae n. sp. and Glorandaniotes norae n. sp. Their morphological affinities to their congeners and their phylogenetic position within the subfamily are discussed. Glorandaniotes vemae n. sp. can be distinguished from all its congeners by the elongate article four on the peduncle on the second antenna, whereas the large and powerful lacinia mobilis, combined with the somewhat elongate telson, are unique features for G. norae n. sp. Glorandaniotes vemae n. sp. is the third species within the genus that is recorded from the Indian Ocean, whereas G. norae is the first Glorandaniotes recorded off the western coast of South America.

A summary of terminologies and nomenclature currently or previously employed to describe tanaidacean appendages and somites are presented together with a proposed new standardized terminology for the order Tanaidacea. Standardized expressions and nomenclatures are suggested for all tanaidacean somites, appendages, and their articles, as well as for the orientation of tanaidacean appendages.

Two types of sexual cannibalism, differing in the sex of the victim, were found among heterosexual pairs of the parasitic isopod Ichthyoxenus fushanensis Tsai and Dai, 1999, residing in the body cavity of the freshwater fish Varicorhinus bacbatulus (Pellegrin, 1908). In one type, categorized as sexual cannibalism, the male was consumed by the female before or after mating. In the other, reversed type, the female was eaten by her mate during or after breeding. Both types of cannibalism occurred during the breeding season from April to November, with female-on-male cannibalism occurring earlier on, and the reversed type later. Both types of cannibalism occurred in pairs inhabiting smaller hosts (<10 cm in body length), which suggests that resource limitation is an important factor triggering the cannibalism. Cannibalism may lead to rapid growth or sex change of the cannibal. The availability of free-living mancas during the breeding season enables a mating pair to be re-formed after cannibalism has occurred. Both types of cannibalism occurred in mating pairs with a low size ratio (below 1.6, female to male), and both resulted in a greater discrepancy between female and male sizes in the re-formed pairs. This increase in size ratio between paired individuals may ultimately lead to an increase in clutch size. Because an individual of I. fushanensis undergoes protandrous sex change, the cannibalistic behavior could not have evolved in response to selection on either the male or female sexuality. Rather, both types of cannibalism may be regarded as the result of competition between paired individuals, which appears to be a by-product in the evolution of a reproductive strategy rather than a consequence of sexual selection.

An analysis of historical patterns in the description of North East Atlantic Decapoda is presented. The discovery curve of decapods as a whole indicates that the decapod fauna of the NE Atlantic is well known, with two major peaks in species description rates being identifiable: 1808–1830 and 1855–1890, the latter corresponding to the era of the major oceanographic expeditions. On a sub- to infraordinal level, three major periods can be discerned. An early period (1758 – mid 1880s) during which proportionally more Brachyura were described, followed by a shorter period (mid 1880s – 1920 during which more attention was devoted to Anomura and less speciose taxa (mainly deep water). From the 1920s onwards, species descriptions of Caridea have achieved prominence. Size, ecological traits, extent of occurrence, and taxonomic fashion are thought to be responsible for the early bias towards Brachyura, whilst the anomuran and caridean phase are more related to field work techniques (deep water dredging in the former) and improved observational techniques.

Crayfish are widely recognized as an important ecological component of stream systems, but there has been limited work to develop and evaluate the reliability of sampling methods for lotic crayfishes, especially efforts that are temporally and spatially comprehensive. We desired a quantitative method to assess crayfish communities in streams with rocky substrate. Our objective was to develop a method to obtain and compare representative density estimates with acceptable variance and reasonable effort, and to illustrate use of the method by using it to 1) describe and compare diurnal habitat associations by lotic crayfish, and 2) detect density changes over time. Our study encompassed four sites on two rivers, two seasons, and 8 y (1991–1998) to evaluate a 1-m² quadrat sampler, and a sampling method that stratified effort among five macrohabitats to reduce variability. This method performed well for both seasons, detecting spatial differences among macrohabitats and temporal differences among years. Spatial differences were expressed as macrohabitat selectivity by the crayfish community, and showed a consistent trend across streams and seasons. In particular, macrohabitats with slower current velocities consistently had the highest densities. Temporal differences included documentation of decreased densities in several macrohabitats across 5 y. Sampling precision, measured by coefficients of variation, was acceptable but not considered high. Statistical power was good for detecting spatial differences, but reduced and variable for detecting temporal changes. Our findings 1) demonstrate the use of stratifying quantitative sampling for lotic crayfish communities by habitats, 2) confirm the importance of evaluating sampling methods, and 3) illustrate the consistent way in which Ozarks crayfish communities used available macrohabitats.

The growth, mortality, and reproduction of Portunus sanguinolentus were studied using size-frequency data obtained from crabs collected in pots in the waters off northern Taiwan from October 2000 to March 2001, and October 2001 to January 2002. The Bhattacharya's method and seasonal von Bertalanffy growth curve were used to estimate growth parameters. The growth curve for males was L_t = 204.75×{1 −e^{–[0.87t + 0.4(0.87/2)sin2(t)]}} and the curve for females was L_t = 194.25×{1 −e^{–[0.97t + 0.4(0.97/2)sin2(t)]}}. A size-converted catch curve was used to estimate the instantaneous total mortality rate (Z), and Pauly's empirical equation was used to estimate the instantaneous natural mortality rate (M). For males, Z = 3.16/year and M = 1.65/year. For females, Z = 3.37/year and M = 1.8/year. The instantaneous fishing mortality rate (F) was 1.51/year and 1.57/year, and the exploitation rate (E) was 0.48 and 0.47 for males and females, respectively. The exponential relationships were presented for relationships of fecundity in number and weight of egg mass in terms of carapace width and body weight. Those relationships were statistically significant (P < 0.01), indicating that the fecundity increased with the size from 4.05 × 10⁵ to 2.44 × 10⁶ eggs.

Hoploparia McCoy, 1849 (Lower Cretaceous (Valanginian)–Miocene) is, by far, the most diverse clawed lobster genus (fossil or Recent); 49 species are known. The genus has been interpreted intuitively to be morphologically primitive and ancestral to some or many modern nephropid genera. Prior to the present study, two separate issues raised the suspicion that Hoploparia is a “wastebasket” genus—a default genus for any fossil lobster with a mainstream nephropid morphology. One issue is the difficulty in characterizing (i.e., coding) the morphology of Hoploparia, as a genus, for cladistic analysis. For Hoploparia, and far more than for other lobster genera, many characters show variable character states. A second issue is that the morphologies of some Recent genera (e.g., Eunephrops and Nephropides) seem easily accommodated within the fossil genus Hoploparia. Both issues stem from an originally ambiguous diagnosis of Hoploparia that has been variously expanded in de facto fashion to the point that, today, nobody really knows what Hoploparia means. Cladistic analyses herein indicate that Hoploparia is paraphyletic and, therefore, support the intuitive judgement that Hoploparia is a wastebasket genus. This paper, the first species-level cladistic analysis of Hoploparia, is not intended to be the sole basis for taxonomic revision but is, instead, intended to generate discussion among lobster specialists. Hopefully, this discussion will bring forth additional characters for cladistic analysis and other new insights that may lead to better supported cladograms addressing lobster taxonomy.

More than 500 nearly complete specimens of the Atlantic ghost crab Ocypode quadrata (Fabricius) were collected from the upper Pleistocene to Holocene Anastasia Formation along beaches in Brevard County, Florida. Such whole-body decapod crustaceans are rare in Quaternary deposits of the southeastern United States. The low degree of disarticulation and the posture of the crabs indicate that they died while in their burrows, probably by winterkill. Fossil O. quadrata were found in two conditions: those with a clearly crab-like form, bearing a loose, friable matrix of shell hash with little cementation, no visible abrasion, no calcite infilling, and no attached fossil or Recent epibionts; and those that were barely recognizable as crabs, with a thick layer of heavily cemented matrix, a highly sand-abraded (polished) surface, some voids filled with calcite-cemented grains or calcite crystals, and some with Recent epibionts in exposed cavities. The nonabraded crabs with friable matrix have been recently exhumed from a poorly consolidated part of the Anastasia Formation or from the sand dunes or upper beach escarpment by storm waves, whereas the abraded crabs have been cast upon the beach from the nearshore subtidal zone by storm waves. Deposition of the Anastasia Formation is thought to have occurred approximately 110,000 YBP. The barrier-island–sand-dune system along the central East Coast of Florida is believed to have formed within the last 7000 yr. The abraded fossil crabs could have accumulated over the past 110,000 yr, but the nonabraded specimens, if derived from the existing beach, are considerably younger.

I investigated mass wandering by the fiddler crab Uca perplexa on Okinawa Island, Japan. Many larger males wandered during the daytime low tide for four continuous days in their reproductive season. Just after exposure of their burrows they moved uphill, then returned to the burrow area before dead low tide without feeding. During the wandering phase, the males did not wave to females to initiate mating. Males resumed waving after the wandering phase. I discuss why the large males wander en masse in relation to the crabs' mating system and larval release.

Ovigerous females of Ucides cordatus were collected at different mangrove areas in Iguape, SP, Brazil, and reared in the laboratory in order to describe each embryonic stage. Accounts of the biometry, internal morphology, and coloration of the eggs were taken. The embryonic development took 19 ± 1 d (27°C, 12:12 h) with eight well-defined stages. A salinity test on embryonic development was conducted, and a better result was obtained in a rearing at 15‰. Eggs are slightly ellipsoid through development and undergo an increase of 13.9% in diameter to 91.7% in volume. Cluster analysis revealed three different groups for diameter (Stages I–II, III–VI, and VII–VIII) and volume (Stages I–III, IV–V, and VI–VIII), supporting the classification of embryos into initial, intermediate, and final stages, which are currently used in studies on the reproductive biology of decapod crustaceans. In this species, the identification of the different embryonic stages can be achieved only if biometric data are combined with information on the internal morphology of embryos and coloration of the eggs.

Taxonomy of mitten crabs has been problematic and confusing. Eriocheir was considered to comprise four species (E. japonica, E. sinensis, E. recta, and E. leptognathus). However, recent taxonomic revision has recognized five species and three genera, Eriocheir being restricted to E. sinensis, E. japonica, and E. hepuensis, and the establishment of two genera for Neoeriocheir leptognathus and Platyeriocheir formosa. The present study analyzed the phylogeny of the species of Eriocheir, sensu lato, based on DNA sequence analysis of mitochondrial 16S rRNA, cytochrome c oxidase I, and the first internal transcribed spacer of nuclear rRNA. The results show that the three Eriocheir, sensu stricto, species are genetically similar, indicating that they have recently radiated. Eriocheir formosa is the sister taxon of these three species, with E. leptognathus the most distantly related taxon within the group. These results support the affinities of the mitten crabs, but the genetic divergence among the crabs provides no support for separating Eriocheir, s. l., to three different genera. We suggest to retain the apparently monophyletic mitten crabs in a single genus until more evidence is available.