Eomystis

Eomystis is an extinct genus of toothed whale belonging to the Mysticeti suborder. Its fossils have been discovered in Oligocene-aged rock formations. Eomystis represents an important transitional form in the evolution of baleen whales, demonstrating features intermediate between fully toothed whales and the modern baleen whales that filter feed. It possessed heterodont dentition, meaning that its teeth were of different shapes and sizes, unlike the homodont dentition (teeth of uniform shape) found in odontocetes (toothed whales). Eomystis is significant for providing evidence of the gradual loss of teeth and development of baleen plates in mysticete evolution. Further research is ongoing to fully understand its phylogenetic relationships and the exact role it played in the diversification of baleen whales.