Tetrachela
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Tetrachela
''Tetrachela raiblana'' is an extinct species of polychelid crustacean from the Late Triassic. It is the only species in the family Tetrachelidae. It is distinguished from most other polychelids, including all the extant Polychelidae, by the retention of the diaeresis (divisions) of the uropodal exopod The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plur ...s. References Polychelida Triassic crustaceans Triassic animals of Africa {{triassic-animal-stub ...
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Karl Beurlen
Karl Beurlen (17 April 1901 – 27 December 1985) was a German paleontologist.Rieppel, Olivier. (2012). ''Karl Beurlen (1901-1985), Nature mysticism, and Aryan Paleontology''. ''Journal of the History of Biology'' 45: 253-299. Beurlen was born in Aalen. He attended University of Tübingen. He completed a PhD in 1923.Levit, Georgy S; Olsson, Lennart. (2007). ''Evolution on Rails Mechanisms and Levels of Orthogenesis''. In Volker Wissemann. ''Annals of the History and Philosophy of Biology 11/2006''. Universitätsverlag Göttingen. pp. 115-119 Beurlen was a proponent of orthogenesis and saltational evolution. He used the term ''metakinesis'' (coined by Otto Jaekel) to describe sudden changes of development in organisms. He also invented the term ''palingenesis'' as a mechanism for his orthogenetic theory of evolution. He was an assistant of Edwin Hennig.Stindl, Reinhard. (2014)''The telomeric sync model of speciation: species-wide telomere erosion triggers cycles of transposon-med ...
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August Emanuel Von Reuss
August Emanuel Rudolph von Reuss (8 July 1811 in Bílina, Bohemia26 November 1873 in Vienna), Austrian geologist and palaeontologist, was the son of Franz Ambrosius Reuss (1761–1830) and the father of ophthalmologist August Leopold von Reuss (1841–1924). He was educated for the medical profession, graduating in 1834 at the University of Prague, and afterwards practising for fifteen years at the Bílinská Kyselka (Biliner Sauerbrunn) spa. His leisure was devoted to mineralogy and geology, and the results of his researches were published in ' (1840–1844) and ' (1845–1846). In 1849 he gave up his medical practice, and became professor of mineralogy at the university of Prague. There he established a fine mineralogical collection, and he became the first lecturer on geology. In 1863 he was appointed professor of mineralogy in the University of Vienna. He investigated the Cretaceous fauna of Gosau, and studied the Crustacea, including Entomostraca, the corals, bryozoa, an ...
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Heinrich Georg Bronn
Heinrich Georg Bronn (3 March 1800 – 5 July 1862) was a German geologist and paleontologist. He was the first to translate Charles Darwin's ''On the Origin of Species'' into German in 1860, although not without introducing his own interpretations, as also a chapter critiquing the work. Bibliography Bronn was born at Ziegelhausen (now part of Heidelberg) in the electoral Palatinate. Studying at the university of Heidelberg he took his doctor's degree in the faculty of medicine in 1821, and in the following year was appointed professor of natural history. He now devoted himself to palaeontological studies, and to field-work in various parts of Germany, Italy and France. From its commencement in 1830 to 1862 he assisted in editing the ''Jahrbuch für Mineralogie'' continued as ''Neues Jahrbuch''. His principal work, ''Letkaea Geognostica'' (2 vols., Stuttgart, 1834–1838; 3rd ed. with F. Romer, 3 vols., 1851–1856), has been regarded as one of the foundations of German strati ...
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Extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, m ...
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Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ...
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Polychelida
Polychelida is an infraorder of decapod crustaceans. Fossil representatives are known dating from as far back as the Upper Triassic. A total of 38 extant species, all in the family Polychelidae, and 55 fossil species have been described. History Polychelida had traditionally been included in the infraorder Palinura, alongside the spiny lobsters and slipper lobsters (now in the infraorder Achelata). In 1995, Gerhard Scholtz and Stefan Richter of the carried out a phylogenetic study of the "Reptantia", and concluded that "Palinura" was paraphyletic. They therefore abandoned that taxon and introduced instead the new clade Polychelida. Classification Polychelida belongs to the group Reptantia, which consists of the walking/crawling decapods (lobsters and crabs). Polychelida is the sister clade to the infraorder Astacidea, which contains the "true" lobsters and crayfish. The cladogram below shows Polychelida's placement within the larger order Decapoda, from analysis by Wolfe '' ...
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Crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods emerged deep in the Crustacean group, with the completed group referred to as Pancrustacea. Some crustaceans (Remipedia, Cephalocarida, Branchiopoda) are more closely related to insects and the other hexapods than they are to certain other crustaceans. The 67,000 described species range in size from '' Stygotantulus stocki'' at , to the Japanese spider crab with a leg span of up to and a mass of . Like other arthropods, crustaceans have an exoskeleton, which they moult to grow. They are distinguished from other groups of arthropods, such as insects, myriapods and chelicerates, by the possession of biramous (two-parted) limbs, and by th ...
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Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. The corresponding series (stratigraphy), series of rock beds is known as the Upper Triassic. The Late Triassic is divided into the Carnian, Norian and Rhaetian Geologic time scale, Ages. Many of the first dinosaurs evolved during the Late Triassic, including ''Plateosaurus'', ''Coelophysis'', and ''Eoraptor''. The Triassic–Jurassic extinction event began during this epoch and is one of the five major mass extinction events of the Earth. Etymology The Triassic was named in 1834 by Friedrich August von Namoh, Friedrich von Alberti, after a succession of three distinct rock layers (Greek meaning 'triad') that are widespread in southern Germany: the lower Buntsandstein (colourful sandstone'')'', t ...
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Raffles Bulletin Of Zoology
''The Raffles Bulletin of Zoology'' is a peer-reviewed open-access scientific journal published by the Lee Kong Chian Natural History Museum at the National University of Singapore. It covers the taxonomy, ecology, and conservation of Southeast Asian fauna.Supplements are published as and when funding permits and may cover topics that extend beyond the normal scope of the journal depending on the targets of the funding agency. It was established as the ''Bulletin of the Raffles Museum'' in 1928 and renamed ''Bulletin of the National Museum of Singapore'' in 1961, before obtaining its current title in 1971. See also * List of zoology journals This is a list of scientific journals which cover the field of zoology. A * '' Acta Entomologica Musei Nationalis Pragae'' * '' Acta Zoologica Academiae Scientiarum Hungaricae'' * '' Acta Zoologica Bulgarica'' * ''Acta Zoologica Mexicana'' * '' ... References Zoology journals Biannual journals Open access journals English-language ...
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Polychelidae
The family Polychelidae contains thirty-eight extant species of blind, benthic lobster-like crustaceans. They are found throughout the world's tropical, sub-tropical and temperate oceans, including the Mediterranean Sea and the Irish Sea. Anatomy The family Polychelidae is notable for the number of chelate (clawed) limbs, with either four or all five pairs of pereiopods bearing claws. This gives rise to the scientific names ''Polycheles'' (many-clawed) and ''Pentacheles'' (five claws). The first pair of periopods are greatly elongated, but often become broken off while specimens are being brought to the surface. The rostrum is very short or absent, and, although eyestalks are present, the eyes are absent. This family can be seen as evidence of the transition from shrimp-like animals to lobster-like animals, since they possess a number of primitive characters (plesiomorphies), such as the pointed telson, in contrast to the rounded telson in lobsters. Discovery Although apparen ...
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Uropod
Uropods are posterior appendages found on a wide variety of crustaceans. They typically have functions in locomotion. Definition Uropods are often defined as the appendages of the last body segment of a crustacean. An alternative definition suggested by Frederick R. Schram restricts the term to those structures arising from the segment before the anal segment (the segment which carries the anus). Under this latter definition, the appendages of the anal segment are caudal ramus, caudal rami, which are analogy (biology), analogous to uropods. Form Uropods are typically biramous – comprising an endopod and an exopod. The exopod is typically the larger, and may be divided in two by a transverse suture known as the diaeresis. The uropods may work in concert with the telson to form a "tail fan". References

{{Reflist, 32em Crustacean anatomy ...
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Exopod
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plural ''coxae''), ''trochanter'', ''femur'' (plural ''femora''), ''tibia'' (plural ''tibiae''), ''tarsus'' (plural ''tarsi''), ''ischium'' (plural ''ischia''), ''metatarsus'', ''carpus'', ''dactylus'' (meaning finger), ''patella'' (plural ''patellae''). Homologies of leg segments between groups are difficult to prove and are the source of much argument. Some authors posit up to eleven segments per leg for the most recent common ancestor of extant arthropods but modern arthropods have eight or fewer. It has been argued that the ancestral leg need not have been so complex, and that other events, such as successive loss of function of a ''Hox''-gene, could result in parallel gains of leg segments. In arthropods, each of the leg segments artic ...
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