Peru: They discover a quadruped whale of 42.6 million years

A group of paleontologists discovered on the Peruvian coast the well-preserved fossil of an amphibian and whales quadruped, a discovery that helps to complete knowledge on the transition of mammals from the continent to the sea.

The new specimen, described in a study published in the journal
Current Biology, has 42.6 million years and complete the picture of the evolution of cetaceans.

The fossil was one kilometer from the Pacific coast at Media Luna Beach, 250 kilometers south of Lima. The jaws were flush with the desert floor, and while digging, the researchers found the lower jaw, teeth, vertebrae, ribs, parts of the front and back leg with long fingers that were undoubtedly webbed.

According to the anatomy of the recovered specimen, researchers believe that this cetacean, about four meters long, could walk and swim.

"Some of the vertebrae of the tail had good similarities to those of the current semi-aquatic mammals, such as otters," said paleontologist Olivier Lambert at the Royal Belgian Institute of Natural Sciences.

"We would then have an animal that would have started using the tail more and more to swim, which differentiates it from older forms of India and Pakistan," he said.

The ancestors of whales and dolphins lived about 50 million years ago in what is now the region of India and Pakistan.

Paleontologists have also discovered partial fossils of 41.2 million years ago in North America, suggesting that at that time cetaceans had lost the ability to lift and walk on land.

Pieces of four-legged whales had already been found in Egypt, Western Sahara, Senegal, Togo and Nigeria, but these fossils were so fragmented that it was impossible to conclude whether these animals could swim.

"This specimen is the most complete for a quadruped whale, with the exception of those in India and Pakistan," said Olivier Lambert.

If the Peruvian whale could swim like an otter, the researchers badume that it probably crossed the Atlantic, aided by east-west currents between the west coast of Africa and America South, two continents then twice as close as today. , about 1300 km.

This would rule out the hypothesis that whales came from North America via Greenland.

The Pisco basin, on the south coast of Peru, still contains many fossils, the conditions of conservation being excellent. "It's a job of at least 50 years," says Olivier Lambert.

AFP Agency