The flattened musk turtle was once found in the upper Black Warrior River system of Alabama, upstream from Tuscaloosa, which is on the fall line between the Piedmont Plateau and the coastal plain. Since 1930,
several dams have been built on the river and near the fall line. The resulting reservoirs were more favorable for another turtle, Sternotherus minor peltifer. Where the ranges of the two turtles overlapped, interbreeding occurred to the detriment of the flattened
musk turtle population.
Genetically pure populations of this turtle are now believed to exist only in the Black Warrior River system, upstream from Bankhead Dam in Blount, Cullman, Etowah, Jefferson, Lawrence, Marshall, Tuscaloosa,
Walker, and Winston Counties of north-central Alabama.
This turtle is mostly found in clear, shallow streams above the fall line. Rocky to sandy-bottomed streams are preferred.
Sternotherus depressus ranges from about 3 to 5 inches (7.5 - 13 cm) in carapace length; record in 4.6 in (11.7 cm). When compared with other musk turtles, Sternotherus depressus has a carapace that is quite flattened. The top of the carapace is
brown and the small plastron is either pinkish or yellowish-brown. The head and neck are greenish with a network of dark lines around them, and there are barbels located on the chin.
come out of the water and deposit their eggs in shallow nests dug into the ground near the stream. Each female chooses a different site. Clutch size appears small; two eggs are reported in one clutch. Eggs are oblong, about 32 mm long, with brittle shells.
The incubation period is probably dependent on temperature and perhaps other physical factors, but ranges from 45 to 122 days. Once hatching begins the actual emergence from the egg takes anywhere from 12 hours to two days. The hatchling has a carapace length
of about 26 mm. Growth to maturity may take four to six years for males, and six to eight years for females.
This turtle feeds primarily on freshwater mollusks andmussels. Large adult musk turtles
have expanded jaws for crushing mollusks.