Smith's description of this characteristic species is masterly, and nothing can be added, save that the radial lirae number 71-78 in adults. The larger of the two specimens illustrated by him seems to be slightly more elevated than normal, causing the foramen to appear more posteriorly situated than in most. Although Barnard (1963a: 292) doubted whether it was distinct from D. elevata (Dunker), levicostata differs in its markedly recurved apex, much weaker and predominantly radial sculpture, in the more oblong, more posteriorly situated foramen, and in the internal callus which surrounds the latter being less strongly truncate behind. In general form there is a far greater resemblance to D. crucifera (Pilsbry), but that has a different type of sculpture. Turton's photographs of his sculpturata exhibit the diagnostic features (in particular the barely elevated radial ribs) of levicostata.
Distribution:
Natal: Tongaat (Smith); Umkomaas, Clansthal, Scottburgh, Shelly Beach (all Natal Mus.); Port Shepstone (Smith).
Pondoland: Mzamba (Natal Mus.).
Eastern Cape; Kei River mouth and Bulugha (East London Museum); Port Alfred (Turton).