Odontochelys
Taken together, these anatomical differences mean that Odontochelys has some of the most primitive features ever seen in a turtle and is somewhat of a transitional fossil. Some scientists, however, are skeptical of this idea. Reisz and Head suggest that Odontochelys does not represent a turtle with a partly evolved shell, but that it is a descendant of an older, land–living turtle, and that the shell became reversed. Such shells can be seen on modern turtles, like the leatherback turtles (the genus Dermochelys).