The taxonomic status of the vipers of the Pelias (kaznakovi) complex in the middle-flow of the Kura River basin in the East Transcaucasia

Abstract

Recently, the Caucasian viper was found in a number of localities in South Ossetia (Tuniyev et al. 2017a,b; Tuniyev et al. 2019) and in the lower gate of the Borzhom Gorge of Eastern Georgia. Animals from the new localities are compared to Pelias kaznakovi from the Western Caucasus – northeastern Turkey and P. dinniki. The canonical discriminate analysis (CDA) showed that the snakes from the left-bank basin of the middle flow of the Kura River in East Georgia and South Ossetia differ significantly from Pelias kaznakovi from Krasnodar Territory and Abkhazia in the mean values of several plastic and meristic characters. Thus, there is discrimination of the groups allocated according to geographic location and gender. Cluster analysis based on meristic characters of pholidosis showed the distance between P. dinniki and the remaining “kaznakovi” complex forms. Based on the results of the analysis of the mitochondrial cytochrome b gene, the snakes from the left-bank basin of the middle flow of the Kura River form a separate cluster, not sister to Pelias kaznakovi. The results obtained on morphology, genetics and ecology of the studied vipers suggest the taxonomic validity of the vipers from the left bank basin of the middle flow of the Kura River in Eastern Georgia and South Ossetia. The species is named after Boris Tuniyev, who made a significant contribution to the study of the Caucasian herpetofauna and taxonomy of the shield-head viper snakes. Among the representatives of the “kaznakovi” complex, males of the new species are characterized by the minimal values of body length, pileus length, head width, number of ventral and subcaudal shields, as well as the shields around the eyes; differences are also noted in the structure of the hemipenis; the females have the minimum values of body length, pileus length, head width, number of shields around the eyes and loreals, fewer wings of zigzag. All known finds are located in the left bank basin of the middle flow of the Kura River from the Borzhom Gorge (east slope of Meskheti Ridge) in Georgia to the mid-altitude mountain districts of South Ossetia (east foothills of Likhsky Ridge and south spurs of Central Caucasus). Biotopes of the new species are character- ized by more xero-mesophilic traits and a moderately warm mezo-climate than the typical mesophilic biotopes of North-Colchian (Krasnodar Territory – Abkhazia) and, especially, Adzharo-Lazistanian (Georgia – Turkey) P. kaznakovi living in the humid subtropical climate.