Astacideans

Astacideans are a superfamily of decapod crustaceans that includes the true lobsters, crawfish (or crayfish), and freshwater lobsters. They belong to the order Decapoda, characterized by having ten legs, five pairs of which are typically used for locomotion. The other two pairs of legs are often modified into claws, with the first pair being the largest and most prominent in many species.

These crustaceans are found in marine, brackish, and freshwater environments across the globe. Marine species, like the familiar lobsters, inhabit the ocean floor, often in rocky or sandy substrates. Freshwater astacideans, such as crayfish, are common in rivers, lakes, and streams. Their diet is typically omnivorous, consisting of small invertebrates, fish, plant matter, and carrion.

Astacideans undergo a larval stage, though it is often less planktonic and more benthic compared to other decapods. They are important components of their respective ecosystems, serving as both predators and prey. Economically, many astacidean species are highly valued as food sources, leading to extensive commercial fishing and aquaculture operations for lobsters and crayfish. Their morphology, including their segmented bodies, exoskeletons, and distinct appendages, is a classic example of arthropod anatomy.