Chrysocetus

Chrysocetus (from Greek chrysous, "golden", and ketos, "whale", in reference to the gold-colored bones of the type specimen) is a genus of extinct early whale known from Late Eocene-aged fossils of the eastern United States and western Africa.

Taxonomy
The type species, Chrysocetus healyorum, is based on a single subadult specimen from the late middle or early late Eocene of Orangeburg County, South Carolina (33.3°N, -80.4°W, paleocoordinates 33.3°N, -72.5°W). The holotype, SCSM 87.195, consists of a partial skull with lower jaws, ten teeth, and the hyoid apparatus; 21 vertebrae, some ribs and a sternum; a partial left forelimb; and partial innominates.

A second species, Chrysocetus fouadassii, is known from Bartonian-age deposits in the Western Sahara (25.1°N, -13.9°W, paleocoordinates 22.4°N, -17.2°W). The species name honors the collector M'Barek Fouadassi, who led a paleontological expedition to the region in 2014. C. fouadassii is known from fragmentary specimens of four individuals. It possessed teeth and vertebrae similar to those of C. healyorum but differs by having a longer humerus, 22.5 cm without the proximal epiphysis. The same bone part of C. healyorum is only 15.6 cm.

Description
Chrysocetus is similar to Zygorhiza except that it lacks the denticles on the cingula of the upper premolars characteristic of Zygorhiza. The premolars of Chrysocetus have smoother enamel than other dorudontines and are more gracile than those of Dorudon.

Paleoecology
C. fouadassii lived in the zone of a shallow shelf with other archaeocetes such as Platyosphys, Eocetus, Pappocetus and indeterminate protocetids. Shark teeth and fish bones were found in the same formation.