Question: what are turtels evolved from

Vera Weisbecker answered on 22 Jun 2011:

Ah, great question! Turtles are one of the great scientific riddles. The problem is that turtles diverged from a reptilian ancestor so long ago that the traces of their ancestry are lost in time. Turtles are a particularly tricky case because they evolved into such a strange shape taht it is really hard to find the similarities between turtles and other reptiles that could be related to them – for example, their skull has a particular shape that no other reptile has. Scientists are now slowly finding out what happened to the turtle skeleton and skull – once that work is finished it will be easier to understand what the turtle ancestor looked like, and what it could have been related to. For example, a lab in Japan recently worked out thath the shoulder girdle of the turtle goes UNDER the rib cage during development because the ribs kind of slide past it. So perhaps we need to look for fossils with a strange relationship between ribs and shoulder girdles…