Why Turtles Have Shells

turtle fossil

We now know why turtles have shells

We now know why turtles have shells, thanks to a discovery made by an eight-year-old boy in South Africa. The Eunotosaurus, one of the first known turtles, used to live in the South African environment around 260 million years ago. It burrowed in the banks of a dried-up pond to be able to withstand the harsh climate.

Nowadays, the turtle’s shell is used as a protective shield. However, ancient turtles relied on it for a different reason, a new study revealed.

Experts looked at the remains of almost 50 ancient proto-turtles (Eunotosaurus Africanus), which were basically ancient reptiles with partial shells. These animals had flat, broad ribs that may have helped them burrow underground, rather than serving as a protective shield, experts found.

At first, scientists believed that the turtle shell evolved for protection purposes. Now, that belief has ben challenged by this recent study. Lead study author, Tyler Lyson declared that the turtle shell was not for protection. Instead it was useful when digging underground to escape the tough South African environment, home to these early turtles.

The history of the evolution of the turtle shell has long eluded archaeologists. This was mostly because there were not that many critical fossils, to begin with. Research of the fossil record has shown that one of the first shifts towards a functioning shell was the broadening of the ribs.

Strangely, broadened ribs aren’t helpful for protection, because they slow down the creature and make it difficult for the animal to breathe and move. Ribs are used to support the body in movement and to provide room for the expansion of lungs. Broadened ribs impend on the torso of the creature, leading to challenged breathing and slower and shorter strides of the animal.

What is more, ribs in most animals look similar, because they serve the same purpose in all species. The ribs of dinosaurs, snakes, whales, humans and other animals look almost the same. Turtles are a notable exception, being highly modified to form the shell.

Kobus Snyman, an eight year old boy from South Africa, found the missing piece of the puzzle: a 260 million year old fossil. It helped scientists to fully understand the turtle shell’s evolution. It’s likely that the burrowing property of the turtle helped it survive the extinction in the Permian-Triassic. Over the last 50 million years, it turned into the modern turtle we know today, with a fully formed shell.

Image Source – Wikipedia