Page 7 - CrociduraWagler_Sara

INSULAR VARIATION IN CENTRAL MEDITERRANEAN CROCIDURA 289

Downloaded by [183.219.240.165] at 10:10 22 March 2014 1 mm

Fig. 4 - Morphotypes of the posterior surface of the condylar process of the mandible of Crocidura Mediterranean taxa (occlusal view). A,
B, ..., H legends as in Figure 3.

Finally, almost 852 of the specimens were re- the five OTU's and the Sicilian one, but this result

attributed, by discriminant analysis, to one of these five applies only to the island of Levanzo. The shrews

OTU's (Table III). An exception was found: Favignana living on the cited five islands are in fact biometri-

in fact did not show any significant distance from the cally smaller than those living in Sicily (see also Ap-

C. suaveolens OTU (whereas for the other four islands pendix 2).

this distance is significant). This result suggests the The presence of morphological clines was checked,

presence in this island of a form related to C. suaveolens, but not found in Sicily, by ranking the A, ... Q cen-

according to the already cited authors. However, a hy- troids along their North-South and East-West geogra-

pothetical colonization by C. suaveolens limited to Favi- phic locations. This permitted to exclude the presence

gnana seems unlikely and the small sample size is proba- of small-size populations (i.e. A, B, and C) in north-

bly responsible for the result. western Sicily, that could have been directly responsi-

Shrews from Gozo and Sicily share the same karyo- ble for the Egadi and Ustica colonization.

type and both populations are biochemically similar Some explanations could be given to explain this

(Vogel, unpublished data); these findings could explain biometrical difference from the Sicilian OTU's, as well

the multivariate analysis results. If shrews on Gozo have as the biometrical homogeneity within the group of

a C. sicula karyotype and are morphologically and bio- five islands. Davis (1983) suggested that the introduc-

metrically similar to those living on the Egadi and on tion of more individuals after the original colonization

Ustica, it can be concluded that all these taxa are rela- and swamping of the founder population may explain

ted to C. sicula, as also shown by the association den- the progressive increase in homogeneity of the sam-

drogram of the mandible (Fig. 2). We should conse- ples, comparing different islands that received coloni-

quently aspect no significant distances between each of zation.