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Orthonectida
Orthonectida () is a small phylum of poorly known parasites of marine invertebrates that are among the simplest of multi-cellular organisms. Members of this phylum are known as orthonectids. Biology The adults, which are the sexual stage, are microscopic wormlike animals, consisting of a single layer of ciliated outer cells surrounding a mass of sex cells. They swim freely within the bodies of their hosts, which include flatworms, polychaete worms, bivalve molluscs, and echinoderms. Most are gonochoristic, with separate male and female individuals, but a few species are hermaphroditic. When they are ready to reproduce, adults leave the host, and sperm from the males penetrate the bodies of the females to achieve internal fertilisation. The resulting zygote develops into a ciliated larva that escapes from the mother to seek out new hosts. Once it finds a host, the larva loses its cilia and develops into a syncytial plasmodium larva. This, in turn, breaks up into numerous individ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesozoa
The Mesozoa are minuscule, worm-like parasites of marine invertebrates. Generally, these tiny, elusive creatures consist of a somatoderm (outer layer) of ciliated cells surrounding one or more reproductive cells. A recent study recovered Mesozoa as a monophyletic group that emerged in the Lophotrochozoa as sister of the Rouphozoa. Some workers previously classified Mesozoa as the sole phylum of the lonely subkingdom Agnotozoa. Cavalier-Smith argued that at least some of the mesozoans are in fact protistans, not animals. In the 19th century, the Mesozoa were a wastebasket taxon for multicellular organisms which lacked the invaginating gastrula which was thought to define the Metazoa. Evolution Mesozoa were once thought to be evolutionary intermediate forms between Protozoans and Metazoans, but now they are thought to be degenerate or simplified metazoa. Their ciliated larvae are similar to the miracidium of trematodes, and their internal multiplication is similar to wha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhopaluridae
Rhopaluridae is a family of worms belonging to the phylum Orthonectida Orthonectida () is a small phylum of poorly known parasites of marine invertebrates that are among the simplest of multi-cellular organisms. Members of this phylum are known as orthonectids. Biology The adults, which are the sexual stage, are mi ..., order and class unknown. Genera: * '' Ciliocincta'' Kozloff, 1965 * '' Intoshia'' Giard, 1877 * '' Prothelminthus'' Jourdain, 1880 * '' Rhopalura'' Giard, 1877 * '' Stoecharthrum'' Caullery & Mesnil, 1899 References Orthonectida {{protostome-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylum (biology)
In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature for algae, fungi, and plants accepts the terms as equivalent. Depending on definitions, the animal kingdom Animalia contains about 31 phyla, the plant kingdom Plantae contains about 14 phyla, and the fungus kingdom Fungi contains about 8 phyla. Current research in phylogenetics is uncovering the relationships between phyla, which are contained in larger clades, like Ecdysozoa and Embryophyta. General description The term phylum was coined in 1866 by Ernst Haeckel from the Greek (, "race, stock"), related to (, "tribe, clan"). Haeckel noted that species constantly evolved into new species that seemed to retain few consistent features among themselves and therefore few features that distinguished them as a group ("a self-contained ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intoshia Linei
''Intoshia linei'' is a species of parasitic worms belonging to the family Rhopaluridae. It is the only species from the phylum Orthonectida which genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ... has been sequenced. References {{Taxonbar, from=Q38714 Orthonectida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfred Mathieu Giard
Alfred Mathieu Giard (8 August 1846 – 8 August 1908) was a French zoologist born in Valenciennes. Biography In 1867 he began his studies of natural sciences at the École Normale Supérieure, followed by work as ''préparateur de zoologie'' at the laboratory of Henri de Lacaze-Duthiers (1821–1901) in Paris. In 1872 he defended his doctoral thesis with a study on compound ascidians titled "''Recherches sur les ascidies composées ou synascidies''". From 1873 to 1882, he was ''professeur suppléant'' of natural history at the faculty of sciences in Lille, and in the meantime, was also affiliated with the Institut industriel du Nord. In 1874 he founded a biological station at Wimereux in order to familiarize his students to marine and terrestrial organisms. At Lille, he is credited for putting together an excellent school of zoology. In 1887 he became a lecturer at the École Normale Supérieure, and from 1888 until his death, he was a professor at the faculty of sciences in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciliocincta
''Ciliocincta'' is a genus of worms belonging to the family Rhopaluridae. Species: *''Ciliocincta akkeshiensis ''Ciliocincta'' is a genus of worms belonging to the family Rhopaluridae Rhopaluridae is a family of worms belonging to the phylum Orthonectida, order and class unknown. Genera: * '' Ciliocincta'' Kozloff, 1965 * ''Intoshia ''Intoshia'' is a ...'' *'' Ciliocincta julini'' *'' Ciliocincta sabellariae'' References {{Taxonbar, from=Q38767 Orthonectida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platyhelminthes
The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates. Unlike other bilaterians, they are acoelomates (having no body cavity), and have no specialized circulatory and respiratory organs, which restricts them to having flattened shapes that allow oxygen and nutrients to pass through their bodies by diffusion. The digestive cavity has only one opening for both ingestion (intake of nutrients) and egestion (removal of undigested wastes); as a result, the food cannot be processed continuously. In traditional medicinal texts, Platyhelminthes are divided into Turbellaria, which are mostly non- parasitic animals such as planarians, and three entirely parasitic groups: Cestoda, Trematoda and Monogenea; however, since the turbellarians have since been proven not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhombozoa
Dicyemida, also known as Rhombozoa, is a phylum of tiny parasites that live in the renal appendages of cephalopods. Taxonomy Classification is controversial. Traditionally, dicyemids have been grouped with the Orthonectida in the Mesozoa, and, as of 2017, molecular evidence appears to confirm this. However, other molecular phylogenies have placed the dicyemids more closely related to the roundworms. Additional molecular evidence suggests that this phylum is derived from the ''Lophotrochozoa. The phylum is not divided in classes or orders, but contains three families, Conocyemidae, Dicyemidae, and Kantharellidae. Anatomy Adult dicyemids range in length from , and they can be easily viewed through a light microscope. They display eutely, a condition in which each adult individual of a given species has the same number of cells, making cell number a useful identifying character. Dicyemida lack respiratory, circulatory, excretory, digestive, and nervous systems. The orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciliocincta Akkeshiensis
''Ciliocincta'' is a genus of worms belonging to the family Rhopaluridae Rhopaluridae is a family of worms belonging to the phylum Orthonectida Orthonectida () is a small phylum of poorly known parasites of marine invertebrates that are among the simplest of multi-cellular organisms. Members of this phylum are known .... Species: *'' Ciliocincta akkeshiensis'' *'' Ciliocincta julini'' *'' Ciliocincta sabellariae'' References {{Taxonbar, from=Q38767 Orthonectida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flatworm
The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates. Unlike other bilaterians, they are acoelomates (having no body cavity), and have no specialized circulatory and respiratory organs, which restricts them to having flattened shapes that allow oxygen and nutrients to pass through their bodies by diffusion. The digestive cavity has only one opening for both ingestion (intake of nutrients) and egestion (removal of undigested wastes); as a result, the food cannot be processed continuously. In traditional medicinal texts, Platyhelminthes are divided into Turbellaria, which are mostly non- parasitic animals such as planarians, and three entirely parasitic groups: Cestoda, Trematoda and Monogenea; however, since the turbellarians have since been proven not to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polychaete
Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm (''Arenicola marina'') and the sandworm or clam worm ''Alitta''. Polychaetes as a class are robust and widespread, with species that live in the coldest ocean temperatures of the abyssal plain, to forms which tolerate the extremely high temperatures near hydrothermal vents. Polychaetes occur throughout the Earth's oceans at all depths, from forms that live as plankton near the surface, to a 2- to 3-cm specimen (still unclassified) observed by the robot ocean probe ''Nereus'' at the bottom of the Challenger Deep, the deepest known spot in the Earth's oceans. Only 168 species (less than 2% of all polychaetes) are known from fresh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
