Pakicetus
Pakicetus is an extinct land mammal discovered in Pakistan's early Eocene layer (dated by evolutionists as approximately 55-33 million years old). It was discovered in 1983 by three paleontologists including Philip Gingerich, who recently analyzed the Darwinius masillae fossil "Ida."
The original finds from 1983 included only skull fragments. Gingerich classified Pakicetus as a cetacean based on its inner ear, and he originally thought that it was aquatic or amphibious. However, full skeletons were discovered in 2001, and these revealed that Pakicetus was a wolf-like land mammal, with legs capable of running.
Creationism
Creationists view it as a land animal with no connection to cetaceans. Indeed, its inner ear is the only cetacean-like feature in Pakicetus.[1]
Evolution
Pakicetus is currently viewed by evolutionists as a transitional form between land mammals and modern, aquatic cetaceans like whales and dolphins.