Turtle

Turtles were a species of reptile.

The Doctor once materialised the TARDIS on the back of a giant prehistoric turtle. (BFA: Absolution)

Bernice Summerfield kept two turtles as pets while living in isolation. (BFA: The Shadow of the Scourge)

Life forms which seemed to be descended from turtles or turtle-like creatures included Sea Devils, Chelonians, and Jixen.