Ancient four legged whale of Peru walked ashore, swam in the sea


WASHINGTON (Reuters) – Scientists have discovered fossils in a southern Peruvian coastal desert of a quadruped whale that thrived at sea and on land some 43 million years ago in a breakthrough that illuminates a crucial stage in the evolution of cetaceans.

The newly discovered Peregocetus whale, which lived about 43 million years ago, is depicted along the southeastern rocky coast of the Pacific in this undated artistic reconstruction obtained by Reuters on April 3, 2019. The fluke of the tail is hypothetical. Alberto Gennari / Brochure via REUTERS

The 13-meter-long mammal, called Peregocetus pacificus, represents a crucial intermediate step before whales fully adapt to a marine life, scientists said on Thursday.

Its four limbs were able to bear its weight in the earth, which means that Peregocetus could return to the rocky shore to rest and perhaps give birth while spending much of his time at sea. His feet and hands had small hooves and were probably trapped to assist in swimming. With long, relatively thin fingers and fingers, moving on land may not have been easy.

His elongated snout and sturdy teeth – large incisors and canines clawed along with meat-cut molars – made Peregocetus adept at catching medium-sized prey like fish.

"We found that it was feeding on water and that its underwater locomotion was easier than on land," said paleontologist at the Belgian Institute of Natural Sciences, Olivier Lambert, who led the research published in Current Biology.

"Some tail region vertebrae share strong resemblances to semi-aquatic mammals, such as otters, indicating that the tail was predominantly used for underwater locomotion," added Lambert.

The evolutionary origins of whales were poorly understood until the 1990s, when fossils of the first whales were found. Several fossils have shown that whales evolved just over 50 million years ago in Pakistan and India from land-dwelling and hoof-living mammals that are close to a medium-sized dog . It took millions of years for them to spread throughout the world.

Peregocetus represents the most complete quadruped whale skeleton outside India and Pakistan, and the first known Pacific region and Southern Hemisphere.

His presence in Peru, Lambert said, suggests that quadruped whales have spread from South Asia to North Africa, crossing the South Atlantic to reach the New World. Peregocetus shows that the first whales to reach the Americas still retain the ability to move ashore.

Over time, the cetacean front members evolved to fins. The hind limbs eventually become mere traces. It was not until about 40 million years ago that the lineage of whales completely evolved into marine animals, so it split into the two groups of live cetaceans today: fin whales that feed on filters and toothed whales like dolphins and killer whales.

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Report of Will Dunham; Edition by Sandra Maler

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