Ushakov Michail V. RussiaDonskoyeGalich’ya Gora Nature Reserve, Voronezh State University, Donskoye village, Zadonsky district, Lipetsk region 399240, Russiaushakov@dev-reserve.vsu.ru Author's articles Sexual differences in the morphometric traits of the black forest-steppe viper, Pelias berus nikolskii (Vedmederja, Grubant et Rudaeva, 1986) (Viperidae, Reptilia), from the Voronezh region