A new distinctive species of pagurid hermit crab (Crustacea: Decapoda: Anomura) from Japan

A new species of pagurid hermit crab, Pagurus decimbranchiae, is described and illustrated based on 20 specimens collected from shallow waters of the Pacific coast of Japan ranging from Boso Peninsula to Tanegashima Island. It is quite distinctive in having the rudimentary arthrobranch on the third maxilliped represented by a single bud, however close morphological similarity is found between the new species and P. moluccensis Haig and Ball. Comparisons are also made among other species, including P. boriaustraliensis Morgan, P. sp. cf. boriaustraliensis sensu Rahayu and Komai (2000) and the members of the P. anachoretus group. The present generic assignment of the new species should be considered provisional, as more extensive study is needed to investigate phylogenetic relationships of the new species and the other species of Pagurus.     

A Revision of Australian River Prawns, Macrobrachium (Crustacea: Decapoda: Palaemonidae)

A taxonomic revision of Australian Macrobrachium identified three species new to the Australian fauna – two undescribed species and one new record, viz. M. auratumsp. nov., M. koombooloombasp. nov., and M. mammillodactylus(Thallwitz, 1892). Eight taxa previously described by Riek (1951) are recognised as new junior subjective synonyms, viz. M. adscitum adscitum, M. atactum atactum, M. atactum ischnomorphum, M. atactum sobrinum, M. australiense crassum, M. australiense cristatum, M. australiense eupharum of M. australienseHolthuis, 1950, and M. glypticumof M. handschiniRoux, 1933. Apart from an erroneous type locality for a junior subjective synonym, there were no records to confirm the presence of M. australe(Guérin-Méneville, 1838) on the Australian continent. In total, 13 species of Macrobrachiumare recorded from the Australian continent. Keys to male developmental stages and Australian species are provided. A revised diagnosis is given for the genus. A list of 31 atypical species which do not appear to be based on fully developed males or which require re-evaluation of their generic status is provided. Terminology applied to spines and setae is revised.     

A re-description of Macrobrachium handschini (Roux, 1933) (Crustacea: Decapoda: Palaemonidae)

Diversity, distribution, seasonal changes in density and relative abundance of Ephemeroptera nymphs were studied in five stations on three streams in and around Shillong, Meghalaya state, North-eastern India. Seventeen species belonging to eight genera and five families were recorded. Diversity (Shannon's index) was governed by the heterogeneity of the substratum which in turn was influenced by catchment disturbances (quarrying, logging, and entry of sewage). Seasonal changes in density were governed by the spate-frequency regime of the streams. Relative abundance showed dominance of one or two species at impacted stations, while in less disturbed ones, a more equitable distribution of species was observed.     

A new species of sergestid shrimp,acetes orientalis (Crustacea: Decapoda,Sergestidae) from Goa,Central West Coast of India

Acetes orientalis, a new species of sergestid shrimp belonging to the genus Acetes H. Milne-Edwards collected from the Mandovi estuary, Goa, Central West Coast of India has affinities to most of the Indo-Pacific species. The petasma of the male has resemblance in shape to. A. sibogae, A. vulgaris, A. sibogalis, A. australis, A. erythraeus and Acetes sp. and very much alike in structure to that of A. sibogae. The female genital area has a pair of protuberance as in A. vulgaris and A. indicus. These combinations in characters along with several other important features which justify the creation of this new species are discussed in comparison with those of the other Indo-Pacific species having closet affinities.     

A redescription of Periclimenaeus fimbriatus Borradaile, 1915, with the designation of a new genus (Crustacea: Decapoda: Palaemonidae)

Specimens of Periclimenaeus fimbriatus Borradaile, 1915, a palaemonid shrimp reported from only three localities in the Western Indian Ocean, are described and illustrated. The species is removed from the genus Periclimenaeus Borradaile and a new genus Paraclimenaeus is designated for its accommodation. The characteristic features of the genus and its relationships are discussed. The palaemonid shrimp genera associated with sponge hosts are reviewed and a key provided for their identification     

Microsatellite loci from the pink shrimp Farfantenaeus notialis (Crustacea,Decapoda)

Farfantepenaeus notialis is an important resource for fisheries in Cuba. For this reason and for a sustainable exploitation it is important to study their population structure and genetic variability. We report and characterize microsatellites as genetic markers from this species. Fifteen microsatellite polymerase chain reaction (PCR) primers were designed and tested in some individuals from different populations. Seven pair of primers showed reliable amplification products and five were polymorphic. The allele number ranged from 4 to 33, and the observed and expected heterozygosities were relatively high with values between 0.63 and 0.74 and 0.56 and 0.81, respectively. Departures from Hardy–Weinberg equilibrium were observed for all loci.     

Embryonic development of the Caridean prawn Macrobrachium mammillodactylus (Crustacea: Decapoda: Palaemonidae)

The freshwater knob-tooth prawn Macrobrachium mammillodactylus is a commercially exploited species in the Philippines. To study the biology of this species, broodstock from the wild was collected, transported to the laboratory and kept in pairs in indoor polyethylene tanks for breeding. Eggs from berried females were sampled to follow the stages of embryonic development until hatching to zoea larva. It took 18.0?±?2.1?days for the eggs to hatch at ambient water temperature between 25 and 28?°C. The morphological landmarks of development at the different stages (pre-cleavage, cleavage, blastula, pre-nauplius, post-nauplius and pre-hatching) of the live embryos are described. Incremental percentage staging was adopted from 0% at fertilization to 100% at hatching and were matched with corresponding morphological development. Egg volume increased significantly toward the mid-to-later stages of development. The eye index also showed a significant increase as the egg developed. The colour of the egg mass changed from light olive green to grey as the eggs progressed in development. The general pattern of development was comparable to other members of the genus Macrobrachium.     

Genetic,ecological, and behavioural divergence between two sibling snapping shrimp species (Crustacea: Decapoda: Alpheus)

Examination of genetic and ecological relationships within sibling species complexes can provide insights into species diversity and speciation processes. Alpheus angulatus and A. armillatus, two snapping shrimp species with overlapping ranges in the north-western Atlantic, are similar in morphology, exploit similar ecological niches and appear to represent recently diverged sibling species. We examined phylogenetic and ecological relationships between these two species with: (i) sequence data from two mitochondrial genes (16S rRNA and COI); (ii) data on potential differences in microhabitat distribution for A. armillatus and A. angulatus; and (iii) data from laboratory experiments on the level of reproductive isolation between the two species. DNA sequence data suggest A. armillatus and A. angulatus are sister species that diverged subsequent to the close of the Isthmus of Panama, and that haplotype diversity is lower in A. armillatus than in A. angulatus. Both species are distantly related to A. heterochaelis and A. estuariensis, two species with which A. angulatus shares some similarities in coloration. Ecological data on the distribution of A. angulatus and A. armillatus from two locations revealed differences in distribution of the two species between habitat patches, with each patch dominated by one or the other species. However, there was no apparent difference in distribution of the two species within habitat patches with respect to microhabitat location. Ecological data also revealed that heterospecific individuals often occur in close proximity (i.e. within metres or centimetres) where sympatric. Behavioural data indicated that these species are reproductively isolated, which is consistent with speciation in transient allopatry followed by post-divergence secondary contact. Our data further resolve taxonomic confusion between the sibling species, A. armillatus and A. angulatus, and suggest that sympatry in areas of range overlap and exploitation of similar ecological niches by these two recently diverged species have selected for high levels of behavioural incompatibility.     

A new species of Macrobrachium (Decapoda, Caridea, Palaemonidae) from Northern Territory, Australia and a key to Australian species of the genus

A new species of freshwater prawn Macrobrachium bullatum sp.n. is described from the Alligator Rivers region of Northern Territory, Australia. The cutting edges of fingers of chelipeds (pereiopod 2) have rows of six opposing, equally spaced, large horny tubercles, interspersed between rows of stiff hairs. A key to Australian species of the genus Macrobrachium is also given.     

Two new species of Bathypalaemonella Balss (Crustacea, Decapoda, Campylonotidae) from the Australian Northwest Shelf

Two new species of shrimp belonging to the campylonotid genus Bathypalaemonella Balss from the Australian Northwest Shelf. R. brevirostris sp.n. and B. pilosipes sp.n., are described and illustrated. constituting the first records of this genus from Australian waters. Present knowledge of the genus is reviewed and the distribution of the known species listed. The two new species can be readily distinguished from the previously described species of Banthypalaemonella by the very characteristic morphologies of the dactyls of their ambulatory pereiopods.     

Ultrastructural aspects of a new species,Vavraia mediterranica (Microsporidia,Pleistophoridae), parasite of the French Mediterranean shrimp,Crangon crangon (Crustacea,Decapoda)

The life cycle stages of a new species of the genus Vavraia (Microsporidia, Pleistophoridae), which parasitizes the shrimp Crangon crangon (Crustacea, Decapoda), were examined by light and electron microscopy. This parasite was monomorphic with polysporous sporogony and developed in the skeletal muscle of the host. The multinucleate sporogonial plasmodium divided by plasmotomy and multiple division into uninucleate sporoblasts. All stages were surrounded by a thick and amorphous dense coat external to the plasmalemma. This structure gradually became a merontogenetic sporophorous vacuole (MSV) where the sporonts developed into sporoblasts. The MSV was filled with episporontal granular secretory products and eventually contained up to 50 uninucleate spores. During spore morphogenesis, these episporontal granular products within the MSV became organized as episporontal tubular-like structures. In transverse sections, these structures showed a mean diameter of 1.0 microm, but disappeared during the final phase of the spore maturation. Mature spores were ellipsoidal to slightly pyriform and measured 2.30 x 1.41 microm. The polar filament was anisofilar and consisted of a single coil with six to seven turns (rarely five). This new species is named Vavraia mediterranica n. sp.     

Burrowing shrimp of the infraorders Gebiidea and Axiidea (Crustacea: Decapoda)

This review is devoted to the different aspects of biology of burrowing shrimp of the infraorders Gebiidea and Axiidea (Crustacea: Decapoda). Information on their taxonomy, morphology and physiology, distribution, burrow architecture, and trophic mode is reviewed. The peculiarities of breeding and development, life history, and the role in the ecosystem of these infaunal species are analyzed. Special attention is given to the species that inhabit Peter the Great Bay of the Sea of Japan.     

Life history tactics of southern velvet shrimp Metapenaeopsis palmensis (Crustacea,Decapoda) in the waters off southwestern Taiwan

The southern velvet shrimp, Metapenaeopsis palmensis, a small, tropical r-strategist shrimp, was investigated to test whether its life history tactics are similar to those of penaeid shrimps. In total, 7,832 shrimps were collected in southwestern Taiwan from April 2002 to August 2011. For the first time, we have identified the shrimp as a multiple spawner. This species has a size-segregated distribution, with the newly recruited early juveniles [<6.00 mm carapace length (CL)] living offshore (water depth = 30 m) and the subadults and mature spawning adults (CL ≥9.39 mm) living inshore (water depth = 15–20 m). They spawn from February to June before the rainy season when the water temperature exceeds 25°C. Only the larvae hatched in the late spawning season will successfully recruit in the dry season in September–November when the bottom water salinity is higher than 33.5 psu. The life history tactics of this species are different from those found by various previous studies on penaeid shrimps.     

Caridina bruneiana, a new species of freshwater shrimp (Decapoda, Caridea, Atyidae) from Negara Brunei Darussalam, Borneo

A new species of the freshwater atyid shrimp, Caridina bruneiana from Negara Brunei Darussalam, Borneo is described. Caridina bruneiana is characterized by its moderately long and deep rostrum, pereiopod shape, spination and segmental ratios, the shape and spination of its posterior telsonic margin, egg size and the presence of an appendix interna on the endopod of the first male pleopod. The distribution of atyid shrimps in forested streams and their possible use as bioindicators of stream water quality in tropical rainforests are briefly discussed.     

Three new species of Paralomis (Crustacea, Decapoda, Anomura, Lithodidae) from the Pacific and Antarctic Oceans

Three new species of the lithodid genus Paralomis from the Sulawesi (Celebes) Islands, P. ochthodes sp.n., Chilean coast, P. tuberipes sp.n., and Antarctic Ocean, P. birsteini sp.n., are described and illustrated. The first two species have features that set them well apart from other species of the genus. Characters are also given to distinguish P. birsteini from the closely allied P. spectabilis Hansen (North Atlantic).     

On a new genus of riverine crab (Crustacea: Decapoda: Brachyura: Potamidae) from northwestern Thailand,with descriptions of two new species

A new genus, Tomaculamon, is set up for two newspecies of potamid river crabs. Tomaculamonstenixys, new species, and T. pygmaeus, newspecies, are both from northwestern Thailand. The newgenus is closest to Potamon Savigny, 1816, butis immediately distinguished by distinct gonopodalcharacters.     

Kakaducaris glabra gen. nov., sp. nov., a new freshwater shrimp from the Kakadu National Park,Northern Territory,Australia, Crustacea: Decapoda: Palaemonidae with the designation of a new subfamily Kakaducaridinae

A new species of palaemonid shrimp from the Northern Territory Kakadu National Park is described and illustrated. Kakaducaris glabra, gen, nov., sp. nov., can not be satisfactorily referred to the described subfamilies of the Palaemonidae and a new subfamily Kakaducaridinae is designated (see addendum).     

Delimitation of sympatric Palaemon (Decapoda,Palaemonidae) species of the Laguna Madre,Mexico

Grass shrimps Palaemon mundusnovus, P. pugio and P. vulgaris sympatrically inhabit in the Laguna Madre, Mexico. They exhibit very close morphological similarity and overlap in their diagnostic characteristics, which has hindered certainty in their identification and has raised doubt regarding their taxonomic validity. In this work, we analyse intra‐ and interspecific morphometric and meristic variability through a multivariate analysis, and we determine the molecular variation using mitochondrial sequences of the 12S, 16S and COX1 genes to confirm the validity of the three taxa as having distinct lineages or to recognize a smaller number of species with phenotypic plasticity. Our results corroborate the taxonomic validity of the three species; however, there is intraspecific plasticity, interspecific overlap of characteristics and greater morphological and molecular similarity between the species P. mundusnovus and P. pugio, whereas P. vulgaris was better delimited. These species form a monophyletic group but the phylogenetic relationship obtained is discussed. Telson length was the primary variable in the principal components analysis, whereas the length of the propodus of the second pereiopod was the best discriminant. The range of variation reported in the characteristics linked to the rostrum is extended, and its influence on the separation of these species is recognized. The joint application of multivariate analysis from morphological variables and molecular tools is recommended to clarify the taxonomic status of species featuring close morphological similarity and sympatric distribution.     

New species and new records of pinnotherid crabs (Crustacea: Decapoda: Brachyura) from the Yellow Sea

Five species belonging to two genera of pinnotherid crabs are reported from the Yellow Sea. Two are new to science, namely: Sakaina glabra sp. nov. and Sakaina granulata sp. nov.; while three species are recorded for the first time from China: Pinnaxodes majorOrtmann, 1894, Pinnaxodes mutuensisSakai, 1939, and Sakaina japonicaSerène, 1964. Sakaina glabra can be easily distinguished from congeners by lacking a thick rim of pubescence along the anterolateral margin of the carapace. Sakaina granulata closely resembles S. asiatica (Sakai, 1933), but differs mainly in having a row of granule-like denticles along the anterolateral margin of its carapace.