Morphological variability among populations of Austropotamobius torrentium (Schrank, 1803) from central Balkan

Abstract

The Balkans is Austropotamobius torrentium (Schrank, 1803) hotspot. In its central parts (Serbia) three main stone crayfish phylogroups are present: CSE (Central and South-East European), SB (Southern Balkans) and LD (Lika and Dalmatia). In order to assess the morphological variability of the stone crayfish we analyzed ten populations from the central Balkans. A total of 145 adult crayfish (total length over 60 mm) were measured during our 2017 field study and 21 linear parameters and individual weight were taken. All measurements were standardized by postorbital length. Of analyzed crayfish 80 were males and 65 females. Performed non-parametric tests (Kruskal-Wallis) have shown that males and females differ in majority of parameters, including those related to weight. Discriminant analysis showed that abdominal and claw widths were the most important for sex separation, with the first one having larger values in females, while the second one being larger in males. Regarding populations, non-parametric tests showed that only stable parameters among male populations were a few characteristics of abdomen, claws and weight, while in female populations those were a bit more numerous. Canonical discriminate analysis was used to assess spatial morphological variability among studied populations (10 populations for males, and 8 for females). The results have shown that separation among male samples is more pronounced than in females. Alongside the first root a clear distinction of Uvac (CSE phylogroup) and Rasina (SB phylogroup) populations from the rest can be observed, while along the second root these two populations differ. Considering that analyzed populations belong to all three main phylogroups our results suggest that morphological variability of the stone crayfish is related more to specific environmental conditions (adaptations) than to separate phylogenetic lineages.