Whale with four legs and hooves that lived 40 million years ago is found in Peru
Scientists believe the marine mammal's four-metre-long (13ft) body was adapted to swim and walk on land
A WHALE with four legs and hooves that roamed the land and sea 40 million years ago has been found in Peru.
The new amphibious species was four-metres long (16ft) and is believed to be first ancestor of whales and dolphins to reach the Pacific Ocean after leaving Asia.
Scientists have unearthed an ancient fossil of the four-legged whale in a coastal desert of southern Peru.
Palaeontologists called it Peregocetus Pacificus - Latin for the travelling whale that reached the Pacific Ocean.
It had small hooves at the tip of its fingers and toes suggesting it could walk on land - but was also had webbed digits and a tail like an otter making it a strong swimmer.
Study author Dr Olivier Lambert, of the Royal Belgian Institute of Natural Sciences, said: "This is the first indisputable record of a quadrupedal whale skeleton for the whole Pacific Ocean, probably the oldest for the Americas, and the most complete outside India and Pakistan.
"It is the most complete skeleton of a quadrupedal (non-pelagicete) cetacean outside Indo-Pakistan.
"It constitutes one of the oldest, if not the oldest, quadrupedal cetacean from the New World and the first indisputable record for the whole Pacific Ocean and Southern Hemisphere. "
THRIVED ON LAND AND SEA
He added: "If you think about Cetaceans the first images that spring to mind are the one of fully aquatic animals but the story of Cetaceans started with small four limbed animals.
"Indeed whales originated more than 50 million years ago from small hoofed animals the size of a dog.
"Palaeontologists discovered many of these early whales in India and Pakistan and these quadrupedal animals gradually acquired adaptations to life in the water but they retained the ability to move on land, so they were amphibious."
He said there were many gaps in the whales' fossil record between them travelling along the northern coast of Africa and making it to North America.
Cetaceans - whales and dolphins - all evolved from a small, four-legged, hoofed ancestor that lived in south Asia more than 50 million years ago.
FOSSIL FOUND IN PERU
The fossilised remains found in 42.6-million-year-old marine sediments along the coast of Peru have shed new light into whales' colonisation of the Americas.
Previous fossil records showed the amphibious mammals crossed the Atlantic from western Africa - at a time the Atlantic was half as wide as it is now.
Dr Lambert said the skeleton showed the new species had a similar anatomy to several early whale ancestors, protocetids, which lived in the Indian Ocean.
He said: "All these shared features suggest similar terrestrial locomotion abilities for this younger protocetid from the Pacific Ocean, with the hind limbs capable of bearing the weight of the body on land.
"In addition, the presence of large pes (rear feet) with elongated fingers and the dorso-plantar flattening of the phalanges with conspicuous lateral flanges indicating webbed pes suggest that hind limbs were actively used for swimming.
"Propulsive movements were either alternate or simultaneous hind-limb paddling or body and tail undulations, as observed in modern river and sea otters, alternating between lift-based propulsion via pelvic undulations, including tail and hind limbs, and drag-based propulsion via independent strokes of the hind limbs."
POWERFUL TAIL FOR SWIMMING
He said it had a powerful tail used for swimming comparable to similar semi-aquatic mammals.
Dr Lambert added: "The moderately elongated snout bearing robust anterior teeth with markedly ornamented enamel and shearing molars suggests that this medium-size protocetid was capable of preying upon relatively large prey, for example large bony fish, an interpretation further supported by the incipient apical dental wear."
Study co-author Mario Urbina, of Museo de Historia Natural-UNMSM, Peru, identified a promising area for digging fossils in the coastal desert of southern Peru, named Playa Media Luna.
In 2011, an international team including experts from Peru, France, Italy, the Netherlands, and Belgium, organised a field expedition, during which they excavated the remains of the ancient whale.
Dr Lambert said: "When digging around the outcropping bones, we quickly realized that this was the skeleton of a quadrupedal whale, with both forelimbs and hind limbs."
The team used microfossils in the sediment layers to date the skeleton precisely to the middle Eocene, 42.6 million years ago.
Dr Lambert said: "The whales would have been assisted in their travel by westward surface currents and by the fact that, at the time, the distance between the two continents was half what it is today."
He said the whales only migrated to northwards after reaching South America.
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The international team continues to study the remains of other whales and dolphins from Peru.
Dr Lambert said: "We will keep searching in localities with layers as ancient, and even more ancient, than the ones of Playa Media Luna, so older amphibious cetaceans may be discovered in the future.
The findings were reported in the journal Current Biology.