Carolinacetus

Carolinacetus is an extinct protocetid early whale found in the Bartonian (40.4 to 37.2 mya) Tupelo Bay Formation (33.3°N 79.7°W / 33.3; -79.7, paleocoordinates 33.3°N 70.9°W / 33.3; -70.9)^[1] in Berkeley County, South Carolina.^[2]

Carolinacetus Temporal range: Middle Eocene, 40.4–37.2 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Suborder:	Whippomorpha
Infraorder:	Cetacea
Family:	†Protocetidae
Subfamily:	†Georgiacetinae
Genus:	†Carolinacetus Geisler, Sanders & Luo 2005
Species
†C. gingerichi Geisler, Sanders & Luo 2005

Carolinacetus is known from an incomplete cranium with portions of the right inner ear, a detached rostrum, and parts of both mandibles with 11 teeth. Preserved from the postcranium are 13 vertebrae and 15 ribs. The holotype was collected in 1994.^[3]

Several anatomical features identifies Carolinacetus as a protocetid (and therefore as a member of Pelagiceti) including: external nares are located above the canine, the supraoccipital (in cetaceans, the part of the occipital bone located above the foramen magnum and directed backwards) is narrow and tubular, accessory cusps absent on M₃, a broad connection between the ectotympanic bulla and the falciform process of the squamosal, axis vertebra with large vertebral foramen.^[4]

In Carolinacetus the naral openings are located in front of P¹, making it the most basal North American cetacean.^[5] Carolinacetus is distinct from other North American cetaceans, it is 8–15% larger than Georgiacetus and differs from it in several cranial characters.^[4]