Sternotherus carinatus (Gray)
Mississippi Musk Turtle.
Peripheral in Escatawpa River and its tributaries in Mobile County. Possibly occurs in Red Creek in Washington County. Long known from Mississippi, it was first documented from Alabama in 1994. MODERATE CONSERVATION CONCERN.
A small (max. carapace length = 17.6 cm [7 in.]) turtle with a prominent vertebral keel present in all individuals from hatchling to old adult. Carapace light brown to orange, with dark spots or streaks; pattern may become obscure as individuals age. Lacks gular scute of other kinosternids, which typically have 11 plastral scutes. Plastron an immaculate yellow. Skin of head and legs gray to brown or pinkish, with small dark spots. In cross-section, shell has one keel and a sharp slope, shell of stripe-necked musk turtle one keel with a gentle slope, and shell of the loggerhead musk turtle has a central vertebral keel, with a pair of secondary lateral keels (Carr 1952, Conant and Collins 1991, Ernst et al. 1994). Based on similarity of pattern and coloration, razor-backed musk turtle appears more closely related to flattened musk and loggerhead musk turtles; stripe-necked and loggerhead musk turtles were once considered subspecies of razor-backed musk turtle. Electrophoretic studies, however, have shown the razor-backed musk turtle to be more closely related to the stinkpot (Ernst et al. 1994).
Southeastern Oklahoma to southern and eastern Texas, southern Arkansas, Louisiana, south-central Mississippi, and extreme southwestern Alabama. In Alabama, only reported from Escatawpa River (Blankenship et al. 1995). Mount (1975) felt species might be present in Alabama, but at the time of his writing had not been found (Conant and Collins 1991, Ernst et al. 1994, Mount 1975).
Throughout majority of distribution inhabits rivers, slow streams, and swamps that have little current, a soft bottom, and abundant aquatic vegetation and bask sites. In Alabama’s Escatawpa River, deviates from this characterization in that the river is a sand-bottomed, blackwater stream, with little to no aquatic vegetation.
LIFE HISTORY AND ECOLOGY:
In comparison to other members of Sternotherus, has strong proclivity to basking. Active from March through November, with daily activity peaks between 4:40 to 11:00 a.m. and 3:00 to 10:00 p.m. from June to September. Females reach maturity in four or five years, males in five or six years. Mating observed in captives in March, with eggs being laid in early May and early June. One or two clutches of eggs are laid per year, with an average of five to seven eggs. Only natural nest reported contained a clutch of two. Generally a bottom feeder; searches for food with a fully extended neck. Omnivorous; feeds on insects, crustaceans, molluscs, amphibians, plants, and carrion. Adults killed by humans, while nests are depredated by many species of mammals, and hatchlings are fed upon by fish, water snakes, and other turtles (Conant and Collins 1991, Ernst et al. 1994).
BASIS FOR STATUS CLASSIFICATION:
Presence in Alabama based on collection of two specimens; therefore, information on life history, ecology, and distribution in state extremely scant.
James C. Godwin