WASHINGTON - It looked like an odd lizard with a bulky body and only the skeletal precursor of a shell, but scientists say 240-million-year-old fossils unearthed in a quarry in southern Germany represent the grandfather of all turtles.
The scientists on Wednesday announced the discovery of the oldest known turtle, a 20cm-long Triassic Period reptile combining traits of its lizard-like ancestors with a set of emerging turtle-like features.
They named it Pappochelys, meaning "grandfather turtle", owing to its position at the base of the turtle family tree.
"Pappochelys indeed forms a missing link for two reasons. It is far older than all turtles known so far. And its anatomy is more primitive in many features, showing the ancestral condition of various body regions," said palaeontologist Rainer Schoch of Germany's State Museum of Natural History Stuttgart.
It is 20 million years older than the previous earliest-known turtle, Odontochelys, from China.
Pappochelys, known from 18 fossil skeletons, had a long tail, broad trunk and, rather than a beak as in later turtles, a lizard-like skull with numerous peg-like teeth suitable for eating insects and small lizards. It resided alongside a freshwater lake and may have used its tail for swimming and legs for steering in the water.
Dr Schoch said Pappochelys, as a transitional creature between lizard-like ancestors and turtles, provides a clearer picture of turtle evolution. Transitional creatures "show how complicated structures like the skull or turtle shell formed step by step". The research appears in the journal Nature.