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Herpetoskylax
''Herpetoskylax'' is an extinct genus of biarmosuchian therapsids which existed in South Africa. The type species is ''Herpetoskylax hopsoni''.Sidor, C.A., and Rubidge, B.S. (2006). "''Herpetoskylax hopsoni'', a new biarmosuchian (Therapsida: Biarmosuchia) from the Beaufort Group of South Africa" In: Amniote Paleobiology, perspectives on the Evolution of mammals, birds and reptiles, edited by Carrano, M.T., Gaudin, T.J., Blob, R.W., and Wible, J.R. Chicago University Press, p. 76-113 It lived in the Late Permian Period. The genus name means ‘reptile-puppy’, from the Ancient Greek ' (, ‘creeping animal’) and ' (, ‘young dog’). The juxtaposition of reptilian and mammalian names highlights the transitional characters of non-mammalian therapsids. The type specimen is CGP 1/67, a skull. The skull and lower jaw were the only components found. Description Skull The skull of ''Herpetoskylax'' is noted to have been preserved unusually well in regards to other biarmosuchia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biarmosuchia
Biarmosuchia is an extinct clade of non-mammalian synapsids from the Permian. Biarmosuchians are the most basal group of the therapsids. They were moderately-sized, lightly built carnivores, intermediate in form between basal sphenacodont " pelycosaurs" and more advanced therapsids. Biarmosuchians were rare components of Permian ecosystems, and the majority of species belong to the clade Burnetiamorpha, which are characterized by elaborate cranial ornamentation. Characteristics The biarmosuchian skull is very similar to the sphenacodontid skull, differing only in the larger temporal fenestra (although these are still small relative to later therapsids), slightly backward-sloping occiput (the reverse of the pelycosaur condition), reduced number of teeth, and single large canine teeth in both upper and lower jaws, and other features (Carroll 1988 pp. 370, Benton 2000 p. 114). In later specialised Biarmosuchia, these resemble the enlarged canines of the Gorgonopsia. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christian Sidor
Christian Alfred Sidor is an American vertebrate paleontologist. He is currently a Professor in the Department of Biology, University of Washington in Seattle, as well as Curator of Vertebrate Paleontology and Associate Director for Research and Collections at the Burke Museum of Natural History and Culture. His research focuses on Permian and Triassic tetrapod evolution, especially on therapsids. Academic and professional background Sidor received a B.S. (with honors) in biology from Trinity College in 1994. He went on to pursue his graduate studies at the University of Chicago, completing his M.S. in 1996 and his Ph.D. in 2000 under the supervision of James Hopson. Sidor won the Romer Prize in 2001 for his doctoral work, a competitive annual award at the Society of Vertebrate Paleontology annual meeting for the best predoctoral student oral presentation. Following his dissertation, Sidor held a postdoctoral fellowship at the National Museum of Natural History (2001) before ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rubidgina
''Rubidgina'' is a genus of Biarmosuchian therapsid from Patrysfontein, Wellwood, South Africa known from RC 55, a skull with lower jaws. This specimen is a putative juvenile. It has been suggested that this specimen actually represents a juvenile of ''Herpetoskylax ''Herpetoskylax'' is an extinct genus of biarmosuchian therapsids which existed in South Africa. The type species is ''Herpetoskylax hopsoni''.Sidor, C.A., and Rubidge, B.S. (2006). "''Herpetoskylax hopsoni'', a new biarmosuchian (Therapsida: Bia ... hopsoni.'' However, because the specimen lacks distinctive features, it cannot be determined if it is actually a juvenile of ''Herpetoskylax'' or if its current name of ''Rubidgina'' should remain. References Biarmosuchia Prehistoric therapsid genera Lopingian synapsids of Africa Fossil taxa described in 1942 {{paleo-therapsid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cistecephalus Assemblage Zone
The ''Cistecephalus'' Assemblage Zone is a tetrapod assemblage zone or biozone found in the Adelaide Subgroup of the Beaufort Group, a majorly fossiliferous and geologically important geological group of the Karoo Supergroup in South Africa. This biozone has outcrops located in the Teekloof Formation north-west of Beaufort West in the Western Cape, in the upper Middleton and lower Balfour Formations respectively from Colesberg of the Northern Cape to east of Graaff-Reinet in the Eastern Cape. The ''Cistecephalus'' Assemblage Zone is one of eight biozones found in the Beaufort Group, and is considered to be Late Permian in age. The name of the biozone refers to '' Cistecephalus'', a small, burrowing dicynodont therapsid. It is characterized by the presence of this species, known especially from the upper sections of this biozone, and the first appearance of the dicynodont '' Aulacephalodon''. History The first fossils to be found in the Beaufort Group rocks th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hipposaurus
''Hipposaurus'' ('horse lizard') is an extinct genus of basal therapsids known from the ''Tapinocephalus'' Assemblage Zone of the Main Karoo Basin, South Africa. Chronologically this is within the Capitanian stage of the Guadalupian Series (Middle Permian). The genus was first described by S.H. Haughton as ''H. boonstrai'' on the basis of a skull and associated skeleton and was later considered a gorgonopsian in the family 'Ictidorhinidae' by Robert Broom. It is now considered a basal biarmosuchian, but its affinities remain uncertain. Some authors note the similarity of its braincase with that of ''Herpetoskylax''. ''H. boonstrai'' is currently known from only two specimens in the Iziko South African Museum, Cape Town. "''H. brinki''" is based on a single skull that was described by D. Sigogneau in 1970;Sigogneau, D. 1970. Révision systématique des gorgonopsiens Sud Arficains. Cahiers de Paléontologie, Paris. n French/ref> however, the poor condition of the holotype me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Therapsid Genera
Prehistory, also called pre-literary history, is the period of human history between the first known use of stone tools by hominins 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 years ago. It took thousands of years for writing systems to be widely adopted, with writing having spread to almost all cultures by the 19th century. The end of prehistory therefore came at different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. It is based on an old conception of history that without written records there could be no history. The most common conception today is that history is based on evidence, however the concept of prehistory hasn't been completely discarded. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theria
Theria ( or ; ) is a scientific classification, subclass of mammals amongst the Theriiformes. Theria includes the eutherians (including the Placentalia, placental mammals) and the metatherians (including the marsupials) but excludes the egg-laying monotremes and various extinct mammals evolving prior to the common ancestor of placentals and marsupials. Characteristics Therians give birth to live young without a shelled egg (biology), egg. This is possible thanks to key proteins called Syncytin-1, syncytins which allow exchanges between the mother and its offspring through a placenta, even Marsupial#Reproductive system, rudimental ones such as in marsupials. Genetic studies have suggested a viral origin of syncytins through the Endogenous retrovirus, endogenization process. The marsupials and the placentals evolved from a common therian ancestor that gave live birth by suppressing the mother's immune system. While the marsupials continued to give birth to an underdeveloped fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lopingian Synapsids Of Africa
The Lopingian is the uppermost series/last epoch of the Permian. It is the last epoch of the Paleozoic. The Lopingian was preceded by the Guadalupian and followed by the Early Triassic. The Lopingian is often synonymous with the informal terms late Permian or upper Permian. The name was introduced by Amadeus William Grabau in 1931 and derives from Leping, Jiangxi in China. It consists of two stages/ ages. The earlier is the Wuchiapingian and the later is the Changhsingian. The International Chronostratigraphic Chart (v2018/07) provides a numerical age of 259.1 ±0.5 Ma. If a Global Boundary Stratotype Section and Point (GSSP) has been approved, the lower boundary of the earliest stage determines numerical age of an epoch. The GSSP for the Wuchiapingian has a numerical age of 259.8 ± 0.4 Ma. Evidence from Milankovitch cycles suggests that the length of an Earth day during this epoch was approximately 22 hours. Geography During the Lopingian, most of the earth was in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectothermy
An ectotherm (), more commonly referred to as a "cold-blooded animal", is an animal in which internal physiological sources of heat, such as blood, are of relatively small or of quite negligible importance in controlling body temperature.Davenport, John. Animal Life at Low Temperature. Publisher: Springer 1991. Such organisms (frogs, for example) rely on environmental heat sources, which permit them to operate at very economical metabolic rates. Some of these animals live in environments where temperatures are practically constant, as is typical of regions of the abyssal ocean and hence can be regarded as homeothermic ectotherms. In contrast, in places where temperature varies so widely as to limit the physiological activities of other kinds of ectotherms, many species habitually seek out external sources of heat or shelter from heat; for example, many reptiles regulate their body temperature by basking in the sun, or seeking shade when necessary in addition to a host of ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endothermic Process
An endothermic process is a chemical or physical process that absorbs heat from its surroundings. In terms of thermodynamics, it is a thermodynamic process with an increase in the enthalpy (or internal energy ) of the system.Oxtoby, D. W; Gillis, H.P., Butler, L. J. (2015). '' Principle of Modern Chemistry'', Brooks Cole. p. 617. In an endothermic process, the heat that a system absorbs is thermal energy transfer into the system. Thus, an endothermic reaction generally leads to an increase in the temperature of the system and a decrease in that of the surroundings. The term was coined by 19th-century French chemist Marcellin Berthelot. The term ''endothermic'' comes from the Greek ἔνδον (''endon'') meaning 'within' and θερμ- (''therm'') meaning 'hot' or 'warm'. An endothermic process may be a chemical process, such as dissolving ammonium nitrate () in water (), or a physical process, such as the melting of ice cubes. The opposite of an endothermic process is an exo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foramen
In anatomy and osteology, a foramen (; : foramina, or foramens ; ) is an opening or enclosed gap within the dense connective tissue (bones and deep fasciae) of extant and extinct amniote animals, typically to allow passage of nerves, artery, arteries, veins or other soft tissue structures (e.g. muscle tendon) from one body compartment to another. Skull The skulls of vertebrates have foramina through which nerves, arteries, veins, and other structures pass. The human skull has many foramina, collectively referred to as the cranial foramina. Spine Within the vertebral column (spine) of vertebrates, including the Human vertebral column, human spine, each bone has an opening at both its top and bottom to allow nerves, arteries, veins, etc. to pass through. Other * Apical foramen, the hole at the tip of the root of a tooth * Foramen ovale (heart), a hole between the venous and arterial sides of the fetal heart * Vertebra#Cervical vertebrae, Transverse foramen, one of a pair ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
