Zeuglodon

Zeuglodon, the earliest genus that can be with certainty assigned to the Cetacea (q.v.). It occurs in the Eocene, especially in Alabama, Louisiana, Mississippi and Arkansas, but has been found in the Barton Clay of Hampshire. The name means "yoked teeth" from the double fang, the genus had originally been thought reptilian, and named Basilosaurus. The molar teeth have compressed crowns with serrated edges.