Ecological niche divergence contributes species differentiation in worm lizards (Blanus sp.) (Squamata: Amphisbaenia: Blanidae) in Mediterranean part of Anatolian peninsula and the Levantine region

Abstract

The genus Blanus Wagler, 1830 (Squamata, Amphisbaenia) contains seven fossorial species found in the East Mediterranean Basin. Recent molecular-based studies suggested that former B. strauchi (Turkish worm lizard) is divided into three species spread from Southern Anatolia to Levantine region: B. strauchi, B. aporus and B. alexandri. Although these species not only have highly similar morphological characters but also are genetically distinct, the ecological niche differentiations have not been studied yet. We aim to predict the suitable habitats for related Blanus species and to determine niche overlaps and niche differentiation by similarity and identity tests. The occurrence records were obtained from literature and our own field surveys. These occurrence locations were assessed in 30 arc-second resolution layer, compatible with bioclimatic parameters from World-Clim ( www.worldclim.org ). Suitable habitat prediction analyses were performed in MaxEnt and the pairwise niche overlap comparisons were made in ENMTools. Our results show that precipitation and temperature dynamics may have an influence on the vegetation types, which provide suitable habitats for these species. Even in the most conservative model, where B.strauchi was designated as the ancestral species, the predicted distribution area was larger than the actual one. The niche overlap analysis confirms that the ecological differentiations among these taxa are valid. This result is in agreement with a previous molecular-based study. We speculate that the Messinian Salinity Crisis had an effect on precipitation and temperature dynamics and niche differentiation among the worm lizards, potentially contributing to species formation.