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Orthacanthus
''Orthacanthus'' is an extinct genus of fresh-water xenacanthid sharks, named by Louis Agassiz in 1836, ranging from the Upper Carboniferous until the Lower Permian. ''Orthacanthus'' had a nektobenthic life habitat, with a carnivorous diet. Multiple sources have also discovered evidence of cannibalism in the diet of ''Orthacanthus'' and of "filial cannibalism" where adult ''Orthacanthus'' preyed upon juvenile ''Orthacanthus.'' The genus ''Orthacanthus'' has been synonymized with ''Dittodus'' (Owen, 1867), ''Didymodus'' (Cope, 1883), and ''Diplodus'' (Agassiz, 1843). About 260 million years ago, ''Orthacanthus'' was the apex predator of freshwater swamps and bayous in Europe and North America. Mature ''Orthacanthus'' reached nearly 3 meters (10 feet) in length. ''Orthacanthus'' teeth have a minimum of three cusps, two principal cusps, and an intermediate cusp, where the principal cusps are variously serrated, with complex base morphology. Additionally, ''Orthacanthus'' can be dia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthacanthus Scale
''Orthacanthus'' is an extinct genus of fresh-water xenacanthid sharks, named by Louis Agassiz in 1836, ranging from the Upper Carboniferous until the Lower Permian. ''Orthacanthus'' had a nektobenthic life habitat, with a carnivorous diet. Multiple sources have also discovered evidence of cannibalism in the diet of ''Orthacanthus'' and of "filial cannibalism" where adult ''Orthacanthus'' preyed upon juvenile ''Orthacanthus.'' The genus ''Orthacanthus'' has been synonymized with ''Dittodus'' (Owen, 1867), ''Didymodus'' (Cope, 1883), and ''Diplodus'' (Agassiz, 1843). About 260 million years ago, ''Orthacanthus'' was the apex predator of freshwater swamps and bayous in Europe and North America. Mature ''Orthacanthus'' reached nearly 3 meters (10 feet) in length. ''Orthacanthus'' teeth have a minimum of three cusps, two principal cusps, and an intermediate cusp, where the principal cusps are variously serrated, with complex base morphology. Additionally, ''Orthacanthus'' can be dia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenacanthida
Xenacanthida (or Xenacanthiforms) is a super-order of extinct shark-like elasmobranchs that appeared during the Lower Carboniferous period. The order includes the families Xenacanthidae, Sphenacanthidae, Diplodoselachidae, and Orthacanthidae. The most notable members of the group are the genera ''Xenacanthus'' and ''Orthacanthus''. Some xenacanths may have grown to lengths of .Beck, Kimberley G.; oler-Gijón, Rodrigo; Carlucci, Jesse R.; Willis, Ray E. (December 2014). "Morphology and Histology of Dorsal Spines of the Xenacanthid Shark Orthacanthus platypternus from the Lower Permian of Texas, USA: Palaeobiological and Palaeoenvironmental Implications". ''Acta Palaeontologica Polonica''. 61 (1): 97–117. doi:10.4202/app.00126.2014 Most forms had large serrated spines extending backwards from the neck. ''Xenacanthus'' had characteristic teeth. Most xenacanths died out at the end of the Permian in the Permian Mass Extinction, with only a few forms surviving into the Triassic peri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboniferous
The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferous'' means "coal-bearing", from the Latin '' carbō'' ("coal") and '' ferō'' ("bear, carry"), and refers to the many coal beds formed globally during that time. The first of the modern 'system' names, it was coined by geologists William Conybeare and William Phillips in 1822, based on a study of the British rock succession. The Carboniferous is often treated in North America as two geological periods, the earlier Mississippian and the later Pennsylvanian. Terrestrial animal life was well established by the Carboniferous Period. Tetrapods (four limbed vertebrates), which had originated from lobe-finned fish during the preceding Devonian, became pentadactylous in and diversified during the Carboniferous, including early amphibian line ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vascularized
Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature by processes of sprouting and splitting. Vasculogenesis is the embryonic formation of endothelial cells from mesoderm cell precursors, and from neovascularization, although discussions are not always precise (especially in older texts). The first vessels in the developing embryo form through vasculogenesis, after which angiogenesis is responsible for most, if not all, blood vessel growth during development and in disease. Angiogenesis is a normal and vital process in growth and development, as well as in wound healing and in the formation of granulation tissue. However, it is also a fundamental step in the transition of tumors from a benign state to a malignant one, leading to the use of angiogenesis inhibitors in the treatment of cancer. The essential role of angiogenesis in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladodoides
''Cladodoides'' is a genus of extinct shark. It appeared in the Frasnian stage of the late Devonian. It has a well-described braincase and brain cavity, and has greatly informed our understanding of the skull, brain, nerves, and jaws of early sharks. ''Cladodoides'' is likely a cladodont This is a typical Cladodont tooth, of a shark called ''Glikmanius''">Glikmanius.html" ;"title="shark called ''Glikmanius">shark called ''Glikmanius'' Cladodont (from Latin cladus, meaning branch and Greek Odon, meaning tooth) is the term for a com ... shark. Remains have been found in Germany. References * {{Taxonbar, from1=Q25398960, from2=Q25357703 Devonian sharks Devonian fish of North America Prehistoric shark genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladodont
This is a typical Cladodont tooth, of a shark called ''Glikmanius''">Glikmanius.html" ;"title="shark called ''Glikmanius">shark called ''Glikmanius'' Cladodont (from Latin cladus, meaning branch and Greek Odon, meaning tooth) is the term for a common category of early Devonian shark known primarily for its "multi-cusped" tooth consisting of one long blade surrounded by many short, fork-like tines, designed to catch food that was swallowed whole, instead of being used to saw off chunks of meat like many modern sharks. The skinny teeth would puncture and grasp the prey, keeping it from wriggling free. Because the most common fossil evidence of cartilaginous fish is teeth, this term is also used for the fossilised teeth themselves. History The fossil tooth of '' Cladodus belifer'', which lived about 260,000,000 years ago in what would someday be Illinois. The roundness of the main tooth, and the small tines around it, show it to be a cladodont. The earliest known shark, ''Clado ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chondrichthyes
Chondrichthyes (; ) is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fishes'', which have skeletons primarily composed of bone tissue. Chondrichthyes are jawed vertebrates with paired fins, paired nares, scales, and a heart with its chambers in series. Extant chondrichthyes range in size from the 10 cm (3.9 in) finless sleeper ray to the 10 m (32 ft) whale shark. The class is divided into two subclasses: Elasmobranchii (sharks, rays, skates, and sawfish) and Holocephali ( chimaeras, sometimes called ghost sharks, which are sometimes separated into their own class). Within the infraphylum Gnathostomata, cartilaginous fishes are distinct from all other jawed vertebrates. Anatomy Skeleton The skeleton is cartilaginous. The notochord is gradually replaced by a vertebral column during development, except in Holocephali, where the notochord stays intact. In some deepwat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monophyly
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic groups are typically characterised by shared derived characteristics ( synapomorphies), which distinguish organisms in the clade from other organisms. An equivalent term is holophyly. The word "mono-phyly" means "one-tribe" in Greek. Monophyly is contrasted with paraphyly and polyphyly as shown in the second diagram. A ''paraphyletic group'' consists of all of the descendants of a common ancestor minus one or more monophyletic groups. A '' polyphyletic group'' is characterized by convergent features or habits of scientific interest (for example, night-active primates, fruit trees, aquatic insects). The features by which a polyphyletic group is differentiated from others are not inherited from a common ancestor. These definitions have taken ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mimipiscis
''Mimipiscis'' is a fossil genus of very primitive ray-finned fishes from the Upper Devonian Gneudna and Gogo Formations of Western Australia. The genus was initially described by Gardiner & Bartram as ''Mimia'' in 1977, a junior homonym of the skipper butterfly genus '' Mimia'' which was already established by Evans in 1953. See also * Prehistoric fish The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish ... * List of prehistoric bony fish References Prehistoric ray-finned fish genera Late Devonian animals Late Devonian fish Devonian bony fish Junior homonyms Gogo fauna {{paleo-rayfinned-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
