According to New Atlas, scientists have discovered a new fossil of an aquatic reptile that may represent the first giant animal ever recorded on Earth. Named Cymbospondylus youngorum, this animal is a new type of ichthyosaur that dates back to the early stages of the age of the dinosaurs and grew extremely quickly into a giant animal.
The fossils found by researchers in the Augusta Mountains in Nevada include a well-preserved skull, 2 meters long, as well as parts of the skeleton and forelimbs, among others. They are thought to be previously unknown ichthyosaur species, which lived about 246 million years ago.
Ichthyosaurs were an incredibly successful family of marine reptiles that dominated the oceans for about 150 million years, lasting almost entirely the reign of dinosaurs. The prototype resembles a dolphin, with an elongated beak, flippers, and occasional dorsal fins, with an average body length of 2 to 4 meters. But some ichthyosaurs are "giants" in the ocean, with a body length of more than 20 meters.
This new species is one of these "giants". C. Youngorum is estimated to be 17 meters long, not the largest ichthyosaur ever recorded—an honor that currently belongs to a later species, which may have been 26 meters (85 feet) long—but it was the largest ichthyosaur species of its time. In fact, when it appeared in the Middle Triassic, it was probably the largest animal ever seen on Earth until then.
Perhaps most impressive is how quickly it reached this size. In C. Before the emergence of youngorum, the first ichthyosaur species appeared only about 3 million years, which is an incredible speed for the huge evolution.
The fossil's finders believe that the animal was able to accomplish this evolutionary feat thanks to the abundance of prey. About 6 million years ago, Earth experienced the worst extinction event ever recorded at the Permian Triassic boundary. By the time ichthyosaurs emerged, many ecological gaps had already been filled by fish, squid, ammonites, and animals known as toothless insects, and this new abundance of food may have supported foods like C. Ichthyosaurus. The rapid growth of predator species such as youngorum.
In many ways, ichthyosaurs and whales are examples of convergent evolution, where natural forces guide unrelated species to form similar anatomy and survival strategies. In addition to similar body structures, both groups appear to have evolved to enormous sizes, although the team found that they evolved at different rates. Ichthyosaurs grew very quickly into a huge size, and then became smaller again. At the same time, whales took more time to evolve to their massive size and are still the largest animals known.
C. Youngorum's skull is currently on display at the Natural History Museum of Los Angeles County. The study was published in the journal Science.