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Ctenorhachis
''Ctenorhachis'' (Greek for "comb spine") is an extinct genus of the family Sphenacodontidae. ''Ctenorhachis'' was related to ''Dimetrodon'', but did not belong to the same subfamily as ''Dimetrodon'' and ''Sphenacodon'', being a more basal member of Sphenacodontidae. ''Ctenorhachis'' lived in the Early Permian epoch. Two specimens are known that have been found from the Wichita Group outcropping in Baylor and Archer counties, north-central Texas. Only the vertebrae and pelvis are known. Articulated vertebrae from the holotype specimen possess blade like neural spines that are greatly enlarged, although not nearly to the extent that can be seen in more derived sphenacodontids such as ''Dimetrodon'' and ''Secodontosaurus'', in which they form a large sail. The pelvis is nearly identical to that of ''Dimetrodon''. As suggested in the original description of the genus, ''Ctenorhachis'' may represent a short-spined sexual dimorph, although the authors find this unlikely.Hook, R. W. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenacodontidae
Sphenacodontidae (Greek: "wedge point tooth family") is an extinct family of small to large, advanced, carnivorous, Late Pennsylvanian to middle Permian pelycosaurs. The most recent one, ''Dimetrodon angelensis'', is from the late Kungurian or early Roadian San Angelo Formation. However, given the notorious incompleteness of the fossil record, a recent study concluded that the Sphenacodontidae may have become extinct as recently as the early Capitanian. Primitive forms were generally small (60 cm to 1 meter), but during the later part of the early Permian these animals grew progressively larger (up to 3 meters or more), to become the top predators of their environments. Sphenacodontid fossils are so far known only from North America and Europe. Characteristics The skull is long, deep and narrow, an adaptation for strong jaw muscles. The front teeth are large and dagger-like, whereas the teeth in the sides and rear of the jaw are much smaller (hence the name of the well-kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Pelycosaurs
This list of pelycosaurs is an attempt to create a comprehensive listing of all genera that have ever been included in the synapsida excluding therapsida and purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful ('' nomina dubia''), or were not formally published (''nomina nuda''), as well as junior synonyms of more established names, and genera that are no longer considered pelycosaurs. The list currently contains 83 generic names. Naming conventions and terminology Naming conventions and terminology follow the International Code of Zoological Nomenclature. Technical terms used include: * Junior synonym: A name which describes the same taxon as a previously published name. If two or more genera are formally designated and the type specimens are later assigned to the same genus, the first to be published (in chronological order) is the senior synonym, and all other instances are junior synonyms. Senior syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the sauropsids ( reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archer County, Texas
Archer County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 8,560. Its county seat is Archer City. It is part of the Wichita Falls metropolitan statistical area. History In 1858, the Texas Legislature established Archer County from portions of Fannin County, Texas, and it organized in 1880. It is named for Branch Tanner Archer, a commissioner for the Republic of Texas. Geography According to the U.S. Census Bureau, the county has a total area of , of which are land and (2.4%) are covered by water. Major highways * U.S. Highway 82 * U.S. Highway 277 * U.S. Highway 281 * State Highway 25 * State Highway 79 * State Highway 114 Adjacent counties * Wichita County (north) * Clay County (east) * Jack County (southeast) * Young County (south) * Baylor County (west) * Wilbarger County (northwest) Geology Archer County is part of the Texas Red Beds, which are strata of red-colored sedimentary rock from the Early Permian. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Taxa Described In 1991
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxa Named By Nicholas Hotton III
In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were set forth in Carl Linnaeus's system in ''Systema Naturae'', 10th edition (1758), as well as an unpublished work by Bernard and Antoine Laurent de Jussieu. The idea of a unit-based system of biological classification was first made widely available in 1805 in the intro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cisuralian Synapsids Of North America
The Cisuralian is the first series/epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the western slopes of the Ural Mountains in Russia and Kazakhstan and dates between 298.9 ± 0.15 – 272.3 ± 0.5 Mya. The Cisuralian is often synonymous with the informal terms early Permian or lower Permian. It corresponds approximately with the Wolfcampian in southwestern North America. The series saw the appearance of beetles and flies and was a relatively stable warming period of about 21 million years. Name and background The Cisuralian is the first series or epoch of the Permian. The Cisuralian was preceded by the last Pennsylvanian epoch (Gzhelian) and is followed by the Permian Guadalupian Epoch. The name "Cisuralian" was proposed in 1982, and approved by the International Subcommission on Permian Stratigraphy in 1996. The Cisuralian Epoch is named after the western slopes of the Ural Mountain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Synapsid Genera
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. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secodontosaurus
''Secodontosaurus'' (meaning "cutting-tooth lizard") is an extinct genus of "pelycosaur" synapsids that lived from between about 285 to 272 million years ago during the Early Permian. Like the well known ''Dimetrodon'', ''Secodontosaurus'' is a carnivorous member of the Eupelycosauria family Sphenacodontidae and has a similar tall dorsal sail. However, its skull is long, low, and narrow, with slender jaws that have teeth that are very similar in size and shape—unlike the shorter, deep skull of ''Dimetrodon'' ("two-measure tooth"), which has large, prominent canine-like teeth in front and smaller slicing teeth further back in its jaws. Its unusual long, narrow jaws suggest that ''Secodontosaurus'' may have been specialized for catching fish or for hunting prey that lived or hid in burrows or crevices. Although no complete skeletons are currently known, ''Secodontosaurus'' likely ranged from about in length, weighing up to . Fossils of ''Secodontosaurus'' have been found in Texa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelvis
The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The pelvic region of the trunk includes the bony pelvis, the pelvic cavity (the space enclosed by the bony pelvis), the pelvic floor, below the pelvic cavity, and the perineum, below the pelvic floor. The pelvic skeleton is formed in the area of the back, by the sacrum and the coccyx and anteriorly and to the left and right sides, by a pair of hip bones. The two hip bones connect the spine with the lower limbs. They are attached to the sacrum posteriorly, connected to each other anteriorly, and joined with the two femurs at the hip joints. The gap enclosed by the bony pelvis, called the pelvic cavity, is the section of the body underneath the abdomen and mainly consists of the reproductive organs (sex organs) and the rectum, while the pelvic f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrae
The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic irregular bone whose complex structure is composed primarily of bone, and secondarily of hyaline cartilage. They show variation in the proportion contributed by these two tissue types; such variations correlate on one hand with the cerebral/caudal rank (i.e., location within the vertebral column, backbone), and on the other with phylogenetic differences among the vertebrate taxon, taxa. The basic configuration of a vertebra varies, but the bone is its ''body'', with the central part of the body constituting the ''centrum''. The upper (closer to) and lower (further from), respectively, the cranium and its central nervous system surfaces of the vertebra body support attachment to the intervertebral discs. The posterior part of a vertebra fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baylor County, Texas
Baylor County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 3,465. Its county seat is Seymour. History In 1858, the Texas Legislature established Baylor County, naming it for Henry Weidner Baylor, a surgeon in the Texas Rangers during the Mexican–American War. It organized in 1879. Geography According to the U.S. Census Bureau, the county has a total area of , of which (3.7%) are covered by water. Major highways * U.S. Highway 82 * U.S. Highway 183 * U.S. Highway 277 * U.S. Highway 283 * State Highway 114 Adjacent counties * Wilbarger County (north) * Wichita County (northeast) * Archer County (east) * Young County (southeast) * Throckmorton County (south) * Haskell County (southwest) * Knox County (west) * Foard County (northwest) Geology Baylor County is part of the Texas Red Beds, which are strata of red-colored sedimentary rock from the Early Permian. The fossils of Permian period vertebrates in the Tex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
