A new species of the genus Vercoia from Okinawa Island,Japan (Crustacea,Decapoda, Caridea,Crangonidae), with descriptions of its zoeal stages

A new crangonid shrimp and its four zoeal stages are described and illustrated in detail from Okinawa Island, Japan. The new species of Vercoia is readily distinguished from V. gibbosa Baker, 1904 Baker W. H 1904 Notes on South Australian decapod Crustacea Transactions and Proceedings and Report of the Royal Society of South Australia, 28, 146–161, pls 27–31  [Google Scholar], V. socotrana Duris, 1992 Duris, Z. 1992. Revision of Vercoia Baker (Crustacea: Decapoda: Crangonidae). Invertebrate Taxonomy, 6: 1437–1457.  [Google Scholar] and V. japonica Komai, 1995 Komai, T. 1995. Vercoia japonica, a new species of crangonid shrimp (Crustacea: Decapoda: Caridea) from Japan. Natural History Research, 3: 123–132.  [Google Scholar], in adult morphology, by the bilobed anterior expansion of the hepatic carina of the carapace, the notched mid-dorsal carina on the fifth abdominal somite, and the presence of the distoventral tooth on the ischium of the second pereopod. The larvae of the new species which are the first larvae of a species assigned to Vercoia to be described, are very similar to those of species of Philocheras, but they differ in the setation of the endopods of the maxillule and maxilla. A key to the adult species of Vercoia is provided.     

A revision of the genus Pandalus (Crustacea: Decapoda: Caridea: Pandalidae)

The genus Pandalus Leach, 1814, is revised based upon the abundant material from collections in various museums or institutions in the world. Altogether 20 species are recognized which appear to form five groups. Nineteen species are recognized in Pandalus, three of which are described as new: P. curvatus from southern Japan, and P. chani and P. formosanus from Taiwan. Four informal species groups are also recognized within the genus: P. montagui group (P. montagui Leach, 1814; P. borealis Krøyer, 1838; P. goniuruStimpson, 1860; P. jordani Rathbun, 1902; P. tridens Rathbun, 1902; and P. eous Makarov, 1935); P. stenolepis group (P. stenolepis Rathbun, 1902; P. curvatus sp. nov.); P. hypsinotus group (P. hypsinotus Brandt, 1851; P. danae Stimpson, 1857; P. prensor Stimpson, 1860; P. gracilis Stimpson, 1860; P. gurneyi Stimpson, 1871; P. nipponensis Yokoya, 1933; P. teraoi Kubo, 1937; P. chani sp. nov.; and P. formosanus sp. nov.); and P. platyceros group (P. platyceros Brandt, 1851; and P. latirostris Rathbun, 1902). The P. platyceros group appears to be most closely related to the genus Pandalopsis Bate, 1888, but Pandalus is retained as a possible paraphyletic group. Protandrous hermaphroditism is known in all but two species of the genus (P. curvatus and P. formosanus), for which only specimens of either male or female have been available. Pandalus propinqvus G. O. Sars, 1870, is transferred to a new monotypic genus Atlantopandalus, because of its lack of hermaphroditism and possession of some unique morphological characters, including one indicating a close relationsip to Dichelopandalus Caullery, 1896. All species are fully described and illustrated. The affinities and important morphological variations of the species are discussed. A key for adults is presented for the identification of the species. Biogeography of the genus is briefly discussed.     

A revision of the Caridina gracilirostris De Man, 1892, species group,with descriptions of two new taxa (Decapoda; Caridea; Atyidae)

Re‐examination of the syntypes of Caridina gracilirostris De Man, 1892 De Man, J. G. 1892. “Decapoden des Indischen Archipels.”. In Zoologische Ergebnisse einer Reise in Niederlandisch Ost‐Indien Edited by: Weber, M. Vol. 2, 265–527. Plates 15–29 [Google Scholar], shows that the type series is composed of three species. These three species are similar in the form of the rostrum, but can be differentiated easily by a combination of rostral formula and sexual appendages. To stabilize the taxonomic status of these species, a lectotype for C. gracilirostris is selected. A lectotype for Caridina appendiculata Jalihal and Shenoy, 1998 Jalihal, D. R. and Shenoy, S. 1998. “Taxonomic revision of some Indian prawn species of genus Caridina H. Milne Edward, 1837 (Atyidae).”. In Proceedings and abstracts of the Fourth International Crustacean Congress, 128–129. Amsterdam, , Netherlands: The Crustacean Socrety.  [Google Scholar], is also designated from among the remaining syntypes of C. gracilirostris. A new species, C. neglecta, is described. Caridina gracilirostris and C. gracilima Lanchester, 1901 Lanchester, W. F. 1901. On the Crustacea collected during the “Skeat” expedition to the Malay Peninsula.. Proceedings of the Zoological Society of London, 1900([1901]): 533–574.  [Google Scholar], are redescribed and figured, and C. appendiculata is transferred to the C. nilotica species group. A new species group is also recognized for C. gracilirostris, C. neglecta, C. gracilima, and a new species, C. longifrons. The C. gracilirostris species group is defined here as taxa possessing a rostrum with subapical teeth, fewer than 10 dorsal teeth, and without any postorbital teeth.     

Partial revision of the genus Fabia Dana, 1851 (Crustacea: Brachyura: Pinnotheridae)

Eight species are now assigned to Fabia Dana, 1851. The present partial revision accepts five, F. byssomiae (Say, 1818), F. concharum (Rathbun, 1893), F. emiliai (de Melo, 1971), F. subquadrata Dana, 1851 (type species) and F. tellinae Cobb, 1973, and recommends a future study to determine whether the Brazilian species F. emiliai, is a junior synonym of F. byssomiae. In addition, a new species, F. carvachoi, from the Gulf of California, México is described. The six species are diagnosed and/or described and figured.     

The freshwater shrimps of the genera Caridina and Parisia from karst caves of Sulawesi Selatan,Indonesia, with descriptions of three new species (Crustacea: Decapoda: Caridea: Atyidae)

The present study reports on collections of hypogean freshwater atyid shrimps of the genera Caridina Milne Edwards, 1837 Milne Edwards, H. 1837. Histoire naturalle des Crustacés, Comprenant l'Anatomie, la Physiologie et la Classification de ces Animaux, Vol. 2, 1–532. Paris (France): Libraire Encyclopedique de Roret.  [Google Scholar], and Parisia Holthuis, 1956 Holthuis, L. B. 1956. The troglobic Atyidae of Madagascar (Crudtacea, Decapoda, Natantia), Mem Inst Sci Madagascar ser.. A., 11: 97–110.  [Google Scholar], obtained from the karst caves and associated epigean waters of Sulawesi, Indonesia. Six species of Caridina were present, of which two are new to science and one is new to Sulawesi, as well as one new species of Parisia. Types of Caridina pareparensis De Man, 1892 De Man, J. G. 1892. Decapoden des Indischen Archipels.. Zool Ergebn Reise Niederland Ost‐Ind., 2: 265–527. pl. 15–29 [Google Scholar], and C. pareparensis parvidentata Roux, 1904 Roux, J. 1904. Décapodes d'eau douce de Cèlébes (Genres Caridina et Potamon).. Rev Suisse Zool., 12(3): 539–572. pl. 9 [Google Scholar], were re‐examined and redescribed; lectotypes for both taxa are designated. Caridina pareparensis parvidentata is here regarded as a distinct species. The new taxa are described, figured and compared with congeners.     

The genus Coralaxius redefined,with the description of two new species (Crustacea: Decapoda: Axiidae)

The genus Coralaxius is rediagnosed, and the type species C. nodulosus (Meinert, 1877), the holotype of which was found to be identical with C. abelei Kensley and Gore, 1982, is redescribed. The two new species of Coralaxius are described, viz. C. galapagensis from the Galapagos Islands, and C. indopacificus from Fiji and the Comoro Islands. On the basis of carapace, gill and appendage characters, it is concluded that C. indopacificus is more primitive than the other two species. The genus is thought to have had a tethyan distribution, with the eastern Pacific representative being cut off from the western Atlantic form with the raising of the Isthmus of Panama.     

A revision of the Caridina serrata species group,with descriptions of five new species (Crustacea: Decapoda: Caridea: Atyidae)

The taxonomy of the Caridina serrata species group (Caridea: Atyidae) is revised. Neotypes of C. serrata Stimpson, 1860, and C. cantonensis Yu, 1938, are designated. Additional information on Caridina sphyrapoda Liang and Zhou, 1993 is provided. Five new species of the Caridina serrata species group are described, namely Caridina nanaoensis from Guangdong Province, C. apodosis from Hong Kong, and C. yulinica, C. wumingensis and C. mutata from Guangxi Province, all in southern China. A key to all members of the species group is included.     

A revision of Caridina yunnanensis and its allied species (Crustacea: Decapoda: Caridea: Atyidae) from Yunnan,southern China,with description of one new species

The taxonomy of the Caridina yunnanensis and its allied species (Caridea: Atyidae) from Yunnan Province in southern China, is revised. A neotype for C. yunnanensis Yu, 1938, is designated. Additional information is provided on C. disparidentata Liang, Yan and Wang, 1984; C. dianchiensis Liang and Yan, 1985; C. mongziensis Liang, Yan and Wang, 1987; and C. disjuncta Cai and Liang, 1999. One new species, Caridina impensa, is described. A key to members of the species group is included.     

A new genus of freshwater crab (Crustacea: Decapoda: Brachyura: Potamidae) from Thailand,with a description of a new species

A new genus, Stelomon, is established for the Thai freshwater crabs Potamon kanchanaburiense Naiyanetr, 1992, and P. pruinosum Alcock, 1909. The unique structure of the male first pleopod is the key diagnostic generic character. One new species, which differs in the form of the male first pleopod, is also described. A key to the species of Stelomon is included.     

A revision of the genus Siamthelphusa Bott, 1968 (Crustacea: Decapoda: Brachyura: Parathelphusidae), with descriptions of five new species from Thailand

The taxonomy of the northern Peninsular Malaysian and Thai freshwater crab genus Siamthelphusa Bott, 1968 (Crustacea: Decapoda: Brachyura: Parathelphusidae) is revised. Nine species are recognized: S. improvisa (Lanchester, 1901), S. holthuisi Naiyanetr and Ng, 1990, S. retimanus n. sp., S. paviei (De Man, 1898), S. acutidens n. sp., S. faxoni (Rathbun, 1905), S. transversa n. sp., S. nan n. sp., and S. variegata n. sp. A neotype is designated for S. improvisa (Lanchester, 1901), the type species of the genus.     

The sentinel crabs of the genus Chaenostoma (Stimpson, 1858) (Crustacea: Brachyura: Macrophthalmidae), with description of a new species and new records

The genus Chaenostoma (Stimpson, 1858) so far includes four distinct species, i.e. C. boscii (Audouin, 1826), C. lisae (Poupin and Bouchard, 2010), C. punctulatus Miers, 1884, and C. sinuspersici (Naderloo and Türkay, 2011). Chaenostoma java n. sp. is here described as a fifth species from Java (Indonesia) easily distinguished from its congeners by the features of the male first pleopod, the penultimate segment of the male abdomen, and the unique female gonopore. The new species is most similar to C. lisae, but they differ in the morphology of the male chelipeds and female gonopores. Chaenostoma lisae is redescribed and recorded from Madagascar, Mayotte I. and New Caledonia. An identification key for the genus is provided.     

A new pontoniine shrimp (Crustacea: Decapoda: Palaemonidae) from the Ryukyu Islands,Japan

An unusual new genus and species of pontoniine shrimp, Nippontonia minirostris gen. nov., sp. nov., from a sponge host from the Ryukyu Is., Japan, is described and illustrated. The new genus appears not to be closely related to any of the previously described genera. The genus is particularly remarkable for the morphology of the fixed finger of the minor second pereiopod, which is without parallel in the Palaemonidae.     

Description of a new species of Demania Laurie, 1906 (Crustacea,Decapoda, Brachyura,Xanthidae) from the Bay of Bengal,Indian Ocean

A new species of xanthid crab, Demania bangladeshensis sp. nov., is described from the Bay of Bengal, Indian Ocean. Demania bangladeshensis appears to be most closely related to Demania toxica Garth, 1971, a poisonous species from the Philippines, but can easily be separated by the differently sculptured carapace, legs and chelipeds.     

Protandric simultaneous hermaphroditism and sex ratio in Lysmata nayaritensis Wicksten, 2000 (Decapoda: Caridea)

Caridean shrimps display a wide variety of sexual systems, including the newly discovered protandric simultaneous hermaphroditism. Protandric simultaneous hermaphroditism is known only from seven species of Lysmata, and it is not clear if this condition is fixed within the genus or if Lysmata includes species that are simply protandric or gonochoric (with separate sexes). This study uses anatomical data, aquarium experiments, and field observations to demonstrate that Lysmata nayaritensis is another protandric simultaneous hermaphrodite. It is shown that, despite occurring in the tropics, this species fits into the “crowd” species category, with high densities in the field and that the field sex ratio is highly male‐biased. Information on the sex allocation and sexual system of more species needs to be examined before these observations can be put into a comparative context within the genus.     

A new pontoniine shrimp genus (Crustacea: Decapoda) from the Yemen,with a note on other species

An unusual new genus and species of coral inhabiting pontoniine shrimp from the Yemen is described and illustrated. The new shrimp is remarkable for its very small size and the unique form of its telson. Three other pontoniine shrimps are also reported from the Yemen for the first time, raising the number of such shrimp species known from southern Arabia to 18.     

A review of the north-western Pacific species of the genus Paguristes (Decapoda: Anomura: Diogenidae), I. Five species initially reported by Ortmann (1892) from Japan

Five species of the hermit crab genus Paguristes Dana, 1851, initially reported by Ortmann (1892) from Japan, are revised based on the materials reported by Ortmann (1892), Doflein (1902), Balss (1913) and Miyake (1978), and on newly collected specimens. The specific status of P. palythophilus Ortmann, 1892, is clarified, and a species confused with P. palythophilus is described as new, P. albimaculatus. It has been revealed that P. kagoshimensis Ortmann, 1892, is actually a junior subjective synonym of P. digitalis Stimpson, 1858. The species heretofore assigned to P. kagoshimensis is described as new, P. versus. It has been confirmed that Paguristes acanthomerus Ortmann, 1892, is a valid species and that P. barbatus sensu Ortmann, 1892, is the same species as P. ortmanni Miyake, 1978. Further, a new species, P. doederleini, is described for P. setosus sensu Ortmann, 1892. It is also shown that a part of the group of specimens identified as Paguristes puniceus by Miyake (1978) is referable to P. doederleini. In addition to the three new species recognized herein, the four previously described species are also redescribed in detail in order to make clear their taxonomic status.     

Larval development of Pandalus gracilis Stimpson (Crustacea: Decapoda: Pandalidae) reared in the laboratory

The complete larval development of Pandalus gracilis Stimpson is described based on larvae reared in the laboratory. The species has four larval stages (stages 1–4) and one postlarval stage (stage 5). The survival rate of the postlarva stage is very high. Of the 40 larvae reared individually, 39 larvae moulted to the postlarva stage within approximately 21 days at a rearing temperature of 15°C. Larval morphological characteristics of the species are described and figured. Larval development of P. gracilis is compared with other Pandalus and Pandalopsis species. Komai (1999 Komai, T. 1999. A revision of the genus Pandalus (Crustacea: Decapoda: Caridea: Pandalidae).. Journal of Natural History, 33: 1256–1372.  [Google Scholar]) divided species of Pandalus into four species groups based on adult morphology. Pandalus gracilis belongs to the P. hypsinotus group. In this study, using larval characters, the P. hypsinotus group can be divided into two groups by the appearance of the mandibular palp and the shape of the telson: the first group contains P. hypsinotus and P. danae, and the second group contains P. gracilis, P. prensor, and P. nipponensis.