Monday, 11 April 2011

The oldest bags from the Triassic: Odontochelis and Proganochelys.

Proganochelys quenstedti
Sea turtles have been around for a long time, we know that. The oldest turtle known, up until 2008, was Proganochelys quenstedti. Its fossils were discovered in Thailand and Germany and dated back to the Triassic period, some 210 million years ago. 
Apparently it was around 1 metre long and heavily armoured by a shell that acted like a cage containing the internal organs. The carapace and plastron were already in the modern form but it had also some additional plates along the shell that, probably, protected its legs. Its tail was protected by spikes and ended in a sort of club.

It could not retract its neck, which was, again, protected by small spines. Overall, not a very pretty site. But again, who needs pretty when you are the oldest bag in the turtledom? For a few years "Proga" was sitting quite happily on a shelf in the American Museum of Natural History and it was showing off its fossilised remains. It must have been a very popular turtle because it had many nicknames: Chelytherium ("Turtle Beast"), Psammochelys ("Sand Turtle"), Stegochelys ("Roof Turtle") and Triassochelys ("Triassic Turtle"), like an Apollo Creed from the Triassic time. A big boost to one's ego, I'd say.

Odontochelys semitestacea
And then it all ended. In 2008 an older fossil was discovered in Ghizou, China: Odontochelys semitestacea. This was a much older las, about 220 million years, and much, much prettier than its younger relative. However, don't get excited, it was still quite different from modern turtles. First of all it only had a plastron, but not the carapace; secondly it had teeth instead of a beak. Apparently the Odontochelys semitestacea was an aquatic turtle since it was found in a marine deposit. Just to complete this quick overview on the old bags, Odontochelys would mean "toothed turtle with a half-shell". Couldn't they just say that?

Thanks for your attention and see you in a while with a real funny bunch from the Jurassic period.

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