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 new species of the genus Nanosesarma (Crustacea: Decapoda: Brachyura: Sesarmidae), and redescription of Nanosesarma jousseaumei (Nobili, 1906), including new records from the Persian Gulf

A new species of sesarmid crab from the Persian Gulf, Nanosesarma sarii n. sp. is described. Further, a poorly known species, N. jousseaumei (Nobili, 1906 Nobili, G. 1906. Faune carcinologique de la Mer Rouge. Décapodes et Stomatopodes. Ann Sci Nat, Zool ser. 9., 4(1): 1–347.  [Google Scholar]), is recorded from the Persian Gulf and recognized as a valid species. N. sarii n. sp. is allied to N. minutum (De Man, 1887) and N. jousseaumei (Nobili, 1906) Nobili, G. 1906. Faune carcinologique de la Mer Rouge. Décapodes et Stomatopodes. Ann Sci Nat, Zool ser. 9., 4(1): 1–347.  [Google Scholar], but is easily distinguishable from them through a number of characters, in particular the upper surface of the palm with a longitudinal granular ridge, the upper surface of the movable finger fully covered with tubercles, and abdomen of the male with the sixth segment wide and the seventh segment remarkably elongate. N. jousseaumei differs from its remaining congeners in having a large gap between the cheliped fingers, a large tubercle proximally on the outer surface of the movable finger, and large teeth on the posterior margin of the merus of the walking legs.     

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.     

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.     

Terrapotamon gen. nov., a new genus of freshwater crabs from Malaysia and Thailand,with description of a new species,Terrapotamon aipooae sp. nov. (Crustacea: Decapoda: Brachyura: Potamidae)

A new genus, Terrapotamon gen. nov., is established to accomodate two species of freshwater crabs, Potamon abbotti Rathbun, 1898 from southern Thailand, and a new species, Terrapotamon aipooae sp. nov. from West Malaysia. Members of this genus are characterized by their inflated carapaces, very acutely triangular external orbital angles, and structure of their first male gonopods.     

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 revision of the family Deckeniidae Ortmann, 1897 (Crustacea: Decapoda: Brachyura: Potamoidea), with description of a new genus (Gecarcinucidae: Gecarcinucoidea) from the Seychelles,Indian Ocean

The family Deckeniidae Ortmann, 1897, is revised and only 2 East African species are recognised, D. imitatrix Hilgendorf, 1869, and D. mitis Hilgendorf, 1898. The identity of the poorly known species from Seychelles, Indian Ocean, Deckenia alluaudi A. Milne Edwards and Bouvier, 1893, is clarified. This species is redescribed, assigned to a new genus (Seychellum gen. nov.), removed from the Deckeniidae sensu stricto and transferred to the family Gecarcinucidae Rathbun, 1904.     

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.     

New records of West and South African Bathyporeia,with the description of four new species and a key to all species of the genus (Crustacea,Amphipoda)

New data on the warm temperate and tropical east Atlantic Bathyporeia species are presented. Four new species are described: Bathyporeia cunctator sp. nov. from South Africa, B. chevreuxi sp. nov. from Senegal, B. gladiura sp. nov. from South Africa, and B. griffithsi sp. nov. from Namibia. Bathyporeia cunctator sp. nov. and B. chevreuxi sp. nov. are very closely related to the west European B. tenuipes Meinert, 1877 and the Mediterranean B. lindstromi Stebbing, 1906 Stebbing, T. R. R. 1906. Amphipoda 1: Gammaridea.. Das Tierreich, 21: 1–806.  [Google Scholar]; these four cryptic species forming the complex tenuipes. Bathyporeia griffithsi sp. nov. and B. gladiura sp. nov. are highly distinctive new species. The morphotype “sunnivae” of Bathyporeia guilliamsoniana is recorded for the first time outside the Mediterranean Sea, in the Canary Islands. An identification key to all known Bathyporeia species is given.     

Establishment of a new subfamily for Shenius anomalus (Shen, 1935) (Crustacea: Decapoda: Brachyura: Dotillidae)

Shenius anomalus (Shen, 1935 Shen, CJ. 1935. On some new and rare crabs of the families Pinnotheridae, Grapsidae and Ocypodidae from China. Chin J Zool., 1: 19–40. 15 figures [Google Scholar]) has previously been assigned to the Macrophthalmidae Dana, 1851, and the Camptandriidae Stimpson, 1858 Serène, R. 1974. Note on the genera and species of the Camptandriinae Stimpson, 1858 (Decapoda, Brachyura: Ocypodidae). Treubia, 28(3): 59–117.  [Google Scholar]. A close examination of adult and first stage zoeal morphology confirms some previous suggestions that S. anomalus is actually an anomalous member of the Dotillidae Stimpson, 1858 Serène, R. 1974. Note on the genera and species of the Camptandriinae Stimpson, 1858 (Decapoda, Brachyura: Ocypodidae). Treubia, 28(3): 59–117.  [Google Scholar]. However, because a number of distinctive features distinguish it from all other dotillid genera a new subfamily Sheniinae is established.     

Taxonomy and ecology of the porcellanid crab Polyonyx cometes Walker, 1887 (Crustacea: Decapoda), with description of a new genus

The taxonomy of the rare porcellanid crab, Polyonyx cometes Walker, 1887 (Crustacea Decapoda), is reconsidered in the light of fresh material from Singapore, as well as the newly obtained first zoeal stage. Polyonyx cometes possesses numerous adult and larval characters which warrant the establishment of a new genus for the species. The species is confirmed as a commensal of the worm Chaetopterus (Annelida, Polychaeta).     

Two new genera of the family Pilumnidae (Crustacea: Decapoda: Brachyura) from Queensland,Australia

Two new genera of Pilumnidae each with a single new species are described from southeastern Queensland waters. Priapipilumnus is defined by the greatly swollen base and simple blunt apex of the male first pleopod and the concomitant posteriorly protruding, bilobed, third abdominal segment. Takedana is separable by the very short spinous anterolateral margins, the swollen branchial regions, the moderately short walking legs, and the strongly spined chelae. Actumnus pugilator is reassigned to Bathypilumnus Ng and Tan, 1984.     

A revision of the genus Prionocrangon (Crustacea: Decapoda: Caridea: Crangonidae)

Additional specimens belonging to the rare crangonid genus Prionocrangon Wood‐Mason and Alcock, collected from recent deep‐sea expeditions in the West Pacific enable a revision of this poorly known genus. The four previously described species are all valid. The type species P. ommatosteres Wood‐Mason and Alcock, , originally known only from the Andaman Sea, is considered to be also distributed in the Philippines and Indonesia. However, the material previously assigned to “P. ommatosteres” by de Man () and Chace () from Indonesia and the Philippines actually represents a new species, P. demani sp. nov., close to P. pectinata Faxon, . Prionocrangon pectinata and P. curvicaulis Yaldwyn, are still only known by their types. The distribution of P. dofleini Balss, is now extended from Japan to Taiwan. Two more new species are recognized. Prionocrangon formosa sp. nov. from Taiwan is closely related to P. curvicaulis while P. paucispina sp. nov. from Taiwan and New Caledonia is unique in having very few dorsal carapace spines. The genus Prionocrangon is newly diagnosed and a key to the species is provided. Nevertheless, a damaged specimen from the Sulu Sea could not be satisfactorily assigned to any of the above seven species, suggesting that this genus may have even higher diversity.     

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 new genus and species of terrestrial isopod from Malaysia (Crustacea,Oniscidea, Platyarthridae)

A new terrestrial isopod, Cephaloniscus sociabilis gen. nov., sp. nov., from Fraser Hill in central Malaysia, is described and illustrated. The new genus belongs to the family Platyarthridae and is distinguished from other members of the family by the characteristic structure of the cephalon. The specimens were collected from the nest of the termite Hospitalitermes sp. (near medioflavus Holmgren) together with the ant Centromyrmex hamulatus (Karavaiev).     

Parasites of shore crabs in the genus Hemigrapsus (Decapoda: Brachyura: Varunidae) and their status in crabs geographically displaced: a review

Two brachyurans of the varunid genus Hemigrapsus from the northwestern Pacific Ocean have invaded coastal regions of the north Atlantic – Hemigrapsus takanoi (sibling species of Hemigrapsus penicillatus) and Hemigrapsus sanguineus in Europe and the latter in the USA. Parasites are known from these crabs in their native habitats, but except for an undescribed larval nematode, none has been found in those examined from their new locations. These parasites include metacercariae of eight species of microphallid trematode, the rhizocephalan barnacles Polyascus polygenea, Sacculina nigra and Sacculina senta, and the obligate gut-inhabiting mesomycetozoan Enteromyces callianassae (potential parasite). The following have been identified in four of the other eight Pacific crabs within the genus (Hemigrapsus nudus and Hemigrapsus oregonensis, northern hemisphere; Hemigrapsus crenulatus and Hemigrapsus sexdentatus, southern hemisphere), none of which have been geographically displaced: metacercariae of two microphallid trematodes; cystacanths of three acanthocephalans Profilicollis antarcticus, Profilicollis botulus and Profilicollis novaezelandensis; larval nematode Ascarophis sp.; nematomorph Nectonema zealandica; entoniscid isopod Portunion conformis; mesomycetozoan Taeniella carcini; and nemertean egg predator Carcinonemertes epialti. The likelihood of the displaced species of shore crabs being rejoined with their native parasites or their susceptibility to becoming infected by similar parasites in their new locations is discussed. In future global displacements of parasitized Hemigrapsus species it is possible that their most serious parasites, rhizocephalans and entoniscid isopods, may infect previously uninfected species. For example, the two eastern Pacific species of Hemigrapsus (H. nudus and H. oregonensis) may be vulnerable to the rhizocephalans and may in turn be a source of entoniscids transported elsewhere.