|Helix troglodytes Morelet, 1848
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.
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 (like the letter X) or beadlike. The foot shows a long caudal horn.
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 (Saphtia Winter, 2008, Pseudosaphtia Winter, 2008 and Vanmolia Winter, 2008), 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:
- Thapsia buchholzi Bourguignat, 1885
- Thapsia buraensis
- Thapsia ebimimbangana Winter, 2008
- Thapsia grandis
- Thapsia microsculpta
- Thapsia rosenbergi Preston, 1909
- Thapsia snelli
- Thapsia troglodytes (Morelet, 1848) - the type species, originally described as Helix troglodytes Morelet, 1848
- Thapsia usambarensis
- Thapsia wieringai Winter, 2008
- Albers J. C. (1860). "Die Heliceen nach natürlichen Verwantschaft systematisch geordnet,ed. 2" (Manuscript edited by E. von Martens): xviii + 359 pp. Engelmann, Leipzig.
- Winter A.J. de (2008). "Redefinition of Thapsia Albers, 1860, and description of three more helicarionoid genera from western Africa (Gastropoda, Stylommatophora)". Zoologische Mededelingen. 82.