Adults grow 28-32 inches. Carapace is low, smooth, oval and uniformly dark gray, brown or black. The pale buff colored plastron is long and narrow and the side margins may be keeled. The head is relatively large and broad. The snout with a slightly hooked upper jaw projects a bit. Large scales run in a strip between the tympanum and eye and there are granular scales on the back of the uniformly brown-black head. Forelegs also have scales on the front. Toes are webbed. Males tails are longer and thicker then females. The young have a white line extending from the corner of the mouth down the neck. With age the develop white random, spider-web-like markings on the central scutes.