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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] |
Kalyptorhynchia
Kalyptorhynchia is a suborder of Rhabdocoela, rhabdocoel flatworms. It contains almost 600 species and has a cosmopolitan distribution. Description All kalyptorhynchs have an anterior muscular proboscis, which is used to capture prey. The proboscis is located inside an invagination of the epidermis called the proboscis-sheath that is closed by a sphincter at the tip of the body. Another synapomorphy supporting the group is the incorporation of the axonemes within the cell body of sperm cells during spermiogenesis. Classification Kalyptorhynchs are traditionally classified into two infraorders: Eukalyptorhynchia, with a cone-shaped proboscis, and Schizorhynchia, with a proboscis formed by two opposite parallel muscular sheets. However, molecular studies have shown that Eukalyptorhynchia, as originally defined, is paraphyletic and includes Schizorhynchia. It becomes monophyletic if the family Cicerinidae is excluded. Current phylogenetic classification: References { ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dalytyphloplanida
Dalytyphloplanida is a suborder of Rhabdocoela, rhabdocoel flatworms. It contains about 1000 species and has a cosmopolitan distribution in both marine and freshwater environments, with several groups having commensal or parasitic lifestyles. Description The suborder Dalytyphloplanida was recently erected based on molecular evidences and few synapomorphy, synapomorphies are known. The possible identified synapomorphies include the presence of small dense granules, as well as an axoneme, axonemal spur and a group of longitudinal microtubules in sperm cells. Classification Traditionally, members of the suborder Dalytyphloplanida were classified into two groups: Dalyellioida and Typhloplanoida, although both were poorly characterized morphologically. Recent molecular studies revealed that those two groups were not separated clades and both were merged in the clade Dalytyphloplanida. Within Dalytyphloplanida two clades were found: Neodalyellida, formed by marine species of the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mariplanellida
Mariplanellidae is a family of rhabdocoel flatworms. It is the only family in the suborder Mariplanellida. Description Species of Mariplanellidae are characterized by a pharynx rosulatus (rosette-shaped pharynx), paired testes and vitellaria, but an unpaired ovary. The female system has two connections between the ovary and the common genital atrium: an efferent connection (female duct) that carries the eggs from the ovaries to the common genital atrium, and an afferent connection (including the bursa, the muscular spermatic duct, the seminal receptacle, and the insemination duct), where sperm is stored after mating and moves towards the eggs for fertilization. Classification Mariplanellidae was originally considered a subfamily, Mariplanellinae, of Trigonostomidae, a family in the suborder Dalytyphloplanida. This classification was based on the shared presence of two connections between the ovaries and the common genital atrium. However, other species in Trigonostomidae ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flatworms
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 classifica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Typhloplanidae
Typhloplanidae is a family of flatworms in the order 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 sym .... It is one of the most species-rich families of Rhabdocoela, comprising around 300 species. They inhabit freshwater, estuarine, marine and terrestrial habitats. They can be benthic or pelagic. Typhloplanidae are predatory. They can reach high densities in their habitats. Most representatives are 1 to 5 mm in length, but a few species, like '' Mesostoma ehrenbergii'', can reach up to 1.5 cm. Subfamilies and genera (incomplete): * Subfamily Ascophorinae Findenegg, 1924 * Subfamily Mesophaenocorinae Norena, Brusa, Ponce de Leon & Damborenea, 2005 * Subfamily Mesostominae Hyman, 1955 ** Genus '' Bothromesostoma'' Braun, 1885 ** Genus '' Mesostoma'' Ehrenberg, ... [...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 symbio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhabditophora
Rhabditophora (from ''rhabdito''-, rhabdite + Greek -φορος ''phoros'' bearer, i.e., "rhabdite bearers") is a subphylum (previously 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 i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fecampiida
Fecampiida is an order of flatworms in the class Rhabditophora. It is a considerably recent clade, erected after molecular studies. Description The order Fecampiida, as currently defined, was erected based on molecular studies. They all are parasitic organisms and are united by a similar development of the basal bodies during spermiogenesis. Classification Three families of Fecampiida were initially classified in different flatworm orders: Urastomatidae and Genostomatidae were considered prolecithophorans, while Fecampiidae was considered a rhabdocoel. When the genus '' Notentera'' was discovered, its relationship with Fecampiidae was clear based on morphology, and both groups were united under Fecampiida. Further ultrastructural studies suggested that Urastomatidae and Genostomatidae were closely related to Fecampiidae and Notenteridae, which was confirmed by molecular studies. Due to similarities in the protonephridial flame bulb, sperm and spermiogenesis, as well a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neodermata
Neodermata is a clade of rhabditophoran flatworms containing the parasitic groups Trematoda, Monogenea and Cestoda. Description All neodermatans are parasites, in many groups having a free-swimming larval stage. The most striking feature uniting all neodermatans is that the ciliated epidermis (typical of most flatworms) is cast off in adult worms, being replaced by a syncytium called tegument or ''neodermis''. Other characters found in all neodermatans are related to the anatomy of the protonephridium and the rootlets of epidermal locomotory cilia. Phylogeny Currently, the monophyly of Neodermata is undisputed, being supported by both morphological and molecular data. It is clear that they evolved from free-living flatworms (turbellarians), but their sister-group was for a long time a matter of debate. The first attempts to reconstruct the phylogeny of flatworms, based on morphological evidence, considered Rhabdocoela to be the sister-group of Neodermata, but this was based ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladocera
The Diplostraca or Cladocera, commonly known as water fleas, is a superorder (biology), superorder of small, mostly freshwater crustaceans, most of which feed on microscopic chunks of organic matter, though some forms are predatory. Over 1000 species have been recognised so far, with many more undescribed species, undescribed. The oldest fossils of diplostracans date to the Jurassic, though their modern morphology suggests that they originated substantially earlier, during the Paleozoic. Some have also adapted to a life in the ocean, the only members of Branchiopoda to do so, though several anostracans live in hypersaline lakes. Most are long, with a down-turned head with a single median compound eye, and a carapace covering the apparently unsegmented Crustacean#Structure, thorax and abdomen. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive hars ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temnocephalida
The Temnocephalida are an order of turbellarian flatworms. Unlike most other turbellarians, all the species in this order are either commensal or parasitic. They can be found living on crustaceans, molluscs, and, in some species, even turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...s. The commensal species typically live in the gill or mantle cavities of their hosts, while the parasites live inside the digestive system. Anatomically, temnocephalidans can be distinguished from related groups by the presence of an adhesive disc on the underside for attachment to the host, and of a number of finger-like projections arising from the head. References Turbellaria Obsolete animal taxa {{flatworm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
