Specimen P 218462 Baleen whale mandible fragments, Mysticeti

Summary

This fossil is a pair of mandible fragments from a baleen whale that lived during the Early Miocene, 21-16 million years ago. Mandible dimensions are proportionate to body size in baleen whales, and these fragments show this whale was approximately 9 metres long. This is much larger than any other baleen whale from this time anywhere in the world, indicating ancient whales from the Southern Hemisphere evolved large body sizes earlier than their northern counterparts.