Searching for the elusive imposter land snails. Description and geographical delimitation of two cryptic Iberus subspecies (Gastropoda, Stylommatophora, Helicidae) in southern Spain

<p>The taxonomic identity of Iberus alonensis has traditionally been surrounded by great controversy because under this name a large number of similarly-shaped populations distributed over a vast geographical area and probably belonging to different species have been subsumed. The publication of the first phylogenetic study on the genus Iberus began to unravel the alonensis complex, defining other likely new lineages. One of them is I. alonensis-like 02, a provisional name assigned to the traditional populations of I. alonensis from Andalusia (southern Spain) but lacks sufficient biogeographic support to be formally defined as a new species. In this study, the potential distribution area of I. alonensis-like 02 is thoroughly explored through systematic sampling. The resulting geographical mapping together with a morphometric study and new molecular evidence allow us to confirm the historical name I. alonensis rhodopeplus as a valid taxonomic denomination which we divide into two cryptic subspecies named I. rhodopeplus rhodopeplus and I. rhodopeplus bastetanus ssp. nov. In addition, the subspecies I. alonensis labiatus has to be renamed. Our findings contribute to revealing the species complex involved under the classic name I. alonensis and to improving our knowledge on the cryptic nature of numerous taxa within the genus Iberus.</p>