Whipenguin

The Whipenguins are the ancestors of the Penguins. They lived from 500,000 B.C. until the Babbelonian Plague wiped them out in 300,000 B.C.

Background
Whipenguins evolved from Pelepengs in about 500,000 B.C. The Whipenguins and the Pelepengs fought each other until the Pelepengs became critically endangered. Pelepengs eventually went extinct, but the Whipenguins survived. They split up into clans, which were united in 300,010 B.C. The tribes grew into a powerful Empire that dominated all of Antarctica. In 307,000 B.C., the emperor was overthrown and the country became an oligarchy. In 304,000 B.C., the united Whipenguin nation collapsed. They'd only last for 4,000 more years until the Babbelonian Plague would bring them to extinction. They were very vulnerable to it, which meant they became extinct. Their fossils have been found almost everywhere.