Late Oligocene

Chandler Bridge Formation

Charleston, Dorchester County near Goose Creek, SC, USA

Excellent 22mm tooth with both roots.

Mammal, Whale.

The squalodont whales of the Oligocene and Miocene were fully-aquatic yet primitive because they still had heterodont teeth (different shapes) reminiscent of their land-based Eocene ancestors.  Their teeth still had the general form of incisors/canines and premolars/molars but were following a trend toward homodonty (all the teeth of the same shape) as seen in modern toothed whales (odontocetes).  They died out by the end of the Miocene.