Tanzartemon gen. nov., a new land snail genus (Gastropoda, Pulmonata, Streptaxidae) from Morogoro District, Tanzania

Tanzartemon is described as a new genus in the Streptaxidae. Two species, T. seddonae and T. mkungwensis, are described from sub-montane forest habitat in the Uluguru Mountains and from the outlying peak of Mount Mkungwe, Morogoro District, Tanzania. The genus is characterised by its globose or depressed globose shell morphology, the presence in the shell aperture of one or more parietal denticles and of several strong, peg like denticles that sit immediately inside the peristome on the basal, palatal or columellar margins. The genitalia are characterised by the presence of a penial sheath that encloses the penis, but does not incorporate a loop of the vas deferens. The specimens do not resemble any known genus in the East African fauna because of the combination of their globose shell and strong apertural dentition. Possible relationships with other morphologically similar streptaxids known from tropicalWest Africa, particularly Lamelliger Ancey, 1884, are discussed, but, based on shell morphology and genital anatomy we conclude that Tanzartemon is likely to be an East African endemic genus that is not closely related to West African forms.We consider it likely that Tanzartemon has either evolved in situ from another morphologically dissimilar African lineage or from lineages found otherwise only in Asia or South America, and, as such, it is of biogeographical interest.