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Dicyemida
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 organism' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicyemida
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 organism' ... [...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 what h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicyemidae
The Dicyemidae is a family of tiny parasites that live in the renal appendages of cephalopods. It contains the following genera and species: * ''Dicyema'' von Kolliker, 1849 * ''Dicyemennea'' Whitman, 1883 * '' Dicyemodeca'' ** '' Dicyemodeca anthinocephalum'' Furuya, 1999 - parasitizes '' Octopus dofleini'' ** '' Dicyemodeca deca'' (McConnaughey, 1957) ** '' Dicyemodeca dogieli'' Bogolepova, 1957 * '' Dodecadicyema'' Kalavati & Narasimhamurti, 1979 ** '' Dodecadicyema loligoi'' Kalavati & Narasimhamurti, 1980 * '' Pleodicyema'' ** '' Pleodicyema delamarei'' Nouvel, 1961 * '' Pseudicyema'' Nouvel, 1933 ** '' Pseudicyema cappacephalum'' Furuya, 2009 ** '' Pseudicyema nakaoi'' Furuya, 1999 - parasitizes Sepia lycidas'' and ''Sepia esculenta ''Sepia esculenta'', the golden cuttlefish, is a cuttlefish Cuttlefish or cuttles are marine molluscs of the order Sepiida. They belong to the class Cephalopoda which also includes squid, octopuses, and nautiluses. Cuttlefish have a u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicyema Macrocephalum
''Dicyema'' is a genus of worms belonging to the family Dicyemidae. Species: * '' Dicyema acciaccatum'' McConnaughey, 1949 * '' Dicyema acheroni'' McConnaughey, 1949 * '' Dicyema acuticephalum'' Nouvel, 1947 - parasitizes ''Octopus vulgaris'' * '' Dicyema aegira'' McConnaughey & Kritzler, 1952 * '' Dicyema akashiense'' Furuya, 2005 * '' Dicyema apalachiensis'' Short, 1962 * '' Dicyema apollyoni'' Nouvel, 1947 * '' Dicyema australis'' Penchaszadeh, 1969 * '' Dicyema awajiense'' Furuya, 2005 * '' Dicyema balanocephalum'' Furuya, 2006 * '' Dicyema banyulensis'' Furuya & Hochberg, 1999 * '' Dicyema benedeni'' Furuya & Hochberg, 1999 * ''Dicyema benthoctopi'' Hochberg & Short, 1970 * '' Dicyema bilobum'' Couch & Short, 1964 * ''Dicyema briarei'' Short, 1961 * ''Dicyema caudatum'' Bogolepova-Dobrokhotova, 1960 * ''Dicyema clavatum'' Furuya & Koshida, 1992 - parasitizes ''Octopus minor'' * ''Dicyema colurum'' Furuya, 1999 - parasitizes ''Octopus fangsiao'' * ''Dicyema dolichocephalum' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 individua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kantharellidae
Kantharellidae is a family of worms belonging to the class 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, ..., order unassigned. The family consists of only one genus: ''Kantharella'' Czaker, 1994. References {{Taxonbar, from1=Q2184637, from2=Q2783387 Dicyemida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lophotrochozoa
Lophotrochozoa (, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. The clade includes animals like annelids, molluscs, bryozoans, brachiopods, and platyhelminthes. Groups Lophotrochozoa was defined in 1995 as the "last common ancestor of the three traditional lophophorate taxa (brachiopods, bryozoans, and phoronid worms), the mollusks and the annelids, and all of the descendants of that common ancestor". It is a cladistic definition (a node-based name), so the affiliation to Lophotrochozoa of spiralian groups not mentioned directly in the definition depends on the topology of the spiralian tree of life, and in some phylogenetic hypotheses, Lophotrochozoa may even be synonymous to Spiralia. Nemertea and Orthonectida (if not directly considered as part of Annelida) are probably lophotrochozoan phyla; Dicyemida, Gastrotricha, and Platyhelminthes may be lophotrochozoans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The larva's appearance is generally very different from the adult form (''e.g.'' caterpillars and butterflies) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. Larvae are frequently adapted to different environments than adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water as adult frogs. By living in a distinct environment, larvae may be given shelter from predators and reduce competition for resources with the adult population. Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like polychaetes and barnacles, adults are immobil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conocyemidae
Conocyemidae is a family of worms belonging to the class 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, an ..., order unknown. Genera: * '' Conocyema'' Van Beneden, 1882 * '' Microcyema'' Van Beneden, 1882 References {{Taxonbar, from=Q275460 Dicyemida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has characterised parasites as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as Armillaria mellea, honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the Orobanchaceae, broomrapes. There are six major parasitic Behavioral ecology#Evolutionarily stable strategy, strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), wikt:trophic, trophicallytransmitted parasitism (by being eaten), Disease vector, vector-transmitted parasitism, parasitoidism, and micropreda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snail
A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastropoda that have a coiled shell that is large enough for the animal to retract completely into. When the word "snail" is used in this most general sense, it includes not just land snails but also numerous species of sea snails and freshwater snails. Gastropods that naturally lack a shell, or have only an internal shell, are mostly called '' slugs'', and land snails that have only a very small shell (that they cannot retract into) are often called ''semi-slugs''. Snails have considerable human relevance, including as food items, as pests, and as vectors of disease, and their shells are used as decorative objects and are incorporated into jewelry. The snail has also had some cultural significance, tending to be associated with lethargy. The sn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonad
A gonad, sex gland, or reproductive gland is a mixed gland 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 spermatozoa. The female gonad, the ovary, produces egg cells. Both of these gametes are haploid cells. Some hermaphroditic animals 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 and follicle-stimulating hormone, produced and secreted by gonadotropes or gonadotrophins in the anterior pituitary gland. This secretion is regulated by gonadotropin-releasing hormone produced in the hypothalamus. Development Gonads start developing as a common primordium (an organ in the earliest stage of development), in the form of genital ridges, which are only l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
