A New Species of the Genus Geoemyda (Chelonii: Geoemydidae) from the Upper Pleistocene of Tokunoshima Island, the Central Ryukyus, Japan

Abstract

Turtle fossils discovered from the putative Upper Pleistocene fissure-filling deposit on Tokunoshima Island of the Amami Group is described as a new species, Geoemyda amamiensis (Chelonii: Geoemydidae). These fossils include a carapace exclusive of peripherals and a few other elements, fragments of a neural, a costal, eight peripherals, an anterior half of the plastron, two epiplastra, and an incomplete right humerus. Geoemyda amamiensis most resembles G. japonica, an extant species endemic to three islands of the Okinawa Group, but is distinguished from the latter by the presence in dorsal view of a short anterior projection in the entoplastron. These two species seem to have split from each other through vicariance within the central Ryukyus.