Remains of Jurassic-era reptiles found in Chile’s Atacama Desert

Santiago, Aug 22 (efe-epa).- Scientists from the University of Chile have identified specimens found in the Atacama Desert as belonging to a Jurassic-era class of reptiles known as plesiosaurs that thrived 160 million years ago in what is now the driest place on the planet.

The first discovery of fossils of this category of marine vertebrates in the Atacama dates from 1861 and research carried out in the 1970s showed that they were plentiful in the water that then covered the area.

But the new finds are the most detailed and informative to date, according to the lead investigator, University of Chile biologist Rodrigo Otero.

The team, including scientists from the university and from the Atacama Desert Museum of Natural and Cultural History, were able to assign two of the three specimens to the genus Muraenosaurus, and the third to the genus Vinialesaurus.

Both reptiles had heads measuring roughly 30cm (11.8in) at the end of long necks extending from robust bodies.

The principal difference between them was in length, with the Muraenosaurus coming in at 6m (19.6ft) and the Vinialesaurus at around 4m (13ft).

Previous finds of the Muraenosaurus were in Europe and Argentina, but the specimen uncovered in the Atacama is more substantial than the fragment from the country just across the Andes.

But the Vinialesaurus specimen is the first detected in the Southern Hemisphere.

All three specimens correspond to the Oxfordian, the earliest age of the Late Jurassic epoch, comprising the period between 157 million and 163 million years ago.

The plesiosaur fossils were unearthed in 2018 during excavations at spots in the basin of the Loa River some 20km (12mi) from the city of Calama.

While the Muraenosaurus specimens consist of elements of the skull, teeth, vertebrae and pectorals, the Vinialesaurus specimen is a fragmentary jaw.

The plesiosaurs lived at a time when a portion of what is now northern Chile was under water and the rest was part of the supercontinent of Gondwana, Otero said.

“In the sector we are studying we have found new materials from marine vertebrates, including cranial remains of ichthyosaurs, marine crocodiles and pliosaurs, along with a diversity of fish that range from very little forms to giant filter-feeding forms estimated to be some 10m long,” he said in a statement released by the University of Chile.

Scientists have long thought that starting in the middle Jurassic, marine vertebrates moved between the southern Pacific Ocean and the northern Tethys Sea – now the Atlantic – via what is known as the Caribbean Seaway, a theory consistent with the discoveries in the Atacama.

“These new records give strong support to the exchange of marine vertebrates between the northern Tethys and the southern Pacific through the Caribbean Seaway during the Middle and Late Jurassic,” Otero said. EFE rfg/dr