Scientists have discovered a fossil of a new ancient marine animal that resembles present-day dolphins. The said fossil gives a hint of how marine reptiles survived mass extinction 250 million years ago.

A study published in the journal Scientific Reports tags the new marine reptile as the Sclerocormus parviceps. The said creature breaks all the past theories of scientists that marine life after the 250-million year extinction evolved slowly as the recent discovery revealed that the Sclerocormus parviceps, in fact, evolved faster.

Aside from its rapid evolution, the Sclerocormus parviceps' appearance also differ from its ichthyosaur cousins. Ichthyosaurs commonly have streamlined bodies and long snouts; however, Sclerocormus parviceps have short snouts and a long tail that resembles a whip. It's also toothless and picks up it food through its snout that functions like a tube.

Olivier Rieppel, the Field Museum’s Rowe Family Curator of Evolutionary Biology, told Christian Science Monitor that the recent discovery shows that these creatures are more diverse.

"Not only is there more diversity in the late lower Triassic as documented now, but the interesting thing is in this later lower Triassic, you have these ichthyosauriforms, these early ichthyosaur animals of which Sclerocormus is one," Riepel added. “But between the lower and middle Triassic, there seems to have been a bottleneck and these early ichthyosauriforms disappeared from the fossil records. And then in the middle Triassic, real ichthyosaurs kick in and had to go through rapid diversification."

She further explained that the "rapid diversification" of these animals shows that in mass extinctions, evolution is always at work, and this is how these creatures survived. Currently, the planet is facing a mass extinction, but it's different from what happened millions of years ago as it's caused by humans. To know more about mass extinctions on Earth, check out the video below.