Arkadelphia Formation
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Arkadelphia Formation
The Arkadelphia Marl, also called the Arkadelphia Formation, is a Formation (geology), geologic formation in Arkansas in Clark County, Arkansas, Clark, Nevada County, Arkansas, Nevada, and Hempstead County, Arkansas, Hempstead counties. It preserves fossils dating back to the late Maastrichtian stage of the Cretaceous Period (geology), period. Paleofauna Bony fish Ray fish, Rays Sharks See also * List of fossiliferous stratigraphic units in Arkansas * Paleontology in Arkansas References

* Cretaceous Arkansas {{Cretaceous-stub Marl formations Geologic formations of Arkansas Fossiliferous stratigraphic units of North America Maastrichtian Stage of North America ...
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Formation (stratigraphy)
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ...
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Cabot, Arkansas
Cabot is the largest city in Lonoke County, Arkansas, United States. As of the 2010 census, the population of the city was 23,776, and in 2019 the population was an estimated 26,352, ranking it as the state's 19th largest city, behind Jacksonville. It is part of the Little Rock-North Little Rock-Conway metropolitan area. History Prior to settlement Before the city of Cabot existed, an 1862 typhoid epidemic took the lives of about 1,500 Confederate soldiers previously under Allison Nelson who were camped at Camp Nelson in the hills surrounding Cabot and Austin. In 1905, 428 poorly marked graves were exhumed by a group of Confederate veterans and moved to a new site at Camp Nelson Confederate Cemetery. Marble gravestones were placed over each grave and a large marble obelisk was erected to honor the dead. In 1982, a group of volunteers from Cabot began maintaining the cemetery, which had fallen into disrepair. Early history The city of Cabot sprang up as a small s ...
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Echiophis
''Echiophis'' is a genus of eels in the snake eel family Ophichthidae Ophichthidae is a family (biology), family of fish in the order (biology), order Anguilliformes, commonly known as the snake eels. The term "Ophichthidae" comes from Greek language, Greek ''ophis'' ("serpent") and ''ichthys'' ("fish"). Snake eels .... It currently contains the following species: * '' Echiophis brunneus'' ( Castro-Aguirre & Suárez de los Cobos, 1983) (Pacific spoon-nose eel) * '' Echiophis intertinctus'' ( J. Richardson, 1848) (Spotted spoon-nose eel) * '' Echiophis punctifer'' ( Kaup, 1860) (Stippled spoon-nose eel) References * Ophichthinae Taxa named by Johann Jakob Kaup {{Anguilliformes-stub ...
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Clupeiformes
Clupeiformes is the order of ray-finned fish that includes the herring family, Clupeidae, and the anchovy family, Engraulidae and sardines. The group includes many of the most important forage and food fish. Clupeiformes are physostomes, which means that their gas bladder has a pneumatic duct connecting it to the gut. They typically lack a lateral line, but still have the eyes, fins and scales that are common to most fish, though not all fish have these attributes. They are generally silvery fish with streamlined, spindle-shaped bodies, and they often school. Most species eat plankton which they filter from the water with their gill rakers. The former order of Isospondyli was subsumed mostly by Clupeiformes, but some isospondylous fishes (isospondyls) were assigned to Osteoglossiformes, Salmoniformes, Cetomimiformes, etc. Their sister group were the extinct Ellimmichthyiformes, which were dominant throughout much of the Cretaceous and into the Paleogene, and o ...
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Catfish
Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not all catfish have prominent barbels or "whiskers", with some seemingly not having them. Siluriformes as a whole are Fish scale, scale-less, with neither the Armoured catfish, armour-plated nor the naked species having scales. This order of fish are Autapomorphy, defined by features of the skull and swimbladder. Catfish range in size and behavior from the three List of largest fish, largest species alive, the Mekong giant catfish from Southeast Asia, the wels catfish of Eurasia, and the piraíba of South America, to detritivorous and scavenging bottom feeders, down to tiny ectoparasitic species known as the Candiru (fish), candirus. In the Southern United States, catfish species may be known by a variety of slang names, such as "mud cat", " ...
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Arius (fish)
''Arius'' is a genus of catfishes (order (biology), order Siluriformes) of the family (biology), family Ariidae. The genus ''Arius'' is distributed in brackish water, brackish and fresh waters of Eastern Africa and south to Southeast Asia. Defining the limits so that ''Arius'' can form a natural grouping has always been a problem. The genus was never properly defined, and many species previously classified in ''Arius'' are now in other genera. Recent authors have recognized this genus as nonmonophyly, monophyetic, rejecting that the genus is a natural grouping. Two unnamed groups are distinguished by accessory tooth plates, which are either very elongated and bearing molar-like teeth, or are oval shaped or subtriangular and bearing acicular (needle-like) or conic teeth. ''A. jatius'' lacks these tooth plates, but has been included in this genus based on its adipose fin and lateral line. The recognition of ''Ariodes'' as a synonym (taxonomy), junior synonym of ''Arius'' is tentati ...
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Apateodus Corneti Naturalis
''Apateodus'' (meaning "confusing tooth") is a genus of prehistoric marine ray-finned fish which was described by Woodward in 1901. It was a relative of modern lizardfish and lancetfish in the order Aulopiformes, and one of a number of prominent nektonic aulopiforms of Cretaceous marine ecosystems. The genus spans from the Albian to the late Maastrichtian, and appears to have been distributed worldwide; specimens have been found in Russia, India, the United States (Colorado, South Dakota, Iowa, Kansas), Canada, the United Kingdom and the Netherlands. Taxonomy ''Apateodus'' has generally been placed in the suborder Enchodontoidei alongside most other Cretaceous nektonic aulopiforms, although its affinities have long been uncertain. However, since the 2000s, it has generally been placed in the family Ichthyotringidae. However, some authors have still placed it as an indeterminate enchodontoid, ichthyotringoid, alepisauroid, or even elsewhere in the Aulopiformes as the sister ...
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Aulopiformes
Aulopiformes is a diverse order (biology), order of Marine (ocean), marine ray-finned fish consisting of some 15 Extant taxon, extant and several prehistoric family (biology), families with about 45 genera and over 230 species. The common names grinners, lizardfishes and allies, or aulopiforms are sometimes used for this group. They are included in the superorder Cyclosquamata, though modern taxonomists consider this superorder to be unwarranted. Many Neontology, extant aulopiforms are deep-sea fishes, with some species recognized as being hermaphroditic, a number of which are able to Autogamy, self-fertilise. Some are benthic, but most are pelagic swimmers (nektonic). A clade of Aulopiformes, the suborder Enchodontoidei and its many constituent families, were dominant nektonic fish throughout much of the Late Cretaceous before the extinction of most of their members around the K–Pg event, with the Dercetidae surviving for some time in the Cenozoic. Taxonomy Past authors have ...
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Apateodus
''Apateodus'' (meaning "confusing tooth") is a genus of prehistoric marine ray-finned fish which was described by Woodward in 1901. It was a relative of modern lizardfish and lancetfish in the order Aulopiformes, and one of a number of prominent nektonic aulopiforms of Cretaceous marine ecosystems. The genus spans from the Albian to the late Maastrichtian, and appears to have been distributed worldwide; specimens have been found in Russia, India, the United States (Colorado, South Dakota, Iowa, Kansas), Canada, the United Kingdom and the Netherlands. Taxonomy ''Apateodus'' has generally been placed in the suborder Enchodontoidei alongside most other Cretaceous nektonic aulopiforms, although its affinities have long been uncertain. However, since the 2000s, it has generally been placed in the family Ichthyotringidae. However, some authors have still placed it as an indeterminate enchodontoid, ichthyotringoid, alepisauroid, or even elsewhere in the Aulopiformes as the sister t ...
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Anguilla (genus)
The Anguillidae are a family of ray-finned fish that contains the freshwater eels. All the extant species and six subspecies in this family are in the genus ''Anguilla'', and are elongated fish of snake-like bodies, with long dorsal, caudal and anal fins forming a continuous fringe. They are catadromous, spending their adult lives in freshwater, but migrating to the ocean to spawn. Eels are an important food fish and some species are now farm-raised, but not bred in captivity. Many populations in the wild are now threatened, and Seafood Watch recommend consumers avoid eating anguillid eels. Physical description Adult freshwater eels are elongated with tubelike, snake-shaped bodies. They have large, pointed heads and their dorsal fins are usually continuous with their caudal and anal fins, to form a fringe lining the posterior end of their bodies. They have relatively well developed eyes and pectoral fins compared to saltwater eels that they use to navigate and maneuver through ...
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