Size and age changes in color in the Rapid racerunner, Eremias velox (Pallas, 1771) (Reptilia, Lacertilia) population on the Sarycum sandy massif

The article is based on materials on age-related changes in the color of the lower surface of the tail and back of the thighs in the population of the Rapid racerunner (Eremias velox velox Pallas, 1771), living on the Sarykum sandy massif. The material was collected in the first ten days of May 2023. A total of 110 individuals were caught and described: 44 males, 36 females and 30 immature individuals. The size characteristics of sex and age groups are given. It is known that in immature individuals the lower surface of the tail and the back of the thighs are blood-red to orange in color, while in adult animals the entire lower surface of the body and tail is white. The research materials clarify the course of these age-related changes. In Sarykum males, the change from juvenile to adult coloration occurs with the onset of sexual maturity. In females, this process is extended and most lizards across a wide range of sizes retain the coloration of the young, with some lightening options. In immature individuals, the coloration in the orange-red range is characteristic of all animals, but in 16.7% of lizards the process of its lightening begins. It can be assumed that the latter will turn out to be males in the future. For the description, the RGB color code table is used according to two color codes: HTML/CSS color name and decimal code (RGB).