Distribution of side bars in grass snakes based on iNaturalist records. Densely documented western part enlarged in bottom map. Small inset map (top) shows subspecies distribution according to Asztalos et al. (2021a): Natrix natrix natrix – yellow, N. n. vulgaris – red, N. n. moreotica – grey, N. n. scutata – green. Hybrid zones hatched. The occurrence of side bars is largely restricted to the hybrid zones between N. natrix and N. helvetica along the western range border of N. natrix and to the range of N. n. moreotica.

  Part of: Fritz U, Ihlow F (2022) Citizen Science, taxonomy and grass snakes: iNaturalist helps to clarify variation of coloration and pattern in Natrix natrix subspecies. Vertebrate Zoology 72: 533-549. https://doi.org/10.3897/vz.72.e87426