Researchers say they've discovered an amphibious ichthyosaur fossil in China.
The dolphin-like marine creature thrived in seas about 250 million to 150 million years ago. It had once lived on land.
UC Davis Earth and Planetary Sciences Professor Ryosuke Motani led the team that discovered the fossil.
He says Icthysaurus were the first gigantic reptile fossils that humans encountered.
"It looked like reptiles, but it looked like fish and that puzzled people at the time -- Georgian Age -- and since then, we've been looking for the transition from the land reptile to the sea reptile," says Motani.
Now, that "transition" or link, has been found.
Motani says the sea version of the reptile had an elongated snout, with a flipper that was unusually large and flexible.
He says he plans to look for more fossils in China next spring.