Tusk

Jack Harkness once recalled an encounter with a six foot tall creature with big white tusks. (TV: Boom Town)

Species with tusks included Aggedors (TV: The Curse of Peladon) boars, (AUDIO: The Stuff of Nightmares) Pellonians, (AUDIO: The Paradise of Death) Rills, (TV: Galaxy 4) Saurians, (PROSE: Lords of the Galaxy) Tanik's species (PROSE: Wish You Were Here) and Thijarians. (TV: Demons of the Punjab)

In the pre-universe before the Time Lords created history, there existed cities with buildings carved into gigantic ivory tusks that sprouted from the ground in mile high arches. (PROSE: Christmas on a Rational Planet)