The shrew (Crocidura sp.) of Gozo, a probable survivor of the Pleistocene fauna of Mediterranean Islands

Abstract

The Pleistocene fauna of Mediterranean islands comprises several endemic mammals all of which are now extinct. The only known exception is Crocidura zimmermanni, the endemic shrew of Crete (Reumer 1986). Many of the species became extinct only after the arrival of man during the Neolithic period. Man, either accidentally or consciously, introduced most of the presently occurring mammals, such as hedgehogs, mice, rats, ungulates, and so forth. According to these authors, Suncus etruscus and two species of the genus Crocidura, C. suaveolens and C. russula, which presently occur on several of the Mediterranean Islands, have also been introduced by man. This interpretation was confirmed for some islands by Poitevin et al. (1986) and Vogel et al. (1986).

The shrews of Sicily, however, could not be confidently referred to one or the other species and, until recently, have been variously assigned to C. caudata, C. sicula, C. suaveolens, C. leucodon, or C. russula by various authors (Miller 1901; Vesmanis 1976, among others). The recent discovery of a particular karyotype with 2n = 36 chromosomes has now demonstrated that the Sicilian shrew is a separate species (Vogel 1988), related to C. canariensis (Maddalena 1990), a species endemic to the Canary Islands and which has a similar karyotype (Hutterer et al. 1987). Once the species was recognized, the question arose as to its origin. Was it introduced by man as many other mammals, or was it a relic of the local Pleistocene fauna? Fieldwork carried out in Gozo reveals that most likely the shrews found in Sicily and Gozo where not introduced by man but rather occurred there before the arrival of man.