Fig. 26
From: From Land to Water: the Origin of Whales, Dolphins, and Porpoises
Diagram showing changes in the pelvis of Indohyus (RR 256) and cetaceans. Pakicetids are the earliest cetaceans and had a pelvis that was similar to most terrestrial mammals (composite of H-GSP 30395, 30213). The pelvis of Ambulocetus was large and weight bearing (H-GSP 18507), but, in Basilosaurus (US National Museum 12261), the pelvis was no longer attached to the vertebrae and the ilium was very reduced. In modern bowhead whales (pictured here is the pelvis of an adult male, B. mysticetus, 98B5), the acetabulum and obturator foramen are lost and the ilium is reduced