Cnidaria is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water and marine environments, including jellyfish, hydroids, sea anemones, corals and some of the smallest marine parasites. Their distinguishing features are an uncentralized nervous system distributed throughout a gelatinous body and the presence of cnidocytes or cnidoblasts, specialized cells with ejectable flagella used mainly for envenomation and capturing prey. Their bodies consist of mesoglea, a non-living, jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell thick. Cnidarians are also some of the few animals that can reproduce both sexually and asexually.
The Portuguese man o' war, also known as the man-of-war or bluebottle, is a marine hydrozoan found in the Atlantic Ocean and the Indian Ocean. It is considered to be the same species as the Pacific man o' war or bluebottle, which is found mainly in the Pacific Ocean. The Portuguese man o' war is the only species in the genus Physalia, which in turn is the only genus in the family Physaliidae.
Hydrozoa is a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specialized individual animals cannot survive outside the colony. A few genera within this class live in freshwater habitats. Hydrozoans are related to jellyfish and corals, which also belong to the phylum Cnidaria.
In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work mainly like muscular hydrostats. Most forms of tentacles are used for grasping and feeding. Many are sensory organs, variously receptive to touch, vision, or to the smell or taste of particular foods or threats. Examples of such tentacles are the eyestalks of various kinds of snails. Some kinds of tentacles have both sensory and manipulatory functions.
Siphonophorae is an order within Hydrozoa, which is a class of marine organisms within the phylum Cnidaria. According to the World Register of Marine Species, the order contains 175 species described thus far.
Physalia is a genus of the order Siphonophorae, colonies of four specialized polyps and medusoids that drift on the surface of the Atlantic, Indian and Pacific oceans. Although these organisms look like a single multicellular organism, each specimen is actually a colony of minute organisms called zooids that have to work together for survival. A gas-filled bladder resembling a blue bottle provides buoyancy, and long tentacles of venomous cnidocytes provide a means of capturing prey. A sail on the float, which may be left or right-handed, propels Physalia about the sea, often in groups. These siphonophores sometimes become stranded on beaches, where their toxic nematocysts can remain potent for weeks or months in moist conditions. Both species of this siphonophore resemble a jellyfish in appearance, with their gas-filled float and cluster of polyps beneath, which can hang up to 30 or 165 ft below the surface of the sea.
Velella is a monospecific genus of hydrozoa in the Porpitidae family. Its only known species is Velella velella, a cosmopolitan free-floating hydrozoan that lives on the surface of the open ocean. It is commonly known by the names sea raft, by-the-wind sailor, purple sail, little sail, or simply Velella.
Pelagia noctiluca is a jellyfish in the family Pelagiidae and the only currently recognized species in the genus Pelagia. It is typically known in English as the mauve stinger, but other common names are purple-striped jelly, purple stinger, purple people eater, purple jellyfish, luminous jellyfish and night-light jellyfish. In Greek, pelagia means "(she) of the sea", from pelagos "sea, open sea"; in Latin noctiluca is the combining form of nox, "night"", and lux, "light"; thus, Pelagia noctiluca can be described as a marine organism with the ability to glow in the dark (bioluminescence). It is found worldwide in tropical and warm temperate seas, although it is suspected that records outside the North Atlantic region, which includes the Mediterranean and Gulf of Mexico, represent closely related but currently unrecognized species.
Nomeidae, the driftfishes, are a family of scombriform ray-finned fishes found in tropical and subtropical waters throughout the world. The family includes about 16 species. The largest species, such as the Cape fathead, Cubiceps capensis, reach 1 m in length.
Atolla wyvillei, also known as the Atolla jellyfish, Coronate medusa, and deep-sea jellyfish, 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.
Praya dubia, the giant siphonophore, lives in the mesopelagic zone to bathypelagic zone at 700 m (2,300 ft) to 1,000 m (3,300 ft) below sea level. It has been found off the coasts around the world, from Iceland in the North Atlantic to Chile in the South Pacific.
Chrysaora hysoscella, the compass jellyfish, is a common species of jellyfish that inhabits coastal waters in temperate regions of the northeastern Atlantic Ocean, including the North Sea and Mediterranean Sea. In the past it was also recorded in the southeastern Atlantic, including South Africa, but this was caused by confusion with close relatives; C. africana, C. fulgida and an undescribed species tentatively referred to as "C. agulhensis".
Porpita porpita, or the blue button, is a marine organism consisting of a colony of hydroids found in the warmer, tropical and sub-tropical waters of the Pacific, Atlantic, and Indian oceans, as well as the Mediterranean Sea and eastern Arabian Sea. It was first identified by Carl Linnaeus in 1758, under the basionym Medusa porpita. In addition, it is one of the two genera under the suborder Chondrophora, which is a group of cnidarians that also includes Velella. The chondrophores are similar to the better-known siphonophores, which includes the Portuguese man o' war, or Physalia physalis. Although it is superficially similar to a jellyfish, each apparent individual is actually a colony of hydrozoan polyps. The taxonomic class, Hydrozoa, falls under the phylum Cnidaria, which includes anemones, corals, and jellyfish, which explains their similar appearances.
Marrus orthocanna is a species of pelagic siphonophore, a colonial animal composed of a complex arrangement of zooids, some of which are polyps and some medusae. Swimming independently in the mid-ocean, it lives in the Arctic and other cold, deep waters. It is a colonial creature that is born from a single egg which is fertilized. Later on, a protozoan forms that eventually grows to form more duplicating members of the colony. It belongs to the order Siphonophorae and the genus Marrus, which also includes M. antarcticus, M. claudanielis, and M. orthocannoides.
Apolemia is a genus of siphonophores. It is the only genus in the monotypic family Apolemiidae.
Porpita prunella is a marine species of hydrozoan organisms within the family Porpitidae. It consists of colonies of zooids. Very little is known about this species, as there have been no confirmed sightings since its discovery in 1801 and naming by Haeckel in 1888. Being in the chondrophore group, it is likely that its behaviour is similar to the other species of the genera in the family. However there are also serious doubts as to its very existence as a separate species and may in fact be a synonym for Porpita porpita instead.
Bathyphysa conifera, sometimes called the flying spaghetti monster, is a bathypelagic species of siphonophore in the family Rhizophysidae. It is found in the northern Atlantic Ocean and off the coast of Southwestern Africa and California.
Physonectae is a suborder of siphonophores. In Japanese it is called 胞泳.
Calycophorae is a suborder of Siphonophores alongside two other suborders Physonectae and Cystonectae. This suborder includes the giant siphonophore, ; one of the longest lengthwise extant creatures (40–50m). While the Physonectae have a pneumatophore, nectophore, and a siphosome, Cystonectae lack a nectophore, and Calycophorae lack a pneumatophore. From the bell-shaped nectophores, Physonectae and Calycophorae are called Codonophores or Greek for bell-bearers. The distribution, morphology, and behaviors of Calycophorae species are vast and greatly depend on the species. Calycophoraes typically consist of two nectophores with a siphosome that have many tentacles that grow out of the siphosome. The Calycophoraes move by propelling water out of the nectophore much like how jellyfishes move. The tentacles act as fishing nets where the nematocysts on the tentacles paralyze their prey which are then later fed on. Calycophorae have three life stages, which are the larval development stage, the polygastric stage, and the eudoxid maturation stage. Each Calycophorae colony forms from one fertilized egg.
Nanomia bijuga, first described by Stefano Delle Chiaje in 1844 and originally named Physsophora bijuga, is a species of mesopelagic siphonophore in the family Agalmatidae As with all members of the siphonophorae order, it is a colonial organism composed of individual zooids. N. bijuga has a fairly broad distribution, and has been observed in the coastal waters off of North America and Europe. The species has been found to occupy both epipelagic and mesopelagic depths. They utilize specialized swimming zooids for both propulsion and escape behaviors. Similar to other siphonophores, Nanomia bijuga employ stinging tentacles for hunting and defense. They primarily feed on small crustaceans, especially krill.
