ANCESTRAL PROBOSCIDEANS (Earliest "Elephants")

The early geologic history of proboscideans is based on some poorly known early genera of Paleocene/Eocene age from northern Africa and also some additional genera of unknown affinities of Oligocene to early Miocene age. By middle Miocene time, the proboscidean record became better established, because by then, the mastodons, mammoths, and elephants evolved. These conclusions are depicted below in my generalized diagram, which is based on my overview of the literature.

There is a lack of agreement among the experts as to whether or not the Paleocene/Eocene “proboscideans” were truly proboscideans. By a series of gradual evolution, these early genera progressively became more and more proboscidean-like (i.e., tusks-like teeth becoming more evident, head becoming larger, and the body becoming heavier). An overview of some of most of these genera is shown in the following four figures.

Eritherium: Paleocene (about 60 million years ago), Morocco, North Africa; fox-size. This genus is commonly mentioned as being the earliest possible proboscidean. It would be the smallest proboscidean and the least evolutionarily derived (i.e., basal member). It did not have true tusks, but it does have what looks like “incipient tusks” in its lower jaw. Not every expert, however, is convinced of that conclusion.

Numidotherium: Early to middle Eocene (about 46 million years ago), southern Algeria, North Africa; three feet high at the shoulder and weighing up to several hundred pounds. It has an “incipient tusk” in its upper jaw. Apparently, this animal, which also had a “trunk,” might have been semi-aquatic in its life habits.

Barytherium: Late Eocene, Sahara, North Africa; six feet high at the shoulder and weighing several hundred pounds. It had two pairs of tusks (one pair in the lower jaw and another pair in the upper jaw). Barytherium was similar in shape to a hippo but apparently with a trunk.

Moerithium: Late Eocene to early Oligocene, Egypt, North Africa; modern-day tapir in size. Skull tapered. It had neither a trunk nor tusks although one of the upper and lower incisors are elongate and could have been “incipient tusks.” This animal also had five toes and a long tail. Drawings of the reconstructed shape of this fossil vary greatly in their appearance! This animal might have lived in swampy areas.

During the Oligocene and early Miocene, there were a few genera (e.g., Phiomia) of proboscidean-like animals with “unknown affinities.”  By middle Miocene time, undoubted proboscideans had evolved and soon became widespread.