Equus caballus antunesi, nova subspecies, was a hypsodont, slender, and rather small horse (around 141cm at the withers), with narrow hooves and protocones longer on P3/-P4/ than on M1/-M2/. It does not fit in any of the different "types" of Pleistocene caballine horses previously recognized but may be related to the horse from the Acheulean of Solana del Zamborino.
Hypsodonty, small size, slenderness, narrow hooves are all characters that can easily be related to ecological conditions. Equus caballus antunesi was probably a horse adapted to rather dry and cold conditions and to a hard ground. It does not seem related at all to the North-European Equus caballus germanicus-gallicus group. 

Remarkable association of a small infraorbital foramen, similar to that in recent Heterocephalus, and of a strong muscular print on the dorsal anterior part of the zygomatic plate and on the premaxillary. Several anatomical structures to be compared with those of Heterocephalus suggest relationships with this genus. Richardus supports the ancestrality of the hystricomorph character in the bathyergids