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Orthonectida
Orthonectida () is a small phylum (biology), 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, Bivalvia, bivalve molluscs, and echinoderms. Most are gonochorism, 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 syncytium, syncytial Plasmodium (li ... [...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 2017 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 what h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylum (biology)
In biology, a phylum (; : phyla) is a level of classification, or taxonomic rank, that is 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 eight phyla. Current research in phylogenetics is uncovering the relationships among phyla within 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 unity"): "perhap ... [...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 (biology), 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 se ..., 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] |
Annelida
The annelids (), also known as the segmented worms, are animals that comprise the phylum Annelida (; ). The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments. The annelids are Symmetry in biology, bilaterally symmetrical, Triploblasty, triploblastic, coelomate, invertebrate organisms. They also have Parapodium, parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistics, Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Siboglinidae, Pogonophora, Echiura and Sipuncula, previ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiralia
The Spiralia are a morphologically diverse clade of protostome animals, including within their number the molluscs, annelids, platyhelminths and other Taxon, taxa. The term ''Spiralia'' is applied to those phyla that exhibit canonical spiral cleavage, a pattern of early development found in most members of the Lophotrochozoa. Distribution of spiralian development across phylogeny Members of the molluscs, annelids, platyhelminths and nemerteans have all been shown to exhibit spiral cleavage in its classical form. Other spiralian phyla (rotifers, brachiopods, phoronids, gastrotrichs, and bryozoans) are also said to display a derived form of spiral cleavage in at least a portion of their constituent species, although evidence for this is sparse. Lophotrochozoa within Spiralia Previously, spiral cleavage was thought to be unique to the Spiralia in the strictest sense—animals such as molluscs and annelids which exhibit classical spiral cleavage. The presence of spiral cleavage in ... [...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 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 genes, other functional regions of the genome such as ... has been sequenced. References {{Taxonbar, from=Q38714 Orthonectida ... [...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 phylum Mesozoa and, from 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 (or class if retained within Mesozoa) contains three families, Conocyemidae, Dicyemidae and Kantharellidae, which have sometimes been further grouped into orders. Authors who treat Dicyemida as an order and separate the family Conocyemidae into a different order ( Heterocyemida) prefer 'Rhombozoa' as a more inclusive and unambiguous name to cover all three families. Anatomy Adult dicyemids range in length from , and they can be easily viewed through a light microsco ... [...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. He served as a professor of zoology at the Faculty of Sciences in Lille. He specialized in parasitology and the genus ''Giardia'' was named after him by Johann Künstler in 1882. Biography Giard was born in Valenciennes to grocer Alfred François Émile and Jeanne Henriette Mortamais. At an early age he became interested in plants and insects. 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 and later the teratologist Gabriel Dareste de la Chavanne. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciliocincta
''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 (biology), phylum of poorly known parasites of marine invertebrates that are among the simplest of multi-cellular organisms. Members of th .... Species: *'' Ciliocincta akkeshiensis'' *'' Ciliocincta julini'' *'' Ciliocincta sabellariae'' References Orthonectida {{protostome-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnathifera (clade)
Gnathifera (from the Greek language, Greek ''wikt:γνάθος#Greek, gnáthos'', “jaw”, and the Latin ''wikt:-fer#Latin, -fera'', “bearing”) is a clade of generally small spiralians characterized by complex jaws made of chitin. It comprises the phyla Gnathostomulida, Rotifera and Micrognathozoa. Chaetognatha has recently been recognised as closely related to the group, with it either being included within Gnathifera or the broader group Chaetognathifera. Gnathiferans include some of the most abundant phyla. Rotifers are among the most diverse and abundant freshwater animals and chaetognaths are among the most abundant marine plankton. Description In most gnathiferans, the anus opens on the dorsal surface of the animal. In micrognathozoans and gnathostomulids, the anus is transient and only forms during defecation. Unlike other gnathiferans, in chaetognaths and the extinct ''Amiskwia'' the anus is located on the ventral surface in a subterminal position. Both Gnatho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platyhelminthes
Platyhelminthes (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") is a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates commonly called flatworms or flat worms. Being acoelomates (having no body cavity), and having no specialised circulatory and respiratory organs, they are restricted 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 can not 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 monophyletic, this classification i ... [...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 (biology), phylum of poorly known parasites of marine invertebrates that are among the simplest of multi-cellular organisms. Members of th .... Species: *'' Ciliocincta akkeshiensis'' *'' Ciliocincta julini'' *'' Ciliocincta sabellariae'' References Orthonectida {{protostome-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
