The Importance of Sternites in Crustaceans

Sternites are the hard, chitinous (polysaccharide-based) plates that make up the exoskeleton of crustaceans such as crabs, lobsters, and shrimp. These plates provide protection for the soft body parts of the crustacean, and also help to maintain the animal's shape and provide support for its movements.

The sternites are typically found on the ventral (belly) side of the crustacean's body, and are arranged in a series of segments along the length of the body. Each segment is made up of several individual plates, which are connected to the surrounding segments by flexible joints. This allows the crustacean to move its exoskeleton and limbs freely, while still providing protection and support.

In addition to their protective function, the sternites also play a role in the crustacean's respiratory system. In some species, the sternites are perforated with small openings that allow water to flow through and reach the gills or book lungs, allowing the animal to breathe.