On the biological significance of certain morphological characters in males of the Smooth newt Triturus vulgaris and of the Palmate newt Triturus helveticus (Urodela: Salamandridae)

The males of Triturus vulgaris and Triturus helveticus can be differentiated by a number of morphological characters whose biological function is unknown. It is suggested that these characters enhance the effectiveness of male displays performed during sexual behaviour. This hypothesis is discussed in relation to the taxonomic and genetic relationships between the two species.