When a terrestrial animal returns to the sea after millions of years, there are some extreme evolutionary changes made. In whales, this is most exemplified by their enormous body mass, which has in the past been believed to be a recent adaptation made by baleen whales as pelagic, active swimmers. However, this is now being contested.

Perucetus colossus is not only a newly discovered species, but a member of a newly discovered genus as well. Its names means the cetacean colossus from Peru, in honor of its homeland. It was discovered by a multinational team with local Peruvian scientists as well as foreigners from Italy, France, Germany, the Netherlands, Belgium, and Switzerland.

P. colossus was a primitive basilosaurid whale from the middle of the Eocene epoch in what is now the Atacama Desert in Peru, in the Ica River Valley. It is believed to have been about nine metric tons larger than the largest blue whale ever discovered (which itself was one hundred and ninety metric tons). However, it was concluded by paleontologists from the University of Pisa in Italy that it could have weighed anywhere between eighty five metric tons and three hundred and forty metron tons.

It had the heaviest bones of any mammal-and they were twice as big as the blue whale’s. It used these big bones for diving in shallow water. This shows that whale sizes peaked over thirty-five million years before the blue whale. It was shorter than the blue whale at twenty meters, but this is still an incredible discovery.

Source: Nature, NYTimes, UNMSM, NLM, WDC, Baleines en Direct