You searched for: “ambulocetus natans
Ambulocetus natans (s) (noun) (a plural that functions as a singular)
An early cetacean (marine mammals commonly known as whales, dolphins, and porpoises) that could walk as well as swim: The Ambulocetus natans is the only species classified under the genus Ambulocetus and because it had the appearance of a 3 meter (10-foot) long mammalian crocodile, it was obviously amphibious.