Morphological and stratigraphic evidence indicates that land-living mesonychian ungulates are broadly ancestral to early amphibious and later aquatic cetaceans. The transition from terrestrial ungulates to aquatic whales is a transition from life in air to life in water. Air and water differ in density and are very different media for sound propagation. Thus perception of air-borne sound by land mammals and perception of water-borne sound by whales require markedly different functional adaptations. Here we describe and compare the basicranial morphology of mesonychian ungulates and archaeocete cetaceans to establish stages of morphological transformation of the basicranium and evolution of hearing in whales. (Go to the link and see more of this paper.)

Publisher: University of Michigan

Month of Publication: July

Year of Publication: 1999

Location: Ann Arbor, MI

Volume Number: 31

# of Pages: 98