Morphological evidence for hidden diversity in the threatened stone crayfish Austropotamobius torrentium (Schrank, 1803) (Decapoda: Astacoidea: Astacidae) in Croatia

• Published in: Journal of crustacean biology 2017-01, Vol.37 (1), p.7-15
• Main Authors: Maguire, Ivana, Marn, Nina, Klobučar, Göran
• Format: Article
• Language: English
• Subjects: Conservation
• ISSN: 0278-0372; 1937-240X
• DOI: 10.1093/jcbiol/ruw012

The stone crayfish Austropotamobius torrentium (Schrank, 1803) is a native European species distributed in central and southeastern Europe. Recent molecular phylogenetic research has shown that at least seven distinct monophyletic phylogroups exist within A. torrentium, with the highest genetic diversity found within the northern-central Dinaric (NCD) region in Croatia. Genetic divergence for some of these phylogroups was sufficiently large to suggest that they might actually represent cryptic species. Our research studied the morphometric and meristic characteristics of stone crayfish populations in the Žumberak-Samoborsko gorje Nature Park (Croatia) situated in the genetically diverse NCD region. The aim was to test whether there are some morphological features that clearly separate stone crayfish belonging to the three previously identified phylogroups into distinct groups based on morphology. We analysed morphological data of stone crayfish belonging to three distinct populations inhabiting small streams within the Žumberak-Samoborsko gorje Nature Park. Analyses showed that there are significant differences in some of the recorded morphometric and meristic characteristics between the studied populations for both males and females. Multivariate discriminant analyses of the measured morphological features revealed the characteristics that clearly separate populations in a similar way as molecular methods. For males, these were the characteristics describing claws, carapace, and rostrum, and for females those describing carapace, rostrum, and total length. Percentage of correctly classified crayfish per population was high (91–100%) for both sexes. Although isolated stone crayfish populations showed morphological and genetic differences, no significant correlations were obtained between genetic and morphometric distances. Analyses of additional samples and application of different genetic markers are needed to elucidate the relationships between the different populations of the stone crayfish.