Late Oligocene

Chandler Bridge Formation

Summerville, SC, USA

20mm tooth.

Mammal, Whale.

The squalodont whales of the Oligocene and Miocene were primitive in that they still had teeth in the general form of incisors/canines and premolars/molars but were following a trend toward homodonty as seen in modern odontocetes.  They died out by the end of the Miocene.