Morphological abnormalities in a population of Pleurodeles waltl (Caudata: Salamandridae) from southwestern Spain

Prevalence of morphological abnormalities usually is less than 5% in most amphibian populations (Ouellet et al. 1997, Vandenlangenberg et al. 2003, Mester et al. 2015). Morphology is closely related to whole-organism performance in amphibians (Zamora-Camacho 2018, Zamora- \nCamacho and Aragón 2019a), and thus, is under strong selection (Watkins 1996). Therefore, this low frequency likely reflects the negative effects of abnormalities on whole-organism performance (Zamora-Camacho and Aragón 2019b). However, amphibian populations are experiencing an \nalarming increase in morphological abnormality rates worldwide (Lanoo 2008, Johnson and Bowerman 2010, Laurentino et al. 2016). Amongst these, the most common are limb malformations, such as misshapen or fused limbs, and missing, or presence of extra limbs and toes (Harris et al. 2008, Johnson and Bowerman 2010, Reeves et al. 2013).