DISCRIMINATION OF THE SHREW SPECIES SOREX -ARANEUS L, 1758 AND SOREX-CORONATUS MILLET, 1828 BY HELP OF A NEW DISCRIMINANCE FUNCTION

Described is a new function to discriminate Sorer araneus from S. coro natus on the basis of skull characteristics. The new function is based upon the measurement of four easily obtainable distances, which hardl y correlate with each other and usually are present in material from o wl pellets. Among 114 biochemically (PAGE) determined specimens the ne w discriminant function assigned 100% correctly, compared to 92,1% wit h the function developed by HAUSSER and JAMMOT (1974) and 89,81% with the index x5/x6 (HANDWERK 1987). In order to be able to discriminate b etween uncompletely conserved skulls indices were determined for skull and mandibles. Using the new discriminant function as well as additio nal indices and characteristics material from collections and owl pell ets from almost all over Baden-Wurttemberg was investigated (ca. 4000 Sorer araneus/coronatus). A comparative study based upon suitable dist ances showed that there exist geoclimatic variations: e. g. individual s from populations in the Alpine foreland are bigger on average than t hose from other climatic regions. Among different climatic regions int erspecific variations are usually larger than intraspecific variations . However, with regard to the constancy of the new discriminant functi on the variations are neglectable because overlapping of single distan ces remains small. In sympatric populations a character displacement c ould not be found.