[3][4] The former species was named after Spanish naturalist Félix de Azara, while the latter species was named after Lieutenant Colonel John James Porteous (1857–1948) and his nephew Don Cecil John Montague Porteous (1884– 1953), who owned land in Argentina.

Body mass ranges anywhere between 100 and 250 g, with males typically larger than females.

They have a stocky, robust body shape with short limbs and ears.

Their foreleg claws are their primary method of digging tunnels through the ground, although the incisors may be used occasionally.

Populations in the Andean Precordilla region of Mendoza display high selectivity for grasses and avoidance of shrubs with a preference for above ground plant material, despite a fossorial lifestyle and harsh environmental conditions that lower food availability.