Shell squat with low spire, angle usually 70-80°. Shell width more than half shell length. Aperture approximately twice as long as spire. Periphery of body whorl situated closer to apex than to base. Sculptured by numerous fine spiral striae. Whorls with slight to no depression below suture; profile of upper whorls straight. Shell robust. Outer lip thick, aperture usually plicate internally. Dark brown parietal scar usually present. Periostracum thick, fibrous, olive-brown. Shell colour dark bluish-brown, usually with thin pale bluish-grey spiral bands, most visible on body whorj; shell sometimes worn, upper whorls usually worn. Aperture sometimes pale whitish to mauve-brown, sometimes dark brownish-violet. Proboscis flesh coloured. Maximum shell length 46 mm.
Description of holotype: Shell sculptured by numerous fine spiral striae. Whorl hardly depressed below suture. Outer lip crenulated at edge, aperture plicate internally. Dark black brown parietal scar present. Periostracum mostly worn, but at outer edge of aperture thick, fibrous olive green-brown. Shell with alternating dark blue-brown and pale blue grey spiral bands. Aperture dark brownish-violet, whitish at anterior tip.
Dimensions: Shell length 32.0 mm; shell width 20.4 mm; aperture length 23.1 mm; aperture width 10.6 mm; spire length 11.6 mm.

Burnupena rotunda inhabits the low intertidal to subtidal zone. In terms of shell shape, it is most similar to B. lagenaria, both species being typically squat, wilh obtuse spires and relatively large apertures. They do differ in the degree of depression below the suture, with fi. rotunda hardly depressed, and B, lagenaria markedly so; internally the aperture of B. rotunda is plicate whilst that of B. lagenaria is not; the shell colour also differs, with B. rotunda dark blue-brown with pale spiral bands, and B. lagenaria flecked or axially flamed, sometimes brown without flecks, although both species are often worn.
This species occurs in a number of museum collections, but has variously been identified as S. limbosa , B. catarrhacta or B. papyracea. However, it is distinct, both morphologically and genetically (Dempster 1995a). Character states that distinguish it from B. c. limbosa have been discussed above. B. rotunda differs from B. catarrhacta in a number of respects: it has a totally different shape, being low-spired and squat; the relative size of the aperture is much larger; there is little or no depression below the suture; the aperture is usually plicate internally; the shell is thick and robust; the periostracum is thick and fibrous; the shell is patterned with spiral bands and not axial flames. The only case in which B. rotunda has been identified as B. papyracea was that of Orr (1956 - ANSP 196303), who figured a specimen of this species as one of her examples of B. papyracea. However, she synonymised B. limbosa with B. papyracea, so it is not clear to which species she initially attributed this specimen. B. rotunda can be distinguished from B. papyracea by the following characters: (1) the overall shape of the shell of B. rotunda is squat with a low spire, whilst that of B. papyracea is more slender; (2) the profile of the upper whorls are convex in B. papyracea, but not so in B. rotunda; (3) the periostracum in B. papyracea is papery, but is fibrous in B. rotunda; (4) the shell colour in B. rotunda is dark with pale spiral bands, but is reddish- to pale brown in B. papyracea.

West coast from Lüderitz (Namibia) southwards, and extending around Cape Point to Simonstown .