Morphometric variation, sexual size dimorphism and character scaling in a marginal population of Montandon's newt Triturus montandoni from the Czech Republic

This study presents for the first time the morphometric characteristics of the Montandon's newt Triturus montandoni population from the Jeseniky Mountains (Czech Republic), where the species reaches the northwest margin of its distribution range and occurs outside the Carpathians. All measurements were taken on live narcotized animals (n = 315). The snout-vent length (SVL) was found to be the best univariate measure of overall body size, highly correlated with PC1 (principal component). Overall 'body shape' as measured by PC2, was determined primarily by the relative length of limbs. Scaling of body characters against SVL (geometric mean regression slope) did not differ between sexes but suggested positive adult allometry for most characters. In absolute terms, males were smaller than females in all examined characters (although not significantly so in length of hind limbs). Males were characterized by relatively longer limbs, larger head, shorter tail and shorter axilla-groin distance. The mean SVL in composite samples varied significantly over three years and between two localities, while the degree of sexual size dimorphism remained stable.