| Comura | |
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| Comura bultyncki | |
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| Genus: | Comura Richter and Richter, 1926 |
Comura is a trilobite in the order Phacopida that existed during the lower Devonian in what is now Eifel, Germany. It was described by Richter and Richter in 1926, and the type species is Comura cometa, originally under the genus Cryphaeus by Richter in 1909. [1]
Agnostida are an order of extinct arthropods which have classically been seen as a group of highly modified trilobites, though some recent research has doubted this placement. Regardless, they appear to be close relatives as part of the Artiopoda. They are present in the Lower Cambrian fossil record along with trilobites from the Redlichiida, Corynexochida, and Ptychopariida orders, and were highly diverse throughout the Cambrian. Agnostidan diversity severely declined during the Cambrian-Ordovician transition, and the last agnostidans went extinct in the Late Ordovician.
Trilobites are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last trilobites disappeared in the mass extinction at the end of the Permian about 251.9 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described.
Phacopida ("lens-face") is an order of trilobites that lived from the Late Cambrian to the Late Devonian. It is made up of a morphologically diverse assemblage of taxa in three related suborders.
The Phacopina comprise a suborder of the trilobite order Phacopida. Species belonging to the Phacopina lived from the Lower Ordovician (Tremadocian) through the end of the Upper Devonian (Famennian). The one unique feature that distinguishes Phacopina from all other trilobites are the very large, separately set lenses without a common cornea of the compound eye.
Phacops is a genus of trilobites in the order Phacopida, family Phacopidae, that lived in Europe, northwestern Africa, North and South America and China from the Late Ordovician until the very end of the Devonian, with a broader time range described from the Late Ordovician. It was a rounded animal, with a globose head and large eyes, and probably fed on detritus. Phacops is often found rolled up ("volvation"), a biological defense mechanism that is widespread among smaller trilobites but further perfected in this genus.
Arachnomorpha is a proposed subdivision or clade of Arthropoda, comprising the group formed by the trilobites and their close relatives (Artiopoda), Megacheira and chelicerates. Under this proposed classification scheme, Arachnomorpha is considered the sister group to Mandibulata.
Resserops is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the middle of the Atdabanian or the early part of the Botomian stage, which lasted from approximately 524 to 518.5 million years ago. This faunal stage was part of the Cambrian Period. It has been found in Spain and southern Morocco. It can be recognised by the sabre-like spines of the headshield that are a smooth continuation of the frontal edge, and the enlarged spines on the 9th segment of the thorax.
Acastellina is a genus of minute trilobites in the order Phacopida, which existed in what is now Germany. It was described by Richter and Richter in 1954. The type species is Acastellina nolens, originally described as a species of Acastella.
Delocare is a trilobite in the order Phacopida, that existed during the lower Devonian in what is now Germany. It was described by Struve in 1958, and the type species is Delocare boopis, which was originally described under the genus Cryphaeys by Richter in 1909. The type locality was in the Eifel mountain range.
Dianops is a genus of phacopid trilobite in the order Phacopida, that existed during the upper Devonian in what is now Germany. It was described by Richter and Richter in 1923, and the type species is Dianops limbatus, which was originally described under the genus Phacops by Richter in 1848. The type locality was in Saalfeld, Thuringia.
Dienstina is a trilobite in the order Phacopida, that existed during the lower Devonian in what is now Germany. It was described by Richter and Richter in 1931, and the type species is Dienstina diensti, which the authors had originally assigned to the genus Phacopidella in 1923. The type locality was in Oberscheld, Rhenish Massif.
Cambrian Series 2 is the unnamed 2nd series of the Cambrian. It lies above the Terreneuvian series and below the Miaolingian. Series 2 has not been formally defined by the International Commission on Stratigraphy, lacking a precise lower boundary and subdivision into stages. The proposed lower boundary is the first appearance of trilobites which is estimated to be around 521 million years ago.
Mallagnostus Howell, 1935, is a trilobite genus belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida Salter (1864) according to Whittington et al. 1997. It lived during the late Lower Cambrian, with remains found in USA, Canada (Newfoundland), Spain, England, Russia, Mongolia, and the early Middle Cambrian as reported from China and Russia (Yakutia).
Cyclopygidae is a family of asaphid trilobites from the Ordovician. Cyclopygids had an extratropical distribution, and there is evidence that they lived in darker parts of the water column. Cyclopygids are characterized by enlarged eyes, with a wide angle of view, both horizontal and vertical, reminiscent of the eyes of dragonflies. These typically touch the glabella directly on the side. Cyclopygids all lack genal spines, but Symphysops carries a forward directed frontal spine on the glabella. It is presumed that at least the members of the genus Pricyclopyge swam upside down and had bioluminescent organs on the third thorax segment. Cyclopygids had between 7 and 5 thorax segments, a wide and stout axis, and short side lobes.
Styginidae is a family of trilobite in the order Corynexochida. Fossils of the various genera are found in marine strata throughout the world, aged from Ordovician up until the family's extinction during the Silurian.
Serrodiscus Richter and Richter 1941. is a genus of Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida. It lived during the late Lower Cambrian, with remains found in Canada, China (Gansu), The United Kingdom (England), Germany (Silesia), Poland, the Russian Federation, and the United States. It is named for the spines on the ventral side of the pygidium, which give it a serrated impression.
Miraspis mira is a spinose species of odontopleurid trilobite in the family Odontopleuridae. Fossils of M. mira are known from the Wenlock-aged Liteň Formation in Loděnice, in Bohemia, Czech Republic, originally described by Joachim Barrande, in 1846, as "Odontopleura mira." In 1917, Richter and Richter split "O. mira" off into its own genus, Miraspis.
Emma Richter was a German paleontologist. She is best known for her work concerning Trilobites.
Tropidocoryphidae is an extinct family of trilobites in the order Proetida.
Tolkienia is an extinct genus of trilobite in the family Acastidae. It consists of three species split from Comura based on morphological differences. The genus was present during the Emsian stage of the Early Devonian epoch around 400 Ma.
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