Mythosaur

Mythosaurs were a non-sentient species native to the Outer Rim planet of Mandalore. Enormous in size, the mythosaurs dominated their world until the arrival of the Mandalorian Taung, led by the warrior known as Mandalore the First. In a campaign to conquer the world for their own, Mandalore the First and his crusaders slaughtered the gigantic beasts and drove them to extinction. The skull of the mythosaur became the symbol of the Mand'alor—the traditional ruler of all the Mandalorian clans—the planet Mandalore, and of the Mandalorians themselves for generations after.

Text and facts from the “Mythosaur/Legends” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.