Fossil in Peru may be the heaviest animal that ever lived – 8/3/2023 – Science

Scientists in Peru have discovered fossils of an animal that may have been the heaviest ever on planet Earth.

It is an ancient and long extinct whale that would weigh around 200 tons.

Only a few of the largest blue whale specimens could have rivaled its weight, researchers say.

The fossilized bones of the animal were unearthed in the desert in southern Peru – which is why it received the name Perucetus colosso.

Dating the sediments around the bones suggests the animal lived about 39 million years ago.

“The fossils were actually discovered 13 years ago, but because of their size and shape it took three years just to get them to Lima (capital of Peru), where they have been studied ever since,” explains Eli Amson, of the discovery team. led by paleontologist Mario Urbina.

Eighteen bones were recovered from the marine mammal, which is a primitive type of whale known as a basilosaurid. This includes 13 vertebrae, four ribs and part of a hip bone.

But even considering the age of the fragments and the fact that they were broken into pieces, scientists were able to decipher a lot about the creature.

It was evident that the bones were extremely dense, the result of a process known as osteosclerosis, in which the internal cavities fill up. The bones were also larger than normal, a result of another process called pachyostosis.

These were not disease traits, the team said, but rather adaptations that would have given this large whale the power to float and forage for food in shallow water. Similar bony features are seen, for example, in modern manatees, or sea cows, which also inhabit coastal zones in certain parts of the world.

“Each vertebra weighs more than 100 kg, which is completely mind-boggling,” says Rebecca Bennion of the Royal Belgian Institute of Natural Sciences in Brussels, who worked on the research.

“It took several men to move them to the middle of the floor in the museum for me to do a 3D scan. The team drilled into the center of some of these vertebrae to calculate the bone density. The bone was so dense that it broke the drill on the first try. attempt.”

When faced with a skeleton of a long-extinct species, scientists use models to try to reconstruct the animal’s body shape and mass. They do this based on what they know about the biology of comparable living creatures.

It is predicted that Perucetus would have been 17 to 20 meters long, which is not exceptional. But your bone mass would be between 5.3 and 7.6 tons. And when organs, muscle and fat are added, the animal could have weighed – depending on estimates – anywhere from 85 to 320 tonnes.

Amson, curator at the State Museum of Natural History in Stuttgart, Germany, believes the average weight was 180 tons.

The largest blue whales recorded during the era of commercial exploitation were at this scale.

“What we like to say is that the Perucetus is in the same field as the blue whale,” he told the BBC.

“But there’s no reason to think that our specimen was particularly large or small; it was probably just part of the general population. It’s worth bearing in mind that when we use the median estimate, it’s already in higher ranges than blue whales. can measure.”

One of the fossils used by scientists as a benchmark is a blue whale that is very familiar to anyone who has visited the Natural History Museum in London.

Nicknamed Hope, the skeleton of this animal gained prominence at the institution when it was hung from the ceiling of the main hall in 2017.

But before it was installed, the skeleton was scanned and described in great detail – which is now an important data resource for scientists around the world.

In life, the skeletal mass of Perucetus would have been two to three times that of Hope, although the London mammal was a good five meters longer.

Richard Sabin, the curator of marine mammals at the Natural History Museum, is thrilled with the new find and would love to take some parts of it for display in London.

“We took the time to scan Hope – to measure not just the weight of the bones but also their shape, and our whale has now become something of a touchstone for people,” he said.

“We don’t stick to labels – like ‘which was the largest specimen?’ – because we know that science at some point will always come up with new data.

“What’s amazing about Perucetus is that it was so massive over 30 million years ago, when we thought gigantism occurred in whales just 4.5 million years ago.”

The discovery was published in the journal Nature.

This text was originally published here.