Limb deformities in Ambystoma rivulare (Caudata: Ambystomatidae), a microendemic and threatened Mexican Salamander

Abstract

Recent global declines and disappearances of amphibian populations have increased the need for information concerning the adversities affecting amphibian populations worldwide. Some of the most alarming cases include the appearance of high incidences of deformities in amphibian populations. Although data about what causes body deformities are inconclusive and information about the frequency of deformities in natural populations is scarce, studying the incidence and characteristics of deformities in salamander populations could serve as an early indicator of environmental disturbance. In this study, we report limb deformities in a population of Toluca Axolotl (Ambystoma rivulare), from the municipality of Amanalco de Becerra, Estado de México, México. We sampled 144 individuals and found cases of ectrodactyly, syndactyly, polydactyly, brachydactyly, hypoplasia, and polymyelia. The percentage of deformed individuals (21.5%) far exceeded expectations for healthy populations. This information is vital for health assessments of amphibian populations and the increasing reports of amphibian diseases and habitat degradation.