Branchiopod

Branchiopoda Temporal range: Upper Cambrian–Recent PreЄ Є O S D C P T J K Pg N
Triops, (Notostraca: Triopsidae) left: dorsal view; right: ventral view
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Branchiopoda Latreille, 1817
Orders
Subclass Sarsostraca Anostraca Subclass Phyllopoda Lipostraca† Notostraca Infraclass Diplostraca Laevicaudata Spinicaudata Cyclestherida Cladocera

Branchiopoda is a class of crustaceans. It comprises fairy shrimp, clam shrimp, Cladocera, Notostraca and the Devonian Lepidocaris. They are mostly small, freshwater animals that feed on plankton and detritus.

Members of the Branchiopoda are unified by the presence of gills on many of the animals' appendages, including some of the mouthparts. This is also responsible for the name of the group (from the Greek: branchia, gills, akin to bronchos, windpipe; Greek: pous, foot). They generally possess compound eyes and a carapace, which may be a shell of two valves enclosing the trunk (as in most Cladocera), broad and shallow (as in the Notostraca), or entirely absent (as in the Anostraca). In the groups where the carapace prevents the use of the trunk limbs for swimming (Cladocera, clam shrimp and the extinct Lipostraca), the antennae are used for locomotion, as they are in the nauplius. Male fairy shrimp have an enlarged pair of antennae with which they grasp the female during mating, while the bottom-feeding Notostraca, the antennae are reduced to vestiges. The trunk limbs are beaten in a metachronal rhythm, causing a flow of water along the midline of the animal, from which it derives oxygen, food and, in the case of the Anostraca and Notostraca, movement.