Deviations in Pholidosis of the Grass Snake Natrix natrix (L. 1758) from the Tatarstan Republic

Abstract

This paper is devoted to the consideration of qualitative and quantitative characteristics of pholidosis deviations in grass snakes and the intraspecific variation of these features. 35 types of deviations were observed: segmentation, incomplete separation, fusion, reduction of scales and the presence of an additional small scale. The frequency and values of individual and population spectra of deviations were higher in adult snakes. Minimal values of all indices were characterized for a sample from the Laishevsky region. Deviations observed in grass snakes occur in other species of snakes, mostly deviations of the ventral and subcaudal scales.