#Oligocene

• Anoplotherium — A fossil ungulate mammal from the late Eocene and Oligocene epochs, characterized by the complete absence of prominent canine teeth and horns, possessing a continuous dentition and a long, robust tail. This extinct genus (Anoplotherium) serves as an essential biostratigraphic marker for reconstructing the fauna and forest environment of the European Paleogene period.
• Anthracotherium — An extinct genus of hippopotamus-like artiodactyl ungulates within the family Anthracotheriidae, that lived during the Oligocene and Miocene epochs across Eurasia and Africa, adapted to a semi-aquatic lifestyle.
• Anthracothere — A fossil ungulate mammal belonging to the family Anthracotheriidae, structurally related to modern hippopotamuses and pigs, which lived during the Eocene and Oligocene epochs, whose skeletal remains have been frequently discovered within geological layers rich in lignite and fossil coal. This large-bodied animal possessed a specific bunodont dentition and short limbs adapted to aquatic or swampy environments, being an essential stratigraphic benchmark for dating carboniferous deposits.