A new subspecies of the Halys pit viper Gloydius halys (Pallas, 1776) (Viperidae, Crotalinae) from Tuva and western Mongolia

Abstract

Description of a new subspecies of the Halys pit viper, or Pallas pit viper, occurring on the territory of southern Tuva, western and southern Mongolia, is given in this paper. The Ubsunur pit viper, Gloydius halys ubsunurensis ssp. nov. differs from other taxa of the complex by a combination of the following morphological features: (1) a large number of ventral scales (V+PreV): 171–188; (2) a large number of subcaudal scales: 47–53 in males and 42–46 in females; (3) a large number of light bands around the body: 35–41; (4) a large number of light bands around the body and tail: 47–63; (5) a light background “desert” coloration of the body dorsal surface. Also, the new subspecies differs by its range and preferred bioclimatic habitat conditions. Populations constituting the new subspecies, on the one hand, manifest themselves as a unified totality, but, on the other hand, they are well separated from other valid taxa of the complex, that is well confirmed by the analysis of the morphological data by the methods of multivariate statistics. In the result of modeling and prediction of the potential distribution of the Ubsunur pit viper in Maxent program zones of optimum were revealed, as well as key bioclimatic factors influencing the pattern of the range. Average annual temperature makes the largest percent contribution (72.4%). The second most important index is precipitation of the wettest quarter of the year (11.1%). Average temperature of the driest quarter of the year and precipitation of the warmest quarter of the year are 7.4% and 6.6%, respectively. Identification key for the taxa of the genus Gloydius distributed on the territory of the former USSR are also given in the paper.