Carapace peculiarities of Hermann's tortoises (Testudo hermanni) in several Balkan populations

Abstract

© NwjZ, Oradea, Romania, 2015. Although highly conservative in major lineages, skeletons of tetrapods can vary within groups. In chelonians, a large portion of the skeleton is "external," which makes it comparatively easy to study. I present several peculiarities in the shape and architecture of shells in the Hermann's tortoise, Testudo hermanni, from five localities in the Balkan Peninsula. These are: a hump in the rear part of the shell (in males), variability in the so-called neural formula (in both sexes), and unusually poorly curved pygal (and supracaudal) element in many males. These oddities were particularly frequent in an insular population, but were found in mainland samples as well. To my knowledge, this study presents the first qualitative and a preliminary quantitative analysis of shell aberrations within and among populations of any Testudo species. More importantly, it was performed on extant populations: this enables monitoring of ontogenetic shell shape development, i.e. the emergence of anomalies, as well as their possible influences and consequences concerning survival and behaviour. Future research should aim at inferring genetic structure within and among Hermann's tortoise populations in the sampled region and in other parts of the Balkans.