The Caridea, commonly known as caridean shrimp or true shrimp, are an infraorder of shrimp within the order Decapoda. This infraorder contains all species of true shrimp. They are found widely around the world in both fresh and salt water. Many other animals with similar names – such as the mud shrimp of Axiidea and the boxer shrimp of Stenopodidea – are not true shrimp, but many have evolved features similar to true shrimp.
Dendrobranchiata is a suborder of decapods, commonly known as prawns. There are 540 extant species in seven families, and a fossil record extending back to the Devonian. They differ from related animals, such as Caridea and Stenopodidea, by the branching form of the gills and by the fact that they do not brood their eggs, but release them directly into the water. They may reach a length of over 330 millimetres (13 in) and a mass of 450 grams (1.0 lb), and are widely fished and farmed for human consumption.
The Achelata is an infra-order of the decapod crustaceans, holding the spiny lobsters, slipper lobsters and their fossil relatives.
Anomura is a group of decapod crustaceans, including hermit crabs and others. Although the names of many anomurans include the word crab, all true crabs are in the sister group to the Anomura, the Brachyura.
The Stenopodidea or boxer shrimps are a small group of decapod crustaceans. Often confused with Caridea shrimp or Dendrobranchiata prawns, they are neither, belonging to their own group.
Eucarida is a superorder of the Malacostraca, a class of the crustacean subphylum, comprising the decapods, krill, Amphionides and Angustidontida. They are characterised by having the carapace fused to all thoracic segments, and by the possession of stalked eyes.
Aeger is a genus of fossil prawns. They first occur in the Middle Triassic, and died out at the end of the Late Cretaceous. A total of 21 species are known.
Luciferidae is a family of prawns. These prawns are small, characterised by bioluminescence and the loss or reduction of some appendages. They are predators of tiny planktonic crustaceans for which their third pereiopod is adapted to capture by having thick, curved spines covering the limb. Until recently, the family was thought to be monotypic, but a 2016 cladistic analysis recognized a second genus apart from Lucifer, named Belzebub.
Hippoidea is a superfamily of decapod crustaceans known as sand crabs or mole crabs.
Dromiacea is a group of crabs, ranked as a section. It contains 240 extant and nearly 300 extinct species. Dromiacea is the most basal grouping of Brachyura crabs, diverging the earliest in the evolutionary history, around the Late Triassic or Early Jurassic. Below is a cladogram showing Dromiacea's placement within Brachyura:
Polychelida is an infraorder of decapod crustaceans. Fossil representatives are known dating from as far back as the Upper Triassic. A total of 38 extant species, all in the family Polychelidae, and 55 fossil species have been described.
Albuneidae is a little-known family of specialized burrowing sand crabs. There are 50 extant species as well as nine fossil species that have been described. Fossil specimens have been described from the Cretaceous, Miocene and Oligocene.
Eubrachyura is a group of decapod crustaceans comprising the more derived crabs. It is divided into two subsections, based on the position of the genital openings in the two sexes. In the Heterotremata, the openings are on the legs in the males, but on the sternum in females, while in the Thoracotremata, the openings are on the sternum in both sexes. This contrasts with the situation in other decapods, in which the genital openings are always on the legs. Heterotremata is the larger of the two groups, containing the species-rich superfamilies Xanthoidea and Pilumnoidea and all the freshwater crabs. The eubrachyura is well known for actively and constantly building its own burrows. The fossil record of the Eubrachyura extends back to the Cretaceous; the supposed Bathonian representative of the group, Hebertides jurassica, ultimately turned out to be Cenozoic in age.
Cheiragonidae is a small family of crabs, sometimes called helmet crabs, placed in its own superfamily, Cheriagonoidea. It comprises three extant species, Erimacrus isenbeckii, Telmessus acutidens and Telmessus cheiragonus, there are no yet evidences of Cheiragonidae in the fossil record. Many of these crabs were formerly treated as members of the Atelecyclidae.
Farfantepenaeus is a genus of prawns in the family Penaeidae. Its eight species were formerly included in the genus Penaeus. It was first published as a genus name in 1972 by Rudolf N. Burukovsky, but without the necessary designation of a type species. That situation was corrected by the same author in 1997. The name Farfantepenaeus commemorates the Cuban carcinologist Isabel Pérez Farfante.
Carpopenaeus is an extinct genus of prawn, which existed during the Upper Jurassic and Cretaceous periods. It contains three species.
Longitergite is an extinct genus of prawn which existed in Russia during the Lower Miocene period. It contains a single species.
Alope is a genus of shrimp in the family Hippolytidae, comprising two species:
Belzebub is a genus of prawns in the family Luciferidae. The species which make up the genus Belzebub were formerly placed in the genus Lucifer but were separated to form Belzebub after a cladistic analysis. They are very small planktonic and benthic prawns with an extreme lateral compression of the carapace with elongated mandibles and anteriors of the pereiopods but lacking pereiopods 4 and 5 and any gills. The pereiopods either lack chelae or they are substantially reduced. The sixth abdominal segment of males has two ventral processes and the telson has a strong ventral process.
Belzebub hanseni, the ghost shrimp or ghost prawn, is a small planktonic and benthic species of prawn from the family Luciferidae.
