Abstract
Twelve specimens of fossil fish from the lacustrine sediments of the Middle Pleistocene Miyajima Formation of Shiobara Group in Tochigi Prefecture are described in this study. Prior to their description, the extant species Tribolodon hakonensis is osteologically examined for a detailed morphological comparison. Our study identified seven individuals of Tribolodon sp. and five individuals of indeterminate cyprinids in the examined fossil specimens. Tribolodon dominates the known published records of fossil fish from this formation, and we attempted to estimate the pH of the Paleo- Shiobara Lake based on the data of Japanese lakes with modern Tribolodon population.
