Shell size typical of the genus; fusiform, elongate, slightly rounded whorls. Suture slightly impressed. Protoconch paucispiral, about 1.3 smooth whorls. Transition to teleoconch almost invisible. Teleoconch with about 4.6-4.7 whorls. Axial sculpture of weak axial riblets on the first whorl and first half of second whorl. Spiral sculpture of broad, flattened spiral cords with narrow interspaces, lacking on first whorl, with 11 cords on second and penultimate whorl and 22 cords on final whorl. The basal cords on the body whorl are stronger and more rounded and ventrally range to the adapical end of the columella. Outer lip thickened, bearing continuation of the spiral sculpture and basal cords. Inside of the outer lip denticulate with 7 denticles. Columellar callus thickened. Parietal callus weak. Columella with a weak rim of semi-merged denticles. Siphonal canal short, open, slightly recurved. Teleoconch whorls white to cream, without any pattern. Protoconch white. Aperture and columella white. Holotype height 6.2 mm.

A. rimatara n. sp. is closest to Aoteatilia caledonica K. Monsecour & D. Monsecour, 2016 with which it shares the axial sculpture on the early teleoconch whorls. It differs in its larger size, the higher number of spiral cords and the presence of denticles on the inside of the outer lip.

French Polynesia, Australes. Rimatara and Rurutu.