ABSTRACT
Acknowledgments .......................................................................................................................... 210 References ...................................................................................................................................... 210
Turtles have one of the most unusual body plans among the amniotes, with a carapace that constrains their behavioral activities differently from all other tetrapods (Gaffney, 1979; Reisz & Laurin, 1991; Laurin & Reisz, 1995; Lee, 1997; Schaffer et al., 1997; Pough et al., 2001; Cebras-Thomas, 2005; Kear & Lee, 2006; Shedlock et al., 2007). Although the origin and evolution of this clade of vertebrates is still unclear despite thorough discussion (Joyce & Gauthier, 2004; Hill, 2005; Nagashima et al., 2005), such a body plan appears to be conservative. However, reduction of the shell has been reported in relation to chelonian life strategies, especially in aquatic turtles (Pritchard, 1979). Evolutionary transformations of the locomotor system in aquatic turtles enable them to display highly adapted mobility and maneuvering, presumably for optimizing searching for food, sexual partners, and areas for egg laying (Davenport & Clough, 1986; Renous & Bels, 1989; Wyneken, 1997; Chapter 5). Although some sea turtle populations nest and feed in the same general areas, others (species or populations within a species) can migrate over great distances. Leatherbacks have probably the
longest migration of all sea turtles because they can be found more than 7000 km from their nesting beaches (Hughes et al., 1998).
