Category Archives: A to Z Challenge

X is for Xylotitan

Xylotitan is a new species of brotothere, a hoofed mammal related to horses and rhinos. Brototheres were giant mammals, considered the earliest of the ‘megaherbivores.’

Among brototheres, Xylotitan is among the smallest, only about the size of a large tapir.

This new species was named in 2016 by Mihlbachler and Samuels.

W is for Washakius

Washakius is a primate known only from the Eocene of the United States.

V is for Viverravus

Viverravus is a carnivorous mammal. Interestingly, I have written up Viverravus in an earlier A to Z Challenge about Paleocene mammals, here. Viverravus as a genus lasted many millions of years.

Here is an early Eocene Viverravus from the Yale-Peabody Museum:

U is for Uintatherium

Uintatherium was a massive hoofed mammal that lived during the Eocene epoch. Superficially, they were rather rhinoceros-like, though they were not related.

Notably, Uintatheres had many horns and protuberances on their skulls, in addition to robust tusks.

T is for Tapocyon

Tapocyon is a genus of miacid carnivores that lived during the Paleocene and Eocene epochs of North America. It was a climbing mammal that likely spent a great amount of time in trees.

S is for Smilodectes

Smilodectes is an extinct primate that lived in North America during the Eocene.

R is for Reithroparamys

Reithroparamys is another extinct rodent from North America. Species of this genus ranged from the late Paleocene into the mid-Eocene. Four species are known from this genus.

Q is for Quadratomus

Quadratomus is an Eocene rodent. There are four species within this genus all of which lived in North America.

P is for Protylopus

Protylopus is an extinct type of camel that lived from the middle to late Eocene in North America. It is the oldest known camel.

O is for Ourayia

Ourayia is a fossil primate, which, like Notoparamys, is related to tarsiers. Like many fossil mammals, it is best known for its teeth.