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Limnomedusae
Limnomedusae is an order of hydrozoans. Taxonomy The taxon was erected by Danish marine biologist Paul Lassenius Kramp in 1938 to accommodate certain families of hydrozoans with biphasic life histories. It includes genera with medusae with ecto-endodermal statocysts and with gonads alongside their radial canals, and also genera which have polyps that are not covered by a theca In biology, a theca (: thecae) is a sheath or a covering. Botany In botany, the theca is related to plant's flower anatomy. The theca of an angiosperm consists of a pair of microsporangia that are adjacent to each other and share a common ar .... Molecular analysis performed by Collins in 2006 has since shown that the Limnomedusae are not monophylic. The family Armorhydridae, which contains a single genus and a single species, '' Armorhydra janowiczi'', is found living in coarse sediment, has hollow tentacles and has no radial canals. It seems to share few morphological features with the other fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrozoans
Hydrozoa (hydrozoans; from Ancient Greek ('; "water") and ('; "animals")) 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. Some examples of hydrozoans are the freshwater jelly ('' Craspedacusta sowerbyi''), freshwater polyps ('' Hydra''), ''Obelia'', Portuguese man o' war (''Physalia physalis''), chondrophores (Porpitidae), and pink-hearted hydroids ('' Tubularia''). Anatomy Most hydrozoan species include both a polypoid and a medusoid stage in their life cycles, although a number of them have only one or the other. For example, ''Hydra'' has no medusoid stage, while '' Liriope'' lacks the polypoid st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microhydrulidae
Microhydrulidae is a family of cnidarians belonging to the order Limnomedusae Limnomedusae is an order of hydrozoans. Taxonomy The taxon was erected by Danish marine biologist Paul Lassenius Kramp in 1938 to accommodate certain families of hydrozoans with biphasic life histories. It includes genera with medusae with ect .... Genera: * '' Microhydrula'' Valkanov, 1965 * '' Rhaptapagis'' Bouillon & Deroux, 1967 References Limnomedusae Cnidarian families {{Hydrozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armorhydridae
Armorhydridae is a family of cnidarians belonging to the order Limnomedusae Limnomedusae is an order of hydrozoans. Taxonomy The taxon was erected by Danish marine biologist Paul Lassenius Kramp in 1938 to accommodate certain families of hydrozoans with biphasic life histories. It includes genera with medusae with ect .... Genera: * '' Armorhydra'' Swedmark & Teissier, 1958 References Limnomedusae Cnidarian families {{Hydrozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olindiidae
Olindiidae is a family of hydrozoans in the order Limnomedusae. They have a polyp phase and a medusa phase. The polyps are generally small (1 mm) and solitary, but a few species are colonial. They have a varying number of tentacles and can reproduce by budding. In the largest species, the medusae can grow to . Centripetal canals may be present or absent and the radial canals are unbranched. The gonads are beside the radial canals, except in ''Limnocnida'', where they are on the manubrium. The fertilised eggs develop into planula larvae which become polyps. These multiply asexually or can bud off medusae. In some species, medusae are only produced when the water temperature exceeds a certain level. Most species are marine, but several can also be found in brackish water and a few, notably '' Craspedacusta'' (such as '' C. sowerbii'') and '' Limnocnida'', are found in fresh water.Didžiulis, Viktoras: Craspedacusta sowerbyi.' NOBANIS - Invasive Alien Species Fact Sheet. Retri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medusa (biology)
Jellyfish, also known as sea jellies or simply jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals, although a few are anchored to the seabed by stalks rather than being motile. They are made of an umbrella-shaped main body made of mesoglea, known as the ''bell'', and a collection of trailing tentacles on the underside. Via pulsating contractions, the bell can provide propulsion for locomotion through open water. The tentacles are armed with stinging cells and may be used to capture prey or to defend against predators. Jellyfish have a complex life cycle, and the medusa is normally the sexual phase, which produces planula larvae. These then disperse widely and enter a sedentary polyp phase which may include asexual budding before reaching sexual maturity. Jellyfish are found all over the world, from surface waters to the deep sea. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monobrachium
''Monobrachium'' is a genus of hydroids. These marine cnidarians form the only genus of the monotypic family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ... Monobrachiidae. Species The genus contains the following species: * '' Monobrachium antarcticum'' Robins, 1972 * '' Monobrachium drachi'' Marche-Marchad, 1963 * '' Monobrachium parasitum'' Mereschkowsky, 1877 References External links * Limnomedusae Hydrozoan genera {{Hydrozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olindias Formosa
The flower hat jelly (''Olindias formosus'') is a species of hydromedusa in the hydrozoan family Olindiidae. Although they look like a jellyfish, they actually belong in the class Hydrozoa, while true jellyfish belong in class Scyphozoa. Flower hat jellies occur in the northwestern Pacific off central and southern Japan, and South Korea's Jeju Island.Patry, W.; T. Knowles; L. Christianson; M. Howard (2014). The hydroid and early medusa stage of Olindias formosus (Cnidaria, Hydrozoa, Limnomedusae). Journal of the Marine Biological Association of the United Kingdom 94(7): 1409–1415. (close relatives live elsewhere, like '' O. sambaquiensis'' found off Argentina and Brazil). The adult form of the flower hat jelly only lives a few months and is typically seen from December to July, with peaks in April and May. During the day they rest on the bottom, often among rocks or algae, but at night they float up to hunt for their prey, typically small fish.Monterey Bay AquariumFlower ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonad
A gonad, sex gland, or reproductive gland is a Heterocrine gland, mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sperm in the form of Spermatozoon, spermatozoa. The female gonad, the ovary, produces egg cells. Both of these gametes are haploid cells. Some hermaphroditic animals (and some humanssee Ovotesticular syndrome) have a type of gonad called an ovotestis. Evolution It is hard to find a common origin for gonads, but gonads most likely evolved independently several times. Regulation The gonads are controlled by luteinizing hormone (LH) and follicle-stimulating hormone (FSH), produced and secreted by gonadotropic cell, gonadotropes or gonadotrophins in the anterior pituitary gland. This secretion is regulated by gonadotropin-releasing hormone (GnRH) produced in the hypothalamus. Development The gonads develop f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family (, : ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". The delineation of what constitutes a family—or whether a described family should be acknowledged—is established and decided upon by active taxonomists. There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexaphilia
''Hexaphilia'' is a genus of freshwater hydrozoans in the family Olindiidae. Like all members of that family, they have a polyp phase and a medusa phase. The genus is monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ..., including only the species ''Hexaphilia scoresbyi''. References Olindiidae Hydrozoan genera Taxa described in 2003 {{Hydrozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
