Historical distribution and mitogenomic phylogeography of the Mediterranean monk seal in the Central Mediterranean region

The Mediterranean monk seal (Monachus monachus Hermann 1779) is one of the most threatened pinniped in the World. The historical species’ range extended from the Black Sea to Gambia and Northern Spain. A thousands-years long history of anthropic persecution has determined a dramatic demographic contraction and population fragmentation with three surviving populations now restricted to the Eastern Mediterranean, Madeira and the Cabo Blanco peninsula (Western-Sahara / Mauritania). The current thesis emphasises the role of combined genetic and bibliographic analysis of academic and grey literature to get a better insight on the monk seal biogeography over the last two centuries. I analysed 55 complete mitogenomes from modern and historical specimens, including an Early Neolithic one, inferring past demographic structures and connectivity. The obtained results highlight signatures of significant mitogenomic variation among ecoregions, reduction of mitochondrial variation and demographic decline over the investigated timeframe. Furthermore, historical clusters already beard low levels of genetic diversity. A possibly extinct mitogenomic lineage is uncovered from the Central Mediterranean region, whose disappearance likely led to the disruption of gene flows connecting western and eastern basins. Genetic data from the global species distribution are supported by sightings and captures records from the Italian coastline, showing the survival of few monk seal isolated nuclei since the 19th century.