Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are anchored to the seabed by stalks rather than being mobile. The bell can pulsate to provide propulsion for highly efficient locomotion. The tentacles are armed with stinging cells and may be used to capture prey and defend against predators. Jellyfish have a complex life cycle; the medusa is normally the sexual phase, which produces planula larva that disperse widely and enter a sedentary polyp phase before reaching sexual maturity.
The Scyphozoa are an exclusively marine class of the phylum Cnidaria, referred to as the true jellyfish. It may include the extinct fossil group the Conulariida, whose affinities are uncertain and widely debated.
Hydrozoa are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most living in salt 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 fresh water. Hydrozoans are related to jellyfish and corals and belong to the phylum Cnidaria.
Aequorea victoria, also sometimes called the crystal jelly, is a bioluminescent hydrozoan jellyfish, or hydromedusa, that is found off the west coast of North America.
The Gulf of Mannar is a large shallow bay forming part of the Laccadive Sea in the Indian Ocean with an average depth of 5.8 m (19 ft). It lies between the west coast of Sri Lanka and the southeastern tip of India, in the Coromandel Coast region. The chain of low islands and reefs known as Adam's Bridge, which includes Mannar Island, separates the Gulf of Mannar from Palk Bay, which lies to the north between Sri Lanka and India. The Malvathu Oya of Sri Lanka and the estuaries of Thamirabarani River and Vaippar River of South India drain into the Gulf. The dugong is found here.
The Laccadive Sea or Lakshadweep Sea is a body of water bordering India, the Maldives, and Sri Lanka. It is located to the southwest of Karnataka, to the west of Kerala and to the south of Tamil Nadu. This warm sea has a stable water temperature through the year and is rich in marine life, the Gulf of Mannar alone hosting about 3,600 species. Mangaluru, Kannur, Kozhikode, Ponnani, Kochi, Alappuzha, Kollam, Thiruvananthapuram, Tuticorin, Colombo, and Malé are the major cities on the shore of the Laccadive Sea. Kanyakumari, the southernmost tip of peninsular India, also borders this sea.
Aequorea forskalea is a species of hydrozoan in the family Aequoreidae. Discovered in 1810 by Péron and Lesueur, A. forskalea was initially found in coastal to offshore waters of the Mediterranean Sea. This species is commonly referred to as the many-ribbed jellyfish. The species is often mixed up with some other members of the genus due to some similarities including the capability of bioluminescence.
Crossota millsae is a species of deep-sea hydrozoan. These small ocean-dwelling creatures are bioluminescent; the light emitted by these jellyfish serves as a defense or warning to other creatures. Males and females have both been described, and it reproduces sexually. They are viviparous and females brood baby medusae attached to the gastric canals inside the sub-umbrellar space.
Crossota is a genus of hydrozoans of the family Rhopalonematidae. The genus comprises five species. Unlike most hydromedusae, these do not have a sessile stage. Rather, they spend their entire lives in the water column as plankton. The genus Crossota is widespread throughout the oceans.
Rhopalonematidae is a family of hydrozoans. The family comprises 15 genera and 36 species.
Vampyrocrossota is a genus of hydrozoans of the family Rhopalonematidae. The genus only contains one species, Vampyrocrossota childressi. Unlike many hydromedusae, these animals do not have a sessile stage. Rather, they spend their entire lives in the water column as plankton. It is the only known species with a medusa that is truly black.
Anodontia alba, or the buttercup lucine, is a species of bivalve mollusc in the family Lucinidae. It can be found along the Atlantic coast of North America, its range extending from North Carolina in the United States to the West Indies.
Anodontia philippiana, or the chalky buttercup, is a species of bivalve mollusc in the family Lucinidae. It can be found burrowing in soft substrate in shallow waters along the Atlantic coast of North America, its range extending from North Carolina in the United States to the West Indies and Bermuda.
Nipponotrophon stuarti is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails.
Voragonema is a genus of hydrozoans belonging to the family Rhopalonematidae. The genus comprises four species. Unlike most hydromedusae, these do not have a sessile stage. Rather, they spend their entire lives in the water column as plankton. Centripetal expansions protruding from the ring canal is a characteristic that separates this genus from other genera in the family Rhopalonematidae.
Maeotias is a genus of hydrozoans in the family Olindiidae. It is a monotypic genus with only a single species, Maeotias marginata, commonly known as the Black Sea jellyfish or brackish water hydromedusa and often referred to as Maeotias inexpectata in the literature. It was first described from the Don and Kuban estuaries of the Sea of Azov, and also occurs in the Black Sea, all of which are areas of low salinity. It has been recorded in several other estuarine locations around the world and is regarded as an invasive species.
Algarvia alba is a species of sea slug, specifically an aeolid nudibranch. It is a marine gastropod mollusc in the family Facelinidae.
Aeginura grimaldii is a species of deep sea hydrozoan of the family Aeginidae. It is found in the north-eastern Atlantic Ocean, Pacific Ocean, and the Arctic Ocean. It has a depth range of 660-1200m deep. Live specimens are bright reddish in color, with pale tentacles, and a light red globous capsule dome containing the dark colored red body. It usually measures no more than 4.5cm from the peak of the bell to the end of the tentacles.
Crossota rufobrunnea is a species of hydrozoan.
Nemopsis bachei is a species of relatively small gelatinous zooplankton hydrozoa found in both marine and estuarine environments. This particular species was first found and described by Louis Agassiz in 1849 from samples that were taken from the coast of Massachusetts. It was also noted and described in 1857 by another name off the coast of South Carolina.
