Bridging the Alps and the Middle East: Evolution, phylogeny and systematics of the genus Wulfenia (Plantaginaceae)

Abstract

AbstractThe genus Wulfenia (Plantaginaceae) demonstrates a striking disjunction between the southeastern Alps (Carnic Alps), the southeastern Dinaric Alps (Prokletije Mountains, Balkan Peninsula) and the Amanos mountains of southern Turkey. This puzzling biogeographic pattern has interested botanists for more than 100 years and Wulfenia has been widely regarded as a Tertiary relict of at least Miocene age in southeastern Europe. Specifically, the identity of populations in the Prokletije Mountains either referred to as disjunct populations of W. carinthiaca or a separate species, “W. blecicii”, has been much debated. Here we analyze AFLP, plastid and nuclear ribosomal sequence data in conjunction with a morphometrical analysis to clarify the taxonomy of the genus and the relationships of the populations to one another. Furthermore, we employ a molecular dating strategy to put these results in a time frame to assess the Miocene relict–hypothesis. Our results provide evidence for a new classification of the genus with four species, W. orientalis, W. glanduligera comb. & stat. nov., W. baldaccii and W. carinthiaca. The split of the last species into populations disjunctly distributed in the southeastern Alps (W. carinthiaca s.str.) and southeastern Dinaric Alps (“W. blecicii”), is not supported either by molecular or morphological data, while we find enough evidence in DNA sequence data, growth site specifics and morphology for W. orientalis var. glanduligera to be treated at the species rank. Our dating analysis suggests that the extant genus is rather young with a crown node age of only about 1.24 Ma and 0.61 Ma for the European populations despite a stem node age of about 10.69 Ma. Thus, Wulfenia as a genus is likely a Miocene relict but its uninterrupted presence on the Balkan Peninsula cannot be demonstrated.