It is difficult to take good detailed pictures of soft-bodied crustaceans (and other invertebrates); photographing animals in alcohol leads to problems with lighting and focus while drying out soft-bodied animals for photography distorts their morphology. To help better capture surface detail, the following procedures are proposed. Specimens should be fixed and stained with a general tissue stain in order to ensure an even coloration, followed by either chemical drying (using hexamethyldisilazane) or critical point drying. Specimens are then mounted to allow for whitening with either ammonium chloride (NH₄Cl) or magnesium oxide (MgO) to highlight areas of high topographic relief. Lastly, to increase the depth of field in the resulting image, photographs should be taken at sequential planes of focus and then spliced together using a software package for that purpose (i.e., Helicon Focus or Leica Applications Suite). This method is especially useful for showing surface detail and for making comparative images of modern crustaceans to compare with fossil specimens.

We evaluate the morphological variation of cirri of two intertidal barnacles in response to different wave-exposure regimes and population densities during growth. Length, diameter and number of segments of the third and sixth cirri were determined in Jehlius cirratus and Notochthamalus scabrosus, two dominant sympatric species in the rocky intertidal zone of Chile. Aggregated and isolated individuals of both species were collected in two coastal localities. Reciprocal transplant experiments were undertaken between wave-protected and wave-exposed zones, in addition to experimental modification of density during growth. For both species, individuals inhabiting wave-protected zones had cirri that were longer, thinner, with a greater number of segments, than in those inhabiting wave-exposed zones. The sixth cirri of J. cirratus were longer, thicker and had more segments in specimens growing at high densities, than in individuals growing in isolation. In N. scabrosus, no density dependent effects were observed in cirral structure. Thus, phenotypic responses differed between species, depending on the morphometric or meristic variable of the cirral pair evaluated. Forty-five days after J. cirratus density conditions and wave-exposure regime were modified in the transplant experiments, changes were observed in cirral length, diameter, and number of cirral segments. No modification was observed in the cirral characteristics over time in specimens whose density was artificially reduced during growth. Results indicate that morphological structures associated with filtration and respiration, vary according to density and degree of wave-exposure. We suggest that cirral phenotypic variability can serve as an adaptive mechanism associated with the changing availability and access to food and contributes to explaining the success of these organisms in environments with high spatial-temporal fluctuations in biotic and abiotic factors.

A major life-history challenge for fairy shrimps (Anostraca) is the unpredictable environment of the ephemeral pool. The duration and predictability of pool inundations affects their life history strategy. The growth and reproduction schedule of a thamnocephalid fairy shrimp, Branchinella (Branchinellites) kugenumaensis, in an unpredictable ephemeral pool in northern Taiwan was monitored from 2004 to 2008. A total of 15 inundation episodes, resulting from typhoons or, occasionally, frontal systems, was recorded over the five-year period. Thirteen episodes lasted no more than 2-3 weeks. Two exceptionally long inundation periods were caused by additional rain events before the pool dried out. We recorded the growth patterns, egg spawning time, and clutch size of each fairy shrimp cohort during each inundation episode. No significant differences were observed in either growth or reproductive pattern from hatching to first spawning between short and long inundation episodes. The fairy shrimps stopped increasing in size during the first clutch production. Upon subsequent rainfall before the pool dried, the shrimp stopped reproducing and resumed growth, demonstrating a discontinuously indeterminate growth pattern, before resuming egg production. Body length was positively correlated with clutch size, and this can be expressed as clutch size  =  0.0059 body length^3.165. The potential reproductive fitness of this indeterminate growth strategy demonstrates optimal resource allocation between growth and reproduction.

The acorn barnacle, Semibalanus balanoides is a sessile, simultaneous hermaphrodite with a large and extensible penis, making it an excellent model system for the study of reproduction in hermaphrodites. Several different factors affecting the likelihood of reproductive success were measured: neighbor distance, body-size, and penis length. We used regression methods to determine the extent to which these factors influenced the reproductive success and found that neighbor distance and body size were the most important factors in determining the probability of fertilization. Penis length was also an important component of mating success and was closely linked to body size. This data can be used to help infer the viability of expanding or contracting populations of acorn barnacles like S. balanoides.

A sacculinid rhizocephalan parasite was recently rediscovered in New Zealand after original recordings from collections in 1931. This new species of Heterosaccus occurred in 93.5% of 1118 Metacarcinus novaezelandiae (Decapoda: Cancridae) collected from Wellington Harbour between May 2006, and March 2007. Of the parasitized crabs, 22.1% had a rhizocephalan externa, 62.7% had a scar, and 15.2% had only the interna. Prevalence of Heterosaccus sp. was similar for male and female crabs and all were castrated. Many of the infected males displayed major morphological changes, which included a wider pleon and extra pairs of biramous pleopods compared to uninfected males (feminisation). Newly emergent externa and externa filled with eggs or embryos were found throughout the year, which indicates a year-round reproductive cycle. However, virgin externae were more common at the beginning of the southern hemisphere summer. A literature survey of Rhizocephala in the South Pacific revealed overall few described species (n  =  20), records of nine genera, and several reported but unidentified species in new hosts. The South Pacific clearly has a rich rhizocephalan fauna, but little is known about the ecology of these parasites in this part of the world.

A population of the ‘eyeless’ hypogean shrimp Spelaeomysis bottazzii was studied over a three-year period in a shallow brackish-water well about 1 km from the Mediterranean coast. Mature males and immature females were numerous year round, whereas breeding females and juveniles were rare. The main stages of young in the brood pouch were embryos, nauplioids, and postnauplioids; all were unpigmented, unlike the postnauplioids in a congeneric species. In this well, the free-living stages fed mainly on autotrophic micro-organisms. The accumulation of fat reserves was judged from the amount of subcuticular fat bodies and from body colour. Fat status improved with increasing body size in both sexes; seasonal variations were not significant. Only ‘fat’ specimens produced eggs. Females incubating eggs were fatter than those with larvae. Field and laboratory findings suggest that fat accumulation near the photic zone is necessary for egg formation, whereas larval incubation is very long and mostly occurs elsewhere, probably in deep groundwater under unfavourable nutritional conditions. The observed post-reproductive reduction of oöstegites may indicate a peculiar strategy to avoid a new breeding cycle before reconstitution of fat reserves. The findings on feeding and reproduction, particularly regarding fecundity and natality, are interpreted as a combination of typically hypogean features along with epigean environmental adaptations.

Paralithodes platypus is a large decapod that inhabits Alaskan and North Pacific waters. Females exhibit a biennial spawning cycle, requiring two years for production of fully mature oöcytes. We used respirometry and video recording to determine: 1) metabolic rates of brooding and post-brooding females, embryos, and larvae at different temperatures, 2) if females exhibit active brood care, 3) oxygen availability within the clutch, and 4) the timing of larval hatching. The rates of oxygen consumption (MO₂) of brooding females was significantly higher than that of post-brooding females at night, but was similar during the day and increased significantly with temperature. MO₂ of crab embryos did not differ with position in the clutch, whereas MO₂ of zoeae averaged 4-fold higher than that of embryos. Larvae from the periphery of the embryo mass, either top or bottom, hatched prior to larvae from the middle of the clutch. Oxygen availability in the embryo mass varied significantly with position in the clutch; saturation was highest at the top (~ 91%), and lowest at the middle (~ 66%). Flapping of the pleon in brooding females was coincident with sudden increases in oxygen availability at the bottom of the embryo mass. The percentage of time that brooding females were engaged in flapping of the pleon was 30% higher at night than during the day. Our results address the cost of brooding in a lithodid crab and the effects of temperature on this behavior. The importance of pleonal flapping to ventilation of the embryo mass and alternative hatching mechanisms is discussed.

The reproductive strategy of red spiny lobster Palinurus elephas from the north coast of Tunisia was investigated. We examined oögenesis of P. elephas by studying the histology of the ovaries. Seven growth substages of oöcytes were distinguished: 1) early primary oöcyte, St1; 2) late primary oöcyte, St2; 3) primary vitellogenic oöcyte, St3; 4) early secondary vitellogenic oöcyte, St4; 5) late secondary vitellogenic oöcyte, St5; 6) hyaline oöcyte, St6; and 7) atretic oöcyte, Atr. The kinetics of oögenesis of females is characterized by six successive ovarian development phases: Juvenile, sexual resting, beginning of vitellogenesis, vitellogenesis, spawning and post-spawning and recuperation. The oöcyte diameter frequency distributions were established for each mature female sampled and fitted by a Weibull function: . At the mature ovarian phases, two populations of oöcytes were distinguished; a fairly synchronous population of large vitellogenic oöcytes (St3 or St4 or St5), and a heterogeneous population of smaller oöcytes from which the next clutch will be recruited. In terms of ovarian organization, P. elephas can be considered as “group-synchronous.” The presence of only one clutch of yolked oöcytes able to be ovulated once during the breeding period suggests that the red spiny lobster spawns only once during every sexual cycle, i.e., P. elephas can be classified as species with a unique spawning period. By definition, such species are known as “synchronous ovulators” and also as “total spawners.”

Niphargus cf. groehni is described from a piece of Eocene Baltic amber. This is the third case when a fossil niphargid amphipod has been discovered. Morphological peculiarities of this specimen and its affinities with other niphargids are discussed.

The definition of the genus Dromilites has become extended over the past nearly 200 years to include most any dromioid crab from Eocene rocks. We examined type material of Dromilites spp. and restrict the genus to four species. The remaining species are removed to other genera or families incertae sedes. The remarkable preservation of the type species and a second species make it possible to assign with confidence Dromilites sensu stricto to Sphaerodromiidae. The unique features of this family, which Guinot and Tavares (2003) had erected as a subfamily within Dromiidae, support its elevation to family status. A new genus referred to Sphaerodromiidae embraces a Campanian (Late Cretaceous) species from South Dakota, Ferricorda kimberleyae (Bishop, 1987). Sphaerodromiidae now extends into the Late Cretaceous. The fossil record of Dromiidae sensu lato and sensu stricto is currently under investigation.

The effects of salinity fluctuation on the growth, molting and energy budget of juvenile Litopenaeus vannamei was investigated at the temperatures of 20, 25, and 30°C. Salinity fluctuation regimes were set in different amplitudes of ± 0, ± 5, ± 10 and ± 15 gL⁻¹ from a control salinity of 20 gL⁻¹. After a 48-day feeding trial, the lowest survival occurred at a salinity fluctuation of ± 15 gL⁻¹ for each temperature investigated. The best growth of shrimp was obtained at salinity amplitudes of ± 5-10 gL⁻¹ at 25 and 30°C. The salinity fluctuation influenced food conversion efficiency but not food intake. The shrimp maintained at salinity amplitudes of ± 5-10 gL⁻¹ expended most of the energy for growth and spent less energy on respiration and excretion at 25 and 30°C. Therefore, salinity fluctuating amplitudes of ± 5-10 gL⁻¹ result in higher growth rates than constant salinity conditions (20 gL⁻¹) through enhanced feed assimilation and reduced energy loss in respiration and excretion.

Accessory sex gland (ASG) in Eriocheir sinensis is the important component of the male reproductive system; its function is still unknown. Here we report that ASG protein can digest the spermatophore wall effectively. By optimizing the incubation temperatures, durations, and secreted protein concentrations using the L₃₀ (5²) orthogonal method, we find the protein concentration was the important factor affecting spermatophore wall digestion. In order to find out the digestion effect and spermatozoa quality, we observed the acrosin activity and survival rate of free spermatozoa obtained by different methods. We found that the survival rate of ASG protein digestion is the highest (98.06%), and its acrosin activity of free spermatozoa was significantly higher (4.290 ± 0.095 µIU/10⁶) than those obtained by traditional trypsinase digestion (2.446 ± 0.251 µIU/10⁶) or mechanical homogenate (1.423 ± 0.109 µIU/10⁶) methods, but it was still significantly lower than those obtained from the spermatheca of mated females (21.729 ± 0.138 µIU/10⁶). Thus, there must be some cooperation between the ASG and other related fertilization organs to improve the acrosin activity of free spermatozoa in vivo. Hence, we colleted the spermatozoa isolated from spermatophores using the trypsinase method and incubated with homogenates from seminal vesicle, accessory sex gland, and spermatheca alone or in combination. We observed that acrosin activity was greatest in samples incubated with an equal mixture of spermatheca and accessory sex gland protein homogenates. We conclude that the accessory sex gland can effectively digest the spermatophore wall to release free spermatozoa and interact with proteins from spermatheca to increase acrosomal enzyme activity of free spermatozoa.

Scylla paramamosain is a commercially important crab species in China. Here we reported 12 novel polymorphic microsatellite markers isolated in S. paramamosain using PCR-based isolation of microsatellite arrays (PIMA). The analysis of genetic variability was performed in a sample of 29 individuals. A total of 82 alleles were detected with an average of 6.8 alleles per locus. The number of alleles, polymorphism information content (PIC), observed and expected heterozygosity per locus ranged from three to 12, from 0.42 to 0.88, from 0.38 to 1.00 and from 0.48 to 0.91, respectively. Three loci significantly deviated from Hardy-Weinberg equilibrium after Bonferroni correction (P < 0.0042) and no significant linkage disequilibrum between pairs of loci was found. Cross-species amplification of these markers was evaluated in three closely related crab species S. tranquebarica, S. olivacea, and S. serrata. This study will potentially be useful for stock management, constructing of a genetic linkage map, mapping economically important quantitative trait loci (QTL), and evaluating the population genetic diversity of S. paramamosain.

Branchinecta brushi is a new species of fairy shrimp described from a pool within the volcanic crater of Cerro Paniri, northern Chile. Its occurrence represents a new altitude record for anostracans (5930 m), and it shares the title for highest altitude occurrence across all of Crustacea with a cladoceran from the same pool, Boeckella palustris. Branchinecta brushi is similar to another Chilean anostracan, B. valchetana. However, B. brushi differs from B. valchetana in the detailed morphology of the male second antennae and gonopods. Male specimens of B. brushi possesses a bulbous, distally spinose medial apophysis on the proximal article of its second antenna as well as short, stout, inwardly curved gonopods. Both sexes are distinguished by very short cercopods. Bringing phylogenetic order to the monogeneric family Branchinectidae will require increased levels of morphological documentation and a better understanding of intra-specific variation. Most crustaceans are not well suited to life at high altitudes; those that thrive at high elevations offer insights not only to their biological tolerances, but also to their various modes of dispersal.

Most copepods exhibit one of three kinds of body architecture: 1) six broad anterior trunk somites and five narrow posterior trunk somites of gymnopleans; 2) five broad anterior trunk somites and six narrow posterior trunk somites of many podopleans; or 3) four broad anterior trunk somites and seven narrow posterior trunk somites of thaumatopsylloids. A phylogenetic analysis using naupliar and post-naupliar characters, with Mystacocarida as the sister taxon of Copepoda, supports the hypothesis that the thaumatopsylloid architecture is the oldest. No narrow somite is transformed into a broad somite during post-naupliar development of thaumatopsylloids. Podopleans and gymnopleans begin their post-naupliar development with one trunk somite fewer than thaumatopsylloids. Podoplean architecture results when the anterior narrow somite of thaumatopsylloids is transformed to the posterior broad somite of podopleans during the first post-naupliar molt. Gymnoplean architecture, the youngest, results when the anterior narrow somite found on podopleans is transformed to the posterior broad somite during the second post-naupliar molt. These developmental transformations of body somites are assumed to explain the evolutionary origins of podoplean and gymnoplean body architectures.

Asiacaris n. gen. is described to accommodate Asiacaris dispar n. sp., collected in the interstitial of the banks of a river on Pha-ngan Island, in the Gulf of Thailand. Asiacaris belongs to Parastenocarididae Chappuis, 1940, based on the following characters: leg 3 sexually dimorphic, modified in the male into a grasping organ; presence of sexual dimorphism on the endopod of leg 4; presence of a dorsal integumental window on cephalothorax and dorso-elliptical integumental windows on tergites of urosomites 2 to 5 in male and on genital double-somite and urosomites 4 and 5 in female; antennule 8-segmented, with an inner process on the 7th segment, first leg with 2-segmented endopod and unarmed exopod-2, and mouthparts armature and segmentation. The apomorphic characters of Asiacaris are represented by the sexual dimorphism of P2 (stronger in male than in female), the fusion of the P5 to the intercoxal sclerite and to the somite and, mostly, by the overall transformation of P4 in the male, which is the longest and strongest leg, a feature never recorded before in any male of freshwater or marine free-living harpacticoids: the endopod is missing, the exopodal segments are all enlarged, and the apical seta is transformed into a hook longer than the last segment of the exopod. The P4 project laterally, creating not only a characteristic habitus, but also possibly a locomotion pattern different from that of all other Parastenocarididae. This modified P4 could be used to grasp the female during coupling, because it forms a second set of pincers, longer and stronger than the one created by the P3.

Two new species of freshwater anomurans, Aegla pomerana and Aegla muelleri (Decapoda: Anomura: Aeglidae), are described from the Itajaí River basin, the major basin of the Atlantic range, located in the northeastern part of the state of Santa Catarina, Brazil. The new taxa can be distinguished from their congeners based on both morphological and molecular evidence (the nuclear gene 28S, and the mitochondrial genes 12S, 16S, COI, and COII). Based on molecular data, A. pomerana has a phylogenetic relationship with A. leptodactyla, but morphologically these two species differ in several characters. Aegla muelleri is a member of the same clade as A. leptochela, but several morphological characters distinguish the two species. New records of occurrence of A. jarai and A. odebrechtii, which occur in the same hydrographic basin, are provided.

Ruffia patagonica, a new genus and species of phreatogammarid amphipod, is described from a coastal cave on Madre de Dios Island (Chilean Patagonia). This is the first record of the family outside continental waters of New Zealand and New Caledonia. The new taxon displays some of the more distinctive features of the family, such as gnathopods with the palm margin lined with numerous unicuspid robust setae and with a denticulated inner margin of the dactylus; fifth pereiopod clearly smaller than pereiopod six and seven; “coxal gill” ( =  exopod) absent from the seventh pereiopod; oöstegites broadened; urosomites with posterodorsal robust setae; and third uropod equiramous with an elongated peduncle and with unsegmented cylindrical rami, the latter provided with numerous robust setae. In addition, the sternites of all pereionites, pleonites, and urosomites show a portion of integument delimited by hyaline frill that is presumably osmoregulatory in function, and is equivalent to the pair of sternal gills displayed by other phreatogammarids on several body somites. The new genus is unique among phreatogammarids in displaying sexual dimorphism in the third epimeral plate, in the protopod of the third pleopod, in the armature of the first uropod, and in the endopod of the second uropod. Even though Phreatogammaridae have been suggested to be related to the broadly distributed marine family, Melphidippidae, their restriction to continental waters of former Notogean territories points to vicariance by plate tectonics of a non-marine ancestor rather than to dispersal as the main mechanism leading to their current distribution pattern.

The systematic status of Galatheacaris abyssalis is assessed on the basis of recently collected material. Mitochondrial DNA analysis reveals that the 16S rRNA sequence from one specimen is identical with that of Eugonatonotus chacei, while the COI sequences of the two taxa diverge only by 0.6% (3 bp), indicating that the two taxa are conspecific. Based on the morphological development of specimens attributed to G. abyssalis, we conclude that this taxon represents the megalopal stage of E. chacei. Therefore, the family Galatheacarididae and the superfamily Galatheacaridoidea should be abandoned.

The karyotype of the Australian crayfish Cherax destructor was studied by examining metaphase chromosome spreads from the testis tissues (TE) and the mitotic cells in division from the regeneration callus of the new forming limb (FL). The sampled tissues showed the same results. A total of 111 mitotic metaphases, 67 TE 44 FL, were examined and the diploid chromosome number ranged from 179 to 207 per metaphase with a mode at 188, the latter being considered the diploid chromosome number (2n  =  188) of the species. The karyotype consisted of 70 metacentric, 42 submetacentric, 48 subtelocentric and 28 telocentric chromosome pairs. The sex chromosomes were cytologically indistinguishable.