The fossils of three ichthyosaurs -- giant marine reptiles that patrolled primordial oceans -- have been discovered high up in the Swiss Alps, and include the largest ever tooth found for the species, a study said Thursday.
With elongated bodies and small heads, the prehistoric leviathans weighed up to 80 metric tons (88 US tons) and grew to 20 meters (yards), making them among the largest animals to have ever lived.
They first appeared 250 million years ago in the early Triassic, and a smaller, dolphin-like subtype survived until 90 million years ago. But the gigantic ichthyosaurs, which comprised most of the species, died out 200 million years ago.
Unlike dinosaurs, ichthyosaurs barely left a trace of fossil remains, and "why that is remains a great mystery to this day," said Martin Sander of the University of Bonn, lead author of the paper in the Journal of Vertebrate Paleontology.