Ancient armored amphibian had world's oddest bite

By Will Dunham

WASHINGTON (Reuters) - A peculiar amphibian that was clad in bony armor prowled warm lakes 210 million years ago, catching fish and other tasty snacks with one of the most unusual bites in the history of life on Earth.

The creature called Gerrothorax pulcherrimus, which lived alongside some of the early dinosaurs, opened its mouth not by dropping its lower jaw, as other vertebrate animals do.

Instead, it lifted back the top of its head in a way that looked a lot like lifting the lid of a toilet seat.

"It's weird. It's the ugliest animal in the world," Harvard University's Farish Jenkins, one of the scientists who describe the mechanics of its bite in the Journal of Vertebrate Paleontology, said in a telephone interview on Friday.

"You almost can't imagine holding your jaws still and lifting your head back to take a bite," Jenkins said.

"There are some vertebrates that will lift their heads slightly or the upper jaws (when they bite). Some salamanders do it slightly. Some fish do it slightly. But no animal is known to have done it this extensively," Jenkins added.

The scientists think Gerrothorax lurked at the bottom of a lake, then with a sudden movement of the skull created a mouth gape that entrapped any fish unfortunate enough to swim by.

Gerrothorax measured about 3 feet (1 meter) long and was stoutly protected by bony body armor reminiscent of chain mail. It had a very flat body and very flat head, short, stubby limbs and well-developed gills, Jenkins added.