The superorder Peracarida is a large group of malacostracan crustaceans, having members in marine, freshwater, and terrestrial habitats. They are chiefly defined by the presence of a brood pouch, or marsupium, formed from thin flattened plates () borne on the basalmost segments of the legs 2] Other characters which unite the group are the possession of a single pair of maxillipeds (rarely 2?3), of mandibles with an articulated accessory process between the molar and incisor teeth in the adults (called the lacinia mobilis), and of a carapace which is often reduced in size and is not fused with the posterior thoracic somites. The young hatch at a post-larval, prejuvenile stage called a manca which lacks the last pair of legs.
General bauplan of a peracarid mandibula: 1. Molar process; 2. Spine row; 3. Lacinia mobilis; 4. Incisor process; 5. Palp
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. The name amphipoda refers to the different forms of appendages, unlike isopods, where all the thoracic legs are alike. Of the 7,000 species, 5,500 are classified into one suborder, Gammaridea. The remainder are divided into two or three further suborders. Amphipods range in size from 1 to 340 millimetres (0.039 to 13 in) and are mostly detritivores or scavengers. They live in almost all aquatic environments; 750 species live in caves and the order also includes terrestrial animals and sandhoppers such as Talitrus saltator. [more]
Cumacea is an order of small marine crustaceans, occasionally called hooded shrimp. Their unique appearance and uniform body plan makes them easy to distinguish from other crustaceans. [more]
Isopods are an order of peracarid crustaceans, including familiar animals such as woodlice and pill bugs. The name Isopoda derives from the Greek roots (iso-, meaning "same") and p?d?? (podos, meaning "foot"). The fossil record of isopods dates back to the Carboniferous period (in the US Pennsylvanian epoch), at least 300 million years ago. [more]
Lophogastrida is an order of malacostracan crustaceans in the superorder Peracarida. They are shrimp-like animals that mostly inhabit the relatively deep pelagic waters of the oceans throughout the world. [more]
Mictacea is an order of crustaceans, erected for six species of small shrimp-like animals of the deep sea and anchialine caves. [more]
Mysida is a group of small, shrimp-like crustaceans, an order in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch, or marsupium, in females. Mysids are mostly found in marine waters throughout the world, but are also important in some fresh- and brackish-water ecosystems of the Northern hemisphere. Some mysids are cultured for experimental purposes and as food source for other cultured marine organisms. [more]
Thermosbaenacea is a group of crustaceans that live in thermal springs in fresh water, brackish water and anchialine habitats. They have occasionally been treated as a distinct superorder (Pancarida), but are generally considered to belong to the Peracarida. Due to their troglobitic lifestyle, thermosbaenaceans lack visual pigments and are therefore blind. [more]
At least 19 species and subspecies belong to the Order Thermosbaenacea.
More info about the Order Thermosbaenacea may be found here.