Dorudon atrox — evolutionary link in the origin of whales Photograph ©1998 Philip Gingerich This skeleton of the middle-to-late Eocene archaic whale Dorudon atrox is on display in the University of Michigan . It is the most complete skeleton of an archaeocete found to date, and documents an important evolutionary link between geologically-older ancestral land mammals and the fully aquatic cetaceans living today. The skeleton was found and collected in Egypt in 1993 by Philip D. Gingerich, William J. Sanders, and graduate student William C. Clyde on a UM Museum of Paleontology field expedition. It was cast and mounted for exhibition by alumna Jennifer Gannon, staff from the Exhibit Museum, W. J. Sanders and M. D. Uhen of the Museum of Paleontology, and a large team of University of Michigan undergraduate students. Note the retention of primitive land-mammal characteristics in Dorudon such as complex teeth in the skull, a flexible elbow, and hind limbs with feet and toes. Advanced characteristics of whales present here include modification of the hands as flippers, development of a long and heavily-muscled lumbus or mid-section of the vertebral column (showing that swimming was powered by the tail), and separation of the hind limbs from the rest of the skeleton (showing that Dorudon could not possibly have used these to support its weight on land). Learn more by visiting the exhibit!