Data from: Multiple refugia and barriers explain the phylogeography of the Valais shrew, Sorex antinorii (Mammalia: Soricomorpha)

The aim of the present study was to investigate the genetic structure of
the Valais shrew (Sorex antinorii) by a combined phylogeographical and
landscape genetic approach, and thereby to infer the locations of glacial
refugia and establish the influence of geographical barriers. We sequenced
part of the mitochondrial cytochrome b (cyt b) gene of 179 individuals of
S. antinorii sampled across the entire species' range. Six specimens
attributed to S. arunchi were included in the analysis. The
phylogeographical pattern was assessed by Bayesian molecular phylogenetic
reconstruction, population genetic analyses, and a species distribution
modelling (SDM)-based hindcasting approach. We also used landscape
genetics (including isolation-by-resistance) to infer the determinants of
current intra-specific genetic structure. The phylogeographical analysis
revealed shallow divergence among haplotypes and no clear substructure
within S. antinorii. The starlike structure of the median-joining network
is consistent with population expansion from a single refugium, probably
located in the Apennines. Long branches observed on the same network also
suggest that another refugium may have existed in the north-eastern part
of Italy. This result is consistent with SDM, which also suggests several
habitable areas for S. antinorii in the Italian peninsula during the LGM.
Therefore S. antinorii appears to have occupied disconnected glacial
refugia in the Italian peninsula, supporting previous data for other
species showing multiple refugia within southern refugial areas. By
coupling genetic analyses and SDM, we were able to infer how past climatic
suitability contributed to genetic divergence of populations. The genetic
differentiation shown in the present study does not support the specific
status of S. arunchi.