Talpa RADIATION

Bannikova, Anna A., Zemlemerova, Elena D., Colangelo, Paolo, Sözen, Mustafa, Sevindik, M., Kidov, Artem A., Dzuev, Ruslan I., Kryštufek, Boris & Lebedev, Vladimir S., 2015, An underground burst of diversity - a new look at the phylogeny and taxonomy of the genus Talpa Linnaeus, 1758 (Mammalia: Talpidae) as revealed by nuclear and mitochondrial genes, Zoological Journal of the Linnean Society 175 (4), pp. 930-948 : 944-945

SCENARIO OF Talpa RADIATION

According to our data the basal part of the Talpa tree appears as a polytomy, which can be attributed to rapid diversification events. Molecular clock results suggest that the onset of this radiation dates back to the latest Miocene ( Table 2) in agreement with previous mitochondrial data ( Colangelo et al., 2010). The fact that three of the four basal lineages are distributed in Asia supports the hypothesis on re-colonisation of Europe from Asia advanced in the above study and indicates a key role of the Near East and Paratethys regions in the evolution of this genus. Whereas the Late Miocene Messinian climatic fluctuations could have led to a nearly complete extinction of Talpini in the western Europe ( Fortelius, 2008), the mountainous areas of the Caucasus, Anatolia, and western Iran retained a sufficient level of humidity in the Late Miocene and Pliocene as follows from the available data on vegetation ( Kovar-Eder, 2003; Kovar-Eder et al., 2006) and thus may have harboured isolated populations of several Talpa lineages (‘caucasica’ and ‘davidiana’ groups). One can hypothesise that the third branch (‘europaea’) also originated from this region. This proposition is consistent with the fact that the only Asian member of the clade, T. levantis , is the sister to the subclade containing all European species. Finally, the fourth major lineage ( T. altaica ) is a geographical outlier, being distributed in Siberia. The place of origin and range history of the Siberian lineage remains unclear.

In general, the evolutionary history of the genus Talpa is characterized by several rounds of radiation and extinction. Although the genus has a long evolutionary history with the first appearance recorded in the Early Miocene of Europe ( Ziegler, 1990) it is evident from the molecular phylogenetic analysis that the modern diversity was formed de novo from a single Late Miocene lineage. It should be emphasised that the genus Talpa (including the Early Miocene taxa) is expected to be paraphyletic relative to the other extant genera of Talpini (i.e., the East Asian clade, including Mogera , Euroscaptor , Parascaptor , Scaptochirus ) because the oldest fossil of Talpa is dated to 20–22 Myr ( Ziegler, 1990) whereas the molecular data suggest a Middle Miocene age for the most recent common ancestor of the crown Talpini ( He et al., 2014; our data). The fact that both Early–Middle Miocene and extant species are attributed to the same genus is explained by morphological conservatism owing to the uniformity of fossorial adaptations ( Barrow & Macleod, 2008). At the other extreme, slow morphological evolution in Talpa manifests as high cryptic diversity at the level of closely related species.

Further studies based on a more extensive sampling of genes and taxa should elucidate the true magnitude of cryptic speciation in fossorial moles and develop a more detailed evolutionary scenario for Talpa .