Almost a quarter of a billion years ago in the state of Nevada, a massive sea monster inhabited the area. Named Cymbospondylus youngorum, the huge fossil of this new ichthyosaur species was found back in 1998 in rocks from the Augusta Mountains.
However, it took until 2015 and with help from a helicopter for all of the fossils to be removed from the site. The remains were then brought to the Natural History Museum of Los Angeles County where experts have since been studying them.
Their detailed analysis revealed that the creature was massive with a skull that measured 6.5 feet in length (2 meters), meaning that the entire body of the Cymbospondylus youngorum would have been more than 55 feet long (17 meters) and weighed about 45 tons. In an email to Live Science, Lars Schmitz, who is an associate professor of biology at Scripps College in Claremont, California, described the species, “Imagine a sea-dragon-like animal: streamlined body, quite long, with limbs modified to fins, and a long tail.”
It lived about 247 million years ago during the Triassic Period. It would have occupied the Panthalassic Ocean off the western coast of what is now North America when the land was the supercontinent of Pangaea. It is believed that the Cymbospondylus youngorum would have feasted on ichthyosaurs that were smaller than itself, as well as fish and perhaps squid.
In a time span of about 2.5 million years, ichthyosaurs grew to massive lengths. Interestingly, it took almost 55 million years for whales to reach their sizes – the same size that it took ichthyosaurs just 1% of their 150-million-year history to achieve.
Schmitz explained this further, “We have discovered that ichthyosaurs evolved gigantism much faster than whales, in a time where the world was recovering from devastating extinction [at the end of the Permian Period].” “It is a nice glimmer of hope and a sign of the resilience of life — if environmental conditions are right, evolution can happen very fast, and life can bounce back.”
As for why ichthyosaurs grew to such massive sizes in such a short time period, it may be partly caused by feasting on large amounts of marine mollusks called ammonoids and eel-like jawless conodonts that grew in population numbers after the mass extinction event. Two studies in relation to the Cymbospondylus youngorum have been published in the journal Science – they can be read here and here.
A picture of the fossil and an image of what the Cymbospondylus youngorum would have looked like can be seen here.