Shell very changeable in its sculpture and in its colour pattern. Slim in outline, turricolate. convex whorls and broad suture. Sculpture made by axial ribs (18-20 on the last whorl) and spiral striae giving a reticulated aspect to the surface. However there were collected specimens either with spiral or axial sculpture and wholly smooth too, especially on the last whorls. Mouth roundish in form, umbilicus just sketched. Apex polygyral, at planktotrophic development and, usually, darker than teleconch. Also the colour pattern is changeable: on a ground light yellow there are present, irregularly, stains and flammulae brown in colour Sometimes some juvenile forms, clear in sculpture, are separable with difficulty from other similar ones. While premature forms without sculpture can be confused with species belonging to genus Rissoa. A really similar species is A. litoralis that however has a paucispiral protoconch and a teleconch with a larger number of spiral little cords, a larger mouth and smaller sizes. Moreover it seems this last species has a distribution limited to the Ionian Sea waters. The examination of some topotypes of the subspecies hyperrudis Oberling. 1970, from Amati et al. (1987), confirms the conspecificity with A. rudis. The adult specimens average measures are around 3-3.5 mm in height.

Habitat: It lives in the infralittoral zone, in an algal habitat. Never common.
Distribution: It is found in several localities of the Mediterranean but always rare enough.