Clio pyramidata Linnaeus, 1767 forma convexa (Boas, 1886) (Mollusca, Pteropoda)

The pelagic fauna of the Red Sea shows special variation induced by its isolated character (Van der Spoel, 1971). Clio pyramidata from the Red Sea is usually incorrectly referred to as the tropical forma lanceolata (Lesueur, 1813) or the typical forma pyramidata Linnaeus, 1767. Some large samples with C. pyramidata from the northern Red Sea made it possible to establish the correct identity of these populations. Though special variation, like described for Diacria and Cavolinia species (Van der Spoel, l.c.), is found for Red Sea populations of C. pyramidata, the populations are not separated as an endemic taxon as the specimens resemble closely Clio pyramidata forma convexa (Boas, 1886) (figs. 1-4). The anterior parts are almost identical to those of convexa as described by Boas; the upper parts show small differences.