MORPHOLOGICAL FEATURES OF THE MOLARS OF THE JAPANESE MOUSE, APODEMUS SPECIOSUS (RODENTIA, MURIDAE), FROM THE KUNASHIR ISLAND

Seven new characters were revealed in 722 molars of the Japanese mouse, Apodemus speciosus, from the Kunashir Island, Kuriles. The absence from the Kunashir population of characters previously identified for the Japanese mouse from the island of Honshu, Japan, both Recent and fossil (Holocene, Middle and Late Pleistocene), as well as the stabilization of new traits, indicates either the Kunashir population could have passed through sharp declines in numbers or a small number of founders, or a new type of nutrition. New features of the molars of the mice supplement the list of the morphological and morphometric characteristics of the Japanese mouse and can serve as the basis for clarifying the morphological features of A. s. ainu, as well as to continue the study of the populations from Hokkaido and the small islands adjacent to it.