Mediterranean populations of the lesser white‐toothed shrew (Crocidura suaveolens group): an unexpected puzzle of Pleistocene survivors and prehistoric introductions

Abstract

An earlier study revealed the strong phylogeographical structure of the lesser white-toothed shrew (Crocidura suaveolens group) within the northern Palaearctic. Here, we aim to reconstruct the colonization history of Mediterranean islands and to clarify the biogeography and phylogeographical relationships of the poorly documented Middle East region with the northern Palaearctic. We performed analyses on 998-bp-long haplotypes of the mitochondrial cytochrome b gene of 143 samples collected around the Mediterranean basin, including islands and the Middle East. The analyses suggest that the Cypriot shrew belongs to the rare group of relict insular Pleistocene mammal taxa that have survived to the present day. In contrast, the Cretan, Corsican and Menorcan populations were independently introduced from the Middle East during the Holocene. The phylogeographical structure of this temperate Palaearctic species within the Middle East appears to be complex and rich in diversity, probably reflecting fragmentation of the area by numerous mountain chains. Four deeply divergent clades of the C. suaveolens group occur in the area, meaning that a hypothetical contact zone remains to be located in central western Iran.

Phylogeography of the weasel (Mustela nivalis) in the western-Palaearctic region: combined effects of glacial events and human movements

“…Several mammalian species have been studied to identify the genetic link between insular and mainland populations (Santucci et al, 1998;Pierpaoli et al, 1999;Cosson et al, 2005;Dubey et al, 2007aDubey et al, , 2008. From these and other studies, it can be concluded that modalities of island colonization are very diverse according to the island and/or species under study, leading to a complex pattern of mammalian composition representing endemic, native or introduced species (Masseti, 1998;Sarà, 1998).…”

Molecular phylogenetics reveals Messinian, Pliocene, and Pleistocene colonizations of islands by North African shrews

“…Amplification conditions consisted of 35 thermal cycles of 30 s denaturation (60 s for the set L14841/H15915) at 94°C, 45 s annealing (60 s, L14841/H15915) at 50°C, and 60 s (120 s, L14841/ H15915) extension at 72°C. For details on DNA purification and cycle sequencing see Dubey et al (2007a).…”

“…Estimation of the divergence time from the molecular data was performed according to a calibration developed previously for the Soricidae by Fumagalli et al (1999), and that allowed fully coherent results in a biogeographic point of view (see, e.g., Vogel et al, 2003;Brändli et al, 2006;Cosson et al, 2005;Dubey et al, 2006Dubey et al, , 2007a. This calibration is based on an estimate of 20 million years for the split between Crocidurinae and Soricinae shrews, and it was developed considering the cytochrome b sequence divergences based on third position transversions, with a rate of 1.36%/Myr (95% confidence interval: 1.08-1.64%/ Myr).…”

“…Interestingly, these small mammals have no morphological peculiarities and were therefore regarded as continental forms introduced by humans. The endemic character of the mammals from Cyprus was discovered only very recently thanks to molecular analyses and dating of the split from continental forms by molecular clock analyses (Cucchi et al, 2006;Dubey et al, 2007a). The Cretan shrew was discovered thanks to the derived karyotype of 2n = 34, not found outside of this island (Vogel, 1986).…”

“…To our knowledge, in regard to mammals, only four Pleistocene island endemic taxa survived the extinction events in the Mediterranean basin: the Cypriot mouse Mus cypriacus (Cucchi et al, 2006), the ''Cyprian shrew" Crocidura suaveolens cypriacus (Dubey et al, 2007a), the Cretan shrew C. zimmermanni , and possibly the Sicilian shrew C. sicula on the Siculo-Maltese archipelago (Vogel et al, 1990). Interestingly, these small mammals have no morphological peculiarities and were therefore regarded as continental forms introduced by humans.…”