Now in contrasting the differences between Bovidae and Antilocapridae the only really useful charachteristic is the shedding of the keratin sheath on the horns. Can paleontologists tell by looking at fossils if the sheath was shed or not?
Their most distinctive feature is their horns, which are like those of bovids in that they consist of a keratinous sheath over a bony core, but differ because the keratinous sheath is shed periodically (annually in males, irregularly in females). These horns are erect and consist of two branches or prongs, a short branch extending forward and located around halfway up the horn, and a longer, backwardly directed tip.
The skulls of members of this family lack sagittal crests. A postorbital bar defines the rear of the orbit. The lacrimal canals of bovids have a single opening, and it lies within the orbit. Pits in front of the orbits, called preorbital vacuities, are often present.