A tale of two snails: "Le Pouchet" from Adanson (Mollusca, Gastropoda, Helicoidea, Helicidae)

As consequence of an uninterrupted series of taxonomic, but mainly nomenclatural errors made up to now by various malacologists, the first land snail species recorded from the Canary Islands (Spain) at the present time has been left without a valid name. This species was discovered by Adanson and published with the pre-Linnean name “Le Pouchet” in 1757. It is now named Hemicycla pouchadan n. sp. and compared with two closely related taxa: H. pouchet (A. Férussac, 1821) and H. plicaria (Lamarck, 1816), H. pouchadan n. sp. being the smallest and more globose. Hemicycla pouchadan n. sp. differs conchologically from both species mainly by its shell ornamentation. The shell surface has numerous series of radially thickened ribs, each one with a strong transversal striation produced by very numerous, fine and densely set, spiral grooves which do not affect the shell surface located between the radial ribs.