Sexual Selection and Sexual Dimorphism in Foreclaw Length of Pseudemys

Sexual selection is thought to be responsible for the evolution of ornamental traits that may signal quality to potential mates. Male turtles in the emydid subfamily Deirochelyinae have markedly elongated foreclaws which they use during courtship. We explore whether claw length indicates male quality as measured by body condition and if the degree of sexual dimorphism in claw length and claw growth trajectories vary among three species of Pseudemys (Pseudemys concinna, Pseudemys floridana, and Pseudemys nelsoni) in the Rainbow Run, Marion County, Florida. Claw length was not correlated with body condition (mass relative to size) in these species. Thus, claw length likely does not serve as an honest indicator of male body condition. Claw length is sexually dimorphic in all three species, with P. concinna showing the highest degree of sexual dimorphism. Claw length increases with plastron length in all three species, but proportional claw length decreases with plastron length in P. floridana and P. nelsoni and increases in male and juvenile P. concinna. Variation in the degree of claw dimorphism and claw growth patterns in this study suggests the possibility of unrecognized diversity and complexity in courtship behavior in Pseudemys.