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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 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 microscope ... [...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 phylum Mes ..., order unassigned. The family consists of only one genus: ''Kantharella'' Czaker, 1994. The only species in the genus is ''Kantharella antarctica''. This species is most closely related to other species of the order ''Dicyemida'', which only has one other family, ''Dicyemidae''. ''Kantharella'' is characterized by species that are parasitic endosymbiotes and live within renal sacs of species of cephalopods. They consist of only about 30 cells and they feed off of nutrients in the urine of cephalopods. Taxonomy The genus contains only one species ''Kantharella antarctica'' and is the only member of the family ''Katharellidae''. ''Katharellidae'' is one of three me ... [...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] |
Dicyemidae
The Dicyemidae is a family of tiny parasites that live in the Cephalopod#Renal appendage, 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'' ** ''Pseudicyema truncatum'' (Whitman, 1883) References {{Authority control Parasites of molluscs Parasitic protostomes Spiralian families Dicyemida ... [...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'' Furuya, 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Larva
A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase of their life cycle. A 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. In the case of smaller primitive arachnids, the larval stage differs by having three instead of four pairs of legs. 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 lar ... [...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 phylum Mes ..., order unknown. Genera: * '' Conocyema'' Van Beneden, 1882 * '' Microcyema'' Van Beneden, 1882 References Dicyemida {{protostome-stub ... [...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, and brachiopods. 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 or placed in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote that develops into an organism composed of cells with two sets of chromosomes ( diploid). This is typical in animals, though the number of chromosome sets and how that number changes in sexual reproduction varies, especially among plants, fungi, and other eukaryotes. In placental mammals, sperm cells exit the penis through the male urethra and enter the vagina during copulation, while egg cells enter the uterus through the oviduct. Other vertebrates of both sexes possess a cloaca for the release of sperm or egg cells. Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. Sexual reproduction also occurs in some unicellular eukaryotes. Sexual reproduction does not occur in pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protostome Phyla
Protostomia () is the clade of animals once thought to be characterized by the formation of the organism's mouth before its anus during embryonic development. This nature has since been discovered to be extremely variable among Protostomia's members, although the reverse is typically true of its sister clade, Deuterostomia. Well-known examples of protostomes are arthropods, molluscs, annelids, flatworms and nematodes. They are also called schizocoelomates since schizocoely typically occurs in them. Together with the Deuterostomia and Xenacoelomorpha, these form the clade Bilateria, animals with bilateral symmetry, anteroposterior axis and three germ layers. Protostomy In animals at least as complex as earthworms, the first phase in gut development involves the embryo forming a dent on one side (the blastopore) which deepens to become its digestive tube (the archenteron). In the sister-clade, the deuterostomes (), the original dent becomes the anus while the gut eventually tun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitic Protostomes
Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) 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 characterised parasites' way of feeding 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 honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the broomrapes. There are six major parasitic strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), trophicallytransmitted parasitism (by being eaten), vector-transmitted parasitism, parasitoidism, and micropredation. One major axis of classification concerns invasiveness: an endoparas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
