This study describes for the first time the ability of catecholamines to induce limb autotomy in the Dungeness crab, Cancer magister. Different concentrations of the biogenic amines dopamine (DA), serotonin, octopamine, norepinephrine, epinephrine, and tyramine, as well as L-dopa and catechol, were individually tested for their ability to elicit autotomy in C. magister. Only the catecholamines dopamine, norepinephrine, and epinephrine were able to stimulate autotomy, whereas the monoamines serotonin, octopamine, and tyramine were not. L-dopa and catechol were also not capable of stimulating autotomy. This suggests that the two phenyl hydroxyl groups on the catechol ring are necessary for ligand/DA receptor binding, whereas the particular biochemical properties of the ethylamine functional group confer ligand/DA receptor binding specificity. Dopamine-stimulated autotomy was concentration-dependent. The D1 receptor agonists and D1 and D2 receptor antagonists failed to respectively induce and inhibit autotomy, which may indicate the presence of a novel subtype of DA receptor in C. magister. Although the particular site of DA injection did not significantly affect the number of legs autotomized, it did appear to influence which legs autotomized. This suggests that DA acts locally, either as a neuromodulator or a neurotransmitter at local nerve synapses or neuromuscular junctions, rather than centrally through neurons descending from the central nervous system.

An actin-encoding cDNA of the kuruma shrimp (Marsupenaeus japonicus) was cloned from a hemocyte cDNA library. To obtain the full length of actin cDNA, a partial cDNA fragment of 517 bp was isolated by reverse transcriptase-polymerase chain reaction (RT-PCR) from poly (A) RNA derived from hemocytes and used as a probe for plaque hybridization. The full actin cDNA was 1,327 bp in length, encoding 376 amino acid residues. The deduced amino acid sequence had 100% identity to that of β-actin from the Pacific white shrimp Litopenaeus vannamei, and extremely high similarity to the sequences of actins in other vertebrates and invertebrates. The cDNA fragments of the actin were amplified by RT-PCR from all organs tested: lymphoid organ, stomach, hepatopancreas, heart, kidney, muscle, eye, ovary, and testis.

The omnivorous crayfish Procambarus clarkii fed selectively on several species of macrophytes, preferring delicate fresh plants that had filamentous or finely-branched architectures. When the macrophytes were dried, powdered, and reconstituted into an alginate gel (thus eliminating among-species differences in physical characteristics), crayfish preferences were altered; previously tough plants that were high in nitrogen and protein were preferred over previously delicate plants that were low in nitrogen and protein. Even though plant structure influences feeding decision of crayfish, the structurally identical macrophyte gels were fed upon differently, demonstrating that nonstructural traits are important feeding determinants. However, plant tissue constituents such as nitrogen, protein, phenolics, lignin, cellulose, or ash were not significantly correlated with feeding preferences. Two high-nitrogen plants that were avoided by crayfish as fresh and as reconstituted tissue (Nuphar luteum macrophyllum and Alternanthera philoxeroides) possessed extracts that reduced crayfish feeding in laboratory assays, demonstrating that macrophyte metabolites can deter some herbivores. As is often observed with large generalist herbivores and omnivores in terrestrial and marine systems, the freshwater crayfish made feeding decisions based upon multiple plant cues (structure, nutrition, chemical defenses).

On the basis of a sampling program performed monthly, a total of 12,033 fiddler crabs, Uca uruguayensis, were collected at the southern end of the Samborombón Bay, Río de la Plata estuary, Argentina, from February 1995 to March 1996. Density ranged from 133 to 207 ind/m² over the 13-mo study period. The overall proportion of male crabs was 0.62. For small crabs, sex ratio was 1:1, but as crab size increased, sex ratio first became female biased and then male biased. Crabs carried eggs from mid-spring to late summer. Prevalence of the parasite Leidya distorta varied between 5.24% and 17.8% throughout the study. Infested male crabs ≥10.5 mm carapace width, which represented only 5.9% of the crabs collected, housed 68.8% of the total parasites recovered. Cryptoniscus larvae were much more frequent among molting (soft) than intermolt (hard) crabs. The cryptonisci infesting intermolt (hard) crabs were aggregated; i.e., they showed a contagious distribution. Females of L. distorta were actively breeding in spring and summer. In autumn, reproductive activity gradually decreased, and by winter, all the adult female parasites showed empty marsupia. The growth of immature parasites appears to stop in winter and resume in spring. The size of the adult marsupial female parasite was positively correlated with that of the host. Because only 1.1% of the mature female crabs carried marsupial parasites, it is unlikely that L. distorta plays a regulatory role in the reproductive potential of the host population.

Male and female reproductive anatomy of a “spearer” mantis shrimp, Squilla empusa, is described using light and scanning electron microscopy as well as dissections. The genital region of females is located medially on the sixth thoracic sternite. It consists of a pair of gonopores connected by a medial genital slit, which leads to a cuticlar sperm storage organ that is shed with every molt. Sperm and accessory material have been located in the seminal receptacle. The accessory material appears to serve as a sperm plug. Females have three internally located cement glands that are visible through the exoskeleton on the thoracic sternite surface. The cement-gland material forms a matrix that holds individual embryos together in a uniform mass. Cement glands develop in synchrony with the ovaries, and development is divided into three stages. Posterior to the gonopores is a medial pore from which material from the cement gland is released. Reproductively active females have ovaries that are oriented anteriorly to posteriorly and are visible dorsally and ventrally through the exoskeleton. Males have paired penes that arise from the last pair of walking legs on the eighth thoracic sternite. The distal end of each penis has two openings: 1) one from the vas deferens that transfers sperm and 2) one from the accessory gland duct that contains sperm plug material for the female seminal receptacle. Male penes are not symmetrical; the left penis is significantly longer when compared to the right penis. Under laboratory conditions, most females that did not have immediate access to males before oviposition produced unfertilized eggs. Two females produced fertilized eggs; one lacked contact with a male for four weeks, and one had constant male contact. The seminal receptacle may normally serve as short-term sperm storage, even though long-term storage was documented. Molting is not related to oviposition. Females produce consecutive broods of eggs an average of 40.6 days apart. Based on the location of the oviducts with respect to the female seminal receptacle, fertilization occurs immediately after the eggs are extruded from the oviducts.

The temporal pattern of population abundance, breeding, and recruitment of the marine shrimp Lysmata wurdemanni is described and analyzed. A population inhabiting the rock jetty in Port Aransas, Texas, U.S.A., was sampled monthly for one year and then bimonthly in a second. Abundances were greatest in the summer, declining during the fall to zero values in early winter, with increases in the late winter and early spring. The disappearance of the population in early winter is attributed to its movement beneath the jetty or to some other location inaccessible to sampling. When the population reappeared in late winter to early spring, it contained a high proportion of larger (older) individuals. The breeding season was seasonal but extended. Most female-phase individuals (FPs) incubated broods of embryos continuously during the warmer months (spring through early fall). Spawning of a new brood occurred soon after hatching of the previous one, as shown by the significant positive correlation between the degree of embryonic development (nearness to hatching) in an FP and the degree of ovarian maturation (nearness to spawning) in its ovotestes. Male-phase individuals (MPs) changing to FPs were found throughout most of the year. Their relative abundance was greatest in late winter to early spring when a group of large MPs, far past minimum FP size, finally changed sex. Recruitment occurred primarily in the spring and summer in both years, although its timing and intensity varied between years. The observed pattern of breeding, recruitment, and population abundances of Lysmata wurdemanni is what might be expected of a primarily tropical species living in an area transitional between the tropical Caribbean and warm temperate Gulf of Mexico biogeographical provinces. The breeding pattern of this shrimp, with an unusual hermaphroditic sexual system, is not strikingly unusual or different from that of gonochoristic shallow-water carideans.

Harlequin shrimp, Hymenocera picta, are monogamous and pair-bonding, and are usually found in isolated singles and pairs in the field. The apparent rarity of this species in their habitat and high levels of aggression between consexuals suggests the possibility of some sort of plasticity in their primary sex determination. In this study, the influence of social environment upon primary sex determination in H. picta was examined experimentally in the laboratory. Naïve juveniles were placed in three novel social environments: paired juveniles, single juveniles, and adult/juvenile pairs. Spacing behavior and the onset of external differentiation were observed during long-term experiments for each social treatment. Gonadal development was also observed. Spacing behavior of paired shrimp reflected the sexual composition of social groups; high intrapair distance (IPD) for same-sex pairs and low IPD for opposite-sex pairs. Sex determination results were not so clear. Two of the three paired juvenile replicates displayed phenotype frequencies different from those expected from a random sample of gonochoristic organisms with a 1:1 sex ratio. However, the third replicate and the combined frequencies did not show any statistical difference from the hypothetical random sample. Furthermore, single juveniles and those paired with adults expressed sex in nearly 1:1 ratios, regardless of the sex of adult conspecifics. Histological examination of juvenile shrimp confirmed that sex was determined as early as four weeks after larval metamorphosis. Therefore, social environment had no clear effect upon sexual phenotype expressed. However, single females attained puberty at a significantly greater age and larger size than did females paired with males. Hence for H. picta, social environment had a measurable effect on the timing of female puberty. This is the first demonstration of this phenomenon in decapod Crustacea.

The maturity and reproductive cycle of female American lobsters (Homarus americanus) were investigated in the southern Gulf of St. Lawrence (sGSL), Canada. The onset of sexual maturity of female lobsters can be established by observations of the ovarian condition, either color or weight, and staging of cement glands but cannot be detected by the morphometry of their abdomens. Females reached 50% maturity between 68.7 mm and 73.3 mm carapace length (L_C). There was a significant geographic difference (P < 0.005) in the size at 50% maturity established by the ovarian development techniques but not by the cement-gland staging technique. Also, there were no annual significant differences (P > 0.005) between the ovarian development techniques used at a single site between 1994 and 1997. To study the reproductive cycle of females, molt stage, ovarian development, and egg spawning were monitored by dissections at the laboratory and by tagging studies in the field. The majority (80%) of small mature females (L_C < 120 mm) in the sGSL had a typical two-year reproductive cycle with molting (with copulation) and spawning in alternating years. However, up to 20% of multiparous females ranging between 65 mm and 109 mm L_C could spawn in successive years instead of the generally accepted two-year cycle, and some could even molt and spawn during the same summer. Similarly, up to 20% of primiparous females could molt and spawn (for the first time) in the same year instead of spawning the following year. A small percentage (5%) of small mature females could also skip molting or spawning for a year. Temperature data suggested that the length of the female reproductive cycle, and possibility of molting and spawning in the same year, were related to the number of degree-days in a particular season.

The reproduction, growth and population dynamics of the deep-water pandalid shrimp Plesionika edwardsii Brandt were studied in the South Tyrrhenian Sea (central Mediterranean Sea, Italy). Individuals were collected between 100- and 350-m depth during an experimental trap survey conducted in the April 1998–November 1999 period. The mean catch did not show differences in relation to either sampling depth or season. Reproduction appeared to be continuous throughout the year even if the main reproductive activity occurred in April–July. The small ovigerous females were 15.5 mm CL, whereas the mean size at which 50% of females were ovigerous (L₅₀) was 18 mm CL. Differences in size at maturity were recorded during the year. The L₅₀ reached the minimum value in June and maximum in October–November, at the end of the breeding season when the reproductive stock was composed mainly of a few large females. A main recruitment cohort was observed in January, although new cohorts of juveniles appeared in each sampling period. The von Bertalanffy growth curve parameters were estimated for both sexes using the relative mean carapace lengths at ages. Females grew faster and reached larger size after maturity than males. Longevity was estimated to be around 3.5 years for both sexes.

The objective of the present research is to study the seasonal morphometric variations of the secondary sexual characters of Aristaeomorpha foliacea and Aristeus antennatus males. Samples were collected from December 1996 to November 1997 using a commercial bottom trawl in a depth range of 446–728 m in the southeastern Ionian Sea (Mediterranean Sea). This is the first attempt to resolve the morphometry of the appendix masculina and appendix interna of these species. Carapace length and lengths and widths of appendix masculina and appendix interna were measured in both species. The relationships between the surfaces of the two appendices and the carapace length in both species were studied. There is a positive allometric growth of these structures in both species. Temporal and bathymetric variation of the above variables are also presented. The possible role of the two appendices in copulation of these two species is discussed.

Two species of mud crab, Scylla olivacea and Scylla paramamosain, occur sympatrically in Ban Don Bay, Surat Thani Province, Thailand, with no evidence of interspecific hybridization. These crabs are part of a traditional and largely unregulated fishery within Ban Don Bay. As part of a study of their reproductive biology and the possible mechanisms explaining their lack of hybridization, size at first maturity was compared between females of the two species. Female S. olivacea and S. paramamosain were collected from Ban Don Bay, and their size at first maturity was estimated using three methods relating abdomen width to body size data: the minimum size at maturity, breakpoint analysis, and probit analysis. All three methods employed revealed that female S. paramamosain attain a larger mean size at maturity than female S. olivacea by as much as 18 to 30 mm internal carapace width (ICW). Although the mean size at maturity is different between species, there is an overlap in the size at maturity between the smallest mature S. paramamosain (ICW = 101 mm) and the largest immature S. olivacea (ICW = 118 mm). Scylla paramamosain has a generally larger body size than S. olivacea; therefore, it is possible that there is a relationship between body size and the size of functional maturity that prevents hybridization between these two species. However, the overlap in the size at maturity observed between the two species means that there is a margin where size could not be the only isolating mechanism, and therefore, other prezygotic isolating mechanisms must also be responsible for maintaining the sympatric species observed. Based on these findings, it is suggested that the local fishery should operate with a minimum legal size of 100 mm and 130 mm ICW for S. olivacea and S. paramamosain, respectively.

The anatomy of the fifth limb of Isocypridina quatuorsetae Kornicker, 1975, is described and illustrated in detail, and it is concluded that the appendage is biramous. The interpretation of the morphology of the fifth limb of I. quatuorsetae is then extrapolated to the fifth limbs of selected members of the families Rutidermatidae, Sarsiellidae, and Cylindroleberididae, which are described and illustrated, and it is concluded that they are also biramous. Members of the Philomedidae have fifth limbs similar to those of the Rutidermatidae and are also biramous.

The female of Botryllophilus sarsi is described as a new species, replacing B. brevipes Sars, 1921, which is a junior homonym of B. brevipes Brément, 1909. The description is based on specimens on loan from the Zoological Museum, University of Oslo. These copepods, living in a polycitorid ascidian, were collected on the west coast of Norway in 1937 and had been identified as B. brevipes Sars. Botryllophilus sarsi belongs to subgroup 1 of morphotype A of the genus and is distinguished from its five congeners by a combination of minor morphological features of body form, antennule, legs, and genitalia. Comparison of B. sarsi with similar botryllophilins and consideration of their ascidian hosts may lead us to question whether the host for B. brevipes Sars is a botryllid.

Three species of harpacticoid copepods are newly reported from long- and short-hydroperiod groundwater and surface freshwater habitats in Everglades National Park, Florida, U.S.A. One is new to science and described herein; Nitokra evergladensis, new species, differs from congeners mainly in details of setation and spination of the endopodites of the swimming legs, the ornamentation of the anal operculum, and the shape and setae of the caudal ramus. Records of members of the genus Nitokra in fresh waters in the U.S.A. are reviewed, and a key to their identification is presented. We present a supplementary description of Attheyella americana, a widespread species previously unrecorded in southern Florida, based on material from the Everglades. Collections of the rare species Bryocamptus newyorkensis in the Everglades have extended its distribution considerably southward. We redescribe both sexes on the basis of specimens collected from Everglades National Park and also from Great Smoky Mountains National Park, Tennessee, and discuss the geographical distribution and habitats of the species. The Everglades “freshwater” harpacticoid fauna is depauperate, having a large proportion of species adapted to marine habitats.

Six naupliar stages are described based on specimens of Stephos longipes Giesbrecht, 1902, obtained from sea ice near Terra Nova Bay, Antarctica. Marked differences between nauplii of Stephos longipes and Paralabidocera antarctica (I. C. Thompson, 1898) were used only to identify the two species in the samples. The copepods Stephos longipes and Harpacticus furcifer Giesbrecht, 1902, accounted for more than 90% of sympagic communities in the annual sea ice at Terra Nova Bay.

We describe Elasmopus warra (Crustacea, Amphipoda) from Pearl Beach in the vicinity of Sydney, Australia. We also investigate the patterns of spatial variation of Elasmopus in coralline algal turf on rocky intertidal shores in this area and examine experimentally the role that two architectural characteristics of coralline turf, the length and density of fronds, have in determining these patterns of abundance. Initial sampling showed that E. warra was more abundant in coralline turf in low- than in mid-shore areas, and often its abundance varied between patches of turf low on the shore. The results of experiments showed that the length of fronds had a much greater effect on the abundance of E. warra than the density of fronds. In low-shore areas, increasing the length of fronds negatively affected the abundance of E. warra. Such a relationship has rarely been reported in the literature, and possible causes for this relationship are discussed. This study showed that the nature of effects of marine plant architecture on the abundance of small crustaceans depend on local conditions and the architectural characteristics being investigated.

The crayfish family Cambaridae is a diverse and important component of North American aquatic diversity. Although the family has enjoyed a relatively high level of taxonomic stability, few phylogenetic hypotheses of relationships within the family using empirical data analyses exist. We present here a phylogenetic analysis of the subgenus Crockerinus, genus Orconectes, using nucleotide sequence data from the mitochondrial gene region Cytochrome Oxidase I (COI). Using both parsimony and likelihood analyses, our results do not support the monophyly of the subgenus Crockerinus and show only partial support for the use of pleopod morphology for classification. For the species examined in this study, COI exhibited a relatively high rate of substitution, especially at the third codon position. This demonstrates the potential use of COI for inferring interspecific relationships among cambarid crayfishes.

The complete larval development of Parapagurodes constans is described, based on laboratory rearing. The species has four zoeal stages plus the megalopa. Each stage is described and illustrated, and detailed comparisons are made with other pagurid larvae in closely related species of Parapagurodes and other pagurid genera.

We provide the first biological data for the southern king crab Lithodes confundens, found intertidally on the Atlantic coast of southern South America (51°21′S–54°20′S). Between October and December 1997 and in December 1999, specimens were found during the ebbtide in crevices of the wave abrasion platform. The size of animals progressively increased from ∼ 50 mm carapace length (CL) in October to ∼ 105 and 75 mm CL in December for males and females, respectively. The sex ratio increased from October to December, from 1:1 to 2:1 male : female. Females molted during December. A total of 61 mating pairs were found at Bahía Grande (51°21′S, 69°02′W), between 16 November and 28 December 1997, and represented 31% of a total of 399 captures. Mating pairs were in precopulatory embrace, which was formed by a male in intermolt condition and a female in ecdysis. The male was always larger than the female. The relative growth of the male right chela was studied with the MATURE computer routine for two different chela dimensions, length and width. Slopes of relationships between chela sizes and CL changed at 89.8 and 87.3 mm CL, respectively. The estimated size of physiological maturity for 82 females was 68.3 mm CL. The smallest male participating in mating pairs was 75.2 mm CL. We suggest 100 mm CL as the legal size for fishery management purposes.

RESUMEN

Se presentan los primeros datos biológicos para la centolla Lithodes confundens, que fueron encontrados en el intermareal de la costa atlántica del extremo austral de Sudamérica (51°21′S–54°20′S). Entre octubre y diciembre de 1997 y en diciembre de 1999, se encontraron especímenes durante las bajamares, asociados a grietas de la plataforma de abrasión de ola. El tamaño de los animales encontrados aumentó progresivamente, de ∼ 50 mm de largo de caparazón (LC) en octubre hasta ∼ 105 y 75 mm LC en diciembre, en machos y hembras, respectivamente. La proporción sexual aumentó de octubre a diciembre de una relación 1:1 a 2:1 machos : hembras. Las hembras mudaron en el intermareal durante diciembre. Un total de 61 parejas en acoplamiento fueron encontradas en Bahía Grande (51°21′S, 69°02′W), entre el 16 de noviembre y el 28 de diciembre de 1997, y representaron el 31% de los 399 animales capturados. Las parejas en acoplamiento estaban en el abrazo precopulatorio, y constituidas por un macho en condición intermuda que siempre fue más grande que la hembra, que estaba en proceso de ecdisis. En los machos, el crecimiento relativo de la quela derecha fue estudiado con la rutina “MATURE”, para las dimensiones largo y ancho de la quela. Las pendientes de las rectas definidas entre los tamaños de la quela y el LC cambiaron a los 89,8 y 87,3 mm LC, respectivamente. La talla de madurez fisiológica, estimada a partir de 82 hembras, fue 68,3 mm LC. El macho más pequeño participando en una pareja fue de 75,2 mm LC. Para un futuro manejo de la pesquería, sugerimos una talla legal de 100 mm LC.

Mole crabs of the genus Emerita (Family Hippidae) inhabit many of the temperate and tropical sandy beaches of the world. The nine described species of this genus are rarely sympatric, and most are endemic to broad biogeographic regions. The phylogenetic relationships among the species have not yet been investigated. Based on presumed morphological synapomorphies, it has been suggested that the species inhabiting the New World constitute a monophyletic group, as do the species inhabiting the Old World. The relationships within the New World species were previously studied using sequence data from Cytochrome Oxidase I and 16S rRNA mitochondrial genes; the results strongly suggested that one of the species, Emerita analoga, was very divergent from the other taxa examined. This observation prompted uncertainty about monophyly of the New World species. The goal of the present study was to elucidate the relationships among the species within the genus Emerita. Partial sequences for the mitochondrial COI and 16S rRNA genes for all nine species of the genus (and several outgroups) were examined. Phylogenetic analyses suggest that E. analoga is closer to the Old World taxa than to the other New World species; thus the New World Emerita species do not constitute a monophyletic group.

The larvae of the mangrove sesarmid crab Neosarmatium indicum (A. Milne-Edwards, 1868), were reared in the laboratory. Five zoeal stages and one megalopa are described in detail and illustrated. Morphologically, the first zoea of N. indicum is similar to those of other species of Neosarmatium, as well as species of the family Sesarmidae, in that they share most of the following characters: no lateral carapace spines, five setae on the endopod of the maxilla, and four terminal setae on the distal segment of the mandibular palp in the megalopal stage. The differences between the first zoea and the megalopa of N. indicum and those of its related sesarmid species are discussed briefly.

A new decapod fauna has been recovered from Eocene rocks of San Diego County, California. Decapod faunas of Eocene age have been rare from California, although they are well described from the northern Pacific coast. Three new species, including Neocallichirus rhinos, Ctenocheles secretanae, and Minohellenus inexpressus, and two new genera and species, Acanthoportunus buchanani and Vegarthron santiago, are reported from this new fauna. A new genus has been erected to accommodate Portunites triangulum and Portunites granulifer; both are herein referred to Maeandricampus, new genus. Callianassa matsoni Rathbun has been reassigned to Neocallichirus. Portions of the cephalothorax and abdomen of a species of Ctenocheles are described from fossils for the first time. Orbitoplax weaveri, previously known from Eocene rocks of California and Oregon, is reported from the Eocene Mission Valley Formation and the Ardath Shale for the first time. In addition, one specimen of a stomatopod of indeterminate genus is noted. The Eocene decapod fauna from California, now containing eighteen genera, has elements common to the northern Pacific coast of North America as well as taxa known only from California; thus, the area appears to have been suited for decapods adapted to a wide variety of temperature and other environmental conditions. Several genera appear to have evolved within the region, whereas others may have been introduced from the Atlantic or Tethys region via the Central American Seaway. The number of Pacific amphitropical genera continues to increase; two portunid genera discussed here display such a pattern, adding to the four already reported for Cretaceous and Tertiary rocks of the region.