Proganochelys is the most primitive turtle known, first appearing about 210 million years ago. We can recognize in this heavily armored animal some of the features that we see in turtles today. One of these is a normal-looking turtle shell, which consists of a large number of bones, including the ribs, that are fused together to form a solid plate. Although the fossil record provides no clues about how the shell evolved, Proganochelys holds a wealth of evolutionary information. It has no teeth -- turtles lost their teeth very early in their history -- and it has a large ear-opening, an evolutionary development in turtles that we do not fully understand. Its limbs are sprawling, as in all turtles, and in contrast to later vertebrates like dinosaurs.

Proganochelys also presents many primitive features that are quite different from later turtles. The neck, for example, which Proganochelys could not retract, is protected by little spikes that are set in the skin. The animal also has a long tail with armored spikes and studs along its length and a club at the end.

Despite all this information, the origins of Proganochelys, like those of its shell, remain a mystery.