Chrysocetus

Chrysocetus; Temporal range: Late Eocene PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Life restoration of Chrysocetus healyorum
	C. fouadassii cast, Vancouver Aquarium
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Infraorder:	Cetacea
Family:	†Basilosauridae
Subfamily:	†Dorudontinae
Genus:	†Chrysocetus; Uhen & Gingerich 2001
Species
	Chrysocetus fouadassiiGingerich and Zouhri, 2015; Chrysocetus healyorumUhen and Gingerich, 2001 (type);

Chrysocetus (from Greek chrysous, "golden", and ketos, "whale", in reference to the gold-colored bones of the type specimen)^[1] is a genus of extinct early whale known from Late Eocene-aged fossils of the eastern United States and western Africa. It is the second smallest basilosaurid after Saghacetus.^[2]

Taxonomy

C. fouadassii cast

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°18′N 80°24′W / 33.3°N 80.4°W / 33.3; -80.4, paleocoordinates 33°18′N 72°30′W / 33.3°N 72.5°W / 33.3; -72.5).^[3] 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.^[1]

A second species, Chrysocetus fouadassii, is known from Bartonian-age deposits of the Aridal Formation of the Western Sahara (25°06′N 13°54′W / 25.1°N 13.9°W / 25.1; -13.9, paleocoordinates 22°24′N 17°12′W / 22.4°N 17.2°W / 22.4; -17.2).^[4] 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, including a left partial dentary (holotype), teeth, some vertebrae, and two left humeri. 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.^[2]

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.^[1]

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.^[2]

Notes

^ ^a ^b ^c Uhen & Gingerich 2001, p. 3
^ ^a ^b ^c P. D. Gingerich and S. Zouhri (August 2015). "New fauna of archaeocete whales (Mammalia, Cetacea) from the Bartonian middle Eocene of southern Morocco". Journal of African Earth Sciences. 111: 273–286. Bibcode:2015JAfES.111..273G. doi:10.1016/j.jafrearsci.2015.08.006.
^ Santee Portland Cement Co. quarry (Eocene of the United States) in the Paleobiology Database. Retrieved September 2023.
^ Gueran (Eocene of Western Sahara) in the Paleobiology Database. Retrieved September 2023.

References

Uhen, Mark D.; Gingerich, Philip D. (January 2001). "New genus of dorudontine archaeocete (Cetacea) from the middle-to-late Eocene of South Carolina". Marine Mammal Science. 17 (1): 1–34. doi:10.1111/j.1748-7692.2001.tb00979.x. hdl:2027.42/73005. OCLC 204061291.

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[MUPDG2001-3-1] Uhen & Gingerich 2001, p. 3

[GingerichZouhri-2] P. D. Gingerich and S. Zouhri (August 2015). "New fauna of archaeocete whales (Mammalia, Cetacea) from the Bartonian middle Eocene of southern Morocco". Journal of African Earth Sciences. 111: 273–286. Bibcode:2015JAfES.111..273G. doi:10.1016/j.jafrearsci.2015.08.006.

[3] Santee Portland Cement Co. quarry (Eocene of the United States) in the Paleobiology Database. Retrieved September 2023.

[4] Gueran (Eocene of Western Sahara) in the Paleobiology Database. Retrieved September 2023.

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