The Caridea, commonly known as caridean shrimp or true shrimp, from the Greek word καρίς, καρίδος, 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.
A germ cell is any cell that gives rise to the gametes of an organism that reproduces sexually. In many animals, the germ cells originate in the primitive streak and migrate via the gut of an embryo to the developing gonads. There, they undergo meiosis, followed by cellular differentiation into mature gametes, either eggs or sperm. Unlike animals, plants do not have germ cells designated in early development. Instead, germ cells can arise from somatic cells in the adult, such as the floral meristem of flowering plants.
Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in this pouch and are not free-swimming characterises the order. The mysid's head bears a pair of stalked eyes and two pairs of antennae. The thorax consists of eight segments each bearing branching limbs, the whole concealed beneath a protective carapace and the abdomen has six segments and usually further small limbs.
The decapod is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various groups these may be reduced or missing. They are, from head to tail:
Amphionides reynaudii is a species of caridean shrimp, whose identity and position in the crustacean system remained enigmatic for a long time. It is a small planktonic crustacean found throughout the world's tropical oceans, which until 2015 was considered the sole representative of the order Amphionidacea, due to unusual morphological features. Molecular data however confirm it as a member of the caridean family Pandalidae, and the confusion of morphology is because only larval phases have so far been studied.
Alvinocarididae is a family of shrimp, originally described by M. L. Christoffersen in 1986 from samples collected by DSV Alvin, from which they derive their name. Shrimp of the family Alvinocarididae generally inhabit deep sea hydrothermal vent regions, and hydrocarbon cold seep environments. Carotenoid pigment has been found in their bodies. The family Alvinocarididae comprises 7 extant genera.
Kiwa is a genus of marine decapods living at deep-sea hydrothermal vents and cold seeps. The animals are commonly referred to as "yeti lobsters" or "yeti crabs”, after the legendary yeti, because of their "hairy" or bristly appearance. The genus is placed in its own family, Kiwaidae, in the superfamily Chirostyloidea. The genus Kiwa is named after the god of shellfish in Polynesian mythology.
Neocaridina davidi is a freshwater shrimp originating from eastern China and northern Taiwan and introduced in the rest of Taiwan, Japan, and Hawaii, which is commonly kept in aquaria. The natural coloration of the shrimp is green-brown, though a wide variety of color morphs exist, including red, yellow, orange, green, blue, violet and black shrimp. Full-grown shrimp reach about 4 centimetres (1.6 in) long. N. davidi shrimp are omnivores that may live 1–2 years. These shrimps have previously been classified as Neocaridina heteropoda and Neocaridina denticulata sinensis, however are now known as Neocaridina davidi which is based on the oldest known published description of the species.
Chrysomallon squamiferum, commonly known as the scaly-foot gastropod, scaly-foot snail, sea pangolin, or volcano snail is a species of deep-sea hydrothermal-vent snail, a marine gastropod mollusc in the family Peltospiridae. This vent-endemic gastropod is known only from deep-sea hydrothermal vents in the Indian Ocean, where it has been found at depths of about 2,400–2,900 m (1.5–1.8 mi). C. squamiferum differs greatly from other deep-sea gastropods, even the closely related neomphalines. In 2019, it was declared endangered on the IUCN Red List, the first species to be listed as such due to risks from deep-sea mining of its vent habitat.
Psalidopus is a genus of shrimp placed in its own family, Psalidopodidae, and superfamily, Psalidopodoidea. It comprises three species, one in the western Atlantic Ocean, and two in the Indo-Pacific.
Pandalus montagui is a species of cold-water shrimp in the family Pandalidae. It is the type species of the genus Pandalus and is variously known as the pink shrimp, Aesop shrimp and Aesop prawn.
Panulirus echinatus, the brown spiny lobster, is a species of spiny lobster that lives on rocky reefs in the tropical western Atlantic Ocean and central Atlantic Islands.
Alpheus tricolor is a crustacean belonging to the family of snapping shrimp. It was first isolated in Indonesia and Sri Lanka. It counts with a setose carapace, an acute rostrum, shallow adrostral furrows and a basicerite with a strong ventrolateral tooth. The lamella of its scaphocerite is not reduced, with an anterior margin that is concave. Its third maxilliped counts with an epipodial plate bearing thick setae, while its first chelipeds are found with their merus bearing a strong disto-mesial tooth; its third pereiopod has an armed ischium, with a simple and conical dactylus. Its telson is broad, distally tapering, with 2 pairs of dorsal spines. The species is named after its characteristic colour pattern, including white, red and orange.
Alpheus fasqueli is a crustacean belonging to the family of snapping shrimp. It was first isolated in Sri Lanka. It counts with a setose carapace, an acute and carinate rostrum, and unarmed orbital hoods. Its basicerite has a strong ventrolateral tooth. The lamella of its scaphocerite is not reduced. Its third maxilliped counts with an epipodial plate bearing thick setae, while its first chelipeds are found with their merus bearing a strong disto-mesial tooth; its third pereiopod has an armed ischium, with a simple and conical dactylus. Its telson is broad, distally tapering, with 2 pairs of dorsal spines. The species is named after Frédéric Fasquel, a photographer who contributed rare shrimp specimens for the Muséum national d'histoire naturelle.
Luckia is a genus of amphipod crustaceans in the family Pontogeneiidae, with the sole species Luckia striki. It is found in hydrothermal vents in the Atlantic Ocean.
Paracrangon is a genus of deep-sea shrimp in the family Crangonidae, found on the Pacific coasts of North America, Asia, and Australia. Morphologically, they are notable for several autapomorphies, most significantly their unique lack of second pereopods, but also for their partially flexible abdomen, which allows them to assume their defensive cataleptic posture. Species also have long spines covering their carapace. They are distinctive among the Crangonid shrimp, and are almost certainly monophyletic. All species except Paracrangon echinata, the type species, are quite rare.
The Kairei vent field is a hydrothermal vent field located in the Indian Ocean at a depth of 2,460 metres (8,070 ft). It is just north of the Rodrigues Triple Junction, approximately 2,200 kilometres (1,400 mi) east from Madagascar. It is the first hydrothermal field discovered in the Indian Ocean and the first of the series of known vents along the Central Indian Ridge.
Alvinocaris alexander is a species of hydrothermal vent shrimp in the family Alvinocarididae, and was first described in 2009 by Shane Ahyong, from specimens found off the Kermadec Islands. A. alexander closely resembles A. williamsi from the Menez Gwen site on the mid-Atlantic ridge.
Rimicaris kairei is a species of hydrothermal vent shrimp originally discovered in August 2000 with the ROV Kaiko on the R/V Kairei. They are named for the R/V Kairei and the Kairei hydrothermal vent field on which they were first discovered. They get energy from chemosynthetic symbiotic bacteria that live in their gut. They reproduce sexually and have a larval stage in which they consume photosynthetic material. Rimicaris kairei lives on four different hydrothermal vent sites on the Central Indian Ridge in the Indian Ocean. They are the most populous invertebrate on these vents. The species is differentiated from other species of Rimicaris Shrimp by a lack of setae, longer flagellar antennae, and less robust pereopods.
Rimicaris exoculata, commonly known as the 'blind shrimp', is a species of shrimp. It thrives on active hydrothermal edifices at deep-sea vents of the Mid-Atlantic Ridge. This species belongs to the Alvinocarididae family of shrimp, named after DSV Alvin, the vessel that collected the original samples described by M. L. Christoffersen in 1986. The name Rimicaris is derived from the Latin word 'rima', which means rift or fissure, in reference to the Mid Atlantic Ridge, and the Greek word 'karis', meaning shrimp. The species epithet 'exoculata' is derived from the Latin term 'exoculo', meaning deprived of eyes, referring to the highly modified, non-image-forming eyes.
