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Kalyptorhynchia
Kalyptorhynchia is a suborder of 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 Spermiogenesis is the final stage of spermatogenesis, during which the spermatids develop into mature spermatozoon, spermatozoa. At the beginning of the stage, the spermatid is a more or less circular cell containing a cell nucleus, nucleus, Golg .... 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, mole ... [...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] |
Gyratrix Hermaphroditus
''Gyratrix hermaphroditus'' is a species of rhabdocoel flatworms in the family Polycystididae. Description The animal is 1 to 1,5 mm long, transparent and colorless. It possesses a proboscis at the anterior end and a sharply pointed stylet. Taxonomy It was described by Christian Gottfried Ehrenberg in 1831. ''Gyratrix hermaphroditus'' represents a species complex. Distribution and Habitat Members of the species complex occur in both marine and inland water habitats. Ecology and Behavior It is known to feed on copepods and cladocerans The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more .... References {{Taxonbar, from=Q2488431 rhabdocoela Platyhelminthes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flatworm
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 no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludwig Von Graff
Ludwig Graff de Pancsova (2 January 1851 – 6 February 1924), known as Ludwig von Graff, was an Austrian zoologist born in Pancsova. In 1871, he received his medical degree in Vienna, afterwards studying zoology at the University of Graz. In 1872, he was an assistant at the zoological institute in Strasbourg, where he worked closely with Eduard Oscar Schmidt (1823–1886). In 1873, he relocated to Munich as an assistant to Karl Theodor Ernst von Siebold (1804–1885), gaining his habilitation during the following year. In 1876, he became a professor at the Academy of Forestry in Aschaffenburg, and from 1884 was a professor of zoology at the University of Graz. Here, he expanded the institute of zoology and its library. In 1896-97, he was rector of the university. Graff was a leading expert on Turbellaria (flatworms), especially remembered for research of its morphology and biological systematics. He gathered material for his studies on numerous expeditions, which includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies homology. Examples of apomorphy are the presence of erect gait, fur, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word —coined by German entomologist Willi Hennig—is derived from the Ancient Greek words (''sún''), meaning "with, together"; (''apó''), meaning "away from"; and (''morphḗ''), meaning "shape, form". Clade ana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axoneme
An axoneme, also called an axial filament is the microtubule-based cytoskeletal structure that forms the core of a cilium or flagellum. Cilia and flagella are found on many cells, organisms, and microorganisms, to provide motility. The axoneme serves as the "skeleton" of these organelles, both giving support to the structure and, in some cases, the ability to bend. Though distinctions of function and length may be made between cilia and flagella, the internal structure of the axoneme is common to both. Structure Inside a cilium and a flagellum is a microtubule-based cytoskeleton called the axoneme. The axoneme of a primary cilium typically has a ring of nine outer microtubule doublets (called a 9+0 axoneme), and the axoneme of a motile cilium has two central microtubules in addition to the nine outer doublets (called a 9+2 axoneme). The axonemal cytoskeleton acts as a scaffolding for various protein complexes and provides binding sites for molecular motor proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermiogenesis
Spermiogenesis is the final stage of spermatogenesis, during which the spermatids develop into mature spermatozoon, spermatozoa. At the beginning of the stage, the spermatid is a more or less circular cell containing a cell nucleus, nucleus, Golgi apparatus, centriole and mitochondria; by the end of the process, it has radically transformed into an elongated spermatozoon, complete with a head, midpiece, and tail. Phases The process of spermiogenesis is traditionally divided into four stages: the Golgi phase, the cap phase, formation of the tail, and the maturation stage. Golgi phase The spermatids, which up until now have been mostly Symmetry (biology), radially symmetrical, begin to develop polarity. The head forms at one end, where the Golgi apparatus creates enzymes that will become the acrosome. At the other end, it develops a thickened midpiece, where the mitochondria gather and the distal centriole begins to form an axoneme. Spermatid DNA also undergoes packaging, becomi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
