- Carapace oval lacking a keel (may be medially depressed) and no posterior serration.
First vertebral not in contact with 2nd marginal.
No marginal scutes are elevated.
Plastron short and narrow with 11 scutes and two well-developed hinges.
Triangular-shaped pectoral scutes.
- Carapace yellow to brown to olive.
Plastron yellow to brown without pigment.
Skin is brown or olive, with pattern present in some individuals.
Head dark brown with yellow spotting and pair of light stripes on face and neck.
Kinosternon subrubrum is the smallest of Texas' mud turtles with adults reaching carapace lengths of 12.5 cm (5 in).
In the United States, the distribution of Kinosternon subrubrum is widespread across the southeastern United States.
The eastern mud turtle is diurnal with two peak activity periods during the day: early in the morning and late in the afternoon. The most terrestrial of Texas' mud turtles, the eastern mud turtle can be found on land as well as in the water. This turtle species is omnivorous, eating aquatic insects, crayfish, snails, amphibians, and carrion.
Nesting is generally May and June, with females laying 2-4 eggs per clutch. Most females lay a single clutch per year, though some females can lay up to 3 per year. Hatching is August and September following an incubation of 90-100 days.
The eastern mud turtle is found in slow moving bodies of water with soft bottoms and aquatic vegetation, including sloughs, streams, lakes, and marshes.
The eastern mud turtle is not a protected species in Texas and can be legally collected with a hunting license.
In Texas, the single subspecies of Kinosternon subrubrum found in Texas, K. s. hippocrepis is only present in the wetter eastern third of the state.