Weird Fossil Turtle With No Shell Sheds Light On The Turtle Evolution


What makes a turtle a turtle? Its shell and its beak, of course! But paleontologists were impressed when they looked at a fossil turtle which was missing one of its usual traits – the shell.

This fossil was analyzed, and scientists concluded that it lived sometime around 228 million years ago. Its body shaped like a Frisbee was shell-less, but it had the toothless beak modern turtles now have.

Paleontologist Olivier Rieppel (Chicago’s Field Museum) is one of the authors of the study published in Nature. He explains that this is a new species of ancient turtles:

“This creature was over six feet long, it had a strange disc-like body and a long tail, and the anterior part of its jaws developed into this strange beak. It probably lived in shallow water and dug in the mud for food.”

The lead author of the study is Li Chun (Institute of Vertebrate Paleontology and Paleoanthropology, China). Together, the authors named the new species Eorhynchochelys Sinensis which means: “dawn beak turtle from China.” It is the first fossil turtle found with a beak – thus dawn beak turtle, and it was discovered in China (– Sinensis)

Rieppel explains that paleontologists haven’t yet found much about turtles origins:

“The origin of turtles has been an unsolved problem in paleontology for many decades. Now with Eorhynchochelys, how turtles evolved has become a lot clearer.”

Mosaic Evolution

Eorhynchochelys developed a beak but had no shell, proof of mosaic evolution which suggests that traits evolve independently and that ancient species had different combinations of the traits we see in modern turtles.

Nick Fraser from National Museums Scotland is one of the authors of the study, explaining that evolution in early turtles was not in a straight line:

“This impressively large fossil is a very exciting discovery giving us another piece in the puzzle of turtle evolution. It shows that early turtle evolution was not a straightforward, step-by-step accumulation of unique traits but was a much more complex series of events that we are only just beginning to unravel.”

Details found in the skull of this fossil also revealed a mystery – were turtle ancestors part of the reptile group of modern lizards and snakes (diapsids – with two holes on the side of the skulls) or were they anapsids (had no such openings).

Rieppel concluded that this fossil was a diapsid and that they know “turtles are not related to the early anapsid reptiles, but are instead related to evolutionarily more advanced diapsid reptiles. This is cemented, the debate is over.”


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