Distribution and morphological variation of Vipera berus nikolskii Vedmederja, Grubant et Rudaeva, 1986 in Western Ukraine, the Republic of Moldova and Romania

Abstract

Morphological variation of vipers of the Vipera berus complex in Eastern Romania, the Republic of Moldova and Western and Central Ukraine was studied using multivariate statistics. Discriminant analysis, based on ten meristic characters in 89.7% of cases (males) and in 92.0% cases (females), was able to separate reference samples of subspecies Vipera berus berus and Vipera berus nikolskii and was conducted to classify snakes from the studied territory. According to these results, V. b. nikolskii inhabits the broad-leaved forests in the forest-steppe zone in the Republic of Moldova, the hilly part of Eastern Romania and Central Ukraine. Specimens from a contact zone between V. b. berus and V. b. nikolskii have intermediate morphology and, thus, could represent the result of introgression. Populations of the Nikolsky's viper from the western part of its range combine high level of morphological differentiation from V. b. berus with the presence of non-black specimens and even include populations without melanistic specimens, previously thought not to occur in this taxon. A morphological description of the largest samples is given and determination of V. b. nikolskii is discussed. © Koninklijke Brill NV, Leiden, 2010.