Towards understanding of the taxonomy within the genus Emmericia Brusina, 1870 (Caenogastropoda: Truncatelloidea)

ABSTRACT Emmericia Brusina, 1870 is the only genus of the family Emmericiidae Brusina, 1870, and it inhabits springs and rivers from north-east Italy to southern Croatia, Bosnia and Herzegovina, and Montenegro. Their variable shells have resulted in taxonomic chaos with from one to sixty seven species recognised in Emmericia. Recently four species have been distinguished: E. patula (Brumati, 1838), E. expansilabris Bourguignat, 1881, E. narentana Bourguignat, 1881, and E. ventricosa Brusina, 1870. In the present study, Emmericia from 13 localities were collected. Principal component analysis on seven biometric characters measured on shells from three localities inhabited by two nominal species demonstrated the distinctiveness of these three studied populations. In contrast, the differences between the two populations representing E. patula were not smaller than between either of them and E. expansilabris. Similar remarks apply to the shells of the other two species. The sequences of the cytochrome oxidase subunit I did not confirm that E. expansilabris is a distinct species, so it is regarded as a synonym of E. patula, but did confirm the distinctness of E. ventricosa, which inhabits the localities higher above sea level. No sequences of E. narentana were obtained.