Meeting Abstract

P2.100  Monday, Jan. 5  Variation in shell shape of flattened and loggerhead musk turtles RIVERA, G.*; MCGILL, R.T.; RIVERA, A.R.V.; BLOB, R.W.; Clemson University; South Carolina Governor’s School for Science and Mathematics; Clemson University; Clemson University grivera@clemson.edu

The flattened musk turtle (Sternotherus depressus) and the loggerhead musk turtle (Sternotherus minor) are closely related species within the family Kinosternidae. While these species can have similar color patterns and are similarly sized, they display distinct shell morphologies, with the carapace of S. depressus being flattened in comparison to S. minor. This variation in shape has been attributed to differences in habitats and anti-predator behaviors, particularly the presence of and preference for sheltered crevices. Sternotherus depressus is endemic to the Black Warrior River Basin of Alabama and inhabits shallow fast-flowing water with rocky substrates. In contrast, S. minor inhabits slow-flowing water with sandy bottoms and is found throughout Alabama and other southeastern states, but is excluded from the Black Warrior River Basin. Although it is well established that shell shape differs between these species, it is not clear if these distinctions are equally prominent for both sexes, or if they are maintained throughout growth to adult size. To examine these questions, we used geometric morphometrics to compare differences in three-dimensional shell shape of Sternotherus depressus and Sternotherus minor for both sexes over a range of sizes. Interspecific differences in shell shape were significant for both males and females; however, males of the two species converge in shape with increasing size. Such convergence in shape might reflect a preference for similar habitats among larger males of these species.