Prehistoric ichthyosaurs evolved rapidly to be as big as whales

 

A newly discovered fossil shows that within just 3 million years of their first appearance on Earth, ichthyosaurs had evolved into 17-metre-long giants

An artist’s impression of Cymbospondylus youngorum

Stephanie Abramowicz

Fossil remains of one of the ocean’s earliest giants have been unearthed in Nevada. Named Cymbospondylus youngorum, this ichthyosaur had a 2-metre-long skull and may have stretched around 17 metres in length.

Lars Schmitz at the W.M. Keck Science Department in California, a member of the team that analysed the remains, describes it as a “jaw-dropping” find.

Ichthyosaurs were marine reptiles that lived between about 249 million and 90 million years ago and had a body shape reminiscent of modern whales and dolphins. Some grew large, and C. youngorum was comparable in size to a modern sperm whale.

It was discovered in roughly 246 million-year-old rocks, so it is only about 3 million years younger than the first ichthyosaurs, which evolved from land-based ancestors. This indicates that ichthyosaurs ballooned in size astonishingly quickly once they took to the seas.