Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria, and terrestrial arthropods such as fireflies. In some animals, the light is bacteriogenic, produced by symbiotic bacteria such as those from the genus Vibrio; in others, it is autogenic, produced by the animals themselves.
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.
The Myodocopida is one of the two orders within the Myodocopa, in turn a subclass of the Ostracoda. The Myodocopida are distinguished by a worm-like seventh limb, and, usually, a rostrum above an incisure (notch) from which the antennae can protrude. Unlike other ostracods, many species of the Myodocopida have lateral compound eyes Over the last thirty years there has been much research into the morphology, behaviour and distribution of myodocopids. More recently, DNA sequences have been used to investigate the phylogeny of various groups.
Cylindroleberididae is a family of ostracods that shows remarkable morphological diversity. The defining feature is the possession of gills: 7–8 leaf-like pairs at the posterior of the body. Other features common to all species in the family include a "baleen-comb" on both the maxilla and the fifth limb, a sword-shaped coxal endite on the mandible, and the triaenid bristles on the basal endites of the mandible.
The Podocopa are a subclass of ostracods. Members of the subclass Podocopa can be differentiated from the other subclass of ostracods (Myodocopa) by the morphology of the second antenna: the Podocopa have a relatively long endopod, whereas the Myodocopa have a relatively long exopod. The seventh limb of the Podocopa has a variety of forms or is absent, but is never an annulated worm-like limb.
The Podocopida are an order of ostracods in the subclass Podocopa. It is the most diverse of the five orders of ostracods, and the only one with freshwater species. The group also has a rich fossil record.
Limnocythere is a genus of ostracod crustaceans in the family Limnocytheridae. It contains the following extant species :
Spelaeoecia is a genus of crustaceans in the family Thaumatocyprididae. One species, the Bermudan endemic S. bermudensis, is listed as critically endangered on the IUCN Red List. It contains the following species:
Canthocamptidae is a family of copepods. Most of the 700 species are confined to fresh water, although there are also marine species. It contains the following genera:
Vargulin, also called Cypridinid luciferin, Cypridina luciferin, or Vargula luciferin, is the luciferin found in the ostracod Cypridina hilgendorfii, also named Vargula hilgendorfii. These bottom dwelling ostracods emit a light stream into water when disturbed presumably to deter predation. Vargulin is also used by the midshipman fish, Porichthys.
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.
Vargula hilgendorfii, sometimes called the sea-firefly and one of three bioluminescent species known in Japan as umi-hotaru (海蛍), is a species of ostracod crustacean. It is the only member of genus Vargula to inhabit Japanese waters; all other members of its genus inhabit the Gulf of Mexico, the Caribbean Sea, and waters off the coast of California. V. hilgendorfii was formerly more common, but its numbers have fallen significantly.
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.
Limnocytheridae is a family of ostracods, containing the following genera:
Azygocypridina lowryi, colloquially known as the baked bean, is a species of ostracod crustacean or "seed shrimp" in the family Cypridinidae. It is found in deep waters off the east coast of Australia.
Azygocypridina is a genus of ostracods in the family Cypridinidae, which appears to be "the least derived living ostracod", having remained largely unchanged for 350 million years. It contains the following species:
Enewton is a genus in the family Cypridinidae. The genus contains bioluminescent species, and in particular is one of the Caribbean genera of bioluminescent ostracods that perform stereotyped bioluminescent mating displays.
Maristella is a genus of ostracods belonging to the Myodocopida (Cypridinidae). The genus belongs to a diverse clade of Caribbean bioluminescent ostracods. Males perform species-specific luminescent courtship displays. It was chosen as one of the top ten species of 2019: WoRMS top 10 - 2019: Maristella chicoi. The video showing these light displays can be seen here.
Cytherella is a genus of seed shrimp in the family Cytherellidae.
