#crayfish genus
- Astacus — Lowercase spelling form for the taxonomic genus Astacus (freshwater crayfish); used in regular text or in binomial species names (such as Astacus astacus, the European crayfish) to denote decapod crustaceans with a rigid exoskeleton and large claws. It represents a fundamental morphological unit in the study of European freshwater fauna, serving as an excellent ecological indicator for the purity of running waters.