Taxonomic status and origin of the shrews (Soricidae) from the Canary islands inferred from a mtDNA comparison with the European Crocidura species

Abstract

European island shrews are either relicts of the endemic Pleistocene fauna, e.g., . Crocidura zimmermanni, or were introduced from continental source populations. In order to clarify the taxonomic status and the origin of the two shrew species from the Canary islands, a 981 bp fragment of cytochrome b gene was investigated in all European Crocidura species and compared with the Canary shrew ( Crocidura canariensis) and the Osorio shrew ( Crocidura osorio). The first shares its karyotype with the Sicilian shrew Crocidura sicula (2 N=36), the second with the Greater white-toothed shrew Crocidura russula (2 N=42), suggesting possible sister species relationships. Results confirm the monophyly of taxa sharing the same karyotype. Genetic distances between C. sicula and C. canariensis suggest a separation since 5 Myr. The first was probably isolated from the North African ancestor after the Messinian desiccation; the second arrived on the Canary islands by natural jump dispersal. Within the 2 N=42 cluster, a first split separated an Eastern line (Tunisia) from a western line (Morocco/Europe) of C. russula. C. osorio clusters together with C. russula from Spain, indicating conspecificy. This suggests a recent introduction from Spain by human.