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 Fresh or FRESH may refer to: People *DJ Fresh (born 1977), UK-based drum and bass artist *DJ Fresh (producer), US-based R&B producer born Marqus Brown Arts, entertainment, and media Films * ''Fresh'' (1994 film), a crime film * ''Fresh'' (200 ...

and

salt water Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride). On the United States Geological Survey (USGS) salinity scale, saline water is saltier than brackish wat ...

. Many other animals with similar names – such as the mud shrimp of

Axiidea Axiidea is an infraorder of decapod crustaceans. They are colloquially known as mud shrimp, ghost shrimp, or burrowing shrimp; however, these decapods are only distantly related to true shrimp. Axiidea and Gebiidea are divergent infraoders of ...

and the boxer shrimp of

Stenopodidea 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. Anatomy They can be differentiated from the Dendrobranc ...

– are not true shrimp, but many have evolved features similar to true shrimp.

Biology

Carideans are found in every kind of aquatic habitat, with the majority of species being marine. Around a quarter of the described species are found in fresh water, however, including almost all the members of the species-rich family

Atyidae Atyidae is a family of shrimp, present in all tropical and most temperate waters of the world. Adults of this family are almost always confined to fresh water. This is the only family in the superfamily Atyoidea. Genera and species The followin ...

and the

Palaemonidae Palaemonidae is a family of shrimp in the order Decapoda. Many species are carnivores that eat small invertebrates, and can be found in any aquatic habitat except the deep sea. One significant genus is ''Macrobrachium'', which contains commercia ...

subfamily Palaemoninae. They include several commercially important species, such as ''

Macrobrachium rosenbergii ''Macrobrachium rosenbergii'', also known as the giant river prawn or giant freshwater prawn, is a commercially important species of palaemonid freshwater prawn. It is found throughout the tropical and subtropical areas of the Indo-Pacific reg ...

'', and are found on every continent except

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...

. The marine species are found at depths to , and from the tropics to the polar regions. In addition to the great variety in habitat, carideans vary greatly in form, from species a few millimetres long when fully grown, to those that grow to over a foot long. Except where secondarily lost, shrimp have one pair of stalked eyes, although they are sometimes covered by the carapace, which protects the cephalothorax. The carapace also surrounds the

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

s, through which water is pumped by the action of the mouthparts. Most carideans are

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

, but some are specialised for particular modes of feeding. Some are

filter feeders Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

, using their setose (bristly) legs as a sieve; some scrape algae from rocks. The snapping shrimp of the genus '' Alpheus'' snap their claws to create a shock wave that stuns prey. Many

cleaner shrimp Cleaner shrimp is a common name for a number of swimming decapod crustaceans, that clean other organisms of parasites. They belong to any of three families, Hippolytidae (including the Pacific cleaner shrimp, ''Lysmata amboinensis''), Pala ...

, which groom reef fish and feed on their parasites and

necrotic tissue Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated diges ...

, are carideans. In turn, carideans are eaten by various animals, particularly fish and seabirds, and frequently host bopyrid parasites.

Lifecycle

Unlike Dendrobranchiates, Carideans brood their eggs rather than releasing them into the water. Caridean larvae undergo all naupliar development within the egg, and eclose as a

zoea Crustaceans may pass through a number of larval and immature stages between hatching from their eggs and reaching their adult form. Each of the stages is separated by a moult, in which the hard exoskeleton is shed to allow the animal to grow. The ...

. The zoea stage feeds on phytoplankton. There can be as few as two zoea stages, (e.g. some freshwater

), or as many as 13, (e.g. some

Pandalidae The family Pandalidae is a taxon of caridean shrimp. These species are commonly called pandalid shrimp. They are edible and have high economic value. They are characterised by the subdivided carpus of the second pereiopod and, mainly, by the la ...

). The post-zoeal larva, often called a decapodid, resembles a miniature adult, but retains some larval characteristics. The decapodid larva will metamorphose a final time into a post-larval juvenile: a young shrimp having all the characteristics of adults. Most adult carideans are benthic animals living primarily on the sea floor. Common species include ''

Pandalus borealis ''Pandalus borealis'' is a species of caridean shrimp found in cold parts of the northern Atlantic and northern Pacific Oceans, although the latter population now often is regarded as a separate species, ''P. eous''. The Food and Agriculture Orga ...

'' (the "pink shrimp"), ''

Crangon crangon ''Crangon crangon'' is a species of caridean shrimp found across the northeastern Atlantic Ocean from the White Sea in the north of Russia to the coast of Morocco, including the Baltic Sea, as well as occurring throughout the Mediterranean and Bl ...

'' (the "brown shrimp") and the snapping shrimp of the genus ''Alpheus''. Depending on the species and location, they grow from about long, and live between 1.0 and 6.5 years.

Commercial fishing

Wild caridean shrimp capture time series

The most significant commercial species among the carideans is ''

'', followed by ''

''. The wild-capture production of ''P. borealis'' is about ten times that of ''C. crangon''. In 1950, the position was reversed, with the capture of ''C. crangon'' about ten times that of ''P. borealis''. In 2010, the global aquaculture of all shrimp and prawn species (3.5 million tonnes) slightly exceeded the global wild capture (3.2 million tonnes). No carideans were significantly involved in aquaculture, but about 430,000 tonnes were captured in the wild. That is, about 13% of the global wild capture, or about 6% of the total production of all shrimp and prawns, were carideans.

Systematics and related taxa

Shrimp of the infraorder Caridea are more closely related to lobsters and crabs than they are to the members of the sub-order Dendrobranchiata (prawns). Biologists distinguish these two groups based on differences in their

structures. The gill structure is

lamellar A ''lamella'' (plural ''lamellae'') is a small plate or flake, from the Latin, and may also be used to refer to collections of fine sheets of material held adjacent to one another, in a gill-shaped structure, often with fluid in between though s ...

in carideans but branching in dendrobranchiates. The easiest practical way to separate true shrimp from dendrobranchiates is to examine the second abdominal segment. The second segment of a carideans overlaps both the first and the third segment, while the second segment of a dendrobranchiate overlaps only the third segment. They also differ in that carideans typically have two pairs of chelae (claws), while dendrobranchiates have three. A third group, the

, contains around 70 species and differs from the other groups in that the third pairs of legs is greatly enlarged. Procarididea are the sister group to the Caridea, comprising only eleven species. The

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

below shows Caridea's relationships to other relatives within Decapoda, from analysis by Wolfe ''et al.'', 2019. The below

shows the internal relationships of eight selected

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...

within Caridea, with the

(freshwater shrimp) being the most basal:

Taxonomy

The infraorder Caridea is divided into 15 superfamilies:

Fossil record

The

fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

of the Caridean is sparse, with only 57 exclusively fossil species known. The earliest of these cannot be assigned to any family, but date from the

Lower Jurassic The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma&nb ...

and

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

. A number of extinct genera cannot be placed in any superfamily: *'' Acanthinopus'' Pinna, 1974 *'' Alcmonacaris'' Polz, 2009 *'' Bannikovia'' Garassino & Teruzzi, 1996 *'' Blaculla'' Münster, 1839 *'' Buergerocaris'' Schweigert & Garassino, 2004 *'' Gampsurus'' von der Marck, 1863 *'' Hefriga'' Münster, 1839 *'' Leiothorax'' Pinna, 1974 *'' Parvocaris'' Bravi & Garassino, 1998 *'' Pinnacaris'' Garassino & Teruzzi, 1993

References

External links

* * {{Taxonbar, from=Q80117 Arthropod infraorders Commercial crustaceans Edible crustaceans Extant Early Jurassic first appearances Seafood Taxa named by James Dwight Dana nrm:Chèrvette simple:Shrimp