Shell elongate, narrow (length:width ratio 2.27-2.45) with high spire (aperture about 0.41-0.45 of total length); columella usually distinctively straight; whorls coarsely granulate, except on basal half of last whorl, which is contrastingly smooth and rather shiny; apex rather narrowly domed, about 7.1-8.3 mm in width at third whorl. Pale brownish-yellow with dark reddish-brown axial bands, usually wavy or interrupted. Attains 103 mm in length.
A coastal species occurring in KwaZulu-Natal and adjacent Pondoland, from the Mtamvuna River north to Durban, and inland to Oribi Gorge. Inhabits leaf-litter in coastal and scarp forest; seldom common.
A. semigranosa is somewhat similar in form to the higher altitude A. drakensbergensis, but the granules are much stronger and do not continue onto the base of the body whorl as in that species. It also resembles A. semidecussata, but is a larger, coarser species, with a broader apex, straighter columella and heavier stripes.