This review examines some of the characteristics and highlights some notable articles of the Journal of Crustacean Biology (JCB) in its first 30 years of existence. A total of 2052 articles appeared in JCB from the first issue in February 1981 to the end of 2009. The number of articles by volume increased from 50 in 1981 to 93 in 2002 and then declined to around 70. From 1981 to 2009, article size varied around a mean of 11 pages (pre-2005 format) but mean number of authors and references by article increased by a factor of 1.87 and 2.20, respectively. JCB content is predominated numerically by taxonomy and systematics (36% of all articles), but other research areas (anatomy, physiology, development, growth-reproduction, life history, behavior, ecology, conservation) were also represented from the outset. JCB's 2-year impact factor increased significantly from 1991 to 2009. Longer-term impact of JCB is evident in the fact that almost half of all JCB articles were cited in 2009 and that the mean age of those cited articles was only slightly less than the mean age of all JCB articles (12.6 vs 13.3 years). However, citations to JCB differ widely across research areas, with articles in taxonomy cited on average at less than half the rate of articles in the areas of ecology or conservation. The most cited JCB articles by combination of research area and decade of publication deal primarily with higher crustaceans (malacostracans) and are reviews or original research articles with cross-disciplinary appeal.

Papers within the broad designation of systematics have figured prominently in the pages of the Journal of Crustacean Biology in its first 30 years. The journal has had great continuity in its editorial policies and practices, having had only three General Editors in 30 years. Not only has the journal published taxonomic material, but also made available material in a variety of subjects that impinge on understanding the evolution and phylogeny of crustaceans, including cladistic phylogeny, biogeography, comparative anatomy, and issues of natural history. An overview of some highlights from the first 30 volumes of the journal is presented; some prognostications for the future are offered.

Crustaceans groom their olfactory organ, the antennules, by wiping them through a pair of mouthpart appendages. Antennular grooming behavior (AGB) can be stimulated in four different species of lobsters by at least one chemical (l-Glutamate (Glu)) found in food. However the one crab species tested thus far was unresponsive. In an effort to determine whether chemically-mediated AGB in the Reptantia is present only in the Macrura (lobster taxa) and lacking in the Meiura (crab taxa), we tested for AGB to chemical stimuli in seven reptantian species in the taxa Palinura (Palinurus elephas, Scyllarides aequinoctialis, S. nodifer), Astacidea (Enoplometopus debelius, Procambarus clarkii), Brachyura (Hemigrapsus sanguineus), and Anomura (Clibanarius tricolor), and one non-reptantian decapod in the taxon Caridea (Palaemonetes pugio). Because asymmetric setae on the lateral flagella of the antennules are the sole source of chemosensory input driving AGB, we also examined antennules for asymmetric setae using SEM. Significant AGB responses to chemical stimuli relative to control seawater was observed in all the macrurans tested with the exception of P. clarkii. E. debelius responded to glycine (Gly) and alanine (Ala), Scyllarides spp. to Gly, Ala, and aspartate, and P. elephas to Gly, Ala and methionine. In the meiurans, a weak but significant response to one chemical stimulus was observed in H. sanguineus, while no responses to chemical stimuli were observed in C. tricolor. Asymmetric setae were observed in all but one of the reptantian species (P. clarkii) but were aligned laterally along the tuft region of the macrurans and medially in the meiurans. The nonreptantian P. pugio did not show any AGB responses to chemical stimuli and lacked asymmetric setae. We propose that laterally-positioned asymmetric setae and chemically-mediated AGB are characters derived in the Macrura.

The genus Hippolyte is represented by typically small shrimps with intriguing mechanisms of reproduction. In order to study possible variability in reproductive aspects among different populations, we conducted an exhaustive comparative study of H. obliquimanus from South (Brazil) and Central American (Costa Rica) waters. The study focuses on fecundity and reproductive output. Mean size of ovigerous females was significantly larger, and both mean reproductive output and mean fecundity were significantly higher in specimens from Costa Rica then in those collected in Brazil. Embryo volume was significantly smaller in the Costa Rican population, and in both populations embryos doubled their volume during embryogenesis. We discuss and compare our findings with the information available regarding H. obliquimanus and other hippolytid shrimp. The reproductive traits of both populations of H. obliquimanus show some important differences which may reflect adaptations to local environmental conditions, demonstrating a high plasticity of reproductive features of the species in Brazilian and Costa Rican waters.

In crustaceans, the presence of large males with highly developed prehensile appendages (chelipeds or gnathopods) generally is suggestive of female monopolization during her receptive period. While mate guarding is common among some malacostracan crustaceans (brachyuran crabs and some amphipod families) it is relatively rare in caridean shrimp. Here we explored sexual dimorphism and the presence of morphotypic differences among males of the dancing shrimp Rhynchocinetes brucei. We furthermore quantified the behavioral events during mating interactions to examine whether mate guarding extends over the entire period of female receptivity. Males and females had similar body sizes, but males developed increasingly larger third maxillipeds and first chelipeds during ontogeny. Large males with hyperdeveloped maxillipeds and very large chelipeds featured a high degree of broken appendages and eyes, which probably results from intrasexual agonistic interactions. About 30% of the non-competitive male-female interactions with post-ovigerous females resulted in successful matings. Males usually initiated body contact with the female shortly after the female's parturial molt, and they frequently touched the female's genital region with their anterior body parts. The first (and in most cases only) spermatophore transfer event occurred at variable times (0.2-7 h) after the female's molt. Following spermatophore transfer some males guarded the female in the cage state (between their pereiopods) until the female had finished spawning and was ovigerous. Post-copulatory mate guarding could last up to 70 min, but not all males guarded the female after the copulation. We suggest that male guarding of the receptive female throughout the mating process reduces the risk of sperm competition.

Females of Aegla strinatii (n  =  466) were sampled monthly (September 2003 to September 2005) by means of sieves and traps from Rio das Ostras (24°38′16.2″S; 48°24′05.2″W), at Jacupiranga State Park, South of São Paulo State, Brazil. The reproductive period was markedly seasonal (from May to September) encompassing the Austral late autumn through late winter. This is in accordance to the pattern of reproductive period variations in relation to the latitudinal climate variability verified in species of Aegla. The proportion of adult females exhibiting the ovigerous condition was higher in young/small specimens as compared to old/large ones, and suggests the occurrence of senescence in the latter group. Average size at the onset of functional maturity in females was estimated as 16.66 mm of carapace length (rostrum excluded). The number of eggs per ovigerous females ranged from 1 to 325. Eggs are slightly elliptical and average size varied according to embryonic stage. Mean (± standard deviation) carapace length of juveniles (n  =  118) was 1.50 ± 0.05mm (range: 1.40-1.65mm).

The portunid crab Callinectes danae is abundant in Brazilian estuaries and coastal areas and is an important item to artisanal fisheries. This study investigated the distribution and population structure by sex and size, the size at sexual maturity, and sex-ratio of the species in Vitória Bay, Espírito Santo, southeastern Brazil. Crabs were collected monthly by nocturnal trawling during one year in six sampling stations distributed along an estuarine gradient and an independent depth gradient. Physico-chemical parameters of water were measured in situ on each station. A total of 3876 individuals were collected: 2537 females (1147 adults, 318 ovigerous, and 1072 juveniles), and 1339 males (444 adults and 895 juveniles). The mean carapace width (including lateral spines) at sexual maturity was 91.3 mm for males and 80.5 mm for females; the female-to-male sex ratio was 1.89∶1. Adult females occurred throughout the bay and year-round, but egg-bearing females were almost exclusively caught in deep and high salinity areas. Adult males and juveniles of both sexes occurred mainly in internal areas of the estuary, nearest river mouths; highest captures were registered in November. Both the scarcity of males, probably resulting from size-selective catch, and the low proportion of ovigerous females, compared with that observed in other Brazilian estuaries, suggest that the population has been overexploited.

We compared seasonal changes in population structures and surface activities in the fiddler crab Uca arcuata between temperate (Yoshinogawa, Japan) and subtropical localities (Shinko, Japan). At Yoshinogawa, male courtship behavior was observed from April to July and pair formation from May to July, whereas at Shinko such mating behavior patterns were observed over two periods (June to September and February to March). Thus, the subtropical population appears to have a longer breeding period than the temperate population. Waving occurred from June to August at Yoshinogawa and during all months (except October and November) at Shinko. Waving frequency was higher during courting periods at all localities, although lower at Shinko compared with Yoshinogawa. Maximum body size and the size at maturity were smaller at Shinko than at Yoshinogawa. Surface and underground couplings were observed at Yoshinogawa, whereas only surface coupling was observed at Shinko. These differences and similarities are discussed from the viewpoint of habitat conditions and population characteristics.

Macrobrachium asperulum is a native freshwater prawn species in Taiwan, and is an ideal model for studying the reproductive biology of freshwater decapods. Also, this species may be a potential aquaculture species. This study was conducted to explore the ovarian development of female M. asperulum, as an important foundation for the knowledge of its reproductive biology. Specimens were collected in four seasons throughout the year to investigate the ovarian cycle and germ cell development, by examining the external morphology and histological structure of the ovaries. The breeding period of M. asperulum is probably from March to September each year. Developing ovaries and germ cells were characterized throughout the entire ovarian cycle. Differentiating germ cells were classified mainly into oögonia, primary oöcytes, secondary oöcytes, and mature oöcytes. Among the four major germ cells, secondary oöcytes were further divided into five types. Summarizing the above examinations and based on the relative frequency of germ cell types, six stages of ovarian cycle were identified, and this prawn is proposed as being a multiple spawning species. Observations of the present study provide important information on the reproductive biology of crustaceans and decapods in general, and also can serve as a significant foundation for the aquaculture of freshwater prawn species.

Larger females generally produce larger offspring with superior qualities because larger body size can reduce susceptibility to predation and starvation. The removal of larger and older individuals from populations can decrease the survival qualities of offspring through maternal influences, and affect subsequent recruitment. Although negative impacts of larger individual-selective fishing need to be taken into consideration in resource management, there have been very few studies on maternal influences in decapod crustaceans despite the fact that this group includes large numbers of important biological resources. Thus, this study examined the effects of female body size on larval body size, weight, and survival period in the coconut crab, Birgus latro, in laboratory experiments. Ovigerous crabs having well-developed eggs were collected in filed and then first stage zoeae were collected from each female in laboratory. Both larval size and dry larval weight increased significantly with increasing female size. Larvae hatched from larger females showed significantly longer survival periods under non-fed conditions. These results suggest larger coconut crab females produce larvae with superior survival qualities. Present harvesting for coconut crab resources selectively removes larger males despite the fact that coconut crab females only mate with males larger than, or approximately equal to, themselves. Therefore, large females have fewer opportunities to mate under the present harvesting system. Larger male-selective harvesting could have greater negative impacts on the reproductive rate of coconut crabs than expected because larval quality is reduced.

Discovery of a single specimen of a shrimp fossil from the Devonian Woodford Shale in the Ryan Quarry, near Ada, Oklahoma, documents the oldest occurrence of a penaeoid decapod crustacean, Aciculopoda mapesi n. gen., n. sp. within the Aciculopodidae n. fam. The specimen lacks any diagnostic features of the primitive Paleozoic eumalacostracans, including caudal furca, but possesses the characteristic form and preservational style of the Superorder Eucarida, particularly the Superfamily Penaeoidea. The shrimp specimen is remarkably preserved; it has been phosphatized, and the muscles of the pleon have been preserved completely enough that discrete muscle bands are discernable. The cuticle of the cephalothorax is shattered into small fragments, whereas that of the pleon is absent except for the telson. Confirmation that this specimen represents a Devonian decapod documents only the second decapod taxon known from the Devonian and the third from the Paleozoic. It is the earliest known shrimp and one of the two oldest decapods, both from North America.

The content of carotenoids and retinoids was compared in the eyes of two Finnish populations of the opossum shrimp, Mysis relicta, which have been reproductively isolated for at least 9000 years: one from the deep, dark, Lake Pääjärvi, the other from the Baltic Sea (Pojoviken Bay). The eyes of the lake population (LP) are highly susceptible to light damage, while those of the sea population (SP) are more resistant. Carotenoids are known to act as antioxidants protecting cells against free radicals and reactive oxygen species; retinoids, on the contrary, may be phototoxic in certain conditions. Analyzed by spectrophotometry and HPLC, the carotenoid content was broadly similar in the eyes of the two populations as regards both total amount and relative proportions of more than 20 components. Noteworthy differences were found in only three of the major components, among these astaxanthin, which was two times higher in SP compared with LP. The most interesting finding was the 1.6-fold higher content of retinoids in LP compared with SP, with retinol as the dominant component (40% of total) in both populations. Retinol is a precursor of the visual-pigment chromophore retinal. The result is consistent with the idea that animals inhabiting extremely dim light environments, where very little photoregeneration of metarhodopsin to rhodopsin can occur, need a large store of chromophore (or precursors) for effective “dark” regeneration of visual pigment. We suggest that almost all the rhodopsin is then in the native state and massive pigment activation following exposure to stronger light may trigger photoreceptor damage. If such animals are handled without due light protection, e.g., when transferred to a new habitat or collected for biological experiments, their vision will be severely impaired.

Although amino acid flux models have been developed in fish and other crustaceans, this is the first study to present an amino acid flux model for crabs. This study investigates the influence of different feeds and the deprivation of food on the free amino acid (FAA) pool, the rate of protein turnover and their relation to the growth and flux of amino acids in the shore crab Carcinus maenas. A model was developed for amino acid flux describing food consumption rates, assimilation rates, protein synthesis rates, growth and protein degradation, and losses. Crabs were fed frozen mussel (Mytilus edulis) tissue (Diet 1) or (fresh) white muscle from salmon (Salmo salar) (Diet 2) at 7% of their body weight per day while other crabs were starved for ten days. In the starved crabs, the amino acids partitioned into protein synthesis made up 36% of the free amino acid pool. There was a 50% reduction in the rate of protein synthesis in the starved crabs compared with the fed crabs. It was estimated that daily dietary amino acid intake might compose up to seven times the crabs' FAA pool. In addition, daily protein synthesis and degradation might respectively remove and return the equivalent of up to 4 times and twice the size of the FAA pool in the fed crabs, respectively. Specimens of C. maenas deposited in body proteins (as net growth) 14% in diet 1 and 40% in diet 2 of their amino acid consumption. The amino acid flux in the fed crabs suggested low protein conversion efficiency compared to other decapod crustaceans, including shrimps and lobsters.

Sites adjacent to (near-field) and distant from (far-field) oil-drilling platforms were sampled for harpacticoid copepods at two locations in the northern Gulf of Mexico off the coast of Louisiana, both at depths of ≈ 1100 m. The sites were located at Garden Banks Area Block 602 (GB 602) and Mississippi Canyon Area Block 292 (MC 292). Near-field sites at both locations were characterized by large numbers of a single undescribed species of harpacticoid copepod, Bathycletopsyllus sp., but this species was essentially absent from far-field sites. We sequenced a 710 bp portion of the mitochondrial cytochrome c oxidase subunit I gene (COX I) to analyze the genetic diversity and population structure of Bathycletopsyllus sp. at the two platforms, and to determine if the harpacticoids examined were either a single species, or a complex of cryptic species. We found that divergence at the COX I gene (maximum 1.6%) was within the range observed for intraspecific variability in previously-studied species of harpacticoid copepods that were well-characterized taxonomically. Thus, the two samples analyzed here were a single species and not a complex of cryptic species. In addition, there was significant genetic heterogeneity between the two samples, suggesting limited gene flow between the two sites. This was expected given the low dispersal potential typical of harpacticoids and the distance between the sites (407 km). Lastly, haplotype diversity and nucleotide diversity were both low in the GB 602 sample, giving a nominally-significant departure from a pure neutral model. This result could indicate the occurrence of selective sweeps, temporal population size variation or other processes not included in the neutral model. In contrast, haplotype diversity and nucleotide diversity were both higher in the MC 292 sample than at Garden Banks, and there was no detectable departure from neutrality. For both samples, diversity at the haplotype and nucleotide levels were within the range seen in shallow-water harpacticoid species inhabiting both uncontaminated and contaminated muddy sediments, so there was no evidence for pollution related effects in the present study.

Most fisheries involving spiny lobsters of the genus Palinurus have been overexploited during the last decades, so there is a raising concern about management decisions for these valuable resources. A total of 13 microsatellite DNA loci recently developed in Palinurus elephas were assayed in order to assess genetic diversity levels in every known species of the genus. Microsatellite markers gave amplifications and showed polymorphism in all species, with gene diversity values varying from 0.650 ± 0.077 SD (Palinurus barbarae) to 0.792 ± 0.051 SD (Palinurus elephas). Most importantly, when depth distribution was taken into account, shallower water species consistently showed larger historical effective population sizes than their deeper-water counterparts. This could explain why deeper-water species are more sensitive to overfishing, and would indicate that overexploitation may have a larger impact on their long-term genetic diversity.

During the development of PCR primer sets for microsatellite marker loci from enriched genomic libraries for three squat lobster species from Galatheidae (Decapoda: Anomura); Munida rugosa (Fabricius, 1775), M. sarsi (Huus, 1935), and Galathea strigosa (Linnaeus, 1761) (collectively known as squat lobsters), a number of unforeseen problems were encountered. These included PCR amplification failure, lack of amplification consistency, and the amplification of multiple fragments. Careful examination of microsatellite containing sequences revealed the existence of cryptic repeated elements on presumed unique flanking regions. BLAST analysis of these and other VNTR containing sequences (N  =  252) indicates that these cryptic elements can be grouped into families based upon sequence similarities. The unique features characterising these families suggest that different molecular mechanisms are involved. Of particular relevance is the association of microsatellites with mobile elements. This is the first reported observation of this phenomenon in crustaceans, and it also helps to explain why microsatellite primer development in galatheids has been relatively unsuccessful to date. We suggest a number of steps that can be used to identify similar problems in microsatellite marker development for other species, and also alternative approaches for both marker development and for the study of molecular evolution of species characterised by complex genome organisation. More specifically, we argue that new generation sequencing methodologies, which capitalise on parallel and multiplexed sequencing may pave the way forward for future crustacean research.

Three species of Triconia belonging to the conifera-subgroup are described from Korean waters (NW Pacific). A new species, Triconia hirsuta, was found that can be distinguished from its sibling T. conifera by a paired patch of long setules on the anterolateral margin of the genital double-somite in the female, and an unusual position of caudal seta II branching off at almost a right angle to the caudal ramus. Males have not been found so far. Both sexes of T. conifera (Giesbrecht, 1891) and T. borealis (Sars, 1918) from Korean waters are redescribed with the addition of morphological details and/or differences not noted in earlier descriptions. Morphological characters of Korean T. conifera are in close agreement with specimens described from the Mediterranean Sea and the Pacific, but differ in several parameters from T. conifera from the Red Sea, which is regarded as a distinct, though closely related, species requiring re-examination. Published data on the community structure and zoogeographical distribution of oncaeids of the conifera-type in the NW Pacific are summarized, and the remaining uncertainties concerning the distribution of species of the conifera-subgroup in these areas are pointed out.

Molecular phylogenetic analyses were conducted on species of some common tanaidacean families within the suborders Apseudomorpha and Tanaidomorpha based on partial DNA sequences for three genes: one mitochondrial (COI) and two nuclear (H3 and 28S). One nuclear gene (28S) resolved the two suborders as monophyletic groups while H3 and COI could only resolve Tanaidomorpha as monophyletic. The total evidence analysis (in-group taxa having at least two out of the three sequences) resolved both suborders as monophyletic, but only Tanaidomorpha showed strong support. All analyses support the monophyly of Kalliapseudidae (two out of three subfamilies represented) with the family clearly separated from the other apseudomorph families represented here. Relationships between and within the other apseudomorph families could not be resolved with strong support. Within Tanaidomorpha, most analyses supported a sister group relationship between the Tanaoidea (Tanaidae) and the Paratanaoidea. Results suggested that the monotypic Hargeria should be considered a junior synonym of Leptochelia, corroborating morphological evidence. Lack of resolution is likely due to inadequate taxon sampling, and differences in topology are largely due to weak support for relationships. This is the first attempt at using molecular data to determine phylogenetic relationships of tanaidaceans.

A neotype of Elasmopus rapax Costa, 1853 is designated based on material from the Fusaro Coastal Lagoon, Central Tyrrhenian Sea, Italy. The species is confirmed as an invasive species in Australian ports. Populations of E. rapax are identified from seven port, harbour, and marina locations around the south-eastern, southern, and south-western coasts. Museum collections indicate that this species has been present in Australia since at least 1884. It is not currently known from tropical Australia.

Elaphognathia cornigera is a sponge-dwelling species of isopod that occurs in the intertidal zone in the main island of Japan. Currently, another population of Elaphognathia has been found from Okinawa-jima Island (classified as Elaphognathia sp.). Although it is quite similar in morphology to E. cornigera, the habitat and seasonal traits are quite different between Okinawa-jima Is. and Izu Peninsula. In this paper, we examined Elaphognathia sp. and E. cornigera from several sampling sites using morphological analysis and ribosomal DNA ITS2 sequences. Morphological analysis revealed adult males of Elaphognathia sp. were distinguished from E. cornigera by the number of pylopod seta: E. nunomurai, 5.5 ± 1.1 (Haneji, N  =  18) and 4.1 ± 1.4 (Odo, N  =  18); E. cornigera, 11.6 ± 2.0 (Amakusa, N  =  18) and 13.7 ± 1.4 (Miura, N  =  18). Elaphognathia sp. were also distinguished from E. cornigera by means of rDNA ITS2 sequences, with differences between the E. cornigera group and Elaphognathia sp. being 5.3 and 5.9%, whereas the sequence differences between E. cornigera from Miura, Shimoda, and Amakusa were relatively low (0.5-1.4%). Thus, we describe a new species, Elaphognathia nunomurai.

The present study investigated the species composition of freshwater shrimp fauna in Kikai-jima Island within the Ryukyu Islands in southern Japan. Six stream-pool sites, with Karimata-no-izumi in the north, followed by Shiomichi, Nagamine, Ooasato, Takigawa, and Urabaru, were sampled from June 2005 to June 2008. We identified eleven species belonging to two families: four Palaemonidae, and seven Atyidae. The most dominant species were Caridina typus as well as C. sakishimensis, which is a redlist (RDB) species sporadically distributed in the Ryukyu Islands. Together with C. typus and C. sakishimensis, M. lar and M. japonicum also dominated most of the study sites in Kikai-jima, and Morista's similarity index showed high similarities between five of the stations, except for Takigawa in the south. The highest densities of shrimp were recorded in Karimata-no-izumi followed by Ooasato, Nagamine, Urabaru at the southernmost, Shiomichi, and Takigawa. Comparing species composition in Kikai-jima and other islands of the Ryukyu group, cluster analyses showed greatest faunal similarity to Kume-jima in the lower central Ryukyus, with the Redlist C. sakishimensis recorded in both islands. This close similarity in shrimp composition between the two distant islands may be attributed to their geological origin and sizes of the islands, both measuring about 60 km² in area.

The hippolytid shrimp genus Lebbeus White, 1847 was previously unknown from Taiwan. However, recent deep-sea surveys off the island have collected numerous specimens comprising four species, three of which are new to science: L. tosaensis Hanamura and Abe, 2003, L. brevirostris n. sp., L. formosus n. sp., and L. unguiculatus n. sp. Lebbeus brevirostris belongs to the group bearing epipods only on the first two pereiopods and is unique in having a short spiniform rostrum. Lebbeus formosus and L. unguiculatus bear epipods on the first three pereiopods. The latter is characteristic in having the dactyli of the posterior pereiopods terminating in a single elongate unguis. Lebbeus formosus is distinct in having a combination of rostral, antennular, telson, and pereiopodal characters.

Two new species of Gourretia from South China Sea are described and illustrated. Gourretia laevidactyla n. sp. is closely allied to G. biffari found from northwest of Barcelona, Venezuela but differs markedly in having a cardiac prominence present and telson appearing truncate on the posterior margin. Gourretia sinica n. sp. appears to be closely related to the West Atlantic species G. laresi known from Venezuela but differs in the rostrum having a narrower acute spine. It is the first record of this genus in China seas.

This study describes the karyology of an isopod, Saduria entomon, and provides for the first time evidence of a XY/XX heterogamety for this species. The presented karyotype [56 (m sm ) 2 st XX/XY] is characterised by the dominance of metacentric and submetacentric chromosomes and is considered as apomorphic. This is the first time a valviferan is described with an XX/XY system. Mitotic and meiotic heterogamety observed in S. entomon suggests more advanced evolution of sex determination within this species in comparison to other Isopoda. Based on Ag-staining the presence of secondary constrictions and satellites on the 22nd pair of homologous chromosomes was identified. Inter- and intra-individual variability in chromosome number (2n  =  58, 2n  =  59 or 2n  =  61) was also observed. The between-species variation in heterogamety in isopods and the within-species variation in chromosomes numbers are discussed.

Freshwater organisms with an amphidromous life cycle are generally thought to disperse widely through marine planktonic larval stages, but only few studies on genetic population structure of amphidromous shrimp exist. We used a 640-basepair region of the mitochondrial gene cytochrome c oxidase I (Cox1) from the amphidromous river shrimp Cryphiops caementarius from five rivers in northern-central Chile to test whether large distances between estuaries (up to 700 km) limit gene flow between populations and result in genetic differentiation among populations. The results revealed high haplotype diversity with no significant geographical structuring, suggesting that gene flow occurs regularly over several hundreds of kilometres, also connecting populations north and south of the Atacama Desert. Seemingly, the terrestrial barrier is overcome by planktonic larval dispersal through the sea, suggesting wide dispersal rather than “stepping-stone” dispersal between estuaries. The population from the southern limit of the geographic distribution of C. caementarius (Río Limari) revealed some weak differentiation in pairwise Φ_ST comparisons, but larger sample sizes are necessary to confirm this. Additional studies are needed for a better understanding of factors that promote different life histories, like marine planktonic dispersal, larval retention in estuaries, or an amphidromous-freshwater transition towards a purely freshwater life cycle.

An arthropod phylogeny derived from nucleotide sequences (Regier et al., 2010) did not consider either the morphology or the development of crustaceans. Examples of a morphological transformation and developmental data appear to provide only limited support for the cladogram because similar morphology and development are found among distantly related crustaceans, while differing morphology and development are found among closely related crustaceans. One reason for the incongruity may be a method of sequence analysis that results in statistical support values. This method samples a population of purposefully-generated cladograms, although there has been only one history of life on earth; in effect the purposefully-generated cladograms are instrumental artifacts.

Canyoning has become a popular recreation activity in the Greater Blue Mountains World Heritage Area (Australia), and park management consider that the activity is having an impact on the local fauna of the fragile canyon ecosystems. Although only limited data exist on the native freshwater crayfish populations that inhabit these canyons, it has been suggested that freshwater crayfish have the potential to act as a rapid bioindicator of human impacts. As a preliminary assessment, we sampled crayfish from two canyons that received high visitation and two with low visitation. We recorded only a single species, Euastacus spinifer and this was found to occur at higher altitudes than previously recorded. There was no significant difference in crayfish abundance or size between visitation levels. There were, however, differences in crayfish abundance between individual canyons. Animals within a canyon had the same colour morph which we deduced to be genetic under selection pressure. We conclude that with an appropriate baseline dataset, crayfish could potentially provide a rapid assessment method for use by canyoners and other non-specialists to underpin management decisions.