A species comes of age: new material and micro-CT scanning reveal the adult of Gulella bicarinata Blume from Kilimanjaro, Tanzania; with a discussion of Mirellia Thiele from Kenya (Pulmonata: Streptaxidae)

Gulella (Paucidentina) bicarinata Blume, 1965 was described from a damaged, immature shell. New topotypic material from Kilimanjaro, Tanzania includes adults which are here described with the aid of micro-CT scans of the unusual shell. The shell and anatomy of adults show similarities with the little-known central Kenyan taxon Mirellia Thiele, whose sole species Ennea prodigiosa E. A. Smith, 1903 is also scanned and dissected. Most workers have treated Mirellia either as a subgenus of Gulella L. Pfeiffer, or as a subgenus of Ptychotrema L. Pfeiffer. These alternatives are discussed and both species are assigned to Mirellia, which is here treated as a genus in its own right.