"Scientists in Egypt have identified a new species of four-legged whale that lived around 43 million years ago." See https://www.bbc.com/news/world-middle-east-58340807 and https://www.npr.org/2021/08/27/1031659020/four-legged-whale-legs-discovered-43-million-years for details.
The BBC article provides the following historical background. "The first whales are thought to have first evolved in South Asia around 50 million years ago. In 2011, a team of palaeontologists in Peru discovered a 43-million-year-old whale fossil with four legs, webbed feet and hooves."
The NPR article says the following.
"A team led by Egyptian scientists have dug up a 43 million-year-old fossil in the Sahara Desert in Egypt of a now-extinct amphibious four-legged whale.
That's right, folks — a whale with legs. ...
"We discovered how fierce and deadly its powerful jaws are capable of tearing a wide range of prey ... this whale was a god of death to most of the animals that lived in its area," Abdullah Gohar, one of the scientists, told Insider.
The new whale is called Phiomicetus anubis, which the scientists named in part after Anubis, the canine-headed Egyptian god associated with mummification and the afterlife. It was likely a top predator at the time, similar to what a killer whale is today.
Whales, it turns out, used to be "herbivorous, deer-like terrestrial mammals," the scientists write. Over the span of about 10 million years, whales turned into carnivorous creatures in the ocean. The discovery of the four-legged creature is part of that evolution."
See also https://www.reuters.com/lifestyle/science/fossil-previously-unknown-four-legged-whale-found-egypt-2021-08-25/ . It says the following.
'CAIRO, Aug 25 (Reuters) - Scientists said on Wednesday they had discovered the 43 million-year-old fossil of a previously unknown amphibious four-legged whale species in Egypt that helps trace the transition of whales from land to sea.
The newly discovered whale belongs to the Protocetidae, a group of extinct whales that falls in the middle of that transition, the Egyptian-led team of researchers said in a statement.
Its fossil was unearthed from middle Eocene rocks in the Fayum Depression in Egypt's Western Desert -- an area once covered by sea that has provided a rich seam of discoveries showing the evolution of whales -- before being studied at Mansoura University Vertebrate Palaeontology Centre (MUVP).
... With rocks covering about 12 million years, discoveries in the Fayum Depression "range from semiaquatic crocodile-like whales to giant fully aquatic whales", said Mohamed Sameh of the Egyptian Environmental Affairs Agency, a co-author.'