Eastern river cooter

Description:

The broad and slightly flattened carapace is olive green to brownish with yellow markings. The plastron is usually a solid pale yellow, but the front half may have dark markings along the edges of the scutes that form an "X," which usually fades in adults. The plastron is not hinged. The skin is dark with yellow stripes. Most individuals have a rearward facing "C" on the second costal scute. The chin looks flat when viewed from the front. The full-grown female is larger than the full-grown male. A male has long front claws. An old turtle may become dark and lose its color pattern. (taken from "A Field Guide to Oklahoma's Amphibians and Reptiles")