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Gnosonesimidae
Rhabditophora (from ''rhabdito''-, rhabdite + Greek -φορος ''phoros'' bearer, i.e., "rhabdite bearers") is a class of flatworms. It includes all parasitic flatworms (clade Neodermata) and most free-living species that were previously grouped in the now obsolete class Turbellaria. Therefore, it contains the majority of the species in the phylum Platyhelminthes, excluding only the catenulids, to which they appear to be the sister group. The clade Rhabditophora was originally erected by Ulrich Ehlers in 1985Ehlers, U. (1985) ''Phylogenetic relationships within the Platyhelminthes''. ''In'' S. Conway Morris; J. D. George; R. Gibson; H. M. Platt (Eds.), ''The origins and relationships of lower invertebrates''. Oxford, Clarendon Press, p. 143-158. based on morphological analyses and its monophyly was later confirmed by molecular studies. Description Rhabditophorans are characterized by the presence of lamellated rhabdites, rodlike granules secreted in the cells of the ep ... [...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 to be monop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrostomum Lignano
''Macrostomum lignano'' is a free-living, hermaphroditic flatworm. It is transparent and of small size (adults reaching about 1.7 mm), and is part of the intertidal sand meiofauna of the Adriatic Sea. Originally a model organism for research on developmental biology and the evolution of the bilaterian body plan, it has since expanded to other important fields of research such as sexual selection and sexual conflicts, ageing and the evolution of the bilaterian body plan, ecotoxicology, and, more recently, genomics. Name The genus name "'' Macrostomum''", meaning "big-mouthed", derives from the Greek μάκρος ''makros'', "large", and στόμα, ''stoma'', mouth. The species name, ''lignano'', comes from the location where this species has so far been found, the sandy beaches and lagoons at and near Lignano Sabbiadoro, Italy. Biology ''Macrostomum lignano'', like all other flatworms, is an unsegmented, soft-bodied bilaterian without body cavity, and no specialized ci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nephridium
The nephridium (plural ''nephridia'') is an invertebrate organ, found in pairs and performing a function similar to the vertebrate kidneys (which originated from the chordate nephridia). Nephridia remove metabolic wastes from an animal's body. Nephridia come in two basic categories: metanephridia and protonephridia. All nephridia- and kidney- having animals belong to the clade Nephrozoa. Metanephridia A metanephridium (''meta'' = "after") is a type of excretory gland found in many types of invertebrates such as annelids, arthropods and mollusca. (In mollusca, it is known as the Bojanus organ.) A metanephridium typically consists of a ciliated funnel opening into the body cavity, or coelom connected to a duct which may be variously glandularized, folded or expanded (vesiculate) and which typically opens to the organism's exterior. These ciliated tubules pump water carrying surplus ions, metabolic waste, toxins from food, and useless hormones out of the organism by directing th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bradynectes
Macrostomorpha is a clade of free living flatworms ranked either as class or subclass in the group Rhabditophora. There are about 260 described species in two orders - marine, freshwater and brackish Macrostomida, which group most of the species diversity, and exclusively marine Haplopharyngida with only three described species. Macrostomorpha constitute a basal group in Rhabditophora, showing such plesiomorphic condition as entolecithal eggs and spiral cleavage Cleavage may refer to: Science * Cleavage (crystal), in mineralogy and materials science, a process of splitting a crystal * Cleavage (geology), the foliation perpendicular to stress as a result of ductile deformation * Cleavage (embryo), in emb .... Another trait found among members of the clade is presence of hard stylet in the male copulatory organ. References Turbellaria Rhabditophora {{flatworm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tricladida
A planarian is one of the many flatworms of the traditional class Turbellaria. It usually describes free-living flatworms of the order Tricladida (triclads), although this common name is also used for a wide number of free-living platyhelminthes. Planaria are common to many parts of the world, living in both saltwater and freshwater ponds and rivers. Some species are terrestrial and are found under logs, in or on the soil, and on plants in humid areas. The triclads are characterized by triply branched intestine and anteriorly situated ovaries, next to the brain. Today the order Tricladida is split into three suborders, according to their phylogenetic relationships: Maricola, Cavernicola and Continenticola. Formerly, the Tricladida was split according to habitats: Maricola, which is marine; Paludicola which inhabits freshwater; and Terricola, which is land-dwelling. Planaria exhibit an extraordinary ability to regenerate lost body parts. For example, a planarian split len ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhabdocoela
Rhabdocoela is an order of flatworms in the class Rhabditophora with about 1700 species described worldwide. The order was first described in 1831 by Christian Gottfried Ehrenberg. Most of rhabdocoels are free-living organisms, but some live symbiotically with other animals. Description Although Rhabdocoela is a highly supported group in molecular studies, there is no clear morphological synapomorphy that unites them. All rhabdocoels have a bulbous pharynx, but this is shared with other flatworm groups, such as Neodermata, Lecithoepitheliata and some species of Prolecithophora. Some possibly identified synapomorphies are found in the ultrastructure of the protonephridial system, but similar constructions exist in other groups. Another possible apomorphy is found in the ultrastructure of the sperm, which has a dense heel on the basal bodies during spermiogenesis, but some groups have lost this feature. Classification Rhabdocoels were traditionally classified in two group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proseriata
Proseriata is an order of free-living flatworms in the class Rhabditophora with over 400 species described worldwide. Description Proseriate flatworms are minute aquatic organisms, usually with an elongate body. There are no strong synapomorphies for the group, but it is supported by molecular studies. The suggested synapomorphies include the lack of lamellated rhabdites, an otherwise synapomorphy of Rhabditophora, and some features of the ultrastructure of the protonephridia and the cilia of epidermal cells. Ecology Most proseriates occur in marine environments, at the coastal zones, and are particularly common in high-energy habitats with medium to coarse sediments, sometimes being the dominant animal group in such areas. They are also common in brackish water, but few species occur in freshwater. Most proseriates are carnivores or scavengers, but some species are ectoparasitic on marine crustaceans. As they occur in very high densities in some habitats, they may have a co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prolecithophora
The ''Prolecithophora'' are an order consisting of an estimated 300 species of small (typically 0.2 – 12 mm, one species up to 50 mm), active, aquatic flatworms. The order lacks a common English name. Most species are shaped like an elongated, stylized droplet, and are opaque white or yellow; they frequently have contrasting bands or spots in colors, such as purple, yellow, red, or brown. They have no to three (normally two) pairs of pigment-cup eyes, and well-developed tactile and chemoreceptor senses. With few exceptions, species are protandric hermaphrodites with internal fertilization. Egg capsules are, according to species, glued to various hard surfaces; the young hatch as miniature copies of their parents. Ecology All prolecithophorans are aquatic, with most living in the oceans. Some species, especially those living in freshwater, are predators and scavengers, but many marine species are associated with colonial animals such as bryozoans or live as symbiont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycladida
The Polycladida represents a highly diverse clade of free-living marine flatworms. They are known from the littoral to the sublittoral zone (extending to the deep hot vents), and many species are common from coral reefs. Only a few species are found in freshwater habitats. Description Polyclads range from to in length with a flattened, roughly oval, body shape and, in many cases, a pair of short tentacles on the head. They are distinguished from other related animals by the presence of a folded pharynx, an elongated intestine with numerous complex diverticula, and multiple ocelli. The etymology of the order name ''Polycladida'' corresponds to the two ancient Greek words (), meaning "numerous", and (), meaning "branch". It refers to the ramified shape of the intestine in these flatworms. Most polyclads hide away from direct light. However, some of the brightly colored species often are active during the day. With their flamboyant coloring they advertise their potential toxi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
