PALEONTOLOGISTS IN PERU have discovered the fossil of 43-million-year-old whale that had four legs, hooves and long, webbed fingers.
The four-legged amphibian, an ancestor of whales, sheds new light on the mammals’ transition from land to the ocean.
The ancestors of whales and dolphins walked on Earth about 50 million years ago in the regions that now comprise India and Pakistan. Paleontologists have previously found partial fossils of the species in North America that were 41.2 million years old suggesting that by this time, the cetaceans had lost the ability to carry their own weight and walk the Earth.
The latest fossil was discovered about one kilometre inland from Peru’s Pacific coast, at Playa Media Luna.
Researchers found the lower jaw, teeth, vertebrae, ribs, parts of front and back legs, and even the whale ancestor’s long fingers that were likely webbed.
Based on its anatomy, scientists say the creature measured about 13 feet – four meters - in length and could both walk and swim.
“Part of the tail’s vertebrae showed similarities with that of present-day semi-aquatic mammals like otters,” lead author Olivier Lambert of the Royal Belgian Institute of Natural Sciences has said.
“This would therefore have been an animal that would have started to make growing use of its tail to swim, which differentiates it from older cetaceans in India and Pakistan.”
Pieces of four-legged whales have been found in Egypt, Nigeria, Togo, Senegal and Western Sahara. But they were so fragmented that it was impossible to decisively conclude whether they could swim.
“This is the most complete specimen ever found for a four-legged whale outside of India and Pakistan,” said Lambert.
If the whale in Peru could swim like an otter, researchers have hypothesized that it likely crossed the Atlantic Ocean from the western coast of Africa to South America. As a result of continental drift, the distance was half that of today – around 800 miles – and the east-west current of the time would have facilitated their travel.
Given its excellent conditions for preservation, the Pisco Basin, off Peru’s southern coast, likely holds numerous fossils.
“We have work for at least the next 50 years,” said Lambert.
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