Data from: Genetic and ecological data reveal species boundaries between viviparous and oviparous lizard lineages

Identification of cryptic species is an essential aim for conservation biologists in order to avoid premature extinctions of 'unrecognized' species, and integrating different types of data can undoubtedly aid to resolve the issue of species delimitation. We studied here two lineages of the common lizard Zootoca vivipara that display different reproductive mode (the viviparous Z. v. vivipara and the oviparous Z. v. carniolica) and that overlap their distributional ranges in the European Alps. With the purpose of delimiting species' boundaries, we analyzed their ecological, genetic and natural history features. 304 samples were collected and analyzed at cytochrome b and 11 microsatellites loci for investigating genetic variation, population structure, individual relatedness and evolutionary histories of the two lineages. Additionally, we compared their ecological niches using 8 ecological variables. Genetic data allowed to show contrasting patterns of genetic structure between the two lineages, different demographic dynamics and to exclude hybridization events. Also strong ecological differences emerged between the two lineages, and niche overlap was limited. Taken together, these results indicate that Z. v. vivipara and Z. v. carniolica should be recognized as two separate species, and particular conservation consideration should be given to the oviparous lineage that tends to live in areas threatened by increasing impact of human activities. However, recent and rapid climate warming might determine an increasing risk for the persistence of the viviparous lineage, being adapted to cold environments.