Branchiopoda is a class of crustaceans. It comprises fairy shrimp, clam shrimp, Diplostraca, Notostraca and the Devonian Lepidocaris. They are mostly small, freshwater animals that feed on plankton and detritus.
Daphnia is a genus of small planktonic crustaceans, 0.2–6.0 mm (0.01–0.24 in) in length. Daphnia are members of the order Anomopoda, and are one of the several small aquatic crustaceans commonly called water fleas because their saltatory swimming style resembles the movements of fleas. Daphnia spp. live in various aquatic environments ranging from acidic swamps to freshwater lakes and ponds.
Malacostraca is the second largest of the six classes of crustaceans just behind hexapods, containing about 40,000 living species, divided among 16 orders. Its members, the malacostracans, display a great diversity of body forms and include crabs, lobsters, crayfish, shrimp, krill, prawns, woodlice, amphipods, mantis shrimp, tongue-eating lice and many other less familiar animals. They are abundant in all marine environments and have colonised freshwater and terrestrial habitats. They are segmented animals, united by a common body plan comprising 20 body segments, and divided into a head, thorax, and abdomen.
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from 1 to 340 millimetres and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far described. They are mostly marine animals, but are found in almost all aquatic environments. Some 1,900 species live in fresh water, and the order also includes the terrestrial sandhoppers such as Talitrus saltator and Arcitalitrus sylvaticus.
Ostracods, or ostracodes, are a class of the Crustacea, sometimes known as seed shrimp. Some 33,000 species have been identified, grouped into 7 valid orders. They are small crustaceans, typically around 1 mm (0.04 in) in size, but varying from 0.2 to 30 mm in the case of the marine Gigantocypris. The largest known freshwater species is Megalocypris princeps, which reach 8mm in length. In most cases, their bodies are flattened from side to side and protected by a bivalve-like valve or "shell" made of chitin, and often calcium carbonate. The family Entocytheridae and many planktonic forms do not have calcium carbonate. The hinge of the two valves is in the upper (dorsal) region of the body. Ostracods are grouped together based on shell and soft part morphology. While early work indicated the group may not be monophyletic and early molecular phylogeny was ambiguous on this front, recent combined analyses of molecular and morphological data suggested monophyly in analyses with broadest taxon sampling, but this monophyly had no or very little support. They have a wide range of diets, and the class includes carnivores, herbivores, scavengers and filter feeders, but most ostracods are deposit feeders.
Clam shrimp are a group of bivalved branchiopod crustaceans that resemble the unrelated bivalved molluscs. They are extant and also known from the fossil record, from at least the Devonian period and perhaps before. They were originally classified in the former order Conchostraca, which later proved to be paraphyletic, due to the fact that water fleas are nested within clam shrimps. Clam shrimp are now divided into three orders, Cyclestherida, Laevicaudata, and Spinicaudata, in addition to the fossil family Leaiidae.
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are referred to as fairy shrimp. They live in vernal pools and hypersaline lakes across the world, and they have even been found in deserts, ice-covered mountain lakes, and Antarctic ice. They are usually 6–25 mm (0.24–0.98 in) long. Most species have 20 body segments, bearing 11 pairs of leaf-like phyllopodia, and the body lacks a carapace. They swim "upside-down" and feed by filtering organic particles from the water or by scraping algae from surfaces, with the exception of Branchinecta gigas, or "giant fairy shrimp", which is itself a predator of other species of anostracans. They are an important food for many birds and fish, and some are cultured and harvested for use as fish food. There are 300 species spread across 8 families.
Lophogastrida is an order of malacostracan crustaceans in the superorder Peracarida, comprising shrimp-like animals that mostly inhabit the relatively deep pelagic waters of the oceans throughout the world.
Cercopagis pengoi, or the fishhook waterflea, is a species of planktonic cladoceran crustaceans that is native in the brackish fringes of the Black Sea and the Caspian Sea. In recent decades it has spread as an invasive species to some freshwater waterways and reservoirs of Eastern Europe and to the brackish Baltic Sea. Further it was introduced in ballast water to the Great Lakes of North America and a number of adjacent lakes, and has become a pest classified among the 100 worst invasive species of the world.
The bloody-red mysid, Hemimysis anomala, is a shrimp-like crustacean in the Mysida order, native to the Ponto-Caspian region, which has been spreading across Europe since the 1950s. In 2006, it was discovered to have invaded the North American Great Lakes.
Microfauna refers to microscopic animals and organisms that exhibit animal-like qualities. Microfauna are represented in the animal kingdom and the protist kingdom.
Bythotrephes longimanus, or the spiny water flea, is a planktonic crustacean less than 15 millimetres (0.6 in) long. It is native to fresh waters of Northern Europe and Asia, but has been accidentally introduced and widely distributed in the Great Lakes area of North America since the 1980s. Bythotrephes is typified by a long abdominal spine with several barbs which protect it from predators.
The Diplostraca or Cladocera, commonly known as water fleas, is a superorder of small, mostly freshwater crustaceans, most of which feed on microscopic chunks of organic matter, though some forms are predatory.
Daphniidae is a family of water fleas in the order Anomopoda.
Paramysis is a genus of mysid crustaceans (Mysidacea) in family Mysidae, distributed in coastal zone of low boreal East Atlantic Ocean, Mediterranean Sea and the basins of Black Sea, Sea of Azov and Caspian Sea.
Mysis diluviana is a mysid crustacean found in freshwater lakes of northern North America.
Leptodora is a genus containing two species of large, nearly transparent predatory water fleas. They grow up to 21 mm (0.83 in) long, with two large antennae used for swimming and a single compound eye. The legs are used to catch copepods that it comes into contact with by chance. Leptodora kindtii is found in temperate lakes across the Northern Hemisphere and is probably the only water flea species ever described in a newspaper; L. richardi is only known from eastern Russia. For most of the year, Leptodora reproduces parthenogenetically, with males only appearing late in the season, to produce winter eggs which hatch the following spring. Leptodora is the only genus in its family, the Leptodoridae, and suborder, Haplopoda.
Polyphemus is a genus of water fleas, and the only genus in the family Polyphemidae. There are two species, P. exiguus and P. pediculus, although allopatric speciation has resulted in a number of cryptic species of P. pediculus. Polyphemus exiguus inhabits open zones in the Caspian Sea, while Polyphemus pediculus exists throughout the Holarctic. It lives in diverse conditions, from small ponds to lakes and estuaries such as the Gulf of Saint Lawrence and the Gulf of Finland. It can be found quite far offshore.
Ephippia are winter or dry-season eggs of the various species of small crustacean in the order Cladocera ; they are provided with an extra shell layer, which preserves and protects the resting stages inside from harsh environmental conditions until the more favorable times, such as spring, when the reproductive cycle is able to take place once again. Ephippia are part of the back of a mother carrying them until they are fully developed. After molting, the ephippium stays in the water, or in the soil of dried puddles, small ponds, and vernal pools. The resting stages are often called eggs, but are in fact embryos with arrested development. Ephippia can rest for many years before the embryo resumes development upon an appropriate hatching stimulus.
Crustaceans belong to the subphylum Crustacea, and form a large, diverse group of arthropods including decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, opossum shrimps, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods emerged deep in the Crustacean group, with the completed group referred to as Pancrustacea. The three classes Cephalocarida, Branchiopoda and Remipedia are more closely related to the hexapods than they are to any of the other crustaceans.
