Across the Channel and Through Time: Did Lesser Horseshoe Bats Colonise Pantelleria From Europe or North Africa?

Abstract

: Islands provide unique opportunities to study historical biogeography, acting as both cradles of endemism and active corridors for species dispersal. The Sicilian Channel, which separates Sicily from the Maghreb, exemplifies this complexity. We investigated the colonisation history of the lesser horseshoe bat (Rhinolophus hipposideros) on Pantelleria Island (southern Italy) to assess whether its population derives from Europe or North Africa. Because R. hipposideros has limited dispersal ability and is largely sedentary, its occurrence on Pantelleria raises questions about past connectivity across the Channel. We analysed mitochondrial markers (COI, cyt-b, 12S) from Pantelleria, Malta, Algeria, and across the species' range. Phylogenetic and haplotype network analyses place Pantelleria and Malta in a well-supported clade sister to North African lineages and distinct from European populations. Time-calibrated analyses based on cyt-b suggest that the Pantelleria-Malta group diverged from North African conspecifics around 200,000 years ago (MIS 7.2). A palaeogeographical reconstruction for this interval indicates lowered sea level reduced the marine gap between Pantelleria and Tunisia to about 68 km, consistent with over-sea colonisation from North Africa. The short available sequences for conspecific European bats suggest considering these inferences as provisional. Within these limitations, our results are most consistent with a Maghrebian origin for Pantelleria's R. hipposideros, while alternative routes (including European sources) cannot be excluded. Broader genomic sampling, especially from Sicily and Morocco, will be required to resolve colonisation direction and fully establish the population's biogeographic history. More generally, our findings reinforce the view of the Sicilian Channel as an asymmetrically permeable biogeographic corridor that can facilitate faunal exchange across the central Mediterranean.