Distribution of the slow worm (Anguis fragilis complex) with possible species delimitation in Serbia

Abstract

In this study, we present an updated distribution data of Anguis fragilis complex species in Serbia. The dataset consists of literature and Internet records, coupled with previously unpublished distribution data gathered in the field. Of the two species of the complex, Anguis fragilis is present in the western and southern parts of the country while Anguis colchica is present in the northeastern and eastern parts of the country. There is an absence of both species in the northernmost parts of the country, due to the lack of adequate habitat. The field records tend to be more abundant in the Mountain-valley altitudinal region, and scarcer and more scattered in the Peripannonian and Pannonian altitudinal regions, which can partly be attributed to the sampling bias. The location and width of the contact zone are still poorly known. It’s hypothesized to follow the Velika Morava river valley to the south and then the boundary between the Carpathian-Balkan and Rhodope mountain ranges in the southeast, but the hybrid zone could be situated more to the west. There is a certain discrepancy, in the literature, between the contact zone proposed by morphological data, and the one proposed by molecular sampling. That stresses the need for thorough sampling in the region and further analyses. Finally, since the taxonomic split between the cryptic slow worm taxa was not yet recognized in our national nomenclature, this paper also presents the official Serbian names for the two species. The species Anguis fragilis will keep the standard Serbian name “Slepić”, while for the species Anguis colchica we prop ose the name “Istočni slepić”.