Here's How Turtle Got Its Shell

Researchers have finally figured out the answer to a question that has been puzzling everyone for a very long time: how did the turtles get their shells?

According to a study, the fossilized remains of a 240 million-year-old reptile have provided researchers with significant insight as to how turtles evolved.

Researchers named the fossil remains of 240 million-year-old reptile - Pappochelys (Greek for "grandfather turtle").

The discovery of Pappochelys fills the gap between the oldest known turtle, 220 million-year-old Odontochelys from China, and 260 million-year-old Eunotosaurus from South Africa, which is thought to be its ancestor.

According to researchers, the fossil provides the missing link between the two specimens.

Researchers noted that the Pappochelys does not closely resemble turtles as we know them today. Instead, it has broad, sturdy ribs that fan out from its spine and a line of hard, shell-like bones along its belly.

"Early on, you first make broad ribs," Hans-Dieter Sues, a paleontologist with the Smithsonian's National Museum of Natural History, explains to NPR. "Then you build the belly shell. Then you complete the back shell. And then you have basically what's a modern turtle."

Researchers described the Pappochelys as being about 8 inches long (20 cm), with slender legs, a long tail and neck, and "a strange, boxy trunk region."

"They are often unexpected and show surprising features," explained Rainer R. Schoch from the Natural History Museum in Stuttgart, Germany, in an interview with Reuters. "They show how complicated structures like the skull or turtle shell formed step by step, and also give evidence on the sequence of evolutionary steps."

The article has ben published in the journal Nature.