Evolution of the molar teeth in elephants as to size and type of grainding surface. Elephas Longitudeinal View (Adapted from Storer, General Zoology)	Elephas (Recent) Stegodon (Pliocene) Mastodon (Pleistocene) Tetrabelodon (Miocene) Palaeomastodon (Oligocene) Moerotherium (Eocene)
Phylogeny of the elephant showing increase in size and in relative length of tusks and proboscis since the Eocene epoch. (Adapted from Osborn, and from R.S. Lull, Fossils, the University Society, New York.)