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106-537: Antarctopelta ( ann- TARK -toh- PEL -tə ; meaning 'Antarctic shield') is a genus of ankylosaurian dinosaur , a group of large, quadrupedal herbivores, that lived during the Maastrichtian stage of the Late Cretaceous period on what is now James Ross Island , Antarctica . Antarctopelta is the only known ankylosaur from Antarctica and a member of Parankylosauria . The only described specimen

212-518: A bone shaft , a metapodial, several undetermined fragments, ossified tendons, and dorsal ribs were used in the study. Based on the spacing and organization of the Outer Circumferential Layer of the bone cortex, Cerda et al concluded that the specimen had reached sexual maturity and was close to adult maturity. During their study, the authors found that one section of bone had an abnormal bone tissue that may have been caused by

318-572: 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

424-409: A supraorbital (brow ridge bone), bore a short spike which would have projected outwards over the eye. Other fossils likely from the quadratojugals (cheek bones), supraorbitals, and right parietal (cranium bone) were identified in 2006, though their poor condition gives little information. The leaf-shaped teeth are asymmetrical , with the majority of the denticles on the edge closest to the tip of

530-443: A tumor or other periosteal reaction . The growth patterns of the bones were not very dissimilar to those of ankylosaurs from lower latitudes. This suggests that the growth rates remained the same, despite different climatic or environmental conditions. This contrasts with hadrosaurs and ceratopsians , which have varying growth rates depending on the latitude. The holotype skeleton was collected about 90 m (300 ft) from

636-455: 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

742-402: 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

848-525: 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

954-639: A decade due to ground frost and harsh weather conditions. Olivero and Scasso had found the specimen in strata from the Gamma Member of the Snow Hill Island Formation , which dates to the Maastrichtian age of the Late Cretaceous period. The material all came from a single individual, but was spread over a 6 square meters (65 square feet) area and collected over several field seasons. The bones were heavily worn due to freeze-thaw weathering, causing many to become fragmented and broken. It

1060-473: 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

1166-401: 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

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1272-580: A group of herbivorous, quadrupedal ornithischians with armored osteoderms adorning the dermis. Prior to the description of Stegouros , it was thought that there were two main families of ankylosaur; Nodosauridae, which has no tail club, and Ankylosauridae, with tail clubs. When first described, Antarctopelta was placed at an indeterminate level within Ankylosauria but was stated to have similarities with both nodosaurids and ankylosaurids. The dentiton and osteoderms share features with nodosaurids, while it

1378-406: A higher estimation of 6 meters (20 feet) and 350 kg (770 lb). The head was small, with jaws lined with small, leaf-shaped teeth . The limbs were short and about equal in length, the forefeet having five toes while the hindfeet had six. Very little of the skull is known, but all of the preserved skull fragments were heavily ossified for protection. One bone in particular, identified as

1484-533: A kind of aquatic, shelled cephalopod, are also found in the layers of the Gamma Member. Genus The composition of a genus is determined by taxonomists . The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: Moreover, genera should be composed of phylogenetic units of

1590-651: A later homonym of a validly published name is a nomen illegitimum or nom. illeg. ; for a full list refer to the International Code of Nomenclature for algae, fungi, and plants and the work cited above by Hawksworth, 2010. In place of the "valid taxon" in zoology, the nearest equivalent in botany is " correct name " or "current name" which can, again, differ or change with alternative taxonomic treatments or new information that results in previously accepted genera being combined or split. Prokaryote and virus codes of nomenclature also exist which serve as

1696-628: A long time and redescribed as new by a range of subsequent workers, or if a range of genera previously considered separate taxa have subsequently been consolidated into one. For example, the World Register of Marine Species presently lists 8 genus-level synonyms for the sperm whale genus Physeter Linnaeus, 1758, and 13 for the bivalve genus Pecten O.F. Müller, 1776. Within the same kingdom, one generic name can apply to one genus only. However, many names have been assigned (usually unintentionally) to two or more different genera. For example,

1802-409: A reference for designating currently accepted genus names as opposed to others which may be either reduced to synonymy, or, in the case of prokaryotes, relegated to a status of "names without standing in prokaryotic nomenclature". An available (zoological) or validly published (botanical) name that has been historically applied to a genus but is not regarded as the accepted (current/valid) name for

1908-454: A result Antarctica was without ice. The environment was mainly dominated by large dense conifer forests, cycads , and ginkgos. The animals inhabiting Antarctica at this time would still have had to endure long periods of darkness during the winter, much like in modern-day Antarctica. Despite being found in marine sediment, Antarctopelta , like all ankylosaurs, lived on land. Other ankylosaurs have also been found in marine sediments, likely as

2014-599: A result of carcasses washing out to sea. The Antarctic Peninsula, including James Ross Island, was connected to South America throughout this time period, allowing interchange of fauna between both continents. In fact, the recent discovery of the Chilean parankylosaurian Stegouros shows that these dinosaurs inhabited also South America. In the Gamma Member, wood fragments, twigs, and leaves have been found in concretions, some being associated with dinosaur fossils like Antarctopelta itself, and were apparently transported by

2120-431: 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

2226-427: A taxon; however, the names published in suppressed works are made unavailable via the relevant Opinion dealing with the work in question. In botany, similar concepts exist but with different labels. The botanical equivalent of zoology's "available name" is a validly published name . An invalidly published name is a nomen invalidum or nom. inval. ; a rejected name is a nomen rejiciendum or nom. rej. ;

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2332-455: A total of c. 520,000 published names (including synonyms) as at end 2019, increasing at some 2,500 published generic names per year. "Official" registers of taxon names at all ranks, including genera, exist for a few groups only such as viruses and prokaryotes, while for others there are compendia with no "official" standing such as Index Fungorum for fungi, Index Nominum Algarum and AlgaeBase for algae, Index Nominum Genericorum and

2438-586: A variety of other fossils, many of them unique as they evolved in the isolation of Antarctica after the breakup of Gondwana. Antarctopelta coexisted with the ornithopod dinosaur Trinisaura in addition to a menagerie of mosasaurs , plesiosaurs , and sharks . During an expedition to James Ross Island off the coast of Antarctica , an incomplete skeleton of an ankylosaur was discovered by Argentine geologists Eduardo Olivero and Robert Scasso in January 1986. However, excavations would not be finished for

2544-448: 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

2650-399: 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

2756-612: Is discouraged by both the International Code of Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants , there are some five thousand such names in use in more than one kingdom. For instance, A list of generic homonyms (with their authorities), including both available (validly published) and selected unavailable names, has been compiled by the Interim Register of Marine and Nonmarine Genera (IRMNG). The type genus forms

2862-460: 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,

2968-485: Is in stark contrast to genera like Struthiosaurus and Ankylosaurus , which have ratios of 1.35 and 0.78 respectively. Neural canals , the area where the notochord would pass through, in these vertebrae are circular in cross-section and much larger than in Stegouros . Two dorsal vertebrae from the synsacrum were unearthed. Two complete and one incomplete sacral vertebrae , the last of which contains parts of

3074-479: 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

3180-459: 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,

3286-440: 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,

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3392-513: Is named after Eduardo Olivero, who discovered the holotype, first mentioned it in print, and has worked in Antarctica for decades. Like other ankylosaurs, Antarctopelta oliveroi was a stocky, herbivorous quadruped protected by armor plates embedded in the skin. Although a complete skeleton has not been found, the species is estimated to have reached a maximum length of 4 meters (13 feet) from snout to tail tip. In 2010 Gregory Paul gave

3498-423: Is poorly known, but fragments were collected. The distal end of the left femur (thigh bone) was found. An estimate of the femur's total length was made, with an approximation of 30 centimetres (12 in) long. Five metapodials and two phalanges from the manus and possibly pes were also found. Ankylosaurs like Antarctopelta and Stegouros had four digits with four metapodials on the manus and pes. Some of

3604-446: 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

3710-460: Is somewhat arbitrary. Although all species within a genus are supposed to be "similar", there are no objective criteria for grouping species into genera. There is much debate among zoologists about whether enormous, species-rich genera should be maintained, as it is extremely difficult to come up with identification keys or even character sets that distinguish all species. Hence, many taxonomists argue in favor of breaking down large genera. For instance,

3816-448: 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

3922-474: Is the type species , and the generic name is permanently associated with the type specimen of its type species. Should the specimen turn out to be assignable to another genus, the generic name linked to it becomes a junior synonym and the remaining taxa in the former genus need to be reassessed. In zoological usage, taxonomic names, including those of genera, are classified as "available" or "unavailable". Available names are those published in accordance with

4028-470: Is the only known examplar of this genus and species, and was the first dinosaur ever found in Antarctica. It consists of three isolated teeth, part of the lower jaw with another tooth in situ , some other skull fragments, vertebrae of the neck, back, hips and tail, some shoulder and hip bones ( scapula , ilium ) a thigh bone ( femur ), foot and hand bones (five metapodials and two phalanges ), and numerous pieces of armor, representing approximately 15% of

4134-571: 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

4240-621: The International Code of Zoological Nomenclature ; the earliest such name for any taxon (for example, a genus) should then be selected as the " valid " (i.e., current or accepted) name for the taxon in question. Consequently, there will be more available names than valid names at any point in time; which names are currently in use depending on the judgement of taxonomists in either combining taxa described under multiple names, or splitting taxa which may bring available names previously treated as synonyms back into use. "Unavailable" names in zoology comprise names that either were not published according to

4346-824: The International Plant Names Index for plants in general, and ferns through angiosperms, respectively, and Nomenclator Zoologicus and the Index to Organism Names for zoological names. Totals for both "all names" and estimates for "accepted names" as held in the Interim Register of Marine and Nonmarine Genera (IRMNG) are broken down further in the publication by Rees et al., 2020 cited above. The accepted names estimates are as follows, broken down by kingdom: The cited ranges of uncertainty arise because IRMNG lists "uncertain" names (not researched therein) in addition to known "accepted" names;

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4452-409: 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

4558-419: The nomenclature codes , which allow each species a single unique name that, for animals (including protists ), plants (also including algae and fungi ) and prokaryotes ( bacteria and archaea ), is Latin and binomial in form; this contrasts with common or vernacular names , which are non-standardized, can be non-unique, and typically also vary by country and language of usage. Except for viruses ,

4664-404: The platypus belongs to the genus Ornithorhynchus although George Shaw named it Platypus in 1799 (these two names are thus synonyms ) . However, the name Platypus had already been given to a group of ambrosia beetles by Johann Friedrich Wilhelm Herbst in 1793. A name that means two different things is a homonym . Since beetles and platypuses are both members of the kingdom Animalia,

4770-442: The tail vertebrae were elongated and flattened. Its tail likely terminated in an arrangement of spiked osteoderms known as a macuahuitl, which resembled an Aztec weapon of the same name . Osteoderms were present on other parts of the body and came in six different shapes, with some being large and flat while others were tall and keeled. It was discovered in rocks of the Gamma Member of the Snow Hill Island Formation , which bears

4876-490: 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

4982-407: 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

5088-411: 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

5194-426: 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

5300-442: The base for higher taxonomic ranks, such as the family name Canidae ("Canids") based on Canis . However, this does not typically ascend more than one or two levels: the order to which dogs and wolves belong is Carnivora ("Carnivores"). The numbers of either accepted, or all published genus names is not known precisely; Rees et al., 2020 estimate that approximately 310,000 accepted names (valid taxa) may exist, out of

5406-407: The base of the Gamma Member of the Snow Hill Island Formation . It is one of only two major dinosaur-bearing rock formations found on Antarctica, bearing all but two of the continent's named dinosaurs. The floral composition, habitat and climate are similar to modern volcanic arches . During the time in which Antarctopelta lived, Earth's climate was much warmer and more humid than it is today and as

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5512-473: 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

5618-411: 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

5724-399: 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

5830-534: The clade Ericaceae . The Gamma Member of the formation has yielded several other vertebrate remains, such as the ornithopod Trinisaura , a vertebral centrum of a lithostrothian sauropod, an aquatic elasmosaurid , and the carnivorous tylosaurine mosasaurs Taniwhasaurus and Hainosaurus . As for fishes and chondrichthyes , the bony fish Enchodus and Apateodus , an indeterminate ichthyodectiformes , and several sharks such as Sphenodus , Cretalamna , and Notidanodon have been collected. Ammonites ,

5936-451: The continent of Antarctica and its armored nature. Antarctica is derived from the Greek words αντ / ant- ('opposite of') and αρκτος / arktos ('bear' referring to the constellation Ursa Major , which points north). The Greek πελτη / pelte ('shield') is commonly used to name genera of ankylosaurs ( Cedarpelta and Sauropelta , for example). The single known species, A. oliveroi ,

6042-540: 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

6148-690: The description of Stegouros . This clade comprises at least four named species of small ankylosaurs from the Southern Hemisphere, the largest of which is Antarctopelta . The following cladogram is reproduced from the phylogenetic analysis of Soto-Acuña et al. (2021): Lesothosaurus Scutellosaurus Emausaurus Scelidosaurus Huayangosaurus Stegosauridae Kunbarrasaurus Antarctopelta Stegouros Nodosauridae Liaoningosaurus Gobisaurus Shamosaurus Ankylosaurinae In their 2024 redescription of Antarctopelta , Vargas & Kaluza updated

6254-487: The end of the tail in support of a large, bony tail club. Antarctopelta and Stegouros have very similar caudal vertebrae, both having flattened distal centra with a prominent ventral groove. This implies that Antarctopelta also had a macuahuitl , a flat, spiked arrangement of osteoderms on the end of the tail. The name is in reference to the Aztec weapon due to its similar appearance and function. The appendicular skeleton

6360-446: The form "author, year" in zoology, and "standard abbreviated author name" in botany. Thus in the examples above, the genus Canis would be cited in full as " Canis Linnaeus, 1758" (zoological usage), while Hibiscus , also first established by Linnaeus but in 1753, is simply " Hibiscus L." (botanical usage). Each genus should have a designated type , although in practice there is a backlog of older names without one. In zoology, this

6466-506: 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

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6572-737: The generic name (or its abbreviated form) still forms the leading portion of the scientific name, for example, Canis lupus lupus for the Eurasian wolf subspecies, or as a botanical example, Hibiscus arnottianus ssp. immaculatus . Also, as visible in the above examples, the Latinised portions of the scientific names of genera and their included species (and infraspecies, where applicable) are, by convention, written in italics . The scientific names of virus species are descriptive, not binomial in form, and may or may not incorporate an indication of their containing genus; for example,

6678-415: 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

6784-482: 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

6890-429: 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,

6996-633: The largest component, with 23,236 ± 5,379 accepted genus names, of which 20,845 ± 4,494 are angiosperms (superclass Angiospermae). By comparison, the 2018 annual edition of the Catalogue of Life (estimated >90% complete, for extant species in the main) contains currently 175,363 "accepted" genus names for 1,744,204 living and 59,284 extinct species, also including genus names only (no species) for some groups. The number of species in genera varies considerably among taxonomic groups. For instance, among (non-avian) reptiles , which have about 1180 genera,

7102-423: 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

7208-402: The left dentary (lower jaw bone) preserving these teeth was recovered, which has a curved tooth row like other ankylosaurs'. Five cervical vertebrae were found in the field, though three were molded by latex and the originally material was subsequently lost. Their centra are proportionally short with amphicoelus (biconcave) ends, bearing a centrum length to height ratio of only 0.57. This

7314-462: The lizard genus Anolis has been suggested to be broken down into 8 or so different genera which would bring its ~400 species to smaller, more manageable subsets. 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

7420-410: 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

7526-450: The macuahuitl there are no vertebrae, creating a largely fleshy space. The osteoderms are spiked and point outwards in a frond-like pattern, suggesting a defensive function. Earlier work suggested that the holotype was a juvenile based on the fusion of bones. However, a 2019 histological analysis by Argentine paleontologist Ignacio Cerda and colleagues found that the holotype individual was sexually mature . Samples from three osteoderms,

7632-403: 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

7738-413: 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

7844-414: 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

7950-459: 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

8056-467: 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

8162-447: The metapodials may be metatarsals , which are slender like those of Stegouros . Fragments from the scapula (shoulderblade) and ilium were unearthed, though the former bone is notably unfused with the coracoid . This suggests that the individual was immature, though histological analysis contradicts this. Six different types of osteoderms were found along with the skeletal remains of Antarctopelta , but very few were articulated with

8268-403: The most (>300) have only 1 species, ~360 have between 2 and 4 species, 260 have 5–10 species, ~200 have 11–50 species, and only 27 genera have more than 50 species. However, some insect genera such as the bee genera Lasioglossum and Andrena have over 1000 species each. The largest flowering plant genus, Astragalus , contains over 3,000 species. Which species are assigned to a genus

8374-428: The name could not be used for both. Johann Friedrich Blumenbach published the replacement name Ornithorhynchus in 1800. However, a genus in one kingdom is allowed to bear a scientific name that is in use as a generic name (or the name of a taxon in another rank) in a kingdom that is governed by a different nomenclature code. Names with the same form but applying to different taxa are called "homonyms". Although this

8480-486: The phylogenetic matrix of Soto-Acuña et al. (2021) and recovered similar parankylosaurian relationships, with the Argentinian Patagopelta also found in this clade. Antarctopelta , based on phylogenetic bracketing and known material, probably had a macuahuitl like its relative Stegouros . This structure was made up of several fused, flat osteoderms that occupied the end of the tail. Inside much of

8586-411: 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

8692-413: 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

8798-607: 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

8904-541: The provisions of the ICZN Code, e.g., incorrect original or subsequent spellings, names published only in a thesis, and generic names published after 1930 with no type species indicated. According to "Glossary" section of the zoological Code, suppressed names (per published "Opinions" of the International Commission of Zoological Nomenclature) remain available but cannot be used as the valid name for

9010-414: 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

9116-449: The sacrum, were collected as well. These vertebrae are firmly ankylosed (fused) with each other and the sacrum. Elements of the ribs were found attached to the sacrals as well as eight fragments from midsections of ribs. Eight caudal vertebrae are preserved from the middle and distal portions of the tail. The distal caudals are associated with ossified tendons on the upper and lower sides. In ankylosaurids , these tendons help to stiffen

9222-470: The same kind as other (analogous) genera. The term "genus" comes from Latin genus , a noun form cognate with gignere ('to bear; to give birth to'). The Swedish taxonomist Carl Linnaeus popularized its use in his 1753 Species Plantarum , but the French botanist Joseph Pitton de Tournefort (1656–1708) is considered "the founder of the modern concept of genera". The scientific name (or

9328-400: The same ocean currents that brought the dinosaur carcasses. From the Gamma Member, Asteraceae pollen grains were collected that are the oldest records of the family. Some of the environment may have been wet and similar to peat bogs, as evidenced by the presence of Sphagnaceae (peat mosses) and several other groups including the clubmoss Selaginella , the firmoss group Lycopodiaceae , and

9434-408: The scientific epithet) of a genus is also called the generic name ; in modern style guides and science, it is always capitalised. It plays a fundamental role in binomial nomenclature , the system of naming organisms , where it is combined with the scientific name of a species : see Botanical name and Specific name (zoology) . The rules for the scientific names of organisms are laid down in

9540-410: 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

9646-465: The skeleton, so their placement on the body is largely speculative. They included the base of what would have been a large spike. Flat oblong plates resembled the ones that guarded the neck of the nodosaurid Edmontonia rugosidens . Large circular plates were found associated with smaller, polygonal nodules, perhaps forming a shield over the hips as seen in Sauropelta . Another type of osteoderm

9752-415: The skeleton. Although the material had been known for decades and written about in three separate publications, Antarctopelta oliveroi was not named until 2006, by Argentine paleontologists Leonardo Salgado and Zulma Gasparini . It was therefore the second named genus of dinosaur from Antarctica after Cryolophosaurus in 1993, despite being discovered first. The genus name refers to its location on

9858-569: The snout and large furrows on the cingula . Seven to eight mesial denticles are found on each Antarctopelta tooth, the highest number known from Parankylosauria , a trait distinguishing it from the related Stegouros . These teeth are also proportionately large compared to those of other ankylosaurs, with the largest measuring 10 millimetres (0.39 inches) across. This compares to the much larger North American Euoplocephalus , 6–7 m (20–23 ft) in body length, which had teeth averaging only 7.5 mm (0.30 in) across. A fragment from

9964-407: 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

10070-497: The specific name particular to the wolf. A botanical example would be Hibiscus arnottianus , a particular species of the genus Hibiscus native to Hawaii. The specific name is written in lower-case and may be followed by subspecies names in zoology or a variety of infraspecific names in botany . When the generic name is already known from context, it may be shortened to its initial letter, for example, C. lupus in place of Canis lupus . Where species are further subdivided,

10176-412: The standard format for a species name comprises the generic name, indicating the genus to which the species belongs, followed by the specific epithet, which (within that genus) is unique to the species. For example, the gray wolf 's scientific name is Canis lupus , with Canis ( Latin for 'dog') being the generic name shared by the wolf's close relatives and lupus (Latin for 'wolf') being

10282-491: 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

10388-403: The taxon is termed a synonym ; some authors also include unavailable names in lists of synonyms as well as available names, such as misspellings, names previously published without fulfilling all of the requirements of the relevant nomenclatural code, and rejected or suppressed names. A particular genus name may have zero to many synonyms, the latter case generally if the genus has been known for

10494-512: 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

10600-576: The values quoted are the mean of "accepted" names alone (all "uncertain" names treated as unaccepted) and "accepted + uncertain" names (all "uncertain" names treated as accepted), with the associated range of uncertainty indicating these two extremes. Within Animalia, the largest phylum is Arthropoda , with 151,697 ± 33,160 accepted genus names, of which 114,387 ± 27,654 are insects (class Insecta). Within Plantae, Tracheophyta (vascular plants) make up

10706-429: The virus species " Salmonid herpesvirus 1 ", " Salmonid herpesvirus 2 " and " Salmonid herpesvirus 3 " are all within the genus Salmonivirus ; however, the genus to which the species with the formal names " Everglades virus " and " Ross River virus " are assigned is Alphavirus . As with scientific names at other ranks, in all groups other than viruses, names of genera may be cited with their authorities, typically in

10812-499: Was found in 1986, the first dinosaur to be found on the continent, by Argentine geologists Eduardo Olivero and Robert Scasso . The fossils were later described in 2006 by paleontologists Leonardo Salgado and Zulma Gasparini , who named the type species A. oliveroi after Olivero. It was a medium-sized ankylosaur, reaching 4 meters (13 feet) in length or more, and showed characteristics of two different families, making more precise classification difficult for many years. This

10918-443: Was oval-shaped with a keel running down the middle. A few examples of this fifth type were found ossified to the ribs, suggesting that they ran in rows along the flanks of the animal, a very typical pattern among ankylosaurs. The final group consisted mainly of small bony nodules which are often called ossicles , and were probably scattered throughout the body. Several ribs were also found with these ossicles attached. Ankylosaurs were

11024-419: Was theorized that one of the phalanges came from a different individual, though this has been disproven. At this site, the specimen was unearthed with a tooth of the shark Notidanodon , likely due to scavenging, as well as bivalves . This implies that the ankylosaur died and floated out to sea, a phenomenon observed in other ankylosaurs. The holotype (specimen used as the basis for the taxon) MLP 86-X-28-1

11130-489: Was thought to have a clubbed tail like ankylosaurids. It had been designated as Ankylosauria incertae sedis before being subjected to a phylogenetic analysis . Later, in 2011 a phylogenetic analysis performed by Thompson and colleagues suggested that Antarctopelta was the basalmost known nodosaurid . In 2021, Sergio Soto-Acuña and colleagues described a new group of ankylosaurs, the Parankylosauria , with

11236-420: Was until 2021, when a nearly complete skeleton of the similar Chilean genus Stegouros was described. This led to the recognition of Parankylosauria, containing Antarctopelta , Stegouros , and Kunbarrasaurus . The head was small, with proportionally large teeth compared to other ankylosaurs' and spikes above the orbits . The neck and back vertebrae were short and circular in cross-section , whereas

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