Meeting Abstract

P3.79  Wednesday, Jan. 6  Functional Implications of Shell Shape Differences between Male and Female Painted Turtles (Chrysemys picta) and Wood Turtles (Glyptemys insculpta) VEGA, Christine M.*; STAYTON, C. Tristan; Bucknell University; Bucknell University cmv007@bucknell.edu

Sexual dimorphism in shell shape is observed in many species of turtle. Females need to be able to accommodate clutches of eggs, and consequently have wider and more highly domed shells, while males tend to have flatter, more streamlined shells. In addition, the males of many terrestrial species show concave plastrons to compensate for the domed shells of the females during mating. This study investigates the mechanical implications of shell shape differences between males and females of two Northeastern US species, Chrysemys picta and Glyptemys insculpta. Landmarks on the specimens’ shells were collected from dorsal, lateral, and ventral views; these data were used to create digital models of the shells for finite element analysis. Eight load cases were analyzed – the resulting data set was used to compare males and females of the same species. Female shells for both turtle species developed significantly lower stresses for a given load than their male counterparts. Male Glyptemys insculpta experience significant stresses because of the concave shape of their plastrons.