Newly discovered Triassic lizard could float underwater to pick off prey - CNN

"A long tail can be used to flick through the water, generating thrust, but the new species we've identified was probably better suited to hanging out near the bottom in shallow sea, using its short, flattened tail for balance, like an underwater float, allowing it to preserve energy while searching for prey," Shang added.

The reptile was well suited for underwater hunting: neutral buoyancy should also have enabled it to walk on the seabed searching for slow-moving prey.

Meanwhile, the skeleton's high density ribs also suggest the reptile had large lungs, increasing the time the species could spend without surfacing.

Paleontologists found another feature that would help Brevicaudosaurus in its underwater exploits: The creature also had thick, long stapes -- bar-shaped bones in the middle ear, used for sound transmission -- which could have helped the reptile hear under the surface.

"Perhaps this small, slow-swimming marine reptile had to be vigilant for large predators as it floated in the shallows, as well as being a predator itself," said co-author Xiao-Chun Wu, a paleobiologist at the Canadian Museum of Nature, in a statement.