Terrestrial and Freshwater Pulmonate Gastropods from the Early Cretaceous Kuwajima Formation, Tetori Group, Japan

Abstract

Five species of pulmonate gastropods are described from the fluvial deposits of the Early Cretaceous Kuwajima Formation (Tetori Group) of Shiramine district, Hakusan City, Ishikawa Prefecture, central Japan. Gyraulus sp., Aplexa kasekikabe sp. nov. and Zaptychius kuwajimaensis sp. nov. appear to be inhabitants of the marginal zone in shallow lakes. Pseudarinia wangyingensis and Tetoripupa costata gen. et sp. nov. are land snails that probably inhabited vegetated swamps located near shallow lakes. T. costata is the earliest record of the stylommatophoran pulmonate clade Pupilloidea. This fauna contains a common and closely related species to the Jehol molluscan fauna from the Early Cretaceous of northern China, and also appears to be utilizable for paleoenvironmental analysis of terrestrial to freshwater microhabitats.