In vivo sexual discrimination in Salamandrina perspicillata: a cros-check analysis of annual changes in external cloacal morphology and spermic urine release

Abstract

In Salamandrina, the lack of visible external sexual dimorphism makes the sexing of individuals difficult without sacrifice. The cloaca of Salamandrina in both males and females appears externally as a slit on an unswollen surface, a trait which is consistent throughout the year. Nonetheless, a slight divarication of its borders allows the recognition of three morphs (A, B and C), respectively characterizing male cloaca (all phases), female cloaca without protruding oviductal papillae (courtship phase) and female cloaca with prolapsed oviductal papillae (oviposition phase). Figures and schematic diagrams are provided to illustrate the differences in detail, which are all recognizable to the naked eye or by means of a hand magnifier. In addition to morphology, another reliable method of sexing salamanders is urine examination, albeit only during the courtship and post-courtship phases. Applying these methods for sex determination, we found a malebiased operational sex ratio in two populations, ranging from 6.6:1 (autumn–winter) to 14:1 (May). Males were confined to terrestrial environments, whereas females were also found in water during oviposition. Salamandrina perspicillata was active throughout the year, except during the hottest months (July–August)