A species in the marine water mite family Pontarachnidae is newly described under the name of Litarachna sagamiensis sp. nov. This species is found in intertidal algae in Sagami Bay on the Pacific coast of Japan. The present new species is characterized by the following: (1) The right and left first coxal plates are separated from each other; (2) the ventral tubercles on the second segment of palp is absent; (3) the ventral tubercle on the fourth segment of palp is present; (4) the ventral glandularium is separated from the first ventral platelet; (5) the ventral glandularium and ventral platelet are located posteriorly to the posterolateral apodeme of fourth coxal plate; (6) the posterolateral apodeme is slender; (7) three pairs of wheel-like acetabula are present in the female; and (8) 49 perigenital setae are present in the male. Litarachna sagamiensis sp. nov. resembles L. duboscqi, L. hongkongensis, and L. marshalli in general morphology, but the new species differs from the latter three species by the condition of the ventral glandularium, the positions of the ventral glandularium and the first ventral platelet, the number of wheel-like acetabula in the female, the shape of the distal margin of medioposterior apodeme in the male, and the number of perigenital setae in the male. This is the third species in the genus Litarachna described from Japan.
Three species of jumping spiders, Nungia epigynaris Zabka 1985, Pancorius submontanus Prószynski 1992 and Thyene orientalis Zabka 1985, all of them new to Japanese fauna, are redescribed on the basis of specimens collected from the Ryukyu Islands. The female of Thyene orientalis Zabka 1985 is described for the first time.
Male spider specimens collected in Thailand were identified as males of Anepsion japonicum Yaginuma 1962. There was no conclusive evidence that female specimens collected at the same time belong to the same species, because the female of the species has not been described. We compared morphological data and mt-COI sequencing data for these female specimens with those of males and concluded that the female specimens belonged to the same species as the males. However, comparison of morphological data for the females and the holotype of Paraplectana japonica Bösenberg & Strand 1906 revealed that Anepsion japonicum Yaginuma 1962 is a junior synonym of P. japonica. Furthermore, after examining the taxonomic features of the holotype of P. japonica, it became clear that this species should be placed in the genus Anepsion. Therefore, the specific name was changed to Anepsion japonicum (Bosenberg & Strand 1906). Consequently, this work permits recording of two new spider species from Thailand: Anepsion depressum (Thorell 1877) and Anepsion japonicum (Bösenberg & Strand 1906).
After examining many specimens identified as Cyrtarachne inaequalis Thorell 1895 from various localities in Japan, females from Okinawajima Is. were found to be morphologically distinguishable from those from the Mainland and to be the independent species, while unidentified male specimens from Okinawajima Is. were found. A comparison of mt-DNA COI gene sequencing data revealed that the males and females from Okinawajima Is. belonged to the same species. The female specimens from the Mainland and Okinawajima Is. were compared with syntypes of C. inaequalis, but neither of the two species could be identified using this approach. Consequently, it was concluded that both of these species are new to science. They are described under the names C. akirai n. sp. (from the Mainland) and C. jucunda n. sp. (from Okinawajima Is.).
Two new species of the spider family Salticidae (Araneae) from Japan are here described: Marpissa yawatai sp. nov. and Mendoza suguroi sp. nov. Although M. yawatai shows similarities in morphology and coloration with the previously described Marpissa nivoyi, the new species can be distinguished by the shape of the lateral cymbial process, the shapes of the embolic base and the retrolateral tibial apophysis on the male palp, and the unique structure of the seminal duct of females. Mendoza suguroi, in contrast, can be easily separated from congeners by its general appearance.