Acidomomys is a plesiadapiform mammal, meaning that is it a precursor to the primates or very closely related to them. It belongs to the family Paromomyidae. Acidomomys hebeticus fossils were described from the late Paleocene, Clarkforkian freshwater limestones of Clarks Fork Basin, Wyoming. They appear to have an unusual dental eruption sequence, differing from Plesiadapis and other primitive primates and possibly indicating differences in facial appearance or life history.