Our previous studies have found that euhermaphrodite-phase shrimp of Lysmata secrete both distance and contact sex pheromones, unique among the shrimp. To gain a better understanding of the chemo-sensory system of shrimp, we studied the setae on the first (antennules) and second antennae of four species of Lysmata, which represent the two social groups (low and high densities) and three distinct external morphological patterns (peppermint shrimp, scarlet lady shrimp, and fire shrimp) in the genus. There were four types of setae in the four species: aesthetascs, denticulate setae, and two types of simple setae. Aesthetascs are only distributed on the proximal lateral antennular flagella, while the other three setae are located on the antennules and the second antenna. Aesthetascs are believed to be olfactory organs in detecting soluble chemical signals, especially for male-female communication during mating, while one or more of the other three setae are responsible for detecting contact pheromones. Lysmata boggessi and L. wurdemanni, peppermint shrimp that live in aggregations, possess significantly higher number of aesthetascs than pair-living species of L. amboinensis (scarlet lady shrimp) and L. debelius (fire shrimp), suggesting a possible correlation between the aesthetasc number and social environment. Sexual dimorphism in the aesthetasc number is found in L. boggessi and L. wurdemanni, with significantly higher numbers in the male-phase shrimp than in the euhermaphrodite-phase shrimp.

The Cambarus acuminatus complex is a poorly known group of crayfish species whose range has traditionally been assumed to extend from the Patapsco River drainage in Maryland southward to the Saluda River basin in South Carolina. During a recent crayfish survey of southeastern Pennsylvania, we collected a member of the C. acuminatus complex [Cambarus (Puncticambarus) sp.] from Valley Creek. Collections were made from several habitats [pools, riffles, shallow lateral areas (SL), main-channel areas (MC)], and dominant substrate classes, current velocity, and depth were recorded in each sampling area. These collections represent a new crayfish record for Pennsylvania and the first documented occurrence of the C. acuminatus complex north of the Patapsco drainage. Life history characteristics of the population of C. (P.) sp. inhabiting Valley Creek are provided and their variation among habitats and seasons is discussed. In pools, C. (P.) sp. density was negatively related to current velocity, depth, and % sand, and positively related to % silt. In riffles, C. (P.) sp. density was negatively related to current velocity. Comparisons among habitats indicated that C. (P.) sp. was abundant in SL but was scarce in MC. Although MC tended to have faster current, greater depth, more sand, and less silt than SL, other factors could have been responsible for the relative scarcity of C. (P.) sp. in MC. More conclusively, there was a positive relationship between C. (P.) sp. density and % cobble in MC of pools, suggesting that activities such as urbanization that result in sediment deposition and burial of rocky substrates may have a negative effect on density in MC. Since MC are important for large, reproductive individuals, reduced density in these areas may affect the reproductive potential of the population. These findings indicate that Valley Creek supports an unusual and potentially threatened crayfish population that requires further study and highlight the need for additional fieldwork in the region.

The current study examines the life history characteristics of Procambarus suttkusi, a species of special concern in the Choctawhatchee watershed, Southeast Alabama, USA. The reproductive biology (reproductive status, size at sexual maturity, egg size and count, and sex ratios), molt patterns, growth, habitat associations, and population density were documented at least monthly from the East Fork of the Choctawhatchee River. Form I males were found from May until mid-September. Because young-of-the-year (rostral cephalothorax lengths ranging from 5 to 10 mm) were first observed at the end of May and ovigerous females were collected in June and July, it was estimated that ovigerous females can be found from April through July. Fecundity ranged from 141 to 228 eggs. Size at sexual maturity was 30.5 and 20 mm for males and females, respectively. Monthly length-frequency diagrams suggested that P. suttkusi may mature its first year and has an estimated life span of at least 36 months. The population density for the East Fork population was estimated at 0.25 individuals/m².

The rusty crayfish, Orconectes rusticus, has spread from its original range throughout much of northeastern North America, often completely replacing native crayfish. I tested the hypothesis that reproductive interference is a mechanism of the rusty crayfish's invasion of streams of the upper Susquehanna River watershed, where O. rusticus is replacing the native O. propinquus. I collected females from allopatric and sympatric sites during the spring reproductive period to measure size-specific probability of reproduction, fecundity, and the frequency of nonviable eggs. The predicted size at which females had a 50% probability of reproducing at sympatric sites was slightly larger for O. rusticus and considerably smaller for O. propinquus compared to allopatric sites, but O. propinquus also differed in size among site types. There were no differences between site types in average clutch size or the frequency of nonviable eggs. The differences in reproduction between allopatric and sympatric sites did not strongly support the reproductive interference hypothesis; instead, they may be a result of differences in O. propinquus size structure, possibly related to environmental differences between upstream allopatric and downstream sympatric sites.

Three techniques used to capture burrowing crayfish were compared for efficiency and efficacy near Big Oaks National Wildlife Refuge. Excavation of burrows, Norrocky burrowing crayfish trap (NBCT), and burrowing crayfish mist nets (BCN) were simultaneously compared for capture efficiency and trap efficacy. Additional research goals were to evaluate patterns in capture rates with changes in seasonal activity, influence of burrow diameter size to capture success, relationships between differences in morphological characteristics of species and capture success, and capture success and habitat quality. Excavation caught significantly more burrowing crayfish than the other two methods (40.7%), but the NBCT (5.2%) was not significantly different from the BCN (4.5%) in trap efficiency. The relative percent efficacy success adjusted for effort of each method was 2.61% for the NBCT and 2.24% for the BCN. Positive correlations between habitat quality and increasing NBCT (r_s = 0.414, P = 0.023) and increasing BCN (r_s = 0.447, P = 0.013) trap efficiency success were found, while no significant linear relationship (r_s = −0.134, P = 0.479) was observed between the Qualitative Habitat Evaluation Index score for habitat quality and excavation success. No significant correlation was observed between NBCT (r_s = −0.273, P = 0.144) or BCN (r_s = −0.286, P = 0.125) and annual date; however, a significant linear relationship was observed for excavation (r_s = −0.372, P = 0.043) and annual date of collection. Individuals of Cambarus (Tubericambarus) polychromatus and Cambarus (Lacunicambarus) species “A” that were collected were significantly different in size; however, this was not a result of gear bias. A positive correlation was observed between C. polychromatus size and habitat quality indicating longer lived individuals occur in higher quality habitats.

Marine organisms have evolved a suite of responses to minimize the exposure to predators. Visual crypsis is one such strategy to avoid predation. Paraxanthus barbiger (Poeppig, 1836) is a species that exhibits different color morphotypes over heterogeneous substrates as a means of protection against visual predators. Our main objectives were to quantify the occurrence of color morphotypes over a three-year period and to investigate, via an experimental approach, on the possible mechanisms involved that would provide crypsis to this species. Field surveys occurred over a three-year period at two nearby sites on the central Chilean coast. Initial observations indicated that small juvenile P. barbiger exhibited higher degrees of color polymorphism than larger (> 20 mm carapace width) conspecifics. Furthermore, survival rates of small (< 10 mm carapace width) P. barbiger exposed to predators increased on heterogeneous substrata under both natural and laboratory conditions. Laboratory experiments further demonstrated that newly settled P. barbiger actively select heterogeneous substrata. Hence, cryptic responses of this species might reduce predation-mediated mortality through color pattern disruption of individuals with respect to their environment.

The feeding ecology of two species of sesarmid mangrove crabs, Perisesarma eumolpe (de Man, 1895) and P. indiarum (Tweedie, 1940), in Mandai Kechil, Singapore was studied through field observations and laboratory experiments. The latter comprised a series of three separate experiments to investigate mangrove leaf species preferences, leaf age preferences, and feeding rates on leaves. Results indicate: 1) both P. eumolpe and P. indiarum are mainly sediment grazers, but also feed on mangrove leaves and roots and occasionally animal matter; 2) both crab species prefer Avicennia alba Blume leaves to other, locally common, mangrove species, i.e., A. officinalis L, A. rumphiana Hallier f, Rhizophora apiculata Blume, Bruguiera gymnorhiza (L.) Sav.); 3) there is no significant preference for leaves of differing ages in the two species; and 4) no difference in daily fresh leaf consumption exists between the two crab species, with P. eumolpe consuming 22 ± 1.97 and P. indiarum consuming 14 ± 1.06 mg dry weight/wet mass g crab/day.

The Manicou or mountain crab, Eudaniela garmani (Pseudothelphusidae), is a freshwater land crab found at high elevations in the forests of Trinidad, Tobago, Margarita, and Eastern Venezuela. Anecdotal data suggest that the Manicou crab reaches sexual maturity at an unusually large size, and, by implication, at a relatively old age. Therefore, management and harvesting of this species need to be informed by accurate determination of the size and estimated age at maturity. Laboratory growth increment and intermoult period data were used to estimate the time for both sexes to mature. Breakpoint analyses and analyses of covariance (ANCOVA) of field-collected data were used to determine male and female morphometric or structural maturity while gross and histological examinations of ovaries were used to determine the size of onset of female sexual maturity. Morphometric maturity was initiated at about 42 and 47 mm carapace width (CW) in female and male crabs, respectively. Female morphometric or structural maturation ceased at about 67 mm CW, about the same size as the onset of female functional maturity (69 mm CW). It is estimated that female crabs attained functional maturity at about 3 years. A minimum capture size is thus recommended between 75 and 80 mm CW for female crabs. Patterns of allometric growth in the major propodus of males and the pleon width in females may be related to territorial and/or courtship behaviour in males and the use of the pleon as an incubation chamber in females.

In this paper, we report data related to the reproductive biology of a cosmopolitan mesobathyal lobster, Polycheles typhlops (Decapoda: Polychelidae), caught in the Sardinian waters between 400 and 1400 m of depth. Macroscopic and microscopic analyses were performed on 1104 females and 895 males. The observation on the gonads leads us to conclude that there are seven and four stages of development for the females and for males, respectively. Monthly variations of the percentage distribution related to various stages of development of the ovary and the presence of ovigerous females indicated that the species does not seem to follow a marked seasonal reproductive model, with a long main period for egg hatching that seems to occur between spring and autumn.

Brachyuran specimens collected from the Albian (Early Cretaceous) age Shell Creek Shale in Montana and Wyoming provide the basis for description of two new species, Zygastrocarcinus waagei and Componocancer roberti. The former represents only the fourth species of a genus that is endemic to the Cretaceous of mid-continental North America. The latter species is assigned to a new superfamily, Componocancroidea; new family, Componocancridae; and new genus, Componocancer, within Heterotremata. Componocancer exhibits a combination of primitive and derived features that is unique among Brachyura.

This study investigates the impact of waterborne xenobiotics on the rock crab Cancer irroratus. Male rock crabs were caged at two polluted sites for five weeks. One site was highly polluted while the other was slightly polluted mainly by metals. A control group was caged in a raceway tank supplied with clean sea water. The activity of branchial ATPases was increased in crabs exposed to pollution, presumably to compensate for the competition of metals with electrolytes and to facilitate the transport of metals out of the cytoplasm. The rock crab was characterized as having high basal levels of glutathione in the digestive gland (∼ 3500 nmol GSH equivalents/g dry weight). Exposure to waterborne pollutants failed to trigger an increase in glutathione concentration, but over time in crabs caged at the highly polluted site it elicited a 26% increment in the relative mass of the digestive gland which is an important site for glutathione synthesis. Neither cytochrome C oxidase, nor lactate dehydrogenase activity in the merus muscle was affected by pollution. By the end of the experiment, somatic growth rate was highest in the control crabs though the crabs caged at the polluted sites also maintained a positive energy balance. Gonadal growth was delayed at the highly polluted site but the size of the gonads caught up with that of the controls by the termination of the experiment.

Adult oveigerous female snow crab, Chionoecetes opilio, were obtained approximately bimonthly from the eastern Bering Sea for embryonic sampling and biometric information. Biochemical analysis of embryo samples included determination of moisture, ash, total lipid, protein content, fatty acid profile, and lipid profile. Moisture increased as the embryos matured. Protein content remained unchanged, ash content increased, and lipid content decreased on a dry weight basis coincident with embryonic development indicating that lipids were the main energy source of developing embryos. The utilization of saturated, monounsaturated, and polyunsaturated fatty acid categories during development was similar but individual fatty acids within each category varied considerably. Over 75% of the C14:0, C18:4(n-3), and C20:1(n-11) fatty acids were consumed during the embryonic development from nauplius to pre-hatch while C22:5(n-3), C20:5(n-3), and C18:1(n-9)cis fatty acids were utilized at 49%, 57%, and 48% respectively. Docosahexaenoic acid, DHA, C22:6(n-3), was among the least utilized fatty acid at 36%. Forward stepwise general discriminant analysis of fatty acid profiles indicated that determination of fatty acid profiles could be used to distinguish between embryos at the nauplius stage and the prehatching stage of development but not among embryos at intermediate stages. Triacylglycerides provided the energy source during development. This research highlights the potential nutrient requirements critical to early life-history development of Bering Sea snow crabs.

We examined potential fertility, egg volume, and water, lipid, and fatty acid content through embryogenesis in a population of female U. rapax from Sebastian Inlet, Florida. Carapace width (CW) ranged from 10.80 to 20.09 mm (N = 184), and each female carried 5000 to 30,000 eggs in the last stage of development. Female CW was found to be a good predictor of the number of eggs in the later stage of development (potential fertility = 7.908 CW^2.7655, R² = 0.749). Egg volume increases (from 0.0079 to 0.0134 mm³) was mildly correlated (r = 0.79) with an increase in egg water content (from 60 to 69%). Egg lipid and fatty acid content decreased through embryogenesis, due to its importance as energy source. The most consumed fatty acids were the monounsaturated (97.81 μg . mg dw⁻¹) followed by the saturated (64.34 μg · mg dw⁻¹) and polyunsaturated (38.69 μg · mg dw⁻¹). Fatty acids 16:0, 18:2n-6, 16:1n-7, and 18:2n-6 are consumed preferentially (39.91, 38.45, 29.4 and 23.93 μg · mg dw⁻¹, respectively), while essential polyunsaturated fatty acids, particularly docosahexaenoic acid (22:6n-3) and eicosapentaenoic acid (20:5n-3), are conserved. Egg fatty acid profile also reflects diet and habitat of adults. A medium-low EPA/DHA ratio suggests U. rapax occupies a medium trophic level. The low ratio (18:1n-7/18:1n-9) and high percentages of 18:1n-9 fatty acid (18%) and essential C₁₈ and C₂₀ polyunsaturated fatty acids (19-23%) suggests adults are omnivores consuming primary producers (like algae and mangrove leaves) and small invertebrates. The high percentage of odd-numbered fatty acids (above 3-3.5%) also suggests scavenger/detritivore behaviour.

The spermatophore morphology and spermatozoal ultrastructure of Diogenes pugilator are described. The spermatophore is typically tripartite made up of an ampulla, a very long stalk and a foot. The two halves making up the ampulla meet at a lateral ridge. The sperm is ovoidal in shape and composed of a large, almost cylindrical, acrosome, which occupies most of the cell volume, capped by a conical operculum, and cupped posteriorly by a cytoplasmic region comprising the nucleus and three arms. The sizes of the different parts of the spermatophore and of the sperm are given and their exterior morphology and ultrastructure described and compared to congeners. The available spermatozoal and spermatophore data is used to place D. pugilator within a sperm phylogeny of the hermit crab family Diogenidae.

Portions of Chile were surveyed for Anostraca. Including the two species of Artemia previously reported from Chile, we found 5 new localities and range extensions for 5 species of Branchinecta. Previous studies on Chilean Anostraca have focused on Artemia, and although Branchinecta was previously reported in Antarctica close to Chilean Air Force installations, and in a few temporal ponds in Southern Patagonia, the species were never determined. Brief habitat descriptions, as well as conservation status, and identification keys are presented and discussed. Additionally, we describe a new species from the Atacama Desert, Branchinecta papillata n. sp.

A new ridgewayiid copepod, Stygoridgewayia trispinosa n. g. and n. sp., is described from continental ground waters of the Cape Range Peninsula and Pilbara regions of Western Australia, as the first occurrence of this family in fresh waters. The new genus can be distinguished from other ridgewayiid genera by a combination of characters that include three digitiform processes and striated membrane on each caudal ramus, fused ancestral segments II-IV and V-VI on the antennary exopod, leg 1 with a subterminal flagellum on the outer spiniform setae of the terminal exopodal segment, legs 3 and 4 with two outer spiniform setae on the terminal exopodal segment, and female leg 5 with reduced armature on the exopod, terminal exopodal segment inserted along the distal margin of the middle exopodal segment, and endopod absent. We postulate that this new ridgewayiid is a particle feeder living in close contact with the sediment surface, and originated in shallow coastal waters and secondarily colonized the freshwater hypogean environment.

Kerguelenica is a genus that was originally described on the basis of female specimens collected off the coast of the Kerguelen Islands by M. Ledoyer in 1977. At the time, Kerguelenica was recognized as a problematic genus in that the family placement was unclear due to the lack of male specimens, and Ledoyer (1977) placed the genus in Pseudocumatidae with some unease. We describe a new species of Kerguelenica from specimens collected from the continental slope of Australia and Tasmania, from depths of 1000-1800 m. The adult male and ovigerous female are fully described and figured. The new species can be distinguished from the only other species in the genus, K. platycephala, by several characters. The new species has an ocular lobe, lacks a pair of dorsal protuberances on the carapace, in maxilliped 3 the ischium is present and the merus is very broad but the carpus is less broad than the merus, the basis of pereiopod 3 is slightly shorter than twice the length of the other articles together, and the telson is more than half the uropod peduncle length. In comparison, K. platycephala has no ocular lobe, bears a pair of dorsal protuberances on the carapace, maxilliped 3 is without an ischium and both the merus and carpus are broad, the basis of pereiopod 3 is 1.5× the other articles together, and the telson is half the length of the uropod peduncles. In other respects, the two species are quite similar in appearance. However, the description of the new species and especially the adult male do not resolve the issue of the family affinity of the genus.

A new species of cephalocarid, Sandersiella kikuchii, is described from central Japan, 300 m depth. It differs from congeners primarily based on the following points: 5-9 hooks on each ventrolateral side of cephalon; exopod proximal segment of thoracopod 6 with long finger-like lateral process (with narrow base) on the dorsal margin; exopodal distal segment of thoracopod 6 pointed distally, not divided into 2 lobes; exopodal proximal segment and pseudopipod of thoracopod 8 furnished with 2 and 2-3 setae respectively. Sandersiella acuminata Shiino, 1965 is redescribed and illustrated based on the holotype.

We describe homosexual pairing and spermatophore transfer from the calanoid copepod Pseudodiaptomus annandalei. The sexually dimorphic right first antenna of a male clasped another male's caudal setae followed by grasping of the urosome by the fifth swimming leg (P5). The P5 transfered the spermatophore. The observation of spermatophore transfer between males is discussed in the light of copepod reproductive biology.