Clanculus thomasi

Lore & Background

The shell of Clanculus thomasi varies between 5 mm and 15 mm. It is umbilicate and conic-globose, with a white maculation on a reddish carmine ground. The five convex whorls are spirally traversed by five very finely granulose lirae: the first two small, the third larger, the fourth small, and the fifth larger than the others. The suture is profoundly impressed and canaliculate. The body whorl has eight lirae on the base encircling the umbilicus. The columella is unequally bidentate, with the basal tooth larger and compressed. The lip at the base is obsoletely denticulate, elsewhere edentulous. The oblique aperture is less ringent than most species of Clanculus, and the fauces are sulcate and nacreous. The umbilicus is white, smooth in young shells, and obsoletely crenulated in adults. A variety is olivaceous green, maculate with white, with a rosy apex; it is a small species with a very prominent, compressed basal tooth and slight crenulations at the margin of the umbilicus, the right lip not dentate.

Reader's Guide

Clanculus thomasi is known from the marine waters off New Caledonia and Lord Howe Island. The species was described in the 19th century, with references including works by Crosse (1862) and later by Salisbury (1936) and Iredale (1938). Its shell characteristics, such as the finely granulose lirae, bidentate columella, and nacreous fauces, place it within the genus Clanculus. The variety with olivaceous green coloration and rosy apex indicates intraspecific variation. The species is documented in the Journal de Conchyliologie and other malacological publications, and its type material is preserved in the collection associated with that journal. The entry in the World Register of Marine Species and other external links confirm its taxonomic standing.

Did You Know?

• The shell size varies between 5 mm and 15 mm.
• The columella is unequally bidentate, with a larger, compressed basal tooth.