page_title: Dorudon
section_title: Taxonomic history
hierarchical_section_title: Dorudon / Taxonomic history
caption_attribution_description: Skeletons of the Eocene archaeocete whale Dorudon atrox. (A, B)– Dorudon atrox (5.0 m; 36.5 Ma) based on UM 101222 and 101215 [11] in lateral and dorsal views, respectively. (C, D).
context_page_description: Dorudon is a genus of extinct basilosaurid ancient whales that lived alongside Basilosaurus 40.4 to 33.9 million years ago in the Eocene. They were about 5 m long and fed on small fish and mollusks. Dorudon lived in warm seas around the world. Fossils have been found along the former shorelines of the Tethys Sea in present-day Egypt and Pakistan, as well as in the United States, New Zealand, and Western Sahara.
context_section_description: Gibbes 1845 described Dorudon serratus based on a fragmentary maxilla and a few teeth found in South Carolina. He concluded that the teeth must have belonged to a mammal since they were two-rooted, that they must have been teeth from a juvenile since they were hollow, and also noted their similarity to the teeth then described for Zeuglodon (=Basilosaurus). When exploring the type locality, Gibbes discovered a lower jaw and twelve caudal vertebrae, which he felt obliged to assign to Zeuglodon together with his original material. Gibbes concluded that Dorudon were juvenile Zeuglodon and consequently withdrew his new genus. He did however allow Louis Agassiz at Harvard to examine his specimens, and the Swiss professor replied that these were neither teeth of a juvenile nor those of Zeuglodon, but of a separate genus just as Gibbes had first proposed.
  Andrews 1906 described Prozeuglodon atrox (="Proto-Basilosaurus") based on a nearly complete skull, a dentary, and three associated vertebrae presented to him by the Geological Museum of Cairo. Kellogg 1936, however, realized that Andrews' specimen was a juvenile, and, he assumed, the same species as Zeuglodon isis, described by Andrews 1906. Kellogg also realized that the generic name Zeuglodon was invalid and therefore recombined it Prozeuglodon isis. Since then many specimens have been referred to Prozeuglodon atrox, including virtually every part of the skeleton, and it has become obvious that it is a separate genus, not a juvenile "Proto-Zeuglodon". Kellogg placed several of the species of Zeuglodon described from Egypt in the early 20th century (including Z. osiris, Z. zitteli, Z. elliotsmithii, and Z. sensitivius) in the genus Dorudon.  Gingerich 1992 synonymized these four species and grouped them as Saghacetus osiris.
   
  The current taxonomic status of Dorudon is based on Uhen 2004's revision of Dorudon and detailed description of D. atrox. Before this, the taxonomy of Dorudon was in disarray and based on a limited set of specimens.
  D. atrox is known from Egypt, D. serratus from Georgia and South Carolina in the United States. The type species D. serratus was, and still is, based solely on two partial maxillae with a few teeth, cranial fragments, and a dozen vertebrae with some additional material, collected but not described by Gibbes, and referred to the type species. Before Uhen 2004, D. atrox was based solely on Andrews holotype skull, lower jaw, and the vertebrae he referred to it, but is now the best known archaeocete species.
  The two species of Dorudon differ from other members of Dorudontinae mainly in size: they are considerably larger than Saghacetus and slightly larger than Zygorhiza, but also differ from both these genera in dental and/or cranial morphology. The limited known material for D. serratus makes it difficult to compare the two species of Dorudon.  Uhen 2004 placed D. atrox in the same genus as D. serratus because of similarities in size and morphology, but kept them as separate species because of differences in dental morphology.  Even-though D. serratus is the type species, the description of Dorudon is largely based on D. atrox because of its completeness. The cranial morphology of D. atrox makes it distinct from all other archaeocetes.
caption: Dorsal and right lateral views of reconstructed skeleton of Dorudon atrox
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