#astacus

• Astaciform — Having the shape, appearance, or anatomical structure resembling that of a crayfish (of the genus Astacus); a morphological adjective used in biology to describe the exterior appearance of certain fossil or contemporary crustaceans presenting a robust cephalothorax, segmented abdomen, and prominent claws.
• Astacoid — Resembling a crayfish or the species of the Astacus genus in form, structure, or general appearance; a morphological adjective used to describe fossil specimens, crustacean larvae, or external anatomical characters (such as the carapace or claws) reminiscent of the river crayfish's structural configuration.
• 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.