Measurement of density and thickness of cuticle of an array of decapod crustaceans indicates that cuticle tends to be thick and dense in benthic organisms and thinner and less dense in nektobenthic decapods. Thin section analysis of the cuticle under crossed polarized light documents a broad range of area of biomineralization. Cuticle density is strongly correlated with area of calcification. One of the nektobenthic decapods in the study exhibited no calcification of the cuticle at all, and thus exhibited the lowest density. These data support the hypothesis that density and thickness of cuticle contribute to adaptation to benthic and nektobenthic lifestyles.

Crayfishes belonging to the family Cambaridae occur in two adult male morphs, Form I which is reproductively competent and Form II which is nonreproductive. In our first experiment, we compared the behavior of Form I and Form II animals by measuring walking, sheltering, feeding, and attraction to a female conspecific in single male Orconectes rusticus. Our data demonstrated that, under laboratory conditions, Form II animals spent significantly more time in shelters than did Form I animals. The two forms did not differ significantly in the other measured behaviors. In our second experiment, we examined agonistic behavior in males of each form. When placed in intraform groups of four animals, Form II crayfish displayed fewer agonistic acts and spent less time fighting than did Form I males. In Form II males, increased sheltering may serve to reduce the risk of predation, and fewer agonistic acts may reflect a lower motivation to compete with other males.

In fiddler crabs, males develop profound left-right asymmetry as a large claw grows opposite a small feeding appendage. Females are symmetrical, with paired small feeding appendages. The claw, used in signaling and contests, may favor adaptive responses in walking legs. This study of sand fiddler crabs, Uca pugilator, investigates differences in leg size and proportion: 1) between major (with the claw) and minor (without the claw) sides, using 404 males from which a pair of legs was removed, and 2) between males and females, using 1085 adults from which a single leg was removed. Among males, only the first walking leg was longer on the major side. This was due to the much greater length of the merus, a proximal long segment that is held parallel to the ground. The merus was longer on the major side in all walking legs. This may permit the claw to be extended away from the body without loss of balance when males either engage in contests over breeding burrows or wave the claw to attract females to burrows. More distal segments, the long carpus manus, held approximately perpendicular to the ground, and the dactyl, anchoring the leg to the ground, were longer on the minor side, resulting in longer minor-side legs for the second to fourth pairs of legs. Female legs were proportioned like those on the minor side, with a long carpus manus relative to the merus. However, rear legs of females are relatively long, which may facilitate holding an egg mass above the surface. In males, minor-side legs were more massive than major side legs. This suggests a greater work load on the minor side, as during contests that escalate to interlocking of claws, where minor side legs are important in pushing the opponent. Legs of females were more massive than those of males. The greater mass of female legs is not necessary to support an egg mass, which weighs less than the claw of a similar-sized male. The stouter legs of females may facilitate digging out of breeding burrows.

The southern rough shrimp Trachysalambria curvirostris is a small-sized penaeid shrimp inhabiting coastal waters of the Indo-West Pacific and eastern Mediterranean Sea. It is commercially important as a target species mainly for small-scale bottom seiners and trawlers in Japan, Korea, China, and Taiwan. In Kagoshima Bay, southern Japan, this species is one of the most dominant species in the benthic community. The reproductive biology of T. curvirostris including ovarian maturation, size at sexual maturity, and spawning season was investigated in Kagoshima Bay. A total of 5,681 female specimens were collected during June 2002 through December 2005. Ovarian maturity stages were divided into three categories (undeveloped, developing, and early ripe or ripe) based on the visual observation of ovaries fixed with 10% formalin and oöcyte diameter. The size at sexual maturity was estimated to be 17.3 mm in carapace length. The gonadosomatic index (GSI) showed a significant increase with progressing ovarian maturity stage and most of the females with GSI ≥ 6% were found to be matured. Percentage occurrence of mature females and inseminated females showed similar seasonal trends and the spawning season was estimated to last from May to November, with a peak during June and July.

The smooth bay shrimp, Lissocrangon stylirostris, was sampled using a beach seine and a hyperbenthic sledge in the summer of 2006 at a dissipative sandy beach in southern Oregon. We investigated possible variations in the population structure due to environmental variables, preferred prey, sexual system employed, impacts due to parasitism by the bopyrid isopod Argeia pugettensis, and possible predators. The population was 63% female, and females were generally larger than males. The density of L. stylirostris varied significantly with the time of day. A cohort of small shrimp was observed from July to September while large adult shrimps were rare during the same months. The net effect was that shrimp densities were stable over the summer. The shrimps fed mostly at night on the mysid Archaeomysis grebnitzkii. The differences in female to male ratio, the larger size of females relative to males, and the relatively little overlap in size frequency distribution between males and females could be because this species exhibits a type of protandry. Both male and female shrimps supported an equal, high prevalence of, level of infestation by A. pugettensis (62%). The parasitized shrimps were larger in size than normal shrimps but had lower weight per length ratio. Very few brooding shrimps were parasitized (0.2%), and a higher percentage of parasitized shrimps had empty stomachs and significantly lower stomach contents. We hypothesize that the parasite is affecting the shrimp by producing variation in its normal size and weight, sterilizing females, and reducing its ability to capture food. Finally, individuals of English sole and Pacific staghorn sculpin individuals preyed on the shrimps.

The hypothesis of an amphidromous life history pattern, with a female hatching migration from the river to an estuary, larval development in saltwater, and a return upriver migration by postlarvae (juveniles) was tested in the river shrimp Macrobrachium ohione in the Atchafalaya River, Louisiana, U.S.A. in 2006. A possible female migration from the river to the Atchafalaya Delta estuary (AD) to hatch incubated embryos was tested by comparing reproductive status of females sampled monthly from stations 146 km (Butte La Rose = BLR), 42 km (Berwick = BR), and 0 km from AD. Females only occurred in traps at AD only during the reproductive season (March to August) but were present throughout the year at other stations. The highest percentages of prehatching females occurred at the AD and BR stations while prehatching females were relatively rare at the upriver BLR station. Salt water requirements for larval development were tested by incubating first stage larvae from individual hatches in freshwater and saltwater (15 ppt) treatments (n = 10). The first stage (nonfeeding) larvae did not molt to second stage (feeding) larvae in freshwater, with significant mortality beginning after day 5. In saltwater, survival was high and most hatching larvae molted to stage 2 after 4-5 days of hatching. An upstream migration of juveniles began in mid-July 2006 and continued until October. Juvenile migrators were observed swimming near the surface from approximately one hour after sunset until at least early morning in a band of hundreds to thousands of individuals 1-2 m wide along the shore. Body size of migrators increased from downstream to upstream, suggesting that juveniles are feeding and growing during the migration. Hypotheses about whether formerly abundant far northern populations migrated to and from the sea are discussed. The decline of the species in the northern part of its range might be partially explained by human impacts on the juvenile migration and subsequent upstream recruitment.

Invasive alien species (IAS) potentially may alter all levels of the ecological organization of aquatic water bodies. Therefore, in the context of the EU Water Framework Directive, they represent a significant pressure that should be considered in the assessment of the ecological status of a water body and in the formation of restorative programs. A study was carried out to examine different sampling techniques and to assess the current population structure and the differences in spatial distribution of the alien crayfish Orconectes limosus at four sites in Lake Varese (Northern Italy). Three methods were used to assess the crayfish population: mark-recapture, catch per unit effort during night-time snorkelling and quadrat sampling. For the mark-recapture exercise the ventral somites of crayfish were marked using visible implant elastomer tags. A laboratory experiment was used to verify the effectiveness of elastomer tags for the species prior to their use in the field. Crayfish were more abundant at sites characterized by stone substrate than at sites dominated by macrophytes. Hydromorphological alteration of the shoreline (quantified using the newly developed lake habitat survey methodology) at one site appeared to promote the establishment of alien crayfish. Crayfish caught by snorkeling in open water led to an underestimation of the smallest size-classes compared with underwater quadrats. Underwater quadrats on stone substrates provide a quantitative estimation of abundance and size-structure allowing the comparisons of crayfish populations from different lakes. This method could be applied to assess the extent of pressure resulting from alien crayfish under the Water Framework Directive. Crayfish biomass was found to be 82.9% of other macroinvertebrates indicating their importance in the structure and functioning of the lake ecosystem. The presence of a second alien species of crayfish, Procambarus clarkii, was recorded for the first time in the lake.

The abundance, sex ratio, growth, sexual maturity, morphological sex dimorphism, and reproduction of the portunid crab Charybdis bimaculata was studied in Tokyo Bay, Japan, between November 2002 and October 2003. Relative abundance [inferred from catch-per-unit-effort (CPUE)] was higher and lower during summer and winter months, respectively. The proportion of males varied between 0.2-0.5 throughout the year and the overall sex ratio was greatly biased toward females. The population had a unimodal size frequency distribution and the life-span was estimated to be about one year. Growth was not depressed in winter and was adequately described by the von Bertalanffy growth equation. The puberty molt in males brought about changes in the relative size of the chelipeds and gonopods and was estimated to occur within a carapace length (CL) range of 12.50-16.00 mm. Puberty in females was evidenced by a sharp increase in the pleon width and was estimated to occur at CLs between 11.34 and 16.74 mm. Morphological sexual dimorphism was observed in all features which showed secondary sexual development (cheliped dimensions, carapace and pleon width, and body weight). Ovarian development was uniformly arrested only during winter but began developing in early spring, and mating (insemination) increased in frequency between spring and summer. Ovigerous females were found in all seasons except for winter, but were more common during the warmer months. Batch fecundity ranged from 8,300 to 38,400 eggs per female and was positively correlated with body size. C. bimaculata displays the typical reproductive features and spawning pattern of temperate portunid crabs in spite of its short life-span.

We describe the reproductive period, fecundity, and average size at the onset of functional maturity of female Aegla franca, the northernmost distributed aeglid species. The reproductive period is markedly seasonal and takes place from May (austral mid-autumn) to August (late winter). Ovigerous females appear quite abruptly in the population by May, and this condition is observed in all adult females sampled regardless of their size. The average size at the onset of functional maturity in females, at which 50% of the females sampled during the reproductive period were considered adults, was 12.75 mm CL. The smallest post-ovigerous female measured 12.06 mm carapace length (CL). Mean fecundity (±S.D.) from 41 females bearing early and intermediate eggs was 129.1 ± 32.2 and corresponded to a mean female CL of 14.11 mm. The elliptical-shaped eggs exhibited significant increase in size along the development stages. The third pair of pleopods bore higher number of eggs than the others. Compiled information regarding the reproductive period reported for aeglids revealed an increase in the breeding period length with latitude. The reproductive period tends to be shorter in localities under larger rainfall variation and smaller temperature variability than in sites with opposite climate conditions. Eggs tend to be fewer in number and larger in size towards lower latitudes. We present an hypothesis that stream water velocity might act as a major selective pressure during the early life history of fluvial aeglids with direct effect on the reproductive pattern.

To consider effective resource management strategies for the coconut crab, Birgus latro, we determined the size of males at sexual maturity by histological methods and investigated an optimal method to estimate the number of sperm in spermatophores. The size of 50% sexual maturity in male coconut crabs was estimated at 22.2 mm thoracic length (TL) on the Hatoma Island, Japan. We established a procedure to soak spermatophores for more than 120 min in a 20% NaOH solution before mixing, and to count the sperm within 24 h after mixing, thereby enabling us to assess the number of sperm per individual and estimate male reproductive potential. Using this method, we investigated the relationship between male size and number of sperm retained by males. Larger male coconut crabs have a higher number of sperm in both the vasa deferentia and testis. The relationships between male size and spermatophore volume also increased with increasing male size, and the sperm quantity packed in a spermatophore increased with increasing spermatophore volume. Thus, male coconut crabs display a size-dependent reproductive output, as is reported for other species of anomurans.

We present the first complete description of a life cycle for a marine ostracode that uses bioluminescence for courtship. The life cycle of Vargula annecohenae consists of five juvenile instars separated by molts and an adult instar following the terminal molt. Body size is tightly conserved within each instar; therefore, most individuals can be reliably identified to instar by the length-to-height regression of carapace size. Sexual dimorphism becomes apparent in the penultimate A-I instar and remains evident through adulthood. Each juvenile instar of V. annecohenae lasts between 10 and 27 days, resulting in an estimated total juvenile development time of three months. Females have multiple broods and give birth to crawl-away juveniles following a 26 ± 1.6 day incubation period. Adults live up to 188 additional days, and thus V. annecohenae has a potential life span of up to nine months. This species is one of the large number of myodocopid ostracode species that use bioluminescence for courtship, and our description of its life cycle provides a foundation for future work on the intricate mating systems and the complex ecological interactions within this group.

We obtained the first zoea stages of six grapsid crabs from laboratory-hatched material: Hemigrapsus penicillatus, H. sanguineus, H. longitarsis, H. sinensis, H. nudus, and H. oregonensis. They are re-described and illustrated in detail. Zoeal characteristics are compared among these species. The main difference between four eastern Asian species (H. penicillatus, H. sanguineus, H. longitarsis, and H. sinensis) and two American species (H. nudus and H. oregonensis) is the character of the antennal exopod tip, which is unarmed in the former and spinulate in the latter. In order to facilitate the study of plankton-collected material, we provide a key for the identification of the zoeae of Hemigrapsus from the northern Pacific.

A new genus and species of raninid crab, Bicornisranina bocki, is described from the Upper Cretaceous Haslam and Pender formations of Vancouver Island, British Columbia, Canada. Bicornisranina bocki (Raninidae: Raninoidinae) shares similar characteristics with other genera within Raninidae, including a bifid anterolateral spine, as seen in Rogueus, and a similar frontal spine conformation as seen in Raninoides. Although B. bocki shares morphological characteristics with other genera within Raninidae, B. bocki possesses a distinct sternum that sets it apart and warrants establishment of a new genus. With the occurrence of Bicornisranina from lower Campanian rocks of Vancouver Island, the range of Raninoidinae is confidently extended into the Cretaceous.

The tolerance of spiny lobster J. edwardsii phyllosoma to the effects of increasing levels of ammonia was assessed at Stages I to IV of larval development. The median lethal concentration (96-h LC₅₀) for total ammonia (and corresponding NH₃-N) were 31.6 (0.97) mg l⁻¹, 45.7 (1.40) mg l⁻¹, 52.1 (1.59) mg l⁻¹, and 35.5 (1.01) mg l⁻¹ at Stage I, II, III and IV, respectively. When Stage II larvae were cultured through to Stage III at total ammonia concentrations of 0.5 (control), 1.4, 3.8, 6.3 and 9.5 mg l⁻¹, the intermoult period increased significantly at and above 6.3 mg l⁻¹ (from 11.2 days in controls to 13.2 days at 9.5 mg l⁻¹). Thus, the no-observable-effect-concentration (NOEC) of total ammonia (and corresponding NH₃-N) at Stage II of 3.8 mg l⁻¹ (0.12 mg l⁻¹) was used as the divisor in the acute:chronic ratio (i.e., 96-h LC₅₀ ÷ NOEC) to estimate the concentrations at Stages I, III, and IV, which were 2.7 (0.08) mg l⁻¹, 4.4 (0.14) mg l⁻¹, and 3.0 (0.09) mg l⁻¹, respectively. These results provide the basis for the design and management of systems for the culture of larval J. edwardsii.

The genus Murunducaris, previously represented by a single species (M. juneae) collected in a hillside flush marsh near Brasília, Brazil, is revised here. The description of M. juneae is emended. Three additional species are assigned to the genus, and its geographical distribution is considerably expanded. Murunducaris noodti n. sp., from the vicinity of Arequipa (Peru), and M. loyolai n. sp., from the island of the city of Florianópolis (Santa Catarina, Brazil) are new to science. Murunducaris dactyloides (formerly Parastenocaris dactyloides), from the Tapajós River, near the city of Santarém (Pará, Brazil) is redescribed and its assignment to this genus is supported by synapomorphies. The diagnosis of the genus Murunducaris is emended. The phylogenetic affinities of species of Murunducaris to other members of the family are briefly discussed.

A new species of Nipponbathynella Schminke, 1973 is described from Korea: N. pectina n. sp. Based on its novelties the generic diagnosis of the genus is amended by which particular weight is given to the structure of the male thoracopod VIII. N. pectina is the third species of the genus and has two unique traits: the carination of the back of each somite, and the comb-shaped uropod.

The Hsp70 gene plays an important role in the animal immune response. In order to analyze the linkage between the genetic polymorphisms of Hsp70 and the virus-resistance trait of the shrimp, we detected SNPs in the coding region of Hsp70 by direct sequencing in 104 specimens of Litopenaeus vannamei from three shrimp populations (one TSV-resistance line and two TSV-susceptibility lines). Five SNPs were found including 661C/A, 712T/C, 782C/T, 892C/T, and 1090C/T in the fragment of Hsp70 (GenBank accession no. AY645906). There were significant difference of the allelic frequency of SNP 892C/T polymorphism between the TSV-resistance population and the two TSV-susceptibility populations (P < 0.001). A TSV-challenged test was performed to divide the shrimps into TSV-resistance group and TSV-susceptibility group. The 892C/T SNP genotypes of each shrimp sample were detected by pyro-sequencing. The allelic frequency of SNP 892C/T were significant difference between TSV-resistance group and TSV-susceptibility group (P < 0.001). The results show that the genetic polymorphisms of Hsp70 are likely associated with virus-resistance trait in populations of L. vannamei.

Anomalies of the number of rostral spines have been recorded in blind lobsters, Polycheles typhlops, caught in Sardinian waters (Central Western Mediterranean). The abnormal specimens, 66 out a total of 789 individuals analysed, showed all the morphometric characteristics of P. typhlops except for the unusual presence of two rostral spines instead of the canonical one. The analysis of partial nucleotide sequences of the mitochondrial cytochrome oxidase subunit I gene (COI) showed that the individuals with two spines were not genetically different from the normal specimens of P. typhlops, while both were quite dissimilar from the other Mediterranean species, P. sculptus. Our results suggest the need of an update of the morphological classification guides for this family combined with a wider genetic study.

The genus Zuzalpheus Ríos and Duffy, 2007 was established for species of the presumably monophyletic Synalpheus gambarelloides species group of the second-most speciose alpheid genus, Synalpheus Bate, 1888. However, the validity of Zuzalpheus as a distinct genus is questionnable. First, Zuzalpheus is embedded within Synalpheus in a previously published phylogeny of Synalpheus based on molecular and morphological data, making Synalpheus paraphyletic. Secondly, the three morphological characters used by Ríos and Duffy (2007) to distinguish these two genera are minor compared to distinctions among other alpheid genera; only two of these characters can be considered valid, and only tentatively so. Therefore, Zuzalpheus is synonimized with Synalpheus. However, Zuzalpheus does remain an available name, which could be used in a future subgeneric classification based on a comprehensive phylogenetic assessment of Synalpheus.