Large ocean fossil discovered in Nevada could hold key to aquatic evolution

An 8-foot-long skull discovered in the Augusta Mountains of Nevada is the largest fossil ever found from its time. The research team believes that the remarkable discovery could provide insight into how modern whales developed, and how to preserve their presence in our oceans. 

The fossil — a newly discovered species of ichthyosaur, a type of large aquatic reptile — dates to about 246 million years ago. The newly-named cymbospondylus youngorum is, according to the research team, the largest animal found from that time period, both in the sea and on land. It currently holds the title of the first giant animal to ever inhabit Earth.

The well-preserved skull was excavated along with part of the creature's backbone, shoulder and forefin. At more than 55 feet long, the ichthyosaur was estimated to be the size of a large sperm whale, according to the study released Thursday by the American Association for the Advancement of Science and the Natural History Museums of Los Angeles County.

The ichthyosaur has an elongated snout and conical teeth, leading researchers to believe it ate squid and fish. It also could have hunted smaller marine reptiles and younger members of its species. 

Paleontologists believe the ichthyosaurs grew exponentially within several million years, and that their growth was due in part to a massive increase in its prey, which included ammonoids and eel-like conodonts. These species' populations boomed after a mass extinction called the end-Permian Extinction.

"That's one way this study stands out, as it allowed us to explore and gain some additional insight into body size evolution within these groups of marine tetrapods," said Dr. Jorge Velez-Juarbe, an associate curator of the Natural History Museum of Los Angeles County.

The cymbospondylus youngorum is "a testament to the resilience of life in the oceans after the worst mass extinction in Earth's history," he added. 

"Ichthyosaur history tells us ocean giants are not guaranteed features of marine ecosystems, which is a valuable lesson for all of us," Lene Delsett and Nicholas Pyenson, co-authors of the piece, wrote about the study. "Especially if we want to sustain the presence of the surviving ocean giants among us that contribute to our own well-being."