Distinctive neural bones in Dipsochelys giant tortoises: Structural and taxonomic characters

The carapace of turtles consists of characteristic dermal bones (neurals, costal, and pleurals) and epidermal scutes. The variation in neural bone configuration in the Indian Ocean giant tortoise genus Dipsochelys is assessed. Study of 42 specimens supports earlier reports that variation is largely restricted to the anterior and posterior bones. Each species of Dipsochelys possesses a distinctive arrangement of neural bones. The configurations are related to the carapace shape with the relative width of the bones and interdigitating processes influencing structural stability. An exceptional configuration is described for the saddle-backed species D. arnoldi, wherein this configuration arises from musculoskeletal adaptations for browsing in this species. J. Morphol. 240:33–37, 1999. © 1999 Wiley-Liss, Inc.