Distribution of Phrynocephalus helioscopus (Pallas, 1771) (Agamidae, Reptilia) in the West Kazakhstan and Atyrau regions of the Republic of Kazakhstan

Based on the results of our 2017–2021 field research, the coordinates of 17 meeting points of the sunwatcher toadhead agama (Phrynocephalus helioscopus) (Pallas, 1771) in the West Kazakhstan and Atyrau regions of the Republic of Kazakhstan are given, from 49°17.256'N, 48°14.048'E in the North to 46°34.330'N, 55°49.319'E in the South. The northern limit of the modern distribution in the Volga-Ural (Volga-Zhaiyk) interfluve is the saline in the Aral-sor lacustrine-saline depression and the Baigutta sor-liman depression in the left bank of the Ural (Zhaiyk) River. The sunwatcher toadhead agama habitats are confined to open spaces with salt lakes and sors. The dependence of the body’s upper side colour of sunwatcher toadhead agamas on the general background of the substrate is illustrated, namely: the colour is brown or dark grey on dark substrates, and light grey or ashy on light substrates. The history of the description of the species by P. S. Pallas and I. I. Lepekhin is briefly considered. According to the original and literary data the modern north-western border of the habitat, passing through the West Kazakhstan and the adjacent regions of the Russian Federation, has been clarified. It goes from the northern coast of the Caspian Sea, through Makhambet district of the Atyrau region, Krasnoyarsk and Kharabalinsky districts of the Astrakhan region, Kurmangazinsky district of the Atyrau region, Akhtubinsky district of the Astrakhan region, Bokeyordinsky district of the West Kazakhstan region, Pallasovsky district of the Volgograd region, and Kaztalovsky and Akzhayik districts of the West Kazakhstan region.