| Named By: | J. H. Geisler, A. E. Sanders & Z. Luo in 2005 |
| Time Period: | Middle Eocene |
| Location: | USA, South Carolina, Berkeley County - Tupelo Bay Formation |
| Size: | Total size of the holotype skull estimated about 1 meter long. Tota size of the body unknown |
| Diet: | Carnivore/Piscivore |
| Fossil(s): | Partial skull, mandibles and post cranial remains including ribs and vertebrae |
| Classification: | | Chordata | Mammalia | Cetacea | Archaeoceti | Protocetidae | |
Carolinacetus is an extinct protocetid early whale found in the Bartonian (40.4 to 37.2 mya) Tupelo Bay Formation (33.3degN 79.7degW / 33.3; -79.7, paleocoordinates 33.3degN 70.9degW / 33.3; -70.9) in Berkeley County, South Carolina.
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.
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.
In Carolinacetus the naral openings are located in front of P1, making it the most basal North American cetacean. Carolinacetus is distinct from other North American cetaceans, it is 8-15% larger than Georgiacetus and differs from it in several cranial characters.