Turtle Fossil "Missing Link"
Tue, 30th Jun 2015
Fossils of a primitive turtle, thought to be the missing link in the evolution of the modern-day turtle, have been found in a lake bed in Germany.
The fossils date back to the Triassic period, around 240 million years ago, and show a small reptile, 20-30cm in length known as 'Pappochelys' - taken from the Greek words for 'grandfather' and turtle'. The skeleton consists of very broad ribs which acted as form of 'belly armour' to protect the turtle from predators. It will take at least another 50 million years before the more familiar 'top shell' seen on modern-day turtles is fully formed.
The lake deposits in Germany where the creatures were found are around 5km in length and contained several well-preserved specimens. It is unclear whether the turtles lived along the lake shore or in the water itself, as evidence has been found to support both. The skeleton of the creature for example, shows a thickening of the bones, which is characteristic of a water-dwelling creature. "What we do know is that the turtle shell first evolved in animals that lived in water, as it provided protection from predators in all directions," says co-author Han-Dieter Sues.
Sues' research, published in Nature, also provides evidence of the evolutionary ancestors of the turtle. There has been a longstanding argument as to whether turtles evolved from the ancestors of snakes and lizards or those of dinosaurs along their evolutionary pathway. Sues' believes that the new fossil will provide a definitive answer to this question, "The skull is diapsid, meaning it has a pair of openings in the skull behind each eye, which is very typical of reptiles such as lizards and snakes."
Pappochelys may not have the upright form of its more famous relations, the fictional Teenage Mutant Ninja Turtles, but with its half-formed shell it provides evidence of an important missing link in the evolution of the turtle and for that reason can certainly be described as a 'hero in a half-formed shell'... turtle power!