Branchiopoda is a class of crustaceans. It comprises fairy shrimp, clam shrimp, Diplostraca, Notostraca, the Devonian Lepidocaris and possibly the Cambrian Rehbachiella. They are mostly small, freshwater animals that feed on plankton and detritus.
Malacostraca is the second largest of the six classes of pancrustaceans 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.
Traditionally, the Myodocopa and Podocopa have been classified as subclasses within the class Ostracoda, although there is some question about how closely related the two groups actually are. The Myodocopa are defined by possession of a poorly calcified carapace, and 8–9 articles in the exopod of the second antenna. The ventral margin of the carapace is not concave, and the valves do not overlap to a great extent.
Limnocythere is a genus of ostracod crustaceans in the family Limnocytheridae. It contains the following extant species :
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.
Goneplax rhomboides is a species of crab. It is known by the common name angular crab because of its angular carapace. Although it is also called the square crab, its shell is in fact more trapezoidal than square. This species is also known as the mud-runner because they are able to run away quickly when threatened.
Gigantocypris, sometimes known as giant ostracod or giant seed shrimp, is a genus of ostracod crustaceans in family Cypridinidae, and among the most well-known members of the class Ostracoda. Its members are extremely large for ostracods, measuring up to 3.2 cm (1.3 in) across, have a globular shape, are typically semi-transparent orange or reddish, and have a large pair of mirror-like eyes that are used to locate their small animal prey. They are found worldwide in dark, deep and cold oceans.
Cyprididae is "the most diverse group of freshwater ostracods". It contains over 1000 species, which represents 50% of the known species of freshwater ostracods. Around 60% of genera in the family are endemic to a single zoogeographic region. The family contains 16 subfamilies, and is most diverse in the Afrotropical realm, with over 300 species in 45 genera. Many Cyprididae occur in temporary water bodies and have drought-resistant eggs, mixed/parthenogenetic reproduction and ability to swim. These biological attributes pre-adapt them to form successful radiations in these habitats. Bennelongia is an interesting of the family Cyprididae. It may be the last true descendant of the Mesozoic lineage of Cypridea, which was a dominant lineage of ostracod in non-marine waters in the Cretaceous.
Candonidae is a family of ostracods, containing around 25% of all known species of freshwater ostracods. Around 75% of genera in the family are endemic to a single zoogeographic region. It contains more than 500 species, of which more than 300 are endemic to the Palearctic realm.
Nototropis falcatus is a species of amphipod crustacean. It is whitish in colour, with brown patches, and grows to a total length of around 7 mm (0.3 in). It lives on soft sediment such as fine sand at depths of 10 to 50 metres, from northern Norway to the west coast of Ireland, including the North Sea, and as far south as the southern Bay of Biscay.
Potamocypris is a genus of ostracod crustaceans in the family Cyprididae. There are currently 44 extant species of Potamocypris. The majority of the species occur in freshwater habitats; only a few species of the genus colonize marine brackish coastal waters.
Potamocypris mastigophora is a species of ostracod crustacean in the family Cyprididae, subfamily Cypridopsinae. It is known from Africa and the southern areas of the Palaearctic.
Potamocypris steueri is a species of ostracod crustaceans in the family Cyprididae, subfamily Cypridopsinae found in marine brackish waters of the Mediterranean Basin as well as in brackish coastal waters of the Black Sea and the Caspian Sea.
Potamocypris variegata is a species of ostracod crustaceans in the family Cyprididae, subfamily Cypridopsinae. It is mainly found in ponds with rich aquatic vegetation, more rarely in slowly flowing streams. The species is distributed throughout Europe, but is also known from North America.
Potamocypris unicaudata is a species of ostracod crustacean in the family Cyprididae, subfamily Cypridopsinae. It is abundantly found in ditches and ponds near the sea shore, where freshwater slightly mingles with sea water. It is known from both Europe and North America.
Potamocypris smaragdina is a species of ostracod crustacean in the family Cyprididae, subfamily Cypridopsinae. It is known from both Europe and North America.
Crustaceans are a group of arthropods that are a part of the subphylum Crustacea, a large, diverse group of mainly aquatic 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.
Calyptraeotheres garthi is a species of pea crab in the family Pinnotheridae. It is found in the southwestern Atlantic Ocean and is a parasitic castrator of the slipper limpet Crepidula cachimilla.
