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A new species of ancient ancestor of the whale has been identified from a fossilized skeleton discovered in Peru.
This illustration shows an artistic reconstruction of two individuals from Peregocetus pacificus, one standing along the rocky coast of present-day Peru and the other feeding on sparse fish. Image credit: A. Gennari.
Appointed Peregocetus pacificus, the four – legged whale lived about 43 million years ago (middle Eocene time).
His skeleton was discovered in the marine sediments of the Playa Media Luna on the south coast of Peru.
It was analyzed by Mr. Olivier Lambert of the Royal Belgian Institute of Natural Sciences and his colleagues from Italy, France and Peru.
"This is the first indisputable record of a quadruped whale skeleton for the entire Pacific Ocean, probably the oldest for the Americas and the most complete outside of the world." India and Pakistan, "said Dr. Lambert.
The anatomical details of the skeleton allowed paleontologists to deduce that the animal was able to maneuver its large body (up to 4 m or 13 feet in length, including tail), both on land and in the water.
For example, the characteristics of the caudal vertebrae (in the tail) are reminiscent of those of beavers and otters, suggesting a significant contribution of the tail during swimming.
"The presence of small hooves at the fingertips and toes of the whale and its morphology of the hip and limbs suggests that this whale could walk on the ground," said Dr. Lambert and his co-authors.
"On the other hand, the anatomical features of the tail and feet, including long webbed appendages, similar to those of an otter, indicate that he was also a good swimmer."
The geological age of Peregocetus pacificus and its presence along the west coast of South America strongly support the hypothesis that primitive cetaceans have reached the New World across the South Atlantic, from the west coast of South America. 39, Africa to South America.
"The whales would have been helped in their journey by the west surface currents and by the time, at the time, the distance between the two continents was half of what it is today. hui, "said the researchers.
"It was only after reaching South America that amphibious whales migrated north to finally reach North America."
The research was published online this week in the journal Current biology.
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Olivier Lambert et al. An amphibian whale from the Middle Eocene of Peru reveals the dispersal of quadruped cetaceans in the South Pacific. Current biology, published online April 4, 2019; doi: 10.1016 / j.cub.2019.02.050
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