Scientists Solve The Mystery behind Evolution of Turtle Shell

[Eugene]

Source: Science World Report

Scientists Solve The Mystery behind Evolution of Turtle Shell

Benita Matilda First Posted: May 31, 2013 08:15 AM EDT

If you've ever wondered how the turtle got its shell, you aren't the only one. Scientists who have long been mystified by this question have finally resolved the mystery. Careful study of model of an ancient ancestor of modern turtles helped them gain a clear insight into how turtles got their shells.

For the study, published in the journal Current Biology, scientists at Yale University and the Smithsonian Institution studied an extinct fossil of a reptile known as Eunotosaurus. The fossil was found in South Africa.

On analyzing the fossil, scientists suggest that the origin of the turtle shell dates back to some 40 million years prior to what was assumed.

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"Eunotosaurus neatly fills an approximately 30-55-million year gap in the turtle fossil record. There are several anatomical and developmental features that indicate Eunotosaurus is an early representative of the turtle lineage; however, its morphology is intermediate between the specialised shell found in modern turtles and primitive features found in other vertebrates," Lyson explains.

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Read more: http://www.scienceworldreport.com/articles/7214/20130531/scientists-solve-mystery-behind-evolution-turtle-shell.htm

[DreamGypsy]

1. The bone of contention...

...was this:

The ink spilled so far has roughly divided the scientific community in two camps. On one side are those who believe that the turtle shell came about as external bony scales, similar to the ones found on armadillos or certain lizards, fused together with the reptile’s internal rib cage. On the other side are those who believe that reptiles’ ribs instead began to broaden until they eventually formed the bony protrusion that is the shell -- mirroring the way that turtles develop in the egg.

The 260-million-year-old Eunotosaurus supports the second interpretation, showing that an animal without external scales had broadened ribs.

Here's the Eunotosaurus fossil:

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Here's the diagram the scientists composed to highlight their findings:



Looks like they could be the winner.

Thanks for the interesting post, Eugene!