Meeting Abstract

S7-1.6  Saturday, Jan. 5  Ecomorphological variation in shell shape of the freshwater turtle Pseudemys concinna across different aquatic flow regimes RIVERA, G.; Clemson Univ grivera@clemson.edu

Species with populations that inhabit a wide range of environments frequently display morphological variations that correlate with differences in environmental parameters. Flow velocity is a critical feature of aquatic environments that has been shown to influence morphology in a broad range of taxa, including many fishes. However, studies examining the effect of flow velocity on fishes often have to interpret the complex interactions between modifications of the body and fins that reduce drag and those that increase propulsion. Turtles provide an optimal system in which to examine the effects of flow velocity on morphology, in part because their rigid shell restricts axial mobility and limits the generation of propulsive forces to movements of the limbs, thus decoupling the morphology of propulsory structures and overall shell morphology. In this study I examined the correlations between flow velocity and shell morphology in the freshwater turtle Pseudemys concinna. Three-dimensional coordinates were collected for landmarks from the shells (carapace and plastron) of museum specimens from several lentic and lotic populations. These landmark data were superimposed using the generalized Procrustes method leaving only shape variation to be analyzed using multivariate techniques. These data provide insight into the following questions: (1) does shell morphology differ between lentic and lotic environments, (2) are different parts of the shell (i.e., carapace vs. plastron) more likely to show environmentally correlated differences, and (3) to what degree are physical constraints associated with high flow vs. predation levels associated with the flow environment responsible for morphological differences.