A New Species of Plesiosorex (mammalia, Eulipotyphla) from the Early Miocene of Japan: First Record of the Genus from East Asia

A nearly complete dentary with preserved i2, p3 and m1 of a relatively large soricomorph from the Dota locality, Kani Basin, Early Miocene (ca. 18.5 Ma), Nakamura Formation of the Mizunami Group in central Japan, is described as a new species of Plesiosorex. It represents the fi rst record of the genus in East Asia. Plesiosorex fejfari sp. nov. has a slender dentary, posteriorly elongated angular and condyloid processes, p3 with two roots, and m1 without hypoconulid or cingulid. Cladistic analysis of Butselia gracilis and seven species of Plesiosorex shows that Butselia is basally positioned with respect to Plesiosorex, and it seems likely that Plesiosorex originated in Europe at the beginning of the Miocene and expanded its distribution to East Asia and North America during the Early Miocene. Two Middle Miocene North American species are more closely related to each other than to European species of the same age.