Studies on skeleton formation in reptiles: Patterns of ossification in the skeleton of Chelydra serpentina (Reptilia, Testudines)

Abstract

Patterns and sequence of ossification are described throughout the skeleton of Chelydra serpentina Linnaeus. Evidence is adduced documenting the decoupling of ossification processes from sequence and patterns of chondrification. Convergence of ontogenetic repatterning in the ossification of the axial skeleton in Chelydra and Squamata is discussed, as are problems of adaptive modification of ossification patterns. The development of a carapace may be correlated with changes of ossification patterns in the postcranial axial skeleton of turtles, but the most striking evidence for the adaptive modification of ossification sequence obtains from a comparison of the limb skeleton and its ossification in Chelydra and in sea turtles