Sexual dimorphism in the Italian endemic species Salamandrina perspicillata (Savi, 1821) and testing of a field method for sexing salamanders

Abstract

Abstract Salamandrina perspicillata is an endemic Italian salamander in which morphological sexual dimorphism is weak and sexes are almost indistinguishable in live specimens. We here report on a simple method for sexing these salamanders in the field on the basis of cloacal morphology and we present new data on the sexual dimorphism in this species. Nine morphological characters were used to assess the amount of sexual dimorphism using a multivariate approach (Mancova: Wilks' λ = 0.248, P < 0.001). Sexes differed significantly in both size (females are larger than males) and shape (females have proportionally longer distance between extremities, males have longer cloacal slit and wider head). The observed pattern of sexual dimorphism is discussed in an evolutionary context. Difference between sexes in the proportion of the V-shaped patch on the head was also tested. Finally, we also report the first preliminary data on the sex ratio of a S. perspicillata population in the wild.