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92-514: Allosauroidea ? Marsh, 1878 Carnosauria is an extinct group of carnivorous theropod dinosaurs that lived during the Jurassic and Cretaceous periods. While Carnosauria was historically considered largely synonymous with Allosauroidea , some recent studies have revived Carnosauria as clade including both Allosauroidea and Megalosauroidea (which is sometimes recovered as paraphyletic with respect to Allosauroidea), and thus including
184-399: A caudofemoralis longus (CFL) muscle that allowed them to flex theirs. Larger carnosaurs are found to have a lower CFL muscle-to-body-mass proportion that smaller carnosaurs. In addition to body similarities, most carnosaurs, especially most allosauroids are also united by certain skull features. Some of the defining ones include a smaller mandibular fenestra , a short quadrate bone, and
276-652: A facultative carnivore from an omnivore . Obligate or "true" carnivores are those whose diet requires nutrients found only in animal flesh in the wild. While obligate carnivores might be able to ingest small amounts of plant matter, they lack the necessary physiology required to fully digest it. Some obligate carnivorous mammals will ingest vegetation as an emetic , a food that upsets their stomachs, to self-induce vomiting. Obligate carnivores are diverse. The amphibian axolotl consumes mainly worms and larvae in its environment, but if necessary will consume algae. All wild felids , including feral domestic cats , require
368-572: A feeding tube is utilized, and sometimes a tracheotomy is also performed to maintain respiration in case of swollen muscles. In a technique illustrated in the 19th century, the flesh of the face is incised along the inferior of the mandible and peeled upward for the bone's removal. Complications can involve difficulties with free flap transfer and airway management. Additional side effects include pain, infection, numbness, and (rarely, fatal) bleeding. Even successful surgeries can result in deformity , with an extreme version being referred to as
460-455: A 'twin fracture' on the opposite side. There is no universally accepted treatment protocol, as there is no consensus on the choice of techniques in a particular anatomical shape of mandibular fracture clinic. A common treatment involves attachment of metal plates to the fracture to assist in healing. The mandible may be dislocated anteriorly (to the front) and inferiorly (downwards) but very rarely posteriorly (backwards). The articular disk of
552-836: A basal grade of carnosaurs, paraphyletic with respect to Allosauroidea. Because the authors amended the definition of Allosauroidea to include all theropods that are closer to Allosaurus fragilis than to either Megalosaurus bucklandii or Neornithes, the Piatnitzkysauridae was found to fall within Allosauroidea. A cladogram displaying the relationships they recovered is shown below. Monolophosaurus Spinosauridae [REDACTED] Megalosauridae [REDACTED] Xuanhanosaurus Piatnitzkysauridae [REDACTED] Asfaltovenator Metriacanthosauridae [REDACTED] Allosauridae [REDACTED] The relationship between allosauroids and megalosauroids
644-402: A bone (ossifies) from Meckel's cartilage, which forms the cartilaginous bar of the mandibular arch and, dorsally, parts of the middle ear. The two sides of the jawbone are inferiorly fused at the mandibular symphysis (the chin) during the first year of life. The cartilage of the ramus is replaced by fibrous tissue, which persists to form the sphenomandibular ligament . Between the lingula and
736-417: A carnosaur. Carnosauria has traditionally been used as a dumping ground for all large theropods. Even non-dinosaurs, such as the rauisuchian Teratosaurus , were once considered carnosaurs. However, analysis in the 1980s and 1990s revealed that other than size, the group shared very few characteristics, making it polyphyletic . Most former carnosaurs (such as the megalosaurids , the spinosaurids , and
828-525: A condition of shock in humans, e.g. when someone's mouth suddenly hangs agape in response to something. The exaggerated visual gag of a jaw dropping to the floor was a trademark of American animation director Tex Avery , who would often employ it when the Big Bad Wolf spies a sexually attractive woman. Gobstoppers , a type of hard candy, are known in North America as jawbreakers due to
920-473: A deceased person's age. Dental remains of Nazi leader Adolf Hitler , including part of a mandible with teeth, were the solitary physical evidence used to confirm his death in 1945. In the Hebrew Bible and Christian Old Testament Book of Judges , Samson used a donkey's jawbone to kill a thousand Philistines . As early as 1900, the phrase jaw-dropping was used as an adjective to describe
1012-534: A diet of primarily animal flesh and organs. Specifically, cats have high protein requirements and their metabolisms appear unable to synthesize essential nutrients such as retinol , arginine , taurine , and arachidonic acid ; thus, in nature, they must consume flesh to supply these nutrients. Characteristics commonly associated with carnivores include strength, speed, and keen senses for hunting, as well as teeth and claws for capturing and tearing prey. However, some carnivores do not hunt and are scavengers , lacking
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#17327797091431104-505: A diprodontan dentition completely unlike that of any other mammal; and eutriconodonts like gobiconodontids and Jugulator , with a three-cusp anatomy which nevertheless functioned similarly to carnassials. Mandible In jawed vertebrates , the mandible (from the Latin mandibula , 'for chewing'), lower jaw , or jawbone is a bone that makes up the lower – and typically more mobile – component of
1196-401: A faint ridge, the oblique line, which is continuous with the anterior border of the ramus. Attached to this is the masseter muscle ( related to mastication ), the depressor labii inferioris and depressor anguli oris (which support the mouth ), and the platysma (extending down over much of the neck ). From the inside, the mandible appears concave. On either side of the lower symphysis
1288-511: A form of endosymbiosis , might have led to symbiogenesis that gave rise to eukaryotes and eukaryotic autotrophs such as green and red algae . The earliest predators were microorganisms , which engulfed and "swallowed" other smaller cells (i.e. phagocytosis ) and digested them internally . Because the earliest fossil record is poor, these first predators could date back anywhere between 1 and over 2.7 bya (billion years ago). The rise of eukaryotic cells at around 2.7 bya,
1380-639: A great diversity of eutherian carnivores in the northern continents and Africa . In South America , sparassodonts were dominant, while Australia saw the presence of several marsupial predators, such as the dasyuromorphs and thylacoleonids . From the Miocene to the present, the dominant carnivorous mammals have been carnivoramorphs . Most carnivorous mammals, from dogs to deltatheridiums , share several dental adaptations, such as carnassialiforme teeth, long canines and even similar tooth replacement patterns. Most aberrant are thylacoleonids , with
1472-444: A newly named clade: Megaraptora. Megaraptora contained Megaraptor , Fukuiraptor , Orkoraptor , Aerosteon , and Australovenator . These genera were allied with the other neovenatorids on the basis of several features spread out throughout the skeleton, particularly the large amount of pneumatization present. The pneumatic ilium of Aerosteon was particularly notable, as Neovenator was the only other taxon known to have that trait at
1564-504: A number of primitive characteristics seen in basal tetanurans such as Allosaurus . Nevertheless, there are still a number of other traits that support megaraptorans as members of the Coelurosauria. Other taxa like Deltadromeus and Gualicho have been alternatively recovered as coelurosaurs or noasaurid ceratosaurs . Several recent analyses do not find a relationship between Neovenator and megaraptorans, which suggests that
1656-661: A scientific consensus has yet to emerge. One such clade is Neovenatoridae , a proposed clade of carcharodontosaurian carnosaurs uniting some primitive members of the group such as Neovenator with the Megaraptora , a group of theropods with controversial affinities. Other studies recover megaraptorans as basal coelurosaurs unrelated to carcharodontosaurs. Other theropods with uncertain affinities such as Gualicho , Chilantaisaurus and Deltadromeus are also sometimes included. Neovenatoridae, as formulated by these authors, contained Neovenator , Chilantaisaurus , and
1748-431: A separate ossific center ( splenial center ), is formed in the human mandible by an ingrowth from the main mass of the bone. At birth, the body of the bone is a mere shell, containing the sockets of the two incisor, the canine, and the two deciduous molar teeth , imperfectly partitioned off from one another. The mandibular canal is of large size and runs near the lower border of the bone; the mental foramen opens beneath
1840-408: A short connection between the braincase and the palate. Allosauroid skulls are about 2.5 to 3 times longer as they are tall. Their narrow skull along with their serrated teeth allow carnosaurs to better slice flesh off of their prey. Carnosaur teeth are flat and have equally-sized denticles on both edges. The flat side of the tooth face the sides of the skull, while the edges align on the same plane as
1932-463: A similar center of mass across all sizes, which is found to be between 37% and 58% of the femoral length anterior to the hip. Other similarities across all carnosaurs include the structure of their hind limb and pelvis. The pelvis in particular is thought to be designed to reduce stress regardless of body size. In particular, the way the femur is inclined reduces the bending and torsion stress. Furthermore, like other animals with tails, carnosaurs possess
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#17327797091432024-448: Is absorbed so that the mandibular canal becomes nearer the superior border. Sometimes with excessive alveolar process absorption, the mandibular canal disappears entirely and deprives the IAN of its bony protection, although soft tissue continues to guard the nerve. The surgical removal ( resection ) of all or part of the jawbone is known as a mandibulectomy . The removal of a small portion
2116-399: Is below the oblique line. The mandibular canal, with the mental foramen opening from it, is closer to the alveolar border. The ramus is oblique in direction, the angle measures about 140°, and the neck of the condyle is more or less bent backward. The posterior of the mandible is notoriously resistant to the full effects of local anesthesia . The IAN provides sensory innervation to much of
2208-460: Is essential for chewing food. Owing to the Neolithic advent of agriculture ( c. 10,000 BCE ), human jaws evolved to be smaller . Although it is the strongest bone of the facial skeleton , the mandible tends to deform in old age; it is also subject to fracturing . Surgery allows for the removal of jawbone fragments (or its entirety) as well as regenerative methods. Additionally,
2300-479: Is irregular; it presents in front a prominent ridge, surmounted by a sharp spine, the lingula of the mandible , which gives attachment to the sphenomandibular ligament ; at its lower and back part is a notch from which the mylohyoid groove runs obliquely downward and forward, and lodges the mylohyoid vessels and nerve. Behind this groove is a rough surface, for the insertion of the medial pterygoid muscle . The mandibular canal runs obliquely downward and forward in
2392-459: Is known as partial mandibulectomy and a larger portion segmental mandibulectomy . This can be performed to remove a tumor, circumvent cancer in nearby areas, and/or in response to infection, osteonecrosis , or injury. The removed portion can be replaced with metal plating or bone from elsewhere in the body. Oral muscles tend to work differently after the procedure, requiring therapy to relearn operations such as eating and speaking. During recovery,
2484-440: Is more pronounced in males but can be visualized and palpated in females. Rarely, a bifid IAN may be present, resulting in a second and more inferiorly placed mandibular foramen. This can be detected by noting a doubled mandibular canal via radiograph. The mandible forms the lower jaw and holds the lower teeth in place. It articulates with the left and right temporal bones at the temporomandibular joints. The condyloid process,
2576-446: Is referred to as the dentary bone or os dentale , and forms the body of the outer surface of the jaw. It is bordered below by a number of splenial bones, while the angle of the jaw is formed by a lower angular bone and a suprangular bone just above it. The inner surface of the jaw is lined by a prearticular bone, while the articular bone forms the articulation with the skull proper. A set of three narrow coronoid bones lie above
2668-521: Is shown below. Coelurosauria [REDACTED] Monolophosaurus Carnivorous A carnivore / ˈ k ɑːr n ɪ v ɔːr / , or meat-eater ( Latin , caro , genitive carnis , meaning meat or "flesh" and vorare meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly muscle , fat and other soft tissues ) as food , whether through predation or scavenging . The technical term for mammals in
2760-937: Is termed an apex predator , regardless of whether it is an obligate or facultative carnivore. In captivity or domestic settings, obligate carnivores like cats and crocodiles can, in principle, get all their required nutrients from processed food made from plant and synthetic sources. Outside the animal kingdom, there are several genera containing carnivorous plants (predominantly insectivores) and several phyla containing carnivorous fungi (preying mostly on microscopic invertebrates , such as nematodes , amoebae , and springtails ). Carnivores are sometimes characterized by their type of prey . For example, animals that eat mainly insects and similar terrestrial arthropods are called insectivores , while those that eat mainly soft-bodied invertebrates are called vermivores . Those that eat mainly fish are called piscivores . Carnivores may alternatively be classified according to
2852-448: Is the mental spine (which can be faint or fused into one), to which the genioglossus (the inferior muscle of the tongue ) attaches; the geniohyoid muscle attaches to the lower mental spine. Above the mental spine, a median foramen and furrow can line the symphysis. Below the mental spine is an oval depression (the digastric fossa of the mandible ) where the digastric muscle attaches. Extending backward and upward on either side from
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2944-571: The Andy Gump deformity after the comic book character , whose design apparently lacks a jaw; proposed reconstruction methods include implanting synthetic material , potentially involving 3D printing . Bone loss (as in osteoporosis ) can be mitigated in the jawbone via bone grafting , which is sometimes performed to support dental implants (replacing teeth individually or in groups ). Mandibular prosthetics date back to ancient Egypt and China , but significant advancements were made in
3036-623: The Cambrian substrate revolution led to increased active predation among animals, likely triggering various evolutionary arms races that contributed to the rapid diversification during the Cambrian explosion . Radiodont arthropods , which produced the first apex predators such as Anomalocaris , quickly became the dominant carnivores of the Cambrian sea. After their decline due to the Cambrian-Ordovician extinction event ,
3128-532: The ceratosaurs ) were reclassified as more primitive theropods. Others (such as the tyrannosaurids ) that were more closely related to birds were placed in Coelurosauria . Modern cladistic analysis defines Carnosauria as those tetanurans sharing a more recent common ancestor with Allosaurus than with modern birds. Carnosaurs share certain distinctive features, one of which is a triangular-shaped pubic boot . They also have 3 fingers per hand, with
3220-423: The lobe-finned fish , became the dominant carnivores of freshwater wetlands formed by early land plants . Some of these fish became better adapted for breathing air and eventually giving rise to amphibian tetrapods . These early tetrapods were large semi-aquatic piscivores and riparian ambush predators that hunt terrestrial arthropods (mainly arachnids and myriopods ), and one group in particular,
3312-409: The mouth (the upper jaw being known as the maxilla ). The jawbone is the skull 's only movable, posable bone, sharing joints with the cranium's temporal bones . The mandible hosts the lower teeth (their depth delineated by the alveolar process ). Many muscles attach to the bone, which also hosts nerves (some connecting to the teeth) and blood vessels . Amongst other functions, the jawbone
3404-437: The order Carnivora is carnivoran , and they are so-named because most member species in the group have a carnivorous diet, but the similarity of the name of the order and the name of the diet causes confusion. Many but not all carnivorans are meat eaters; a few, such as the large and small cats ( Felidae ) are obligate carnivores (see below). Other classes of carnivore are highly variable. The ursids , for example: while
3496-531: The temnospondyls , became terrestrial apex predators that hunt other tetrapods. The dominance of temnospondyls around the wetland habitats throughout the Carboniferous forced other amphibians to evolve into amniotes that had adaptations that allowed them to live farther away from water bodies. These amniotes began to evolve both carnivory, which was a natural transition from insectivory requiring minimal adaptation; and herbivory , which took advantage of
3588-423: The triconodontid Jugulator , the deltatheroidans and Cimolestes . Many of these, such as Repenomamus , Jugulator and Cimolestes , were among the largest mammals in their faunal assemblages, capable of attacking dinosaurs. In the early-to-mid-Cenozoic, the dominant predator forms were mammals: hyaenodonts , oxyaenids , entelodonts , ptolemaiidans , arctocyonids and mesonychians , representing
3680-461: The Allosauroidea as Allosaurus , Sinraptor , their most recent common ancestor , and all of its descendants. Thomas R. Holtz and colleagues and Phil Currie and Ken Carpenter , among others, have followed this node-based definition. Depending on the study, Carnosauria and Allosauroidea are sometimes considered synonymous. In such cases, several researchers have elected to use Allosauroidea over Carnosauria. The following family tree illustrates
3772-501: The Arctic polar bear eats meat almost exclusively (more than 90% of its diet is meat), almost all other bear species are omnivorous , and one species, the giant panda , is nearly exclusively herbivorous . Dietary carnivory is not a distinguishing trait of the order . Many mammals with highly carnivorous diets are not members of the order Carnivora . Cetaceans , for example, all eat other animals, but are paradoxically members of
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3864-490: The Latin word mandibula 'jawbone' (literally, 'used for chewing'), from mandere 'to chew' and -bula ( instrumental suffix). In addition to mastication, the joint of the jawbone enables actions such speech and yawning , while playing a more subtle role in activities such as kissing and breathing . The mandible of vertebrates evolved from Meckel's cartilage , left and right segments of cartilage which supported
3956-775: The Middle Jurassic, around 176 mya. The last definite known carnosaurs, the carcharodontosaurs , became extinct in the Turonian epoch of the Cretaceous, roughly 90 mya; reportedly later remains of carcharodontosaurids, from the late Maastrichtian (70–66 mya) Bauru Group in Brazil , were later interpreted as those of abelisaurids . The phylogenetically problematic megaraptorans , which may or may not be carnosaurs, became extinct around 66 mya. Unquillosaurus , discovered in rocks dated to 75-70 mya, might potentially also be
4048-465: The above hypothesis. Novas and colleagues conducted an analysis in 2012 which found that Neovenator was closely related to carcharodontosaurids, simultaneously found Megaraptor and related genera to be coelurosaurs closely related to tyrannosaurids . However, Novas et al. subsequently found that megaraptorans lacked most of the key features in the hands of derived coelurosaurs including Guanlong and Deinonychus . Instead, their hands retain
4140-452: The abundance of coal forest foliage but in contrast required a complex set of adaptations that was necessary for digesting on the cellulose - and lignin -rich plant materials. After the Carboniferous rainforest collapse , both synapsid and sauropsid amniotes quickly gained dominance as the top terrestrial animals during the subsequent Permian period. Some scientists assert that sphenacodontoid synapsids such as Dimetrodon "were
4232-444: The almost exclusively plant-eating hooved mammals . Animals that depend solely on animal flesh for their nutrient requirements in nature are called hypercarnivores or obligate carnivores , whilst those that also consume non-animal food are called mesocarnivores , or facultative carnivores , or omnivores (there are no clear distinctions). A carnivore at the top of the food chain (adults not preyed upon by other animals)
4324-407: The angle measuring from 110° to 120°, also the adult condyle is higher than the coronoid process and the sigmoid notch becomes deeper. The adult mandible is the skull's largest and strongest bone. In old age, the bone can become greatly reduced in volume where there is a loss of teeth, and consequent resorption of the alveolar process and interalveolar septa. Consequently, the chief part of the bone
4416-411: The anterior branchial arch in early fish . Fish jaws surface in species of the large arthrodire genus Dunkleosteus ( fl. 382–358 million years ago ), which crushed prey with their quickly articulating mouths. The lower jaw of cartilaginous fish , such as sharks , is composed of a cartilagenous structure homologous with Meckel's cartilage. This also remains a significant element of
4508-426: The anterior third, nearer its external surface. It contains the inferior alveolar vessels and nerve, from which branches are distributed to the teeth. The mandible has two main holes ( foramina ), found on both its left and right sides: The inferior alveolar nerve (IAN), a branch of the mandibular nerve (itself a major division of the cranium's trigeminal nerve ), enters the mandibular foramen and runs forward in
4600-473: The bone is of great forensic significance. In humans , the mandible is the largest and lowest bone in the facial skeleton . It is the only movable bone of the skull (discounting the vibrating ossicles of the middle ear ). It is connected to the skull's temporal bones by the temporomandibular joints . In addition to simply opening and closing, the jawbone can articulate side to side as well as forward and back. The mandible consists of: The body of
4692-411: The canine tooth the cartilage disappears, while the portion of it below and behind the incisor teeth becomes ossified and incorporated with this part of the mandible. About the sixth week of fetal life, intramembranous ossification takes place in the membrane covering the outer surface of the ventral end of Meckel's cartilage, and each half of the bone is formed from a single center which appears, near
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#17327797091434784-399: The center but raised on both sides to form the mental tubercle . Just above this, on both sides, the mentalis muscles attach to a depression called the incisive foramen . Vertically midway on either side of the body, below the second premolar tooth, is the mental foramen , through which the mental nerve and blood vessels pass. Running backward and upward from each mental tubercle is
4876-540: The dentary, only few other bones of the lower jaw remain in mammals; the former articular and quadrate bones survive as the malleus and the incus of the middle ear. In recent human evolution , both the oral cavity and jaws have shrunk in correspondence with the Neolithic-era shift from hunter-gatherer lifestyles towards agriculture and settlement, dated to c. 10,000 BCE . This has led to orthodontic malocclusions . The mandible forms as
4968-565: The end of the Mesozoic era, dating to the early Maastrichtian stage of the latest Cretaceous period, about 70 million years ago. The cladogram below follows a 2016 analysis by Sebastián Apesteguía, Nathan D. Smith, Rubén Juarez Valieri, and Peter J. Makovicky based on the dataset of Carrano et al. (2012). Metriacanthosauridae [REDACTED] Allosauridae [REDACTED] Carcharodontosauridae [REDACTED] Deltadromeus Gualicho Subsequent analyses have contradicted
5060-469: The feet along with small scales. A series of knobs on the ulna of Concavenator have been interpreted by some authors as quill knobs theorized to have supported primitive quills; however this interpretation has been questioned, and they have been suggested to represent traces of ligaments instead. Within Carnosauria, there is a slightly more exclusive clade, Allosauroidea . The clade Allosauroidea
5152-413: The first terrestrial vertebrate to develop the curved, serrated teeth that enable a predator to eat prey much larger than itself". In the Mesozoic , some theropod dinosaurs such as Tyrannosaurus rex are thought probably to have been obligate carnivores. Though the theropods were the larger carnivores, several carnivorous mammal groups were already present. Most notable are the gobiconodontids ,
5244-506: The fracturing risk they impose on teeth. Owing in part to the forensic evidence of Hitler's death being limited to his dental remains (including a jawbone fragment broken and burnt around the alveolar process), some fringe accounts (bolstered by the Soviet Union , which captured Berlin in 1945) allege that Hitler faked his death (ostensibly along with Eva Braun ). In later decades, American real-estate businessman Fred Trump had
5336-461: The head to the hip is between 38% and 46% of the total body length. Carnosaurs scaled their limbs relative to their body in a way similar to how other large theropods, like the tyrannosaurids , did. During the Cretaceous, some carnosaurs grew to sizes similar to those of the largest tyrannosaurids. These large carnosaurs lived in the same time period as the other large theropods found in the upper Morrison and Tendaguru formations. Carnosaurs maintained
5428-415: The human mandible has four sides, two surfaces, four borders, and two processes. On the outside, the ramus is flat and marked by oblique ridges at its lower part. It gives attachment throughout nearly the whole of its extent to the masseter muscle. On the inside at the center there is an oblique mandibular foramen , for the entrance of the inferior alveolar vessels and nerve . The margin of this opening
5520-535: The interrelationships between the four major groups (or families) of carnosaurs. It is a simplified version of the tree presented in the 2012 analysis by Carrano, Benson and Sampson after they excluded three "wildcard" taxa Poekilopleuron , Xuanhanosaurus , and Streptospondylus . Metriacanthosauridae [REDACTED] Allosauridae [REDACTED] The composition of the clade Carnosauria has been controversial among scientists since at least 2010 . Different clades have been recovered by different authors, and
5612-482: The jaw in some primitive bony fish, such as sturgeons . In reptiles , Meckel's cartilage ossifies into the (multiple) bones of the lower jaw, while mammals of the Cretaceous (145–66 Mya) had both Meckel's cartilage and a mandible. In lobe-finned fishes and the early fossil tetrapods , the bone homologous to the mandible of mammals is merely the largest of several bones in the lower jaw. In such animals, it
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#17327797091435704-429: The jaws by the teeth; about the fourth year it is 140°. The fibrocartilage of the mandibular symphysis fuses together in early childhood. In the adult, the alveolar and subdental portions of the body are usually of equal depth. The mental foramen opens midway between the upper and lower borders of the bone, and the mandibular canal runs nearly parallel with the mylohyoid line. The ramus is almost vertical in direction,
5796-423: The late 19th century with new techniques for attaching prosthetics to a depreciated jawbone as well as bone grafting. In 2010, the first successful face transplant was conducted on a Spanish farmer after a self-inflicted gun accident ; this included the replacement of the entire mandible. The mandible can provide forensic evidence because its form changes over a person's life, and this can be used to determine
5888-522: The latter were not carnosaurs or allosauroids. As a result of these findings, and the fact that Neovenator itself is the only uncontroversial neovenatorid, the family Neovenatoridae sees little use in recent publications. In 2019, Rauhut and Pol described Asfaltovenator vialidadi , a basal allosauroid displaying a mosaic of primitive and derived features seen within Tetanurae . Their phylogenetic analysis found traditional Megalosauroidea to represent
5980-410: The lower symphysis is a ridge called the mylohyoid line , where the mylohyoid muscle attaches; a small part of the superior pharyngeal constrictor muscle attaches to the posterior ridge, near the alveolar margin . Above the anterior ridge, the sublingual gland rests against a smooth triangular area, and below the posterior ridge, the submandibular gland rests in an oval depression. The ramus of
6072-399: The majority of non- coleurosaurian members of theropod clade Tetanurae . Other researchers have found Allosauroidea and Megalosauroidea to be unrelated groups. Distinctive characteristics of carnosaurs include large eye sockets , a long narrow skull and modifications of the legs and pelvis such as the thigh ( femur ) being longer than the shin ( tibia ). Carnosaurs first appeared in
6164-403: The mandible and its teeth, making it a target of block anesthesia . Injecting the nerve is challenging due to the amount of surrounding soft tissue . American surgeon William Stewart Halsted developed a technique using a syringe and cocaine which was performed successfully by 1885. One fifth of facial injuries involve a mandibular fracture. Mandibular fractures are often accompanied by
6256-413: The mandible is curved, and the front part gives structure to the chin . It has two surfaces and two borders. From the outside, the mandible is marked in the midline by a faint ridge, indicating the mandibular symphysis , the line of junction of the two halves of the mandible. This ridge divides below and encloses a triangular eminence, the mental protuberance (the chin), the base of which is depressed in
6348-414: The mandibular arch (occasionally noted also in partially edentulous cases). This resorption can occur to such an extent that the mental foramen is virtually on the superior border of the mandible, instead of opening on the anterior surface, changing its relative position. However, the more inferior body of the mandible is not affected and remains thick and rounded. With age and tooth loss, the alveolar process
6440-459: The mandibular canal, supplying sensation to the gums and teeth. Before passing through the mental foramen, the nerve divides into two terminal branches: incisive and mental nerves. The incisive nerve runs forward in the mandible and supplies the anterior teeth. The mental nerve exits the mental foramen and supplies sensation to the chin and lower lip. Males generally have squarer, stronger, and larger mandibles than females. The mental protuberance
6532-467: The mental foramen. By the tenth week, the portion of Meckel's cartilage which lies below and behind the incisor teeth is surrounded and invaded by the dermal bone (also known as the membrane bone). Somewhat later, accessory nuclei of cartilage make their appearance, as These accessory nuclei possess no separate ossific centers but are invaded by the surrounding dermal bone and undergo absorption. The inner alveolar border, usually described as arising from
6624-596: The niches of large carnivores were taken over by nautiloid cephalopods such as Cameroceras and later eurypterids such as Jaekelopterus during the Ordovician and Silurian periods. The first vertebrate carnivores appeared after the evolution of jawed fish , especially armored placoderms such as the massive Dunkleosteus . The dominance of placoderms in the Devonian ocean forced other fish to venture into other niches, and one clade of bony fish ,
6716-468: The percentage of meat in their diet. The diet of a hypercarnivore consists of more than 70% meat, that of a mesocarnivore 30–70%, and that of a hypocarnivore less than 30%, with the balance consisting of non-animal foods, such as fruits , other plant material, or fungi . Omnivores also consume both animal and non-animal food, and apart from their more general definition, there is no clearly defined ratio of plant vs. animal material that distinguishes
6808-555: The physical characteristics to bring down prey; in addition, most hunting carnivores will scavenge when the opportunity arises. Carnivores have comparatively short digestive systems, as they are not required to break down the tough cellulose found in plants. Many hunting animals have evolved eyes facing forward, enabling depth perception. This is almost universal among mammalian predators, while most reptile and amphibian predators have eyes facing sideways. Predation (the eating of one living organism by another for nutrition ) predates
6900-627: The position of Carnosauria within Theropoda. It is a simplified version of the tree presented in a synthesis of the relationships of the major theropod groups based on various studies conducted in the 2010s. Coelophysoidea [REDACTED] Dilophosauridae [REDACTED] Ceratosauria [REDACTED] Megalosauroidea [REDACTED] Carnosauria / Allosauroidea [REDACTED] Tyrannosauroidea [REDACTED] Compsognathidae [REDACTED] Maniraptora [REDACTED] The cladogram presented below illustrates
6992-411: The powerful action of the masticatory muscles; but, the alveolar portion is the deeper of the two, and, consequently, the chief part of the body lies above the oblique line. The mandibular canal, after the second dentition, is situated just above the level of the mylohyoid line ; and the mental foramen occupies the position usual to it in the adult. The angle becomes less obtuse, owing to the separation of
7084-413: The prearticular bone. As the name implies, the majority of the teeth are attached to the dentary, but there are commonly also teeth on the coronoid bones, and sometimes on the prearticular. Most vertebrates exhibit a simpler scheme, as bones have either fused or vanished. In teleosts , only the dentary, articular, and angular bones remain, while in living amphibians , the dentary is accompanied only by
7176-607: The prearticular, and, in salamanders , one of the coronoids. The lower jaw of reptiles has only a single coronoid and splenial, but retains all the other primitive bones except the prearticular and the periosteum. In birds, the various bones have fused into a single structure. In mammals, most have disappeared, leaving only the mandible. As a result, there is only articulation between the mandible and temporal bones, as opposed to articulation between articular and quadrate bones . An intermediate stage can be seen in some therapsids , in which both points of articulation are present. Aside from
7268-414: The ramus, and then horizontally forward in the body, where it is placed under the alveoli , with small openings for nerves. On arriving at the incisor teeth , it turns back to communicate with the mental foramen, giving off two small canals which run to the cavities containing the incisor teeth. In the posterior two-thirds of the bone the canal is situated nearer the internal surface of the mandible; and in
7360-402: The rise of commonly recognized carnivores by hundreds of millions (perhaps billions) of years. It began with single-celled organisms that phagocytozed and digested other cells, and later evolved into multicellular organisms with specialized cells that were dedicated to breaking down other organisms. Incomplete digestion of the prey organisms, some of which survived inside the predators in
7452-663: The rise of multicellular organisms at about 2 bya, and the rise of motile predators (around 600 Mya – 2 bya, probably around 1 bya) have all been attributed to early predatory behavior, and many very early remains show evidence of boreholes or other markings attributed to small predator species. The sudden disappearance of the precambrian Ediacaran biota at the end-Ediacaran extinction , who were mostly bottom-dwelling filter feeders and grazers , has been hypothetized to be partly caused by increased predation by newer animals with hardened skeleton and mouthparts. The degradation of seafloor microbial mats due to
7544-411: The second and third digit being approximately equal in length. The femur is larger than the tibia. Another defining feature of carnosaurs is that the chevron bases on their tails have anterior and posterior bone growth. The largest carnosaurs can reach up to 10 meters in length. The length of the body from the tail to the hip is between 54% and 62% of the total body length, and the length of the body from
7636-410: The second year, near the alveolar margin. The body becomes elongated in its whole length, but more especially behind the mental foramen, to provide space for the three additional teeth developed in this part. The depth of the body increases owing to increased growth of the alveolar part, to afford room for the roots of the teeth, and by thickening of the subdental portion which enables the jaw to withstand
7728-549: The skull. From analyzing the skull of different carnosaurs, the volume of the cranial vault ranges between 95 milliliters in Sinraptor to 250 milliliters in Giganotosaurus . Allosaurus and Concavenator preserve skin impressions showing their integument . In Allosaurus, skin impressions showing small scales measuring 1-3 mm are known from the side of the torso and the mandible . Another skin impression from
7820-407: The socket of the first deciduous molar tooth. The angle is obtuse (175°), and the condyloid portion is nearly in line with the body. The coronoid process is of comparatively large size, and projects above the level of the condyle. After birth, the two segments of the bone become joined at the symphysis, from below upward, in the first year; but a trace of separation may be visible in the beginning of
7912-491: The superior (upper) and posterior projection from the ramus, makes the temporomandibular joint with the temporal bone. The coronoid process, superior and anterior projection from the ramus. This provides attachment to the temporal muscle . Teeth sit in the upper part of the body of the mandible. The frontmost part of teeth is more narrow and holds front teeth. The back part holds wider and flatter (albeit grooved) teeth primarily for chewing food. The word mandible derives from
8004-512: The temporomandibular joint prevents the mandible from moving posteriorly, making the condylar neck particularly vulnerable to fractures. Further, various jawbone damage can cause temporomandibular joint dysfunction , with symptoms including pain and inflammation . The jawbone can also become deviated in mandibular lateral displacement , a condition which can offset facial symmetry and cause posterior crossbite . The mandibular alveolar process can become resorbed when completely edentulous in
8096-675: The time. Neovenatorids were envisioned as the latest-surviving allosauroids, which were able to persist well into the Late Cretaceous due to their low profile and coelurosaur-like adaptations. Later studies supported this hypothesis, such as Carrano, Benson & Sampson large study of tetanuran relationships in 2012, and Zanno & Makovicky description of the newly discovered theropod Siats in 2013, which they placed within Megaraptora. Fukuiraptor and Australovenator were consistently found to be close relatives of each other; this
8188-429: The ventral side of the neck preserves scutes . An impression from the base of the tail preserves larger scales around 2 cm in diameter. However, it has been noted that these may be sauropod scales due to their similarity and the fact that non-theropod remains were discovered associated with the tail of this particular Allosaurus specimen. Concavenator preserves scutes on the underside of the tail, as well as scutes on
8280-432: Was also supported by a provisional analysis published by Andrea Cau in 2021. This publication is also the origin of the hypothesis that several "compsognathids" from Europe may have been juvenile carnosaurs. The results of this analysis differ from those of Rauhut and Pol in that Cau finds Megalosauroidea to be monophyletic and the sister-taxon of Allosauroidea within Carnosauria. An abbreviated version of this phylogeny
8372-508: Was also the case for Aerosteon and Megaraptor . Orkoraptor was a "wildcard" taxon difficult to place with certainty. Phylogenetic studies conducted by Benson, Carrano and Brusatte (2010) and Carrano, Benson and Sampson (2012) recovered the group Megaraptora and a few other taxa as members of the Neovenatoridae. This would make neovenatorids the latest-surviving allosauroids; at least one megaraptoran, Orkoraptor , lived near
8464-483: Was originally named by Othniel Charles Marsh , but it was given a formal definition by Phil Currie and Zhao, and later used as a stem-based taxon by Paul Sereno in 1997. Sereno was the first to provide a stem-based definition for the Allosauroidea in 1998, defining the clade as "All neotetanurans closer to Allosaurus than to Neornithes ." Kevin Padian used a node-based definition in his 2007 study which defined
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