A new species of the hitherto monotypic bivalve genus Peregrinamor (Galeommatidae) was found attached to the ventral side of the cephalothorax of a small thalassinidean shrimp, Upogebia carinicauda (Stimpson, 1860) (Upogebiidae) collected from tidal flats of Amami-Ohshima Island, Ryukyu Archipelago in Japan. The bivalve is dorso-ventrally flattened and pilfers suspended matter intercepted by the host's filtering basket. This new species, Peregrinamor gastrochaenans, can be discriminated from the type species of the genus, P. ohshimai Shoji, 1938, by its laterally more inflated shell with a permanent postero-ventral gape and by the expanded, fleshy posterior mantle protruding from the gape. Adaptations of the bivalve to the small host species and possible functions of the postero-ventral gape are discussed.
Tanaidacean and anthurid isopod material from the benthos at 1300m depth off Angola is described, including a new species of each of Malacanthura (Isopoda, Anthuridae) and of Collettea (Tanaidacea, Anarthruridae). The known ranges of Pseudotanais denticulatus Bird and Holdich, 1989, Paranarthrura intermedia Kudinova-Pasternak, 1982, and P. insignis Hansen, 1913 are extended further south in the Atlantic.
The larval development of the swimming crab Charybdis natator (Herbst, 1789) was studied from first zoea to megalopa under laboratory conditions. Six zoeal stages and one megalopal stage were identified, and detailed descriptions and illustrations are provided for each stage. At an average salinity and temperature of 31±1‰ and 23±1℃, the megalopa was attained 38 days after hatching. Morphologically, the first zoea of C. natator is very similar to those of other species of Charybdis in having lateral spines on the carapace ; three pairs of serrate setae on the posterior margin of the telson furca ; one plus six setae on the endopod of the maxillule ; and five setae on the endopod of the maxilla. The differences between the first zoea and megalopa of C. natator and those of its congeners are discussed.
Two new species of oribatid mites of the family Zetomotrichidae, Ghilarovus saxicola sp. nov. and Mabulatrichus litoralis sp. nov., are described from cliffside habitats of Japan. The authorship of the name Zetomotrichus bidentata Hammer, 1977 is discussed.
Two new mite species of the genus Thinoseius are described and illustrated on the basis of material collected from intertidal zones in northern Japan. Another intertidal species, Thinoseius occidentalipacificus Klimov, 1998, is recorded from Japan for the first time. Thinoseius sawadai sp. nov. and T. occidentalipacificus inhabit tidal wrack, and T. setifer sp. nov. was found on the pleopods of the sea slater Ligia cinerascens Budde-Lund, 1885 (Isopoda). This is the first record of eviphidid mites from a ligiid isopod. The deutonymphs of T. occidentalipacificus and T. setifer show a probable sexual dimorphism in the number of dorsal and/or opisthogastric setae.
The reduviid genus Onychomesa Wygodzinsky, 1966 is reported from Japan for the first time, with the description of the new species O. gokani. The species inhabits grassy vegetation of Iriomote-jima Island, the Ryukyus, Japan.
The males, mature larvae, and a nest of an Australian paper wasp, Ropalidia proletaria Richards, 1978, are described for the first time. Not only the female adult morphology but also the morphologies of the male, larva, and nest suggest that R. proletaria is closely related to R. plebeiana Richards, 1978, rather than to R. revolutionalis (de Saussure, 1853) as Richards (1978) suggested.
Parasikukia maculata, a new genus and species of Cyprinidae, is described on the basis of two specimens collected from a small river in Phetchaburi Province, Thailand. The new form is similar to the species of Sikukia in having a deep body and adipose eyelids, but it differs from the latter in the cephalic lateral line system, the shape and number of gill rakers, the numbers of circumpeduncular scales and vertebrae, the position of the lateral line on the caudal peduncle, and the shape of the second hypural. Parasikukia maculata is unique among the small barbs of Southeast Asia in having a small, distinct, dark, saddle-shaped spot anterior to the origin of the dorsal fin.