Fossil hunters have found the remains of a giant carnivorous amphibian that patrolled ancient lakes and rivers at the dawn of the age of the dinosaurs.

The salamander-like predator grew to the size of a small car and feasted on the fish that thrived in the waterways of the Late Triassic Period, more than 200m years ago.



The new species, Metoposaurus algarvensis, belonged to a wider group of amphibians that were common in lower latitudes 220m to 230m years ago, when the dinosaurs began to dominate the land.



Researchers from the University of Edinburgh identified the new species from a haul of bones dug from mudstone in Loulé, in the Algarve region of southern Portugal. The bone bed may contain the remains of hundreds of amphibians that perished when an ancient lake dried up. To date, only a fraction of the site has been excavated.

“There is a real jumble of bones in there, but it’s been challenging to remove them because they come from a bone bed that is about half a metre thick and goes into the hillside,” said Steve Brusatte, who led the study. The team have spent two field trips excavating bones from the site and hope to return to collect more of the remains.



The new species, which in adulthood measured two metresfrom snout to tail, is the first member of the Metoposaurus group of amphibians to be discovered on the Iberian peninsula. Others have been found in Germany, Poland, Africa, India and North America.



According to a report in the Journal of Vertebrate Paleontology, differences in the jaw structure, and parts of the skull where the spinal cord meets the brain, reveal the Portuguese remains to be a new species. The creature had a long, flat head, likened by Brusatte to a toilet seat lined with thousands of tiny teeth.



Remains of other Metoposaurs held in museums have occasional bite marks on their bones, the likely result of ancient encounters with early dinosaurs that waded into ponds and lakes in search of food.

Though a top predator in its own right, Metoposaurus had small, weak limbs for such a large animal. The relative puniness of its legs meant it could not venture far onto land, and so could easily be stranded if its watery home dried out.

Most of the Metoposaurs were wiped out during a mass extinction about 201m years ago, long before the demise of the dinosaurs. The event marked the end of the Triassic Period, when the vast prehistoric landmass known as Pangea began to tear apart into the continents we see today. Giants rifts in the land and an upsurge in violent volcanic activity killed off many of the major vertebrates, including large amphibians, leaving space for the dinosaurs to rise to prominence.



“There would have been dramatic swings in the environment as Pangea broke apart. Even though it took a long time, these big amphibians did not cope with that well at all,” said Brusatte.