The orbit was large and in a median position, the muzzle not particularly elongated and the neurocranium was rather small.

The premolars progressively grew in size from the first to the fourth, and there was a strong fold in the parastyle.

Adiantoides was first described in 1949, based on fossils including a nearly complete skull and a mandible from the Mendoza Province of Argentina.

Subsequently, in 1983, Adiantoides magnus was described, based on a mandible from the Middle Eocene locality Cañadón Vaca in the Sarmiento Formation, in the Chubut Province of Argentina.

Adiantoides is the best known genus of the Adianthidae, a group of small sized litopterns with characteristic teeth.