Ichthyosaurs are no stranger to researchers. The group of marine reptiles is known to have flourished across the world’s oceans for more than 150 million years. But, the reptile evolved on land, before returning to the oceans. The origins of this evolutionary step has long eluded researchers. Until today.
This missing step comes in the form of Cartorhynchus lenticarpus according to the researchers’ report in the journal Nature. Check out the nearly complete (only a piece of the tail was missing) fossil below.
The fossil was discovered in China’s Anhui Province and is about 248 million years old. It’s about 1.5 feet long, and unlike ichthyosaurs who called the sea home, this one sported flexible flippers much like those you would find on a seal.
The C. lenticarpus also had short nose similar to land reptiles versus the long, beak-like snouts most ichthyosaurs had.
In a press release, lead author Ryosuke Motani talked about how the discovery goes beyond evolutionary science. The C. lenticarpus was alive just 4 million years after the largest mass extinction event in Earth’s history. This recent discovery sheds some light on how long it took predators like this to reappear.
“This was analogous to what might happen if the world gets warmer and warmer,” Motani said. “How long did it take before the globe was good enough for predators like this to reappear? In that world, many things became extinct, but it started something new. These reptiles came out during this recovery.”
Science AAAS touched on the evolution of C. lenticarpus in greater detail.
C. lenticarpus evolved just a few million years after the end-of-Permian mass extinctions, which wiped out as many as 90% of the species on land and 70% of those in the oceans. Therefore, Fischer says, many ecological niches were vacant and ready for evolution to fill them with new and interesting creatures. Reptiles returning to the seas were just one such experiment, and C. lenticarpus was just one species in that gradual evolution.
Image credits: Stefano Broccoli/University of Milan, Ryosuke Motani/UC Davis