Сrabs (liocarcinus holsatus), on the sand in the black sea, rear view

animal arthropoda arthropods benthos biological black sea fauna brachyura cancer claws crab crabs crawfish crayfish crustacea crustacean crustaceans decapoda ecological ecology exoskeleton holsatus hydrobiology invertebrate liocarcinus macro macropipus malacostraca marine nature organisms portunidae reproduction reptantia biology swimming undersea underwater water world wild wildlife