These turtles are large and flat with a layer of skin covering the carapace. Smooth Softshells lack horny plates on the shell, which are instead covered with a leathery skin. The carapace is broad, flat, and round, and lacks the spines of other softshell species. It also lacks dark spots and markings on the carapace and limbs. This species’ carapace is pale brown with a yellowish margin, with a dark line bordering toward the middle. The head and limbs are brown and are shaded with yellow or olive. A yellow stripe runs from the tip of the elongated snout through the eye and onto the neck (except in older females). The underside of the turtle is white, and often has bluish tinting over the plastral bones. The webbing of the feet can be bluish, grey, or yellow, and are often unmarked but they may sometimes display some dark speckles.
This turtle is very unlikely to be confused with any species except the Spiny Softshell. The Smooth Softshell differs from the Spiny in being flatter and more circular, and lacking the "spines" on the front of the carapace. Furthermore, the transverse ridges inside the nostrils are not present in the Smooth Softshell.
Ecology and Conservation
This species is somewhat less of a generalist than the Spiny Softshell in habits; it is found almost exclusively in large rivers. Here, it spends a large amount of time in sandy areas and can occasionally be seen basking on logs and banks of the rivers. These turtles are generalist carnivores. A speedy and strong swimmer, this species spends most of its time in or near the water, but can move quickly on land as well. Smooth Softshells prefer larger streams with current, fairly clear water, and a sandy bottom.
Smooth Softshell populations are declining due to human factors, such as agricultural runoff and pollution.
The bulk of the distribution for the Smooth Softshell centers around Midwestern and Midsouthern rivers; following the Mississippi to central Minnesota, the Missouri through southern North Dakota, and the Ohio to western Pennsylvania. Populations extend through eastern Nebraska, Kansas and Oklahoma, and eastern Texas. In the Midwest, this species occurs in Ohio, Indiana, Illinois, Iowa and Missouri, and is a species of Special Concern in Wisconsin and Minnesota.
The Smooth Softshell's distribution in Indiana follows major rivers, including the Wabash, Ohio, and Blue.
The Midland Smooth Softshell (Apalone mutica mutica) is the only subspecies that occurs in Indiana. These turtles are members of the family Trionychidae, which has a total of two representatives in Indiana.
Conant, R. and J. T . Collins. 1998. Reptiles and Amphibians of Eastern and Central North America. Third Edition, Expanded. Houghton Mifflin, New York, NY.
Ernst, C. H. and J. E. Lovich. 2009. Turtles of the United States and Canada. Second Edition. The Johns Hopkins University Press, Baltimore, MD.
Minton, S. A. Jr. 2001. Amphibians and Reptiles of Indiana. Indiana Academy of Science, Indianapolis, IN.