Tanystropheus prehistoric reptile, illustration. This long-necked fish-eating reptile is thought to have been an aquatic animal most of the time. It lived around 245-228 million years ago during the Middle Triassic. Tanystropheus could reach a length of 6 metres long. If a predator caught it by the tail, it could detach it and regrow another one. Fossils of the reptile were first found in Germany, Europe and other fossils have been found in Asia.