“…Because multivariate morphometric methods proved to be useful for identifying cryptic species (Adams & Funk, 1997;Bain et al, 2003;Klimov et al, 2004;Sanders, Malhotra & Thorpe, 2006), they were combined with mitochondrial (mt)DNA-based phylogeography to detect differences between closely related and morphologically similar taxa. The morphological structure considered here is the first lower molar (m1), as widely used in systematics and microevolutionary studies of Microtus species (Barnosky, 1990;Brunet-Lecomte & Chaline, 1991;Spitzenberger et al, 2000;Piras et al, 2009;Quéré & Le Louarn, 2011;Renvoisé et al, 2012). Moreover, original chromosome data for obscurus specimens from China are presented and compared with those of Russian and Turkish obscurus (Meyer et al, 1996;Golenishchev et al, 2001;Kryštufek & Vohralík, 2005;Bulatova et al, 2007Bulatova et al, , 2010b, as well as arvalis (Meyer et al, 1996).…”