Two-hundred 44 million years ago, an 8.6 meter-long monster ruled the ocean that covered what is today America's western desert.

In a study supported by the National Geographic Society, an international team of scientists describes the giant predator, whose fossilized remains were found on a remote Nevada mountain range in 2010. Named Thalattoarchon saurophagis – or lizard-eating sovereign of the sea – the ichthyosaur is the first top predator in the marine food chain that fed on prey its own size, similar to modern orca whales.

Thalattoarchon had a massive skull and jaws, with large teeth that could easily slice through other marine reptiles in the Triassic seas. Ichthyosaurs lived at the same time as dinosaurs and roamed the oceans for 160 million years.

The appearance of Thalattoarchon comes just eight million years after a massive extinction that killed as many as 96 percent of the world's marine species. The report, which appears in the journal Proceedings of the National Academy of Sciences, concludes that the relatively rapid rise of the predator shows how quickly an ecosystem can recover and evolve. The authors say this ancient history sheds new light on the dynamics of Earth's evolution and the impact humans are having on today's environment.