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Saturday, May 02, 2020

Turtle shell


How the turtle got its shell: Amazing fossils are solving the mystery

For years, the oldest turtle fossils we could find had fully formed
shells. Now, more primitive fossils are revealing the strange
tale of how turtle shells evolved
FE 29 April 2020


New Scientist Default Image
Dorling Kindersley Ltd/Alamy

CONSIDER the floating fortress that is a sea turtle. It seems to fly gracefully through the water even though it is encased in heavy armour. This combination of poise and protection evolved like any wonder of the animal kingdom, yet until recently the fossils we had found made it seem as if they emerged fully formed hundreds of millions of years ago. In fact, scientists who study the evolution of these animals have a running joke: turtles might as well have come from space.
In the past few years, however, truly ancient fossils have been discovered and they are helping to unravel this real-life just-so story. As we uncover fresh clues, we are learning that the tale of how the turtle got its shell reads nothing like we had previously guessed.
In the UK, the word “turtle” usually refers to the reptiles that swim in the sea, but these are just one branch of a larger group that includes species that burrow in desert sand and slog through swamps. Whether we are talking about a Galapagos tortoise, green sea turtle or red-eared terrapin at the pet shop, they all belong to an order called Testudines – which zoologists tend to call the turtles or chelonians.


Read more: https://www.newscientist.com/article/mg24632800-800-how-the-turtle-got-its-shell-amazing-fossils-are-solving-the-mystery/#ixzz6LKXU1lbZ

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