(CNN)The whales we know today look nothing like they did millions of years ago.
Instead, cetaceans, the group including today's whales and dolphins, evolved 50 million years ago from small four-legged animals with hooves.
Rather than being one of the largest creatures on Earth, as they are now, they came from creatures that were the size of an average dog.
Paleontologists have discovered skeletons of these early creatures in India and Pakistan, but this new find, as discussed in Thursday's edition of the journal Current Biology, was found in the Pisco Basin on the southern coast of Peru.
The 2011 find by Mario Urbina and his international team contained several surprises.
"As this is the first four-legged whale skeleton for South America and the whole Pacific Ocean, the discovery in itself was a major surprise," study co-author Olivier Lambert wrote in an email. Lambert works at the Royal Belgian Institute of Natural Sciences. "We were also surprised with the geological age of the find (42.6 million years ago) and with the preservation state [of] so many bones from most parts of the skeleton, even including a patella (kneecap), some small ankle bones, and the last phalanges with marks of tiny hooves."
This is the oldest known whale found i