Before the study, eretmorhipis was only known from partial fossils with missing skulls, said Ryosuke Motani, a paleontologist at the University of California, Davis and co-author of the study.

"This is a very strange animal. When I started thinking about the biology I was puzzled," he said.

The discovery has great significance in further understanding prehistoric ecological diversity of marine predators, the plate movement of the Earth and the evolution of marine ecosystems, scientists said in a statement.

Eretmorhipis was found at a fossil lagoon which used to be a shallow sea. It evolved in the lower Triassic Period, a geologic time that spanned about 51 million years to the beginning of the Jurassic Period.

Succeeding the Permian Period, a time when the Earth suffered the largest extinction in history and 96 percent of marine species and 70 percent of terrestrial vertebrates died out, the Triassic Period marked the revival of the planet's biosphere and the evolution of life.

The fossils provide new evidence for the full restoration of marine ecosystems after the mass extinction at the end of the Permian Period, scientists said.