Twelve species of bryozoan (ten phylactolaemates and two ctenostomes) were collected in Lake Biwa and the nearby satellite lakes. Phylactolaemate species were identified by statoblast morphology, and ctenostome species by colony morphology. Fredericellids were the most abundant phylactolaemates in Lake Biwa. Many colonies of Fredericella indica Annandale, 1909, identified by piptoblast morphology, were found in the southern part of the lake. In this genus, only Fredericella sultana (Blumenbach, 1779) had been previously reported from Japan; this is the first report of F. indica. A species of Fredericella having piptoblasts with a tiny, membrane-like ridge at the margin of the valves and weak reticulation on the surface was found in dredge material from the northern part of Lake Biwa; this species is herein described as a new species, Fredericella toriumii. The plumatellid Plumatella fungosa Pallas, 1768 represents an additional new record for Japan. An encrusting ctenostome was identified as a new species, Hislopia prolixa, on the basis of zooid size and morphology, tentacle number, budding pattern, and gut morphology. Hislopia prolixa was also collected from various other localities in Japan. The gut morphology reconstructed in 3D images, zooid morphology, and budding pattern are compared between H. prolixa and several other species of Hislopia. The gut of H. prolixa is larger and the gizzard wall is thicker than in two other species. The budding pattern is similar to that of H. malayensis Annandale, 1916, but accelerated relative to two other species; young buds are already beginning to form the next generation of bud. Some colonies of H. prolixa had many ovaries; the average number was 40 per zooid. Colony morphology suggests that H. prolixa is more closely related to H. cambodgiensis (Jullien, 1880) than to H. natans Woods, Anurakpongsatorn and Mahujchariyawong, 2006.
A quadrannulate species of the genus Orobdella Oka, 1895 from Tsushima Island, Japan, Orobdella tsushimensis sp. nov., is described. It differs from other quadrannulate species of Orobdella in possessing the following combination of characters: color yellowish, III and IV uniannulate, male gonopore at XI b6, gastropore in XIII a1/a2, female gonopore in XIII a1/a2, 1/2+5 between gonopores, XXVI triannulate, gastroporal duct small and bottleshaped, epididymides in XVI to XIX, and atrial cornua coniform.
A new species of ostracod, Semicytherura sagittiformis sp. nov., is described from a sandy beach in Shizuoka Prefecture, central Japan. It lives in pore-waters of marine sandy sediments and is ecologically associated with other interstitial ostracods (e.g., Parapolycope and Microloxoconcha). Semicytherura sagittiformis is one of the smallest species in the genus Semicytherura, and its carapace size is comparable with those of some large interstitial ostracods. This fact suggests that a small carapace is the most important character for adaptation of ostracods to an interstitial environment.
Relationships among the three species of nocturnal hornet of the genus Provespa Ashmead, 1903 are cladistically analyzed based on adult morphological characters and mitochondrial DNA sequence data. Monophyly of Provespa is supported and the species relationships are expressed as (P. barthelemyi+(P. anomala+P. nocturna)). Provespa barthelemyi (Du Buysson, 1905) is distributed mainly in the southeastern part of the Asian continent from eastern India to Indochina, while P. nocturna Vecht, 1935 and P. anomala (Saussure, 1854) occur mainly in Sumatra, Borneo, and the southern part of the Malay Peninsula. The speciation and biogeography of Provespa are briefly discussed, with reference to a supposed vicariance event around the Isthmus of Kra.