A refined method for craniometrical identification of the sibling vole species Microtus arvalis and Microtus rossiaemeridionalis in Europe and the Asiatic part of Turkey

On the basis of karyologically identified individuals of the common vole Microtus arvalis and the sibling vole Microtus rossiaemeridionalis from Europe and the Asiatic part of Turkey, a canonical craniometric classification function for the differentiation of these sibling species was worked out. The function is sex-independent and includes four craniometric parameters measured in millimeters (Y= 3.026 *Cranial height between bullae ossae + 2.811* Alveolar length of upper molars - 0.470* Zygomatic width - 2.281* Length of incisive foramen - 20.365; with centroids -1.135 for M. arvalis and 1.977 for M. rossiaemeridionalis). It shows high statistical reliability and classifies correctly 97.8% of the initial samples of karyologically determined specimens.