Quantifying the intersexual and interspecific morphometric variation in two resembling sympatric lacertids: <em>Iberolacerta horvathi</em> and <em>Podarcis muralis</em>

Abstract

Podarcis muralis and Iberolacerta horvathi are sympatric, frequently syntopic, lacertids through the entire range of I. horvathi and very similar in their general body size and shape, as well as in most ecological traits. We morphologically compared adults from the area of sympatry using biometric measurements and performed analyses to investigate their sexual size and shape dimorphism. A total of 34 males and 24 females of I. horvathi, and 25 males and 23 females of P. muralis, all adult individuals, were measured. Both species showed sexual size dimorphism with females being longer (snout-vent length, SVL) than males. After SVL correction (ANCOVA), head width, length and height and mass showed to be sexually dimorphic in both species. Males carry relatively wider, longer and higher heads and were heavier than conspecific females. I. horvathi heads were more flattened than those of P. muralis and P. muralis were heavier than I. horvathi. Both species displayed the same pattern of sexual dimorphism regarding body size, head size and shape not only in direction but also in magnitude. All results confirm that both species are very similar in studied biometric characters and, together with their ecological similarities, these suggest in absence of other factors they are likely to interact when living together.