Fossils over 247 million years old reveal new ichthyosaur species

Chinese scientists discovered the skeleton of a prehistoric fish lizard that has never been described in Guangxi Autonomous Region.

According to the study published in the journal PeerJ, the creature named Baisesaurus robustus lived 247.2 to 251.9 million years ago. At over 3m long, it is the largest ichthyosaur, or ichthyosaur, ever discovered in China during the Early Triassic period.

The study's lead author Han Fenglu, an associate professor at the School of Earth Sciences at the China University of Geosciences in Wuhan, stressed that the new discovery has broadened the distribution range of ichthyosaurs in China. , suggesting that this group of ancient marine reptiles was more widespread than previously assumed.

Simulation of the newly discovered species of Baisesaurus robustus in China.

The Guizhou Geological Survey found fossils of Baisesaurus robustus in limestone in the Zhebao region of the Guangxi Autonomous Region and invited paleontologists from the School of Earth Sciences, the University of Alberta in Canada and the Archeological Center Wuhan Geological Survey participated in specimen analysis.

At the Wuhan Geological Survey Center, the team recovered the fossil for more than three months and found it had relatively slender ribs and did not thicken where they connect to the body. In addition, the lower ribs have a long, thin protrusion in the middle. These are characteristics unique to ichthyosaurs.

The good preservation of the individual bones suggests that the fossils were buried in situ, but water currents may have disturbed the skeletons after the muscle and soft connective tissue had disintegrated.

"Compared to other ichthyosaurs, Baisesaurus had long and strong front bones. That suggests the creature was a stronger swimmer and probably traveled longer distances during the Tethys Ocean migrations." They were probably the top predators at that time," said Han.

Ichthyosaurs lived during the Triassic and Jurassic periods, about the same time as the dinosaurs, and became extinct about 90 million years ago. They have an elongated fish-like body, with large eyes and a large caudal fin. Scientists suspect they evolved from terrestrial reptiles, but their origins and early evolution remain a mystery.

Fish lizards previously found in China, in the provinces of Hubei and Anhui, also date from the early Tam Diep period, but most are smaller than 1.5 m and are capable of road swimming. weak length.