Bulletin of the Mizunami Fossil Museum

Monograph of the Mizunami Fossil Museum No. 8

The Cenozoic decapod crustacean fauna from West Japan comprises 153 species in 90 genera. Se1ected 142 species in 84 genera of decapods, one species of a stomatopod, two species in Bathynomus (isopod), and one species of an amphipod are figured in this vo1ume.

Descriptive remarks, references, occurrences and geologic range for each species are presented. The following nine species of decapods are first recognized from Cenozoic deposits in West Japan: Neocallichirus sp. (Callianassidae) from the lower Pliocene Maja Formation, Pachycheles sp. (Porcellanidae) from the midd1e Miocene Mizunami Group, Epigodromia areolate (Ihle)(Dromiidae), Ranilia misakiensis (Sakai) (Raninidae), Etisus splendidus Rathbun (Xanthidae) and Nursia speciose Dana (Leucosiidae) from the upper Pleistocene Ryukyu Group, Psopheticus sp. aff. P. stridulans Wood-Mason (Goneplacidae) and Naxioides sp. (Majidae) from the upper P1iocene Kakegawa Group, and Randallia eburnean Alcock (Leucosiidae) from the upper Pliocene Masuda Formation and upper P1eistocene Ryukyu Group. Callianassa bona Imaizumi and Calliax okamotoi Karasawa are transferred to Neocallichirus Sakai. Mursia aff. armata de Haan, reported from the upper P1iocene Kakegawa Group by Karasawa (1993), is reidentified with Mursia aff. australiensis Campbell, based on newly obtained specimens from the upper Pliocene Masuda Formation.

Thirty-five decapod assemblages and their palaeoecology are summarized. The geochronological change of the Cenozoic decapod fauna, discussed by Karasawa (1993), is slightly modified.