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Karauridae
The Karauridae are a family of stem-group salamanders (Caudata) that are known from the Middle Jurassic to Late Jurassic in Central Asia (Kazakhstan and Kyrgyzstan) and Western Europe (United Kingdom). The family includes three members: ''Karaurus'' from the Middle-Late Jurassic Karabastau Formation of Kazakhstan, ''Kokartus'' from the Middle Jurassic Balabansai Formation of Kyrgyzstan, and ''Marmorerpeton'' from the Middle Jurassic Forest Marble Formation of England and Kilmaluag Formation of Scotland. The members are some of the oldest known salamanders. The family is united by several morphological characters, including sculptured skull roof bones. Like some modern salamanders, karaurids were neotenic. Members of the family likely fed via suction feeding Aquatic feeding mechanisms face a special difficulty as compared to feeding on land, because the density of water is about the same as that of the prey, so the prey tends to be pushed away when the mouth is closed. This probl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caudata
The Caudata are a group of amphibians containing the extant salamanders (Urodela) and all extinct species of amphibians more closely related to salamanders than to frogs. They are typically characterized by a superficially lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. Disagreement exists between different authorities as to the definition of the terms "Caudata" and "Urodela". Some maintain that Urodela should be restricted to the crown group, with Caudata being used for the total group. Others restrict the name Caudata to the crown group and use Urodela for the total group. The former approach seems to be most widely adopted and is used in this article. Evolution The origins and evolutionary relationships between the three main groups of amphibians ( apodans, urodeles and anurans) is a matter of debate. A 2005 molecular phylogeny, based on rDNA analysis, suggest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karaurus
''Karaurus'' (meaning ''head-tail'') is an extinct genus of stem-group salamander (Caudata) from the Middle to Late Jurassic (Callovian–Kimmeridgian) Karabastau Formation of Kazakhstan. It is one of the oldest salamanders known. ''Karaurus'' was large for a Jurassic salamander, about long, and very similar anatomically to modern salamanders. ''Karaurus'' is thought to have fed using suction feeding via the enlargement of the buccal cavity on small fish and invertebrates, with the well developed palatal dentition (teeth on the roof of the mouth) and marginal teeth helping to grasp prey. ''Karaurus'' is thought to form a clade with ''Kokartus'' from the Middle Jurassic (Bathonian) of Kyrgyzstan, and ''Marmorerpeton'' from the Bathonian of Britain, together forming the Karauridae, which are closely related to crown salamanders. Like other members of Karauridae, ''Karaurus'' is neotenic Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karaurus Sharovi
''Karaurus'' (meaning ''head-tail'') is an extinct genus of stem-group salamander (Caudata) from the Middle to Late Jurassic (Callovian–Kimmeridgian) Karabastau Formation of Kazakhstan. It is one of the oldest salamanders known. ''Karaurus'' was large for a Jurassic salamander, about long, and very similar anatomically to modern salamanders. ''Karaurus'' is thought to have fed using suction feeding via the enlargement of the buccal cavity on small fish and invertebrates, with the well developed palatal dentition (teeth on the roof of the mouth) and marginal teeth helping to grasp prey. ''Karaurus'' is thought to form a clade with ''Kokartus'' from the Middle Jurassic (Bathonian) of Kyrgyzstan, and ''Marmorerpeton'' from the Bathonian of Britain, together forming the Karauridae, which are closely related to crown salamanders. Like other members of Karauridae, ''Karaurus'' is neotenic Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forest Marble Formation
The Forest Marble is a geological formation in England. Part of the Great Oolite Group, it dates to the late Bathonian stage of the Middle Jurassic.Weishampel, David B; et al. (2004). "Dinosaur distribution (Middle Jurassic, Europe)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 538–541. . Lithology The primary lithology of the formation typically consists of greenish grey variably calcareous silicate mudstone, with lenticular cross bedded limestone units deposited in a marine setting. Dinosaurian fauna Ornithischians Saurischians Microvertebrate fauna Despite the formation being nearly entirely marine, at several localities abundant remains of terrestrial microvertebrates are found, the primary locality being the Kirtlington Mammal Bed (designated 3p) in Kirtlington Quarry near Kirtlington, Oxfordshire. Another important locality is Watton Cliff near Eype in Dorset. Amp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kokartus
''Kokartus'' is an extinct genus of prehistoric stem-group salamander (Caudata) from the Middle Jurassic Balabansai Formation of Kyrgyzstan. The absence of clear lines of arrested growth and annuli in long bones suggests that the animals lived in an environment with stable local conditions. Like other members of Karauridae, it is thought to have been neotenic. ''Kokartus'' is thought to have fed using suction feeding via the enlargement of the buccal cavity on small fish and invertebrates, with the well developed palatal dentition (teeth on the roof of the mouth) and marginal teeth helping to grasp prey. See also * Prehistoric amphibian * List of prehistoric amphibians This list of prehistoric amphibians is an attempt to create a comprehensive listing of all genera from the fossil record that have ever been considered to be amphibians, excluding purely vernacular terms. The list includes all commonly accepted g ... References Prehistoric salamanders Middle Jurassic amp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marmorerpeton
''Marmorerpeton'' is an extinct genus of prehistoric stem group-salamanders that lived in Britain during the Bathonian stage of the Middle Jurassic. They are among the oldest known salamanders. Two species were named when the genus was first described by Susan E. Evans et al. in 1988, ''M''. ''freemani'', and ''M''. ''kermacki'', from fragmentary remains found via screenwashing in the Forest Marble Formation of England. Due to the size of their osteocytic lacunae suggesting a large genome size and some morphological characters, like the presence of calcified cartilage in the medulla of its humerus, it was assumed that ''Marmorerpeton'' was neotenic. New more complete remains of a new species ''M. wakei'' were described in 2022 from the Kilmaluag Formation of the Isle of Skye, Scotland. These conclusively demonstrated that ''Marmorerpeton'' was neotenic, and was a member of the family Karauridae, with the other two members of the family, ''Karaurus'' and ''Kokartus'' being known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of the Mesozoic, Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified. The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic magmatic province, Central Atlantic Magmatic Province. The beginning of the Toarcian Stage started around 183 million years ago and is marked by an extinction event associated with widespread Anoxic event, oceanic anoxia, ocean acidification, and elevated temperatures likely caused by the eruption of the Karoo-Ferrar, Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear boundary with the Cretaceous and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bathonian First Appearances
In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age. Stratigraphic definitions The Bathonian Stage takes its name from Bath, a spa town in England built on Jurassic limestone (the Latinized form of the town name is ''Bathonium''). The name was introduced in scientific literature by Belgian geologist d'Omalius d'Halloy in 1843. The original type locality was located near Bath. The French palaeontologist Alcide d'Orbigny was in 1852 the first to define the exact length of the stage. The base of the Bathonian is at the first appearance of ammonite species '' Parkinsonia (Gonolkites) convergens'' in the stratigraphic column. The global reference profile for the base of the Bathonian (a GSSP) was ratified as Ravin du Bès, Bas-Auran area, Alpes de Haute Provence, France in 2009. The top of the Ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Amphibian Families
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suction Feeding
Aquatic feeding mechanisms face a special difficulty as compared to feeding on land, because the density of water is about the same as that of the prey, so the prey tends to be pushed away when the mouth is closed. This problem was first identified by Robert McNeill Alexander. As a result, underwater predators, especially bony fish, have evolved a number of specialized feeding mechanisms, such as filter feeding, ram feeding, suction feeding, protrusion, and pivot feeding. Most underwater predators combine more than one of these basic principles. For example, a typical generalized predator, such as the cod, combines suction with some amount of protrusion and pivot feeding. Suction feeding Suction feeding is a method of ingesting a prey item in fluids by sucking the prey into the predator's mouth. It is a highly coordinated behavior achieved by the dorsal rotation of the dermatocranium, lateral expansion of the suspensorium, and the depression of the lower jaw and hyoid. Suct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoteny
Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compared to other primates. In progenesis or paedogenesis, sexual development is accelerated. Both neoteny and progenesis result in paedomorphism (as having the form typical of children) or paedomorphosis (changing towards forms typical of children), a type of heterochrony. It is the retention in adults of traits previously seen only in the young. Such retention is important in evolutionary biology, domestication and evolutionary developmental biology. Some authors define paedomorphism as the retention of larval traits, as seen in salamanders.Schell, S. C. ''Handbook of Trematodes of North America North of Mexico'', 1985, pg. 22 History and etymology The origins of the concept of neoteny have been traced to the Bible (as argued by Ashley Monta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilmaluag Formation
The Kilmaluag Formation is a Middle Jurassic geologic formation in Scotland. It was formerly known as the Ostracod Limestone for the abundance of fossil freshwater ostracods within it. The Kilmaluag Formation is very fossiliferous, with ostracods, gastropods, bivalves, trace fossil burrows, and vertebrate fossil remains. Vertebrate fossils include fish, crocodylomorphs, mammals, small reptiles, amphibians and some large reptile remains including dinosaurs and pterosaurs.Panciroli E, RBJ Benson, S Walsh, RJ Butler, TA Castro, MEH Jones, SE. Evans. 2020Diverse vertebrate assemblage of the Kilmaluag Formation (Bathonian, Middle Jurassic) of Skye, Scotland Earth and Environmental Transactions of the Royal Society of Edinburgh nline1-22 Geology The Kilmaluag Formation is Bathonian, and dates to around 167 million years old. It is part of the Great Estuarine Group of the Hebrides Basin, a series of sediments laid down as the land rose and fell in the area running between what is now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
