Thapsia


Thapsia is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Helicarionidae. Species in this genus are found in tropical western Africa, from Senegal to Gabon.

Description

Species attributed to the genus Thapsia sensu lato have shell diameters ranging from about 15 to 30 mm, with 5½-6½ whorls. These rather featureless dextral shells are characterized by a low spire and their yellow to brown color. The spiral sculpture of the postembryonic shell is slender. In some larger species the sculpture of the radial ribs is formed crosswise or beadlike. The foot shows a long caudal horn.

Species

Thapsia was originally designated in 1860 by German zoologist Johann Christian Albers as a subgenus of Nanina Gray, 1834, non Risso, 1826.
This genus is a heterogeneous assemblage. Because the shell characters of this genus converge with those of the larger specimens of some closely related genera, the delimitation of species to Thapsia s.l. is difficult. There very few papers that describe the anatomical features of this genus.
Thapsia contains the following species: