A newly discovered fossil of a tiny turtle like creature has led scientists to finally solve the mystery of how the turtle got its shell. However, the story is not a Rudyard Kipling funny fable! The findings were published in the journal Nature on Wednesday, and track the evolution of the turtle body plan through millions of years of history.
Pappochelys, whose name means “grandfather turtle,” lived about 240 million years ago in a warm sub-tropical lake, Hans-Dieter Sues, a co-author of the Nature study and curator at the Smithsonian Museum of Natural History in DC, told NPR.
By examining fossils that spanned millennia and continents, researchers were able to figure out how the modern turtle’s unique shell transformed from what was just a brief area of bones on the belly about 240 million years ago.
The origin of the turtle shell has long puzzled scientists. Though they had fossils of turtle predecessors from the beginning and the end of the Triassic period, there was little evidence of what happened to ancient turtles during the intervening years.
The bones of the 260 million-year-old Eunotosaurus, a reptilian creature found in South Africa, had wide, flat ribs and a sprawling, turtle-like figure, but it was far from the armour-encased animal we know today.
The next time a turtle ancestor popped up in the fossil record, the Odontochelys about 220 million years before present, it had a fully developed belly plate called a “plastron” that would eventually expand to enclose the turtle’s whole body, protecting it from attacks from above and below.
But there was nothing in the huge 40 million-year void between the two ancient species to explain where that plastron came from.
“Hopefully we’ll find more,” Robert Reisz, a palaeontologist at the University of Toronto, told National Geographic after the Odontochelys was first found in 2008. “We’re closing the gap, but there is still a big morphological gap between this turtle and its non-turtle ancestors.” Enter Pappochelys, the hero of our story, ready and willing to fill that gap! The exciting new discovery has added some much needed excitement into the slow and steady life of a turtle! And if you own a turtle then you now know exactly how it got its shell!