Paleontological Research, vol. 4, no. 2, pp. 107-129, June 30, 2000 © by the Palaeontological Society of Japan Taxonomic revision of Pisulina (Gastropoda: Neritopsina) from submarine caves in the tropical Indo-Pacific YASUNORI KANO 1 and TOMOKI KASE2 ' Department of Biological Sciences, Graduate School of Science, the University of Tokyo, 3-23-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan (Mailing address: Department of Geology, National Science Museum, 3-23-1 Hyakunincho, Shinjuku-ku, Tokyo 169-0073, Japan:
[email protected]) 2 Department of Geology, National Science Museum, 3-23-1 Hyakunincho, Shinjuku-ku, Tokyo 169-0073, Japan (kase ©kahaku.go.jp) Received 1 December 1999; Revised manuscript accepted 14 February 2000 Abstract. Species of the tropical Indo-Pacific gastropod Pisulina (superorder Neritopsina), previ- ously known only from empty shells and regarded as a genus of Smaragdiinae (Neritidae), are re- vised on conchological criteria. Pisulina dwells in gloomy to totally dark, tropical and subtropical, shallow-water submarine caves, where their empty shells are ubiquitous. Study of the previously described modern and fossil species and examination of newly collected material from more than 50 submarine caves on Pacific islands show that there are six species in the genus: P. adamsiana Nevill and Nevill, 1869 (Holocene), P. subpacifica Ladd, 1966 (late Miocene), P. biplicata Thiele, 1925 (Recent), P. maxima new species (Recent), P. tenuis new species (Recent), and Pisulina sp. (Pleistocene). An analysis of previously unstudied shell characters (shell form, shell microstruc- ture, protoconch morphology, and opercular features) of Pisulina and other modern, representative genera of Neritopsina places the genus close to the freshwater and brackish-water genus Neritilia, based on three unique characters (inclined protoconch, spiral ridges on the protoconch surface, and perpendicularly arranged prisms in the outer shell layer), and both genera are herein included in the family Neritiliidae.