Bartosz Borczyk

1 Introduction Grass snakes of the genus Natrix Laurenti, 1768 are widely distributed across the Palearctic region, with most species confined to the Western Palearctic. The genus comprises five species. Two are well-defined water snake species: the phylogenetically earliest diverging species, the viperine snake Natrix maura (Linnaeus, 1758), and the dice snake Natrix tessellata (Laurenti, 1768). Natrix maura inhabits Northwestern Africa, the Iberian Peninsula, and parts of Western Europe, while N.

1. Introduction The snake suborder is a very specialised radiation of squamate reptiles that encompasses more than 4000 extant species [1]. They evolved a very particular feeding apparatus among tetrapods [2,3,4,5,6]. Although their skull diversity is well studied (see [7] for a review), data on their jaw musculature are restricted to relatively few groups, the papers are usually descriptive, and comparisons deal with only distantly related taxa (e.g., [8,9,10,11,12,13,14,15,16,17]).