The fossil of a strange marine reptile called Sclerocormus parviceps proves that reptiles actually evolved faster than previously thought during the mass extinction 250 million years ago, according to a study published on May 23 in the journal Scientific Reports. Sclerocormus was an ichthyosauriform but unlike other ichthyosauriforms, it did not have teeth, had a short snout, and long whip-like finless tail.

The international team of researchers explains that Darwin’s model of evolution dictates animals experience gradual but small changes over time but the Sclerocormus disproves all the ideas of how ichthyosauriforms should have looked like.  Ichthyosauriforms resembles present-day dolphins a bit with its long snouts, streamlined bodies and tail fins.

Unlike its relatives, however, the Sclerocormus’ snout indicates that it created pressure to suck food, kind of like a syringe. On the other hand, other ichthyosaurs had conical teeth used to catch their food.

marine reptile

This is a Sclerocormus parviceps, the newly described marine reptile. Credit: Da-yong Jiang

“Sclerocormus tells us that ichthyosauriforms evolved and diversified rapidly at the end of the Lower Triassic period,” says Olivier Rieppel, the curator of evolutionary biology at The Field Museum in Chicago. “We don’t have many marine reptile fossils from this period, so this specimen is important because it suggests that there’s diversity that hasn’t been uncovered yet.”

The reptile’s rapid evolution also sheds light on how life adapts to environmental changes, particularly during a mass extinction. Rieppel says that further investigations about the Sclerocormus’ recovery and ecosystem may not help solve the crisis that humans face but these can still improve current theories on evolution.

The mass extinction 250 million years ago involved destructive volcanic eruptions, climate change and increased sea levels. Scientists believe that the event affected marine life the most, killing 96 percent of all marine species.

This study entailed the collaboration of researchers from University of California, Davis, Università degli Studi di Milano, National Museums Scotland, The Field Museum, Smithsonian’s National Museum of Natural History, Chinese Academy of Sciences, Peking University, and Anhui Geological Museum.