The Genus Theba (Mollusca: Gastropoda: Helicidae), Systematics and Distribution

Our knowledge concerning taxonomy and zoogeography of the fossil and recent species of the helicid genus Theba is summarized and enlarged. The fossil T. arinagae spec. nov. is described from Gran Canaria. The recent T. andalusica spec. nov. and T. sacchii spec. nov. are described from the southernmost part of the Iberian peninsula and the southernmost part of Morocco, respectively. This implies that four fossil and ten recent Theba species are recognized. Two of the fossil species are very insufficiently known. Some recent species are polytypic, which results in 17 (sub)specific taxa in total. Neotypes are selected for T. subdentata legionaria and T. solimae. The nominate subspecies of T. pisana is shown to be aberrant because of its very wide range; the other Theba (sub)species have much smaller ranges, situated in W. Morocco, Western Sahara, the southernmost part of the Iberian peninsula and some Atlantic islands.