The Morphology and Taxonomic Status of Astacus colchicus (Decapoda: Astacidae) from Georgia, with a Key to the Genera of Western Palaearctic Astacidae

Abstract A survey was conducted on recently collected specimens of the rare eastern European astacid crayfish, Astacus colchicus. The study included a detailed examination and illustration of external morphology, mandible, gastric mill, and gills. Comparative analysis was carried out by comparing the morphology with other European members of the same family, Astacidae, namely Astacus astacus, Austropotamobius fulcisianus, Austropotamobius torrentium, and Pontastacus leptodactylus. The diagnosis of the genus Astacus was updated, and a taxonomic key of European Astacidae is provided and illustrated. This comprehensive study enhances our understanding of the morphology and taxonomy of Astacidae, particularly shedding light on the distinctive features of Astacus colchicus in comparison to other closely related species.