The effects of six-day starvation and subsequent 30-day ad libitum refeeding on the growth responses of juvenile Chinese shrimp, Fenneropenaeus chinensis, (with weight range 0.486–0.569 g) reared under different temperatures (18, 22, 26, and 30°C) have been examined. The shrimp responded to a switch from starvation to ad libitum feeding by exhibiting hyperphagia and a growth spurt. At the end of the experiment, the starved-ad libitum fed shrimp maintained at 18, 22, and 26°C weighed approximately the same as the controls fed ad libitum throughout the experiment, whereas those at 30°C failed to catch up in weight to the control shrimp. In the initial six days of realimentation, the previously starved shrimp showed significantly lower food conversion efficiency (wet weight gain per unit food intake) than the controls, but from then on, there were no significant differences. The results suggest that hyperphagia was the mechanism responsible for compensatory growth in Chinese shrimp. Six-day starvation led to significant increase in moisture and reductions in protein, lipid, and energy content of the shrimp. At the end of the experiment, however, there were no significant differences in body composition. This indicated that compensatory growth was accompanied by a full recovery in body composition. Molt increment (g) and intermolt period (days) were greatly affected by starvation in combination with temperature: at 18, 22 and 30°C, not at 26°C, the previous six-day starvation brought about a significant prolongation in the intermolt over the whole experiment; at two lower temperatures (18 and 22°C), not at two higher temperatures (26 and 30°C), the starved-ad libitum fed shrimp had markedly increased molt increment compared with the controls.

The sand-bubbler crab, Dotilla fenestrata (Hilgendorf, 1869), has evolved a surface deposit feeding habit and exhibits stereotyped and flexible behaviours that allow this species to respond to both the predictable and unpredictable elements of intertidal environments. In a mangrove swamp of Kenya, field studies revealed that, at the emergence from burrows with the receding tide, a portion of this crab's population abandoned the residential zone and wandered in droves. The rest fed and engaged in other surface activities exclusively around their burrow (either a feeding-trench burrow or an igloo). Laboratory analyses were carried out to assess the functional significance of the choice of D. fenestrata between these opposing spatial strategies. If crabs are small individuals or ovigerous females, the only option is to engage in burrow-orientated activities. For the other population categories, the choice will depend on the richness in edible organic content of the substrate in the residential area and on the balance between the risk of being preyed upon and the benefits of foraging over richer substrata.

The behavior of juveniles of the Japanese endemic crayfish Cambaroides japonicus (Decapoda: Cambaridae) was observed in the field and in the laboratory. In addition, the occurrence and placement of spermatophores on adult females is described from specimens inhabiting small brooks at Otaru and Hamamasu, Hokkaido, Japan, sampled from 1998 to 1999. The second stage juveniles left their mother permanently after some exploration behavior. In adult females, spermatophores were attached to the surface of the seminal receptacle (annulus ventralis), which is situated at the posterior margin of the seventh thoracic sternite. In C. japonicus the invagination of the annulus ventralis is not deep enough to hide the male spermatophores. Previous studies of the Astacidae reported that juveniles left their mother at the second stage, that spermatophores were attached to the surfaces of sternal plates of the last three pereopods, and that an annulus ventralis did not exist. In contrast, Cambaridae juveniles normally detach from the mother at the third stage, but they may detach and stay longer with the parent until the fourth stage. There is variability in this trait. The spermatophores are completely hidden in the annulus ventralis of adult females. Therefore, although C. japonicus belongs to the family Cambaridae, the juvenile stage that detaches from the mother is the same as that reported in Astacidae. The position of the spermatophore attached to the adult female exhibits an intermediate state between that of the Astacidae and that of the Cambaridae.

A blue strain of the yabby Cherax destructor albidus was compared to two normal-coloured strains of C. d. destructor and C. d. albidus for brood size and juvenile weight. Reproductive performance of the blue strain was found to be significantly poorer than the two normal-coloured strains. Similarly, the weight of newly independent juveniles was also found to be significantly lower for the blue strain. No differences were detected between the two normal-coloured strains in either reproductive performance or size of newly independent juveniles. The phenotypic differences between the blue strain and normal-coloured strains are most likely genetic. However, further studies are needed to investigate whether these differences are due to pleiotropy or inbreeding effects.

A comparative survey of both benthic and pelagic populations of the cumacean Bodotria similis was conducted in Oura Bay, Izu Peninsula, Japan. In the benthic populations, Bodotria similis, Bodotria pulex, Cumella spp., and Dimorphostylis spp. were dominant, and B. similis and B. pulex were spatially segregated throughout the year. The density of B. similis in the benthic population was low in summer and autumn, increased during winter, and was highest in early spring. Seasonal fluctuations in size classes and sex ratios within the benthic population were minimal, and ovigerous females and manca larvae occurred throughout the year. Size-frequency histograms of the benthic population suggest the presence of six developmental stages for each sex and that females produce more than one brood in their lifetime. Nighttime patterns of occurrence of planktonic Bodotria similis varied seasonally but peaked just after the sunset in spring and winter. The swimming individuals consisted of males and young, but ovigerous females were not found. Many manca larvae and juveniles with soft carapaces appeared from November to March, and large males with hard exoskeletons dominated in April and May. Nocturnal swimming of Bodotria similis is probably related to the molting of young, range extension, and possibly the mating behavior of adults.

The population structures of Aratus pisonii and Sesarma rectum were analysed in order to compare their life histories. These two sinchronotopic species occupy distinct mangrove microhabitats in Ubatuba, São Paulo, Brazil. In order to compare the population dynamics of these two species, age and reproductive status of crabs were estimated by obtaining monthly collections over a 2-year period. Aratus pisonii follows an annual population cycle. Highest frequencies of ovigerous females were recorded during spring and summer, while juvenile recruitment peaked during the winter when the adult population was less representative. The life span of A. pisonii was estimated to be one or two years. On the other hand, recruitment of S. rectum was continuous throughout the year. Adults were consistently present in all months, suggesting that the life span of S. rectum is longer than that of A. pisonii, and its reproduction might be continuous. Temperature is correlated with frequency of breeding females and juveniles in A. pisonii, while no such correlations are found in S. rectum. These results suggest that the population dynamics of these two grapsid crabs is considerably different.

Growth and reproduction were studied in the coral gall crab Hapalocarcinus marsupialis from fringing reefs in the Egyptian Red Sea. The host coral was Stylophora pistillata. The galls were divided into five stages, and the later stages contained larger crabs and a higher proportion of ovigerous females. Female crabs ranged from 1.17 to 5.33 mm in carapace width. They matured at about 2.5-mm carapace width (probably in the fourth instar); maturity was indicated by an increase in abdomen size, ripening ovaries, mating, and egg laying. The largest females were probably in the seventh instar. After maturity females survived for some 10 months and were ovigerous for 80% of that time, producing eight or more broods. These were all fertilised from the original mating. Reproductive investment was high, both per brood and per year.

Two zoeal and one megalopal stages of Petrolisthes unilobatus Henderson, 1888, are described and illustrated on the basis of laboratory-reared material. Petrolisthes unilobatus is easily distinguished from other species of Petrolisthes by the absence of setules (first zoea) or plumose setae (second zoea) on the dorsal surface of the second and third segments of the second maxilliped endopod. Zoeal characters of this species most closely agree with those of Group 1 identified by Osawa (1995), but differ from this group by having only a single short plumose seta on the posteromedian margin of the telson in second zoea. We provide a modified table of Osawa's larval groups and propose an additional larval group, Group 7, for P. unilobatus.

Amphipods, like most swimming crustaceans, employ a drag-based mechanism to produce thrust. The propulsors are paddle-shaped pleopods that move parallel to the direction of motion. These paired abdominal limbs generate both the propulsive thrust and the respiratory currents that bathe the thoracic gills. This study addresses the basic kinematics of motion and the pleopodal skeletomusculature of the deep-sea scavenger Eurythenes gryllus. The limb beat cycle consists of a power stroke where the three pleopod pairs, with their setal fan outstretched, swing sequentially through an arc parallel to the body axis, and then return anteriorly in a collapsed and bent configuration. The joint connecting the body to the muscular peduncle is complex, allowing promotion and remotion along the main body axis. Several hard plates for extrinsic muscle attachment are surrounded by arthrodial membrane. The extrinsic musculature is proportioned accordingly, with a large mass of muscles controlling the power stroke and a few long muscles generating the recovery stroke forces. The intrinsic musculature within the peduncle and annular rami serves two functions: (1) many long, thin muscle fibers within the peduncle function as support muscles responsible for shape changes; (2) large, strap-like muscles control flexion for the recovery stroke and abduction-adduction of the exopod for the power stroke. Several ancillary skeletal structures enhance swimming efficiency: reinforcement in the pleonal wall for muscle attachment, coupling hooks between the pleopod pair to effectively create a single paddle, the complementary shapes of the exopod and endopod, and an exopodal hook that facilitates the complete collapse of the pleopods on the recovery stroke. The functional design of the pleopod maximizes efficient recovery stroke motion while still providing strong remotion during the recovery stroke.

Stage IV phyllosoma larvae of the packhorse lobster, Jasus verreauxi (H. Milne Edwards, 1851), were observed while feeding to determine the processing ability and involvement of mouthparts. Phyllosomata were presented live brine shrimp, Artemia salina (Linnaeus, 1758), mussel flesh, Perna canaliculus (Gmelin, 1791), and jellyfish, Aurelia sp., and were given chemical or tactile stimulation to induce a feeding response. Larvae were observed tearing their food with maxillipeds 2 and 3, before maceration by maxillipeds 2 and maxillae 1, mastication by mandibles and labrum, and subsequent ingestion of finer particles via a suction action induced by foregut contractions. Phyllosomata became entangled in food material and did not feed when provided soft tissue, such as jellyfish and mussel gonad. Maxilliped action increased when larvae were provided with harder prey, which indicated greater energetic investment required to process the food. Our observations suggest that phyllosomata are capable of processing fleshier prey items than Artemia, which is traditionally used as food in artificial culture. An ideal food source for phyllosomata should not readily break up and foul the water, should be free of microbes, and should be energetically economical to capture and masticate.

I quantified relative growth of the walking legs of the Japanese mitten crab Eriocheir japonica (de Haan) in the Saigo River, Fukuoka Prefecture, Japan. By plotting the third walking leg merus length (LML) against carapace width (CW), I could distinguish four growth phases for both sexes; I then fitted a regression line of allometry (Log Y = a Log X b) to each phase. In the first phase (not sexed, CW < 4 mm), growth was positively allometric, and relative length of legs increased (a = 1.37). In the second phase (4 mm ≤ CW < 20 mm), growth was nearly isometric, and legs remained relatively longer (a = 1.05 for males and 1.04 for females). In the third phase (20 mm ≤ CW < 40 mm for male, and 20 mm ≤ CW < 37 mm for female), growth was negatively allometric, and relative leg length decreased (a = 0.82 for males and 0.70 for females). In the fourth phase (CW ≥ 40 mm for males and CW ≥ 37 mm for females) including adult crabs, growth was negatively allometric, and the legs become relatively shorter; for males, relative growth was more negative than for females (a = 0.82 for males and 0.92 for females). These patterns reflect the migratory habit in the life cycle of E. japonica. The first phase occurred just after settlement and metamorphosis (instars 1–3) before starting upstream migration and was preparatory for the migration. The second phase coincided with the period of upstream migration and dispersal. Relatively longer legs increase locomotor activity against the flow and help crab dispersion to the wide area along the river. The third phase is the growth phase after active migration until crabs attain maturity. The fourth phase is the maturity phase, during which adults participating in reproduction emerge and sexual dimorphism becomes evident. There was a morphological variation in fourth phase males (relatively long legs in smaller males and relatively short legs in larger males). The possibility of variation of mating strategy is discussed.

Examination of 32 species from seven families of marine asellote isopods (Crustacea, Malacostraca) showed that 15 of these species were infested with ciliate epibionts. The diversity of the ciliate epibiosis was fairly high (mean = 3.8 epibiont ciliate species per host species; range 1 to 10 species). Ciliates were absent from species of the family Janiridae and were rare on desmosomatids. The prevalence was high (≥ 37%) on two ischnomesid species (Ischnomesus norvegicus and Heteromesus frigidus), and on three munnopsid species (genus Ilyarachna). Mean intensity was fairly low (1.3–10.5) overall, but high on I. norvegicus (29.2). Some ciliate species showed host preferences. Predatory ciliates (subclass Suctoria) were most common on host species of the families Munnidae and the Nannoniscidae and some of the Ischnomesidae species, whereas suspension-feeding ciliates (subclass Peritrichia) were found on six host species only, belonging to the family Ischnomesidae or the subfamily Ilyarachninae (Munnopsidae). Grooming, body texture of the isopods, and their burrowing or their use of pits and holes in the substrate may shape the pattern of ciliate epibiosis. Abrasion during burrowing or redox conditions found within the sediments may explain the absence or near absence of ciliates from Haploniscus bicuspis and the desmosomatids. By contrast, suspension- or detritus-feeding epibionts live on hosts which use shallow open pits or holes in the substrate (ilyarachnids, some ischnomesids).

We describe two new species in the new calanoid genus Camerundiaptomus. The new genus is currently known only from the rainforests of Cameroon, where its abundance is extremely low. The only other calanoid found was a known species of Tropodiaptomus. It was rare as well. Fish predation is cited as one among possible reasons for the rarity of calanoids in the Cameroon forest zone specifically, and for the generically impoverished calanoid fauna of tropical lowland Africa in general.

Sediment samples were taken during a short-term study of the distribution of meiofauna from a coastal lagoon in Sinaloa (northwestern Mexico). Several species of harpacticoids (Copepoda: Harpacticoida) were observed among the taxa recovered. Some of these species are new to science, whereas some others are new records for Mexican brackish systems. Three species of Apodopsyllus (Harpacticoida: Paramesochridae) are described herein. One of them, A. alejandrovillalobosi sp. nov. proved to be closely related to its northern congener A. vermiculiformis known from California and British Columbia. Apodopsyllus samuelgomezi sp. nov. and A. pseudocubensis sp. nov. constitute new records of the neotropical arcuatus-chilensis-cubensis lineage. Apodopsyllus samuelgomezi sp. nov. is unique within this clade in the male P6 with two long inner setae. Apodopsyllus pseudocubensis sp. nov. was found to be allied to its Cuban relative A. cubensis. These two species share the general shape of female P5 and male P6.

Austinograea rodriguezensis sp. nov. is the first bythograeid crab to be described from the Indian Ocean. Specimens were collected from 22 km north of the Rodriguez Triple Junction, at 2,420 to 2,450 m depth, during the KR00-05 Indian Ocean Cruise (JAMSTEC) in August 2000. This is the fourth species of the genus Austinograea described and the tenth in the family Bythograeidae. This crab inhabits black smoker complexes (temperature 360°C, pH 3.4) with other vent-associated animals, including Rimicaris shrimps, Bathymodiolus mussels, Alviniconcha snails, unidentified actiniarians, and zoarcid fish. Austinograea rodriguezensis differs remarkably from the other three species of Austinograea in the male gonopod and chela morphology. However, other characters of the species are very similar to Austinograea williamsi. A key to the species of the genus Austinograea is provided.

Hexapodid crabs are recorded from Taiwan for the first time. A new genus and new species, Latohexapus granosus, is described. Most similar to Hexapus and Hexapinus, Latohexapus can easily be distinguished by its proportionately much broader carapace with prominent granulated and well-defined regions, a very broad thoracic sternum which has a deep transverse groove between thoracic sternites 3 and 4, and a male first pleopod which extends well beyond the male telson. Paeduma orientalis (Rathbun, 1909) is also recorded from Taiwan on the basis of a female specimen.

Until now morphological and molecular datasets have failed to agree on phylogenetic relationships within the Crustacea Thecostraca (=Facetotecta, Ascothoracida, and Cirripedia). Three recent phylogenetic studies using 18S ribosomal DNA sequences from selected Cirripedia (Thoracica, Rhizocephala, and Acrothoracica) and Ascothoracida revealed Acrothoracica and Ascothoracida as a monophyletic group. This result disagrees with several larval and spermal morphological features supporting Cirripedia as a monophyletic group. We reanalyzed the same molecular data set including a new Facetotecta sequence using neighbor-joining and maximum likelihood, but incorporating the model of evolution that fits the data best, and maximum parsimony approaches. Our results strongly support the morphological hypothesis that the cirripedes form a monophyletic group, with the Acrothoracica as sister group to the Thoracica Rhizocephala. Moreover, all the phylogenies showed the Facetotecta as the sister group to the remaining Thecostraca (Ascothoracida Cirripedia).

We sequenced approximately 2,000 nucleotides of the 18S ribosomal DNA gene to test previous morphological hypotheses concerning family and superfamily relationships within the Anomura. Twelve new sequences from the superfamilies Galatheoidea, Paguroidea, Hippoidea (all Anomura), and Callianassoidea (Thalassinidea) were generated, and these were combined with three previously published sequences from GenBank to estimate phylogenetic relationships among these taxa. Our results show a clear separation of the Aeglidae from the other galatheoid families, which form a sister group with the Paguroidea. Within the Galatheoidea, chirostylids and porcellanids are sister groups. Hippoidea was revealed as the most basal taxon within the anomurans.

The status of Austropotamobius berndhauseri (Crustacea, Decapoda) was re-examined by the combination of two recent genetic studies based on the analysis of the mitochondrial 16S rRNA gene obtained from sampling across the entire range of the white-clawed crayfish species complex. From the phylogenetic tree obtained, the results clearly demonstrate two clusters (A and B) separated by a strong genetic divergence (5.0 ± 1.0%) corresponding to A. italicus and A. pallipes species. Within A. italicus, three mtDNA lineages were found corresponding to A. i. italicus, A. i. carinthiacus, and A. i. carsicus. Austropotamobius berndhauseri specimens are not genetically distinct from A. i. carinthiacus distributed in Austria. This group is more closely related to A. i. italicus (1.4 ± 0.5%) than A. i. carsicus (3.6 ± 0.7%) which is concordant with allozyme data. These data support the redefinition of A. berndhauseri as being A. italicus carsicus.

Some species of the genus Metaplax belonging to the family Grapsidae have occasionally been reported to perform waving display that is a characteristic behavior in the family Ocypodidae but uncommon in grapsids. The morphology and life styles of species of Metaplax are also quite similar to those of the ocypodid genus Macrophthalmus. To examine whether ecological and morphological similarities between Metaplax and Macrophthalmus are based on convergent evolution or their common evolutionary history, 841-bp nucleotide sequences from the 16S mitochondrial ribosomal RNA gene of 19 grapsids, 10 ocypodids, and 3 camptandriids, including four species of Metaplax and four species of Macrophthalmus, were analyzed. The resultant phylogenetic tree revealed that both families Grapsidae and Ocypodidae are polyphyletic. Macrophthalmus was distinct from any other ocypodid genera studied, forming a sister group relationship with grapsid species of the subfamily Varuninae, and Metaplax, Cyclograpsus, and Helice of the subfamily Sesarminae. Metaplax, Cyclograpsus, and Helice were found to be more closely related to Varuninae than to other Sesarminae species, indicating that the subfamily Sesarminae is polyphyletic. These relationships were in agreement with the distribution pattern of a tRNA^Val gene rearrangement on the inferred tree. This molecular phylogenetic analysis suggests that the behavioral and morphological similarities observed between Metaplax and Macrophthalmus species are probably due to convergent evolution, despite a close phylogenetic relationship. The waving display in intertidal crabs of the families Grapsidae and Ocypodidae may have evolved several times in their lineages, associated with exposed semi-terrestrial habitat of the intertidal environment.