Geographic Variation of Dymecodon pilirostris (Eulipotyphla: Talpidae) with an Insight to Mountain Island in Japan

Mountains are home to many endemic species. Such organisms are isolated by the environmental gradient around mountains. Such isolation would affect various kinds of populations' diversity of mammalian species among mountains in Japan. This study examined the skull morphology of the lesser Japanese shrew mole Dymecodon pilirostris True, 1886 (Eulipotyphla: Talpidae), which is distributed in high mountain areas of Honshu, Shikoku, and Kyushu Islands, Japan. Univariate and multivariate analyses were performed on the basis of 19 measurements obtained from 104 skull specimens. The results showed morphological differences among mountain ranges, in overall skull size, teeth row length, and mandibular height. This morphological divergence was revealed in mountain ranges in Honshu, even among the neighboring mountain ranges from Akaishi, Kiso, and Hida, so-called the Japan Alps. The geographic divergent pattern suggests that the morphological evolution of D. pilirostris occurred in each mountain island in Japan. Received 13 March 2023. Accepted 30 April 2024.