ABSTRACT
The profound structural changes that are correlated with the development of the turtle shell render the skeletal morphology of turtles difficult to compare with that of other reptiles. There are also no fossil intermediates known that link turtles with a more generalized group of reptiles. This not only renders the analysis of the phylogenetic relationships of turtles difficult but also engenders debates about primary homology assessments (Rieppel, 1996; Hill, 2005; for discussion, see Harris et al., 2007). In the present contribution, a brief historical survey of the changing ideas about turtle origins will be followed by a summary of the current status of the debate. A concluding section will discuss the ecological setting of turtle origins.
