A systematic revision of Circassina from the western Caucasus region (Gastropoda: Hygromiidae)

Abstract

This paper presents a comprehensive revision of Circassina (Gastropoda: Hygromiidae). Circassina is divided into two subgenera. The nominotypical subgenus is characterized by an inflation forming a brim at the base of the dart apparatus, whereas Circassina (Abchasohela) is characterized by a granular shell sculpture. Circassina (Circassina) includes C. frutis (with the subspecies C. f. frutis, C. frutis circassica and C. frutis veselyi), which ranges from the northwestern slope of the Caucasus Mountains throughout most of Georgia to northernmost Armenia and the Eastern Pontic Mountains in Turkey, and C. lasistana new species, which is only known from the Vileyet Artvin in Turkey. Circassina (Abchasohela) includes C. christophori, C. pachnodes, C. pergranulata new species, C. septentrionalis new species and C. stephaniae. All species of Circassina (Abchasohela) are restricted to Abkhasia and the adjacent Russian regions in westernmost Caucasia. The shell and the genitalia of each taxon are described and illustrated. All synonyms and all locality records are listed. The distribution of the species is illustrated on a UTM-grid map.