Very similar, but not identical: morphological taxonomic identification to improve the resolution of fine-scale distribution of Zootoca (vivipara) carniolica. Supplementary Materials

Improving the knowledge about the distribution of threatened species is a fundamental step forward for implementing effective measures for species conservation. Distribution maps of herpetological species are often inferred from morphological identification but, in some cases, morphology alone is not reliable for assessing the distribution of lookalike species. The common lizard Zootoca vivipara includes several lineages which, to date, cannot be distinguished by any conventional morphological traits. Therefore, a reliable taxonomic identification for the main Zootoca lineages is only feasible with genetic data. In this study, we identify a morphological trait that can be used to distinguish individuals of the parapatric Z. v. vivipara and Z. carniolica, without the support of molecular analyses. This method may provide a cost-effective tool to better depict the distribution of the threatened Z. carniolica and therefore prioritize the conservation of the locations where the oviparous Alpine lineage is found.