Jellyfish, also known sea jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria.
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.
Rhizostomeae is an order of jellyfish. Species of this order have neither tentacles nor other structures at the bell's edges. Instead, they have eight highly branched oral arms, along which there are suctorial minimouth orifices. These oral arms become fused as they approach the central part of the jellyfish. The mouth of the animal is also subdivided into minute pores that are linked to coelenteron.
Periphyllidae is a family of jellyfish containing four genera and six species. The most well-known member of the family, Periphylla periphylla, is usually considered a deep-sea species, but it forms large blooms in surface waters of Norwegian fjords.
Atolla wyvillei, also known as the Atolla jellyfish or Coronate medusa, is a species of deep-sea crown jellyfish. It lives in oceans around the world. Like many species of mid-water animals, it is deep red in color. This species was named in honor of Sir Charles Wyville Thomson, chief scientist on the Challenger expedition.
Atolla is a genus of crown jellyfish in the order Coronatae. The genus Atolla was originally proposed by Haeckel in 1880 and elevated to the monotypic family level, as Atollidae by Henry Bigelow in 1913. The six known species inhabit the mesopelagic zone. The medusae possess multiple lobes called lappets at the bell margin. Medusae also have eight tentacles, alternating with eight rhopalia, and twice as many lappets occur as tentacles.
Lucernariidae is a family of stalked jellyfish containing two genera.
Lychnorhiza lucerna is a species of jellyfish in the order Rhizostomeae. It is found off the Atlantic coasts of South America.
Cephea is a genus of true jellyfish in the family Cepheidae. They are found in the Indo-Pacific and eastern Atlantic oceans. They are sometimes called the crown jellyfish, but this can cause confusion with the closely related genus Netrostoma or the distantly related species in the order Coronatae. They are also sometimes called the cauliflower jellyfish because of the cauliflower-looking form on top of its bell.
The helmet jellyfish, sometimes called the merchant-cap, is a luminescent, red-colored jellyfish of the deep sea, belonging to the order Coronatae of the phylum Cnidaria. It is the only species in the monotypic genus Periphylla and is one of the rare examples in Scyphozoa which life-cycle lacks a polyp stage. This species is photophobic and inhabits deeper parts of the oceans to avoid light. It may be found at the surface on dark nights.
Alatina is a genus of box jellyfish within class Cubozoa. It is the largest of the three known genera in the family Alatinidae, and the only one which is not monotypic. It contains the following ten species:
Actinostola callosa is a species of sea anemones in the family Actinostolidae in the order Actiniaria. It is a deep sea species and occurs in both Pacific and Atlantic Oceans from the continental shelf to abyssal depths.
Coronamedusae is a subclass of jellyfish in the class Scyphozoa. It is the sister taxon of Discomedusae and contains about 50 named species, all included in the order Coronatae. Jellyfish in this subclass are either small medusae living in shallow marine environments, or large medusae living in the deep sea.
Linantha is a genus of crown jellyfish in the family Linuchidae. It is a monotypic genus and the only species is Linantha lunulata which was first described by the German biologist Ernst Haeckel in 1880. It is found in the tropical eastern Pacific Ocean in the vicinity of the Galápagos Islands.
Chiropsella bronzie is a species of box jellyfish. It is considered much less of a threat to humans than some of its relatives. The species was described in 2006, and is one of four species in the genus Chiropsella. Chiropsella bronzie can be found in shallow waters off the coast of Queensland, Australia.
Desmonema is a genus of jellyfish under the Cyaneidae family found in colder waters near the Antarctic region and off of the coast of Argentina. They have a bell diameter that can extend over 1 meter and wide tentacles that are grouped together in clusters. They share similar anatomical and physiological structures to the genus Cyanea. Their sophisticated structures like the thick tentacles, sensory systems, and gastrovascular system allow Desmonema to easily capture and extracellularly digest their prey. In recent years, Desmonema were reported to have a commensal relationship with fishes under the Trachurus genus and a parasitic relationship with specimens of the Hyperia genus. The genus name derives from the Ancient Greek desmós (δεσμός), meaning "bond", and nêma (νῆμᾰ), meaning "thread".
Nausithoe is a genus of jellyfishes belonging to the family Nausithoidae.
Versuriga is a monotypic genus of jellyfishes belonging to the monotypic family Versurigidae. The only species is Versuriga anadyomene. This species is rare, only having been sighted in a limited region. However, it can be identified by its gradient-like coloration, as well as its umbrella shaped bell, which is common amongst other members of the class Scyphozoa. This species is important for many reasons, ranging from ecological interactions to socioeconomic benefits. Notably, Versuriga is able to form commensalistic relationships with other organisms, impacting biodiversity, as well as being a food source for humans and other predators.
