Two new species of the commensal shrimp genus Periclimenaeus Borradaile, 1915, (Decapoda,Palaemonidae) from the Maldive Islands

Two new species of the commensal shrimp genus Periclimenaeus Borradaile, found in the waters of the Maldive Islands, Indian Ocean, are described and illustrated. P. tchesunovi sp. nov. is related to P. rastrifer Bruce. The former may be distinguished by its deeper rostrum, with dentition 6/1, the presence of supraorbital tubercles, and broad, spatulate fingers on the first pereiopods. P. zarenkovi sp. nov. closely resembles P. diplosomatis Bruce in the presence of minute denticulations on the dactylar cutting edge of the major second pereiopod, but differs from it by a deeper rostrum with 5 dorsal teeth, more robust chelae of the second pereiopods, and small dorsal telson spines.     

The complete larval development of Sadayoshia edwardsii (37) (Decapoda: Anomura: Galatheidae) described from laboratory‐reared material

The complete larval development of Sadayoshia edwardsii (Miers, ) is described and illustrated from laboratory‐reared material. The development comprises four zoeal and one megalopal stages. Diagnostic zoeal characters of Sadayoshia are provided and these are compared with other galatheid genera for which the larval morphology is known. Zoeas of S. edwardsii are readily distinguished from those of other galatheid species by the setation of the maxillular endopod together with the basis and endopod of the first maxilliped. The megalop of S. edwardsii has a flattened, triangular‐shaped rostrum, which differs remarkably from that of the adult. Although the rostral shape resembles that of Galathea megalops, the armature of the lateral margins is different between megalops of the two genera. The present larval study suggests that Sadayoshia is more closely allied to Galathea than to Munida.     

Studies on the provenzanoi and other pagurid groups: VI. Larval and early juvenile stages of Pagurus ochotensis Brandt (Decapoda; Anomura; Paguridae) from a northeastern Pacific population,reared under laboratory conditions

Zoeal, megalopal, and early juvenile stages of Pagurus ochotensis (Brandt, 1851) from a northeastern Pacific population are described from laboratory-reared individuals. Zoeal and megalopal development in this population is compared with that described for a population of this species from Hokkaido, Japan. First and second juvenile crab stages of this species are described for the first time. The nearly identical developmental morphology of the two populations supports the earlier synonymy of the northeastern Pacific species, Pagurus alaskensis (Benedict) with P. ochotensis.     

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 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 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.     

The larval development of the spider crab Rochinia gracilipes (Crustacea: Majoidea: Epialtidae: Pisinae) reared in the laboratory

The larval development of the spider crab Rochinia gracilipes Milne-Edwards, 1875 (Crustacea: Decapoda: Brachyura: Majoidea: Epialtidae: Pisinae) is described and illustrated from laboratory-reared larvae. Development consisted of two zoeal stages and one megalopa, following the typical pattern in Majoidea. Zoea I of R. gracilipes, R. debilis and R. carpenteri differed in lengths of the rostral spine of the carapace, in the number of setae and aesthetascs of several head appendages (exopods of antennules, endopods of maxillules, and endopods and scaphognathites of maxillae) and in the length of posterolateral processes of abdominal somites; lateral carapace spines were present only in R. carpenteri and pleopod buds only in R. debilis. Megalopae of Rochinia gracilipes and R. carpenteri differed in several notable characters: a dorsal spine and long rostrum of the carapace, as well as spines in coxa and ischium of pereiopods, appeared only in R. carpenteri, and podobranchiae of the 3rd maxilliped appeared only in R. gracilipes; they also differed in setation of abdomen and pleopods. The comparison of the available information on Pisinae larval development suggested that larval morphology would not help to accurately understand the phylogenetic relationships of this subfamily of spider crabs.     

Macrobrachium malayanum (Roux, 1934) stat. nov. (Decapoda,Palaemonidae) as a synonym of M. geron Holthuis, 1950, with notes on its distribution

Macrobrachium pilimanus malayanus (Roux, 1934) is synonymized with M. geron Holthuis, 1950 and accorded full species status as M. Malayanum (Roux, 1934) stat. nov. A lectotype is also designated. Variation within M. malayanum and differences between this species and M. pilimanus (De Man, 1879) are discussed, and the taxonomy of the species clarified. New records of M. malayanum are presented for Sarawak and Sumatra.     

Anomuran Crustacea (Paguridea,Porcellanidae, and Hippidea) from Oman,principally from Dhofar province,southern Oman

Anomura (Crustacea, Decapoda) are described from 5 collection sites in Dhofar (southern Oman) and from near Muscat (northern Oman). These consist of the following: Paguridea: Aniculus erythraeus, Calcinus (3 species), Cestopagurus coutieri, Clibanarius (3 species), Dardanus (5 species), Diogenes (2 species), Paguristes (2 species) and Coenobita scaevola; Porcellanidae: Pachycheles (2 species), Petrolisthes (7 species), Pisidia (3 species) and Polyonyx (1 species, probably undescribed); and Hippidea: Emerita holthuisi, Hippa pacifica and Albunea steinitzi. The anomuran fauna of the region is not well known, and that of Dhofar has not previously been investigated. The present records establish a number of significant range extensions. The anomura species composition of Dhofar is discussed in relation to that of other areas of the Indian Ocean. In general, pagurideans appear less cosmopolitan, and more parochial within the region than porcellanids. This is discussed in relation to larval dispersal and other factors.