Schagonaria | |
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Genus: | Schagonaria Poletaeva, 1955 |
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Schagonaria is a genus of trilobite, an extinct group of marine arthropods. The only known species, S. tannuola occurs in the earliest Middle Cambrian of Russia (Amgaian, Ulukhema River, Tuva Region). It is related to Paradoxides , but can be distinguished from it by only slightly forward expansion of the glabella, a character shared with Anabaraceps and Primoriella . In Primoriella the front of the glabella touches the roll-like border, causing it to slightly bulge forward, in Anabaraceps there is a roll-like preglabellar field as wide as the flat border in front of it, but in Schagonaria the glabella may or may not touch the frontal border, but neither the border, nor if present the preglabellar field is particularly convex. The glabella of Schagonaria is more than twice as long as wide, and differs from Primordiella in which it is less than twice as long as wide. The articulate middle part of the body (or thorax) has 16 segments. The tailshield (or pygidium has a spatulate shape. [1]
Dalmanites is a genus of trilobite in the order Phacopida. They lived from the Late Ordovician to Middle Devonian.
Agnostus, is a genus of agnostid trilobite belonging to the Family Agnostidae, that lived during the late Middle Cambrian – early Upper Cambrian. It is the type genus of the family Agnostidae and is subdivided into two subgenera, Agnostus and Homagnostus.
Triarthrus is a genus of Upper Ordovician ptychopariid trilobite found in New York, Ohio, Kentucky, and Indiana, eastern and northern Canada, China and Scandinavia. It is the last of the Olenid trilobites, a group which flourished in the Cambrian period. The specimens of T. eatoni that are found in the Beecher's Trilobite Bed, Rome, New York area are exquisitely preserved showing soft body parts in iron pyrite. Pyrite preservation has given scientists a rare opportunity to examine the gills, walking legs, antennae and digestive systems of trilobites, which are rarely preserved. Triarthrus is therefore commonly used in science texts to illustrate trilobite anatomy and physiology.
Meniscuchus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the Botomian stage, which lasted from approximately 522 to 516 million years ago. This faunal stage was part of the Cambrian Period. Meniscuchus has been found in the USA, Canada, Russia and Australia.
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.
Olenelloides armatus is an extinct, small sized olenelloid redlichiid trilobite arthropod. It lived during the later 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. The most conspicuous feature is the hexagonal head shield that carries 6 ray-like spines..
Nevadella is an extinct genus of trilobites, fossil marine arthropods, with species of average size. It lived during the late Atdabanian stage, which lasted from 530 to 524 million years ago during the early part of the Cambrian Period.
Acadagnostus is a genus of trilobite from the Middle Cambrian, with 7 species currently recognized. The type species A. acadicus has the widest distribution known from any peronopsid and has been found in North America, Greenland, England, Western Europe, Eastern Europe, Central Asia, the Altai Mountains, the Siberian shield, China, and Australia.
Mesonacis is an extinct genus of trilobite that lived during the Botomian, found in North-America, and the United Kingdom. Some of the species now regarded part of Mesonacis, have previously been assigned to Angustolenellus or Olenellus (Angustolenellus). Angustolenellus is now regarded a junior synonym of Mesonacis.
Alokistocaridae is a family of ptychopariid trilobites that lived from the Botomian epoch of the Early Cambrian until the Late Cambrian. Alokistocarids were particle feeders and left small furrows which are occasionally preserved. Their remains are found worldwide. Elrathia kingii, one of the most collected trilobites in the world, is a typical alokistocarid.
Conocoryphe is a genus of primarily eyeless trilobites belonging to the family Conocoryphidae. They lived during the Middle Cambrian period, about 505 million years ago. These arthropods lived on the sea bottom (epifaunal) and lived off dead particulate organic matter.
Odontochile is a genus of trilobites in the order Phacopida, family Dalmanitidae.
Richterops is an extinct genus of trilobite arthropods. The genus 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 second half of the Lower Cambrian. It has been found in southern Morocco. It can be recognised by the long spines of the headshield that are a smooth continuation of the frontal edge, and the enlarged spines on the 11th segment of the thorax.
Geragnostus is a genus of very small agnostid trilobites whose fossils are found Ordovician-aged marine strata from Eurasia, North America and Argentina.
Psychopyge is a genus of trilobite, that lived during the upper Emsian and has been found in Germany and Morocco. It is characterized by the swordlike extension from the front of the head.
Cedaria is a small, rather flat trilobite with an oval outline, a headshield and tailshield of approximately the same size, 7 articulating segments in the middle part of the body and spines at the back edges of the headshield that reach halflength of the body. Cedaria lived during the early part of the Upper Cambrian (Dresbachian), and is especially abundant in the Weeks Formation.
Kendallina is a genus of trilobite with an inverted egg-shaped outline, a wide headshield, small eyes, small deflected spines, 12 thorax segments and a small, short tailshield. It lived during the Upper Cambrian in what are today Canada and the United States.
Orygmaspis is a genus of asaphid trilobite with an inverted egg-shaped outline, a wide headshield, small eyes, long genal spines, 12 spined thorax segments and a small, short tailshield, with four pairs of spines. It lived during the Upper Cambrian in what are today Canada and the United States.
Primoriella is a genus of trilobite, an extinct group of marine arthropods. The only known species, P. bella occurs in the uppermost Lower Cambrian of Russia. It is related to Paradoxides, but can be distinguished from it by only slightly forward expansion of the (glabella) a character shared with Anabaraceps and Schagonaria. In Primoriella however, the front of the glabella touches the roll-like border, causing it to slightly bulge forward, while in Anabaraceps there is a roll-like preglabellar field as wide as the flat border in front of it. The glabella of Primordiella is less than twice as long as wide, and differs from Schagonaria in which it is more than twice as long as wide. The thorax and pygidium are not known.
Anabaraspis is a genus of redlichiid trilobite. A. splendens occurs in the uppermost Lower Cambrian and lowest Middle Cambrian of Russia. In Anabaraspis there is a long area in front of the glabella which is not differentiated in a border and a preglabellar field. This is a unique character in the family Paradoxididae. The frontal lobe of the central raised area of the headshield is slightly pointed, rather than rounded or truncate, a character shared with Plutonides, though, in Plutonides it hangs over the short anterior border.