Systematics of Ariantinae (Gastropoda, Pulmonata, Helicidae), a new approach to an old problem

A new starting-point in Ariantinae systematics is presented by combining data on traditional shell morphology and genital anatomy, with phylogeny reconstructions based on DNA sequence data. For nearly all genera and subgenera one or more shells are depicted and drawings of the proximal part of the genital organs are shown to illustrate the morphological diversification within the subfamily. For as much as our material allowed it, partial sequences are presented for Histone H3 (H3), Cytochrome c oxidase subunit I (COI), Cytochrome B (CytB) and 16S ribosomal RNA (16S). Some of the allegedly speciose genera like Chilostoma and Campylaea (Zilch, 1960) do not represent monophyletic groups of species, whereas most of the remaining nominal taxa (e.g. Causa, Dinarica, Josephinella, Faustina, Liburnica, Kosicia and Thiessea) warrant a separate taxonomic status indeed. Sequence data from individual markers were informative at the species-level, but not for higherlevel phylogenetics. Insight in genus-level relationships was obtained after concatenation of the individual datasets. The Ariantinae are estimated to have originated during the late Cretaceous (Campanian), not later than ca. 80 million years ago. The enigmatic and morphologically aberrant, monotypic genus Cylindrus is shown as the sister-group of Arianta, a genus including A. arbustorum, which is also unusual in shell-shape and habitat. Ariantopsis and Wladislawia are classified as subgenera of neither Campylaea nor Chilostoma, but Cattania. Sabljaria is considered a subgenus of Dinarica. The nominal genus Superba is shown to be paraphyletic; additional data should demonstrate whether Superba has to be synonymised with Liburnica. The Ariantinae are here divided in 21 genera (2 new) and 13 subgenera (3 new).