The presence, distribution, and histological features of lipofuscin granules were investigated in brains of the dendrobranchiate decapods Marsupenaeus japonicus Bate, 1888, Melicertus kerathurus (Forskål, 1775), Parapenaeus longirostris (Lucas, 1846) (family Penaeidae), and Aristeus antennatus (Risso, 1816) (family Aristeidae). Autofluorescent lipofuscin granules were prominent in wax sections of olfactory-lobe cell masses (OLCMs) of all the species but P. longirostris, in which the pigment granules could be distinctly identified only in histological sections of samples embedded in resin. Although quantification was not carried out in this study, the amount of lipofuscin was visibly higher in larger and older individuals. Lipofuscin granules are secondary lysosomes of heterogeneous content that derive from autophagic vacuoles. In samples treated for electron microscopy, cytoplasmic inclusions assumed to be lipofuscin granules stained positive with Sudan Black B, whereas all brains processed for light microscopy (embedded in either paraffin wax or resin) were Sudan Black B negative. No acid phosphatase activity was evidenced cytochemically in lipofuscin granules of M. japonicus OLCMs. The variable histochemical properties of lipofuscins suggest that, as has been shown previously for other decapods, the most accurate method for localization and quantification of the age-pigment in dendrobranchiates is the one based on autofluorescence. This technique is thought to be valuable in assessment of the age structure of shrimp natural stocks.

The effect of 16 weeks starvation and 6 weeks refeeding on the size and chemical composition of the hepatopancreas of 2 size classes of C. destructor (20–40 g and 40–60 g) maintained at 2 temperatures (10°C and 25°C) was investigated under laboratory conditions. The response to starvation was not influenced by size class. In fed animals, the wet hepatosomatic index (HSI_w-%) and dry hepatosomatic index (HSI_d-mg/g) increased to 7% at week 2 and 36 mg/g at week 10 respectively, whereas in starved animals HSI_w and HSI_d decreased to 2.6% and 3.6 mg/g at week 10 respectively. Hepatopancreas moisture (HM-%) of fed animals decreased to 51% after 10 weeks, whereas in starved animals it increased to a maximum of 81% after 2 weeks. In fed animals, hepatopancreas lipid (HL-mg/g), protein (HP-mg/g), and ash (HA-mg/g) reached a maximum of 30 mg/g at week 10, 7.8 mg/g at week 6, and 2 mg/g at week 4 respectively. Hepatopancreas carbohydrate (HNFE-mg/g) in fed animals fluctuated considerably. In starved animals, HL did not significantly change for the first 4 weeks, and a minimum of 0.5 mg/g occurred at week 8. In contrast, HP decreased for the first 2 weeks to 3 mg/g, and HNFE decreased for 4 weeks to 0.67 mg/g after which no significant change occurred. Ash levels in starved animals generally decreased for 12 weeks to 0.36 mg/g. Low temperature reduced the rate of utilization of hepatopancreas nutrients. About 7 months of starvation at 10°C is required for the hepatopancreas to become nutritionally depleted. Refeeding starved animals resulted in an increase in wet and dry hepatosomatic indices and all hepatopancreas nutrients and a decrease in hepatopancreas moisture. Complete recovery of the hepatopancreas of starved animals following refeeding, to levels recorded in the fed control animals, was recorded for the HSI_w, HA, and HNFE. The various hepatopancreas condition indices used here are discussed in relation to their practical value and accuracy in predicting animal condition, and a classification is presented. The adaptive significance of hepatopancreas size and nutrient storage capacity is also discussed.

A detailed description of the 4th podobranch of the marron Cherax tenuimanus is given, describing four filaments distinguished by their apical morphology: rounded, pointed, alar, and hooked. Four response patterns of these filaments to silver staining (3 minutes in 0.25% solution of AgNO₃ and then exposed by immersion in Kodak developer for 30 seconds) were recognized: 1) staining filaments with an unbroken film of stain along the length, 2) non-staining filaments without stain response, 3) mottled filaments had patches of staining along the length of the filament, 4) mosaic filaments which stained in rosette patterns.

To examine albinism, cheliped tissue was reciprocally transplanted into the autotomized stump of the walking leg (and vice versa) between albino and wild crayfish. Two of the 24 walking-leg stumps of albino crayfish formed a claw, and three of the 49 leg stumps of wild crayfish formed claws. Dactyl and pollex tissues of wild (and albino) crayfish were transplanted into an eyestalk stump and rostrum stump of 20 albino (and wild) crayfish, respectively. In albino crayfish, one normal claw and six abnormal chelipeds developed from the eyestalk stump, and seven abnormal chelipeds developed from the rostrum stump. In wild crayfish, one normal and seven abnormal chelipeds developed from the eyestalk stump, and four abnormal chelipeds developed from the rostrum stump. Dactyl tissue of wild (and albino) crayfish was inserted into the carapace near the eyestalk of 11 albino (and wild) crayfish. In six of each of the albino and wild crayfish, a dactyl-like structure developed from the graft. All of the regenerated structures were the same color as the host. These results suggest that the albinism in this crayfish is caused by a deficiency of some hormonal factor(s).

The purpose of this study was to determine the shell utilization pattern of Calcinus tibicen using the percentage of the different shell types that were occupied, the morphometric relationship between hermit crabs and occupied shells, as well as shell availability based on the empty shells and living gastropods observed. Specimens were collected at two-month intervals from January to November 1998 along the rocky shore of Praia Grande, Ubatuba, using a specific methodology adapted to the irregular surface of the area. Of 1,069 shells collected, empty shells were less frequent (4.11%) than shells occupied by either hermit crabs (23.11%) or living gastropods (72.78%). A total of 247 hermit crabs were captured occupying seven of the twelve shell species collected in the field. Only Stramonita haemastoma was occupied in significant numbers (71.26%). There was a differential shell utilization pattern between sexes; males were most abundant in S. haemastoma shells while the ovigerous females occupied Leucozonia nassa. Regression analysis showed a close correlation between the dimensions of the crabs and the utilized shells. In this study, shell occupation by C. tibicen varied as a function of shell type availability, with intraspecific differences in occupation patterns also occurring.

The objective of this study is to investigate the patterns of shell utilization in Petrochirus diogenes in the Ubatuba region, SP, Brazil. Hermit crabs were obtained from 1993 to 1996 with the aid of a shrimp fishery boat equipped with two double-rigged trawling nets. Shells were identified and weighed, and their maximum aperture width was measured. Hermit crabs were weighed, and their shield length was recorded. A total of 634 P. diogenes specimens, occupying shells of 12 gastropod species, was obtained. The shells of Tonna galea, Zidona dufresnei and Strombus pugilis were the most frequently occupied, the first marked by its larger aperture width and lower average weight. Small hermit crabs inhabited a wide variety of gastropod shells due to their higher availability. However, the utilization of T. galea shells became predominant as the crabs attained larger sizes. Differences in weight and aperture width are known to encourage certain shell utilization patterns and may affect growth and reproduction of hermit crabs.

Reproductive traits of Pagurus lanuginosus are described and compared with three sympatric, congener species. Female P. lanuginosus mature at about 5 mm shield length, spawn clutches in autumn and spring, and are considered to have two or more clutches per year. Among the four sympatric Pagurus species (P. lanuginosus, P. middendorffii, P. filholi, P. nigrofascia), spawning season, hatch-out season, annual spawning times, maturity size, and incubation period differed. Specific differences in annual spawning times and some related traits may be explained by differences between species in maximizing the fitness component. Species with several clutches each year and a short incubation may segregate settlement timing to reduce intra- and interspecific competition for unpredictably supplied small shells among settling and newly settled crabs and, thus, maximize the number of clutches per annum. Alternatively, species with single annual clutch, early spring hatch out, and long incubation may be selected to maximize larval survival and/or settlement success if early spring is the optimal season for larval settlement success.

The effects of sex ratio on the spawning frequency of females and on male mating behavior were examined in the spiny king crab, Paralithodes brevipes. Two types of guarding behavior were categorized based on when the male began guarding the female, that is, pre- and post-molting types, when the male starts guarding the female either before or after her molt, respectively. Males reared under a female-biased sex ratio more often showed the post-molting type than did males reared under an even ratio. Guarding duration for the pre-molting type, from the start of guarding to female molting, was significantly longer when the sex ratio was even than when females were more numerous (female : male ratio = 5:1). While there was no significant difference in the molting frequency of females between the two sex ratios, frequencies of egg extrusion were significantly lower for the female-biased ratio than for the even sex ratio. These results suggest that the sex ratio affects the mating behavior of P. brevipes and might be an important factor to manage wild populations and to produce seed crabs effectively in nursery tanks.

Cyprid larvae of the lepadomorph Octolasmis colonize the gill chambers of the edible mangrove crab Scylla seratta (Forskål, 1755). In a natural population of 856 mangrove crabs from southern Thailand, 260 individuals were infested by 3,670 Octolasmis cor and 1,758 O. angulata, including 1,014 subadults, 168 cyprids, and 38 peduncles of the two species. This population of gill chamber symbionts was examined to investigate the relationship between barnacle size and barnacle spatial distributions. The habitat of the branchial chamber was partitioned for study into gills one through eight, the inside (hypobranchial) and outside (hyperbranchial) gill surfaces, and the proximal, medial, and distal regions of each gill. The collective data from 260 crabs were pooled for an analysis that showed a nonrandom relationship between the size of octolasmids and thier location within the gill chamber. On the inside gill surfaces O. angulata attained its largest average size on gills 3, 7, and 8, whereas on the outside surface the barnacles were largest on gills 4 and 5. Octolasmis cor attained its greatest average size on the inside surface of gill number 6. Comparisons of barnacles from the three gill regions also revealed some significant differences in average barnacle size. Positive correlations among barnacle size, barnacle number, and barnacle density were present. Moreover, there was a significant correlation between the total numbers of barnacles and the average size of O. cor on the inside surfaces of gill numbers 1 to 8, whereas it was not significant for O. angulata. There was also a significant correlation between barnacle densities and barnacle size in O. cor but not O. angulata. Positive correlations were also observed among higher numbers of barnacles, larger barnacles, and higher numbers of advanced reproductive stages. Areas with higher densities also were areas of higher average fecundity.

Larvae of the common intertidal chthamalid barnacles Jehlius cirratus and Notochthamalus scabrosus were obtained from mature adults collected in central and northern Chile and cultivated in the laboratory at temperatures typical of the conditions encountered by larvae in these regions. Morphological and developmental descriptions of the six naupliar stages and the cyprid stage of both species are given. Both species clearly present the general pattern of development for chthamalids, in which the structural characters of the cephalic shield and abdominal process, in conjunction with the utilization of the alphabetical setation formula for antennae, facilitate the identification and differentiation between larval stages. The average time of naupliar larval development of J. cirratus and N. scabrosus in sea-water temperature ranging 15–18°C was 31 and 37 days, while larvae cultivated in temperatures ranging 18–20°C completed naupliar development after 13 and 20.2 days, respectively. This represents a 58% and 45.5% reduction in naupliar development time with a three-degree increase in mean sea water temperature for J. cirratus and N. scabrosus, respectively. The development time from cyprid until settlement and metamorphosis of N. scabrosus lasted between 9 and 11 days, depending on the temperature, while cyprid development for J. cirratus lasted 8 days at 18–20°C. The average sizes of the naupliar and cyprid stages were similar between the species at both temperature ranges. Although the increased temperature reduced the time of larval development, it did not significantly affect larval sizes.

The fiddler crab Uca arcuata (De Haan, 1835), which lives on intertidal mud flats, occasionally builds a cylindrical mud chimney that encircles its burrow entrance. Chimneys were more often found with burrows of females than with those of males (22% versus 10%). For both sexes, smaller individuals were more likely to construct chimneys. Chimneys were more abundant during the periods of male waving activity (May–August), but their abundance was unrelated to the semilunar tidal cycle. We experimentally demonstrated that individuals without burrows more often entered burrows without chimneys than burrows with chimneys. Because individuals compete for burrows, the function of chimney construction may be to decrease the likelihood that an individual loses its burrow to an opponent. The seasonal variation in chimney construction as well as differences in the probability of construction among various sex and size classes also support this conclusion.

To evaluate the suitability of using coded microwire tags (CWTs) to mark early-benthic-stage Caribbean spiny lobster, Panulirus argus, we compared the survival, growth, and feeding of tagged and untagged lobsters held in the laboratory through the first five juvenile molts. We also examined the growth of 65 microwire-tagged lobsters released into the wild as early-benthic-stage juveniles. Tag retention rates of lobsters held in the laboratory were 86% for those tagged as first-stage juveniles and 96% for those tagged as second-stage juveniles; virtually all tag loss was confined to the first post-tag molt. Survival and growth rates of tagged second-stage juveniles in the laboratory did not significantly differ from those of untagged lobsters, but first-stage-tagged juveniles had lower growth rates than untagged lobsters did and a 25% post-tagging mortality rate. The mean growth rate of juveniles released into the wild was 0.82 mm CL/wk, but growth differed by season; no sex- or habitat-specific differences in growth were observed. Data obtained from these recaptured lobsters provide the first detailed estimates of growth of P. argus under natural conditions during the earliest part of their benthic life and illustrate the potential usefulness of coded microwire tags in mark-recapture investigations of juveniles for this and other species.

Mitochondrial DNA sequence variation in the 16S rRNA gene was used to estimate the phylogenetic relationships of Austropotamobius pallipes. The program ModelTest was used to test alternative models of evolution for our data using likelihood ratio tests. Both the minimum evolution tree with the HKY85 model and the maximum likelihood analysis supports the separation of two major clades (A and B) and three clades within clade A. The two major groups A and B showed genetic differentiation of 4.6% and could be in accordance with the classification on the specific status of A. italicus and A. pallipes. Within clade A, three clades were found corresponding to crayfish sampled in Spain-Italy-France, Austria, and Slovenia. In accordance with morphological data extracted from recent papers, a new classification based on the presence of three subspecies (italicus, carinthiacus, and carsicus) within A. italicus is proposed.

South America contains three endemic genera of parastacid freshwater crayfishes (i.e., Parastacus Huxley, Samastacus Riek, and Virilastacus Hobbs), with a current total of ten described species. A previous author has argued that each of these genera has closer affinities with genera from Australia than to each other. We sequenced approximately 500 nucleotides of the 16S gene from mitochondrial DNA to estimate phylogenetic relationships among the South American genera of freshwater crayfishes and determined their phylogenetic positioning relative to the Australian genera. We sampled seven species representing all three genera from South America with 19 individuals. These sequences were combined with other Australasian crayfishes for a total representation of 54 sequences covering 13 genera. Our results indicate that the South American genera form a well-supported monophyletic group closely related to a subset of the Australasian crayfishes (Paranephrops and Parastacoides). Our results also provide strong support for the currently recognized generic designations.

Phylogenetic relationships within Metapenaeopsis remain largely unknown. The modern revision of the genus suggests that the shape of the petasma, followed by the presence of a stridulating organ, are the most important distinguishing taxonomic features. In the present study, phylogenetic relationships were studied among seven Metapenaeopsis species from the Indo-West Pacific based on partial sequences of mitochondrial 16S rRNA and cytochrome c oxidase I (COI) genes. Mean sequence divergence was 6.4% for 16S and 15.8% for COI. A strikingly large nucleotide distance (10.0% for 16S and 16.9% for COI) was recorded between M. commensalis, the only Indo-West Pacific species with a one-valved petasma, and the other species with a two-valved petasma. Phylogenetic analyses using neighbor-joining, maximum parsimony, and maximum likelihood generated mostly identical tree topologies in which M. commensalis is distantly related to the other species. Two clades were resolved for the remaining species, one with and the other without a stridulating organ, supporting the main groupings of the recent taxonomic revision. Results of the present study also indicate that the deep-water forms represent a relatively recent radiation in Metapenaeopsis.

A new genus and species, Hampsonellus brasiliensis, is described. This species has been found in shallow, marine, soft bottoms on the southern Atlantic coast of Brazil. We discuss the principal generic differences in the Cephalocarida, which are in reproductive modifications of limb structure of posterior thoracopods.

Streptocephalus sirindhornae, new species, the first freshwater anostracan from Thailand, is widespread in the northeast of the country. It is morphologically closest to the Indian species S. dichotomus, but a sequence analysis of its SSU rDNA gene reveals that its closest relative is in fact the Indian species-pair S. dichotomus-S. simplex, that it is probably a conserved member of the S. dichotomus-group, and that it shares some relationship with the S. torvicornis-group.

Branchinecta mackini Dexter, 1956 (Crustacea, Anostraca) has been thought to occur both east and west of the Continental Divide of North America for more than 30 years. My study revealed that individuals from east of the Divide are morphologically distinct from those found west of the Divide. Males consistently differed in the shape of the distal end of the antenna. The eastern taxon is described and given the name Branchinecta readingi new species.

Botryllophilus bamfieldensis, new species, is described on the basis of specimens of both sexes living in a compound ascidian from the Bamfield area in Barkley Sound, west coast of Vancouver Island, Canada. The morphological details of the female fit the diagnostic features for morphotype A of the genus. The female can be distinguished from its eight congeners by the sharply pointed triangular apex of the cephalosome, the weakly segmented metasome, and the markedly elongated exopods of left legs 1–4. The male of the new species differs from the only known male of a species of morphotype A (B. abbotti) in that the endopod of leg 1 bears five variously shaped spines and five plumose setae. It is proposed that females of nine species of morphotype A be further divided into two subgroups based on two patterns of armature for legs 1–4.

We redescribe Speocyclops yezoensis Ito on the basis of specimens from Japan and from Alaska and Tennessee, U.S.A. The combination of the segmentation of the swimming legs; the lack of dimorphism in the structure of the swimming legs, except for the modified terminal spine of the leg 3 endopodite in the males of some populations; the partly fused proximal segment of leg 5; and, in the female, the peculiar structure of the seminal receptacle provide grounds to propose a new genus Itocyclops to accommodate this taxon. A new record from Tennessee is the first from the eastern U.S.A.