The Herpetological Journal

pp.105-109

Authors: Jaime Bosch And Rafael Márquez

Abstract: Determining the sex of midwife toads in the field is not easy. Non-pregnant females and males not tending clutches are difficult to sex without dissection. We provide a method to determine the sex of individuals based on the study of linear variables. Fifteen morphological variables were measured from samples of two species of midwife toad in the Iberian Peninsula (Alytes obstetricans and Alytes cisternasii). Some variables, corrected for the size of the animal, show significant differences between sexes. A discriminant analysis between the sexes in both species shows a high power for discrimination (95% in A. obstetricans and 97.6% in A. cisternasii). The significant variables in A. obstetricans were: snout-urostyle length, distance between the nostrils, distance between the anterior end of the middle metacarpal tubercle and the tip of the third finger, and distance from elbow to third finger tip. The significant variables in A. cisternasii were: head width, jaw bottom length, vertical diameter of the tympanum, distance between the nostrils, and tibia-fibula length.