First report of Bufo bufo (Linnaeus, 1758) from Sardinia (Italy)

The Common toad Bufo bufo (Linneaus, 1758) was found for the first time in Sardinia, during herpetological surveys carried out in 2016. The species appears to be well established in the finding area. Many adults and juveniles, tadpoles at different developmental stages, and eggs have been found during repeated monitoring. In order to infer the geographic origin of the Sardinian population, we amplified two mitochondrial markers (16S, cytb) and compared sequences with those available for the species across its 48 natural range. We also screened samples for the presence of Bd pathogen to assess the risk of infection mediated by the species in the area. Results suggest that Sardinian individuals are genetically close to the Central Italian populations, although they show a unique distinct haplotype. Though the species should be considered allochthonous to the Island, further molecular and ecological data are urgently needed to assess the genetic structure and the possible impact on the local fauna, which is largely composed by endemic taxa. Particularly, possible interactions with other native amphibians like the green toad Bufo balearicus (Boettger, 1880), also present in the area, should be investigated, both in terms of competition for breeding sites and genetic pollution, as these species are already known to hybridize in the wild.