Peninsular Florida (it intergrades with the Eastern Mud, Kinosternon s. subrubrum, in the northern part of the state and then the Eastern and Mississippi mud turtle, K. s. hippocrepis, in the panhandle)
The carapace (upper shell) length is 2.75 – 4.92 in. (70-125 mm) with the plastron (lower shell) relatively large and with two movable hinges rather than one. The color of the domed, smooth carapace can be brown, olive, yellowish, or black; in juveniles the carapace can have three longitudinal keels (raised ridges). The head and neck are generally brown with a variety of lighter colored stripes or mottling. Unlike other species of Kinosternon, the ninth marginal scute (plate or lamina) does not extend dorsally, and the first vertebral scute does not contact the second marginal. This subspecies has a much smaller bridge than the Eastern Mud. Males of this form are larger in body size than females.