Dorudon

Dorudon is an extinct genus of early whales that lived in warm seas during the Eocene, roughly 40 million years ago. Its fossils show a fully aquatic whale with small hind limbs and powerful swimming adaptations.

Archaeoceti: Archaeoceti is the parvorder of extinct early whales that includes transitional forms between land mammals and modern whales. Dorudon belongs to this diverse group of Eocene whales.
Whale locomotion: Whale locomotion is the movement of cetaceans through water, chiefly powered by vertical tail strokes. Dorudon's tail vertebrae and body form indicate propulsion by a fluke.
Dorudon atrox: Dorudon atrox is a species of basilosaurid whale known from Eocene fossils, especially in Egypt. This best-known species provides much of the anatomical evidence for Dorudon.
Richard Owen: Richard Owen was a British comparative anatomist and paleontologist who named numerous fossil animals. Owen established the genus Dorudon in the nineteenth century.
Cetacea: Cetacea is the mammalian order comprising whales, dolphins, and porpoises. Dorudon is an early member of the lineage now represented by living cetaceans.
Fluke: A fluke is the horizontal tail fin of a whale, used to generate thrust in swimming. Dorudon's vertebral anatomy indicates it had a functional tail fluke.
Basilosaurus: Basilosaurus is an extinct genus of large, fully aquatic archaeocete whales from the late Eocene. It was a larger basilosaurid that lived alongside Dorudon in ancient seas.
Basilosauridae: Basilosauridae is a family of extinct, fully aquatic archaeocete whales from the Eocene. Dorudon is classified within this family of long-bodied early whales.
Eocene: The Eocene is a geological epoch lasting from about 56 to 34 million years ago. Dorudon lived during this warm epoch, when early whales diversified.
Pachyostosis: Pachyostosis is unusually dense bone growth that increases skeletal mass, often aiding buoyancy control in aquatic animals. Dense bones in some early whales helped counter buoyancy in shallow-water habitats.

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AmbulocetusRelated: Its streamlined body and reduced hind limbs mark a more aquatic condition than Ambulocetus.