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65-691: Tyrannosauroidea (meaning 'tyrant lizard forms') is a superfamily (or clade ) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period . By the end of the Cretaceous Period , tyrannosauroids were the dominant large predators in the Northern Hemisphere , culminating in

130-499: A BioCode that would regulate all taxon names, but this attempt has so far failed because of firmly entrenched traditions in each community. Consider a particular species, the red fox , Vulpes vulpes : in the context of the Zoological Code , the specific epithet vulpes (small v ) identifies a particular species in the genus Vulpes (capital V ) which comprises all the "true" foxes. Their close relatives are all in

195-420: A "hybrid formula" that specifies the parentage, or may be given a name. For hybrids receiving a hybrid name , the same ranks apply, prefixed with notho (Greek: 'bastard'), with nothogenus as the highest permitted rank. If a different term for the rank was used in an old publication, but the intention is clear, botanical nomenclature specifies certain substitutions: Classifications of five species follow:

260-497: A basal tyrannosauroid as well, slightly more distantly related to Tyrannosauridae than Eotyrannus and Appalachiosaurus . Alectrosaurus , a poorly known genus from Mongolia, is definitely a tyrannosauroid but its exact relationships are unclear. Other taxa have been considered possible tyrannosauroids by various authors, including Bagaraatan and Labocania . Siamotyrannus from the Early Cretaceous of Thailand

325-567: A fast evolutionary radiation that occurred long ago, such as the main taxa of placental mammals . In his landmark publications, such as the Systema Naturae , Carl Linnaeus used a ranking scale limited to kingdom, class, order, genus, species, and one rank below species. Today, the nomenclature is regulated by the nomenclature codes . There are seven main taxonomic ranks: kingdom, phylum or division, class, order, family, genus, and species. In addition, domain (proposed by Carl Woese )

390-638: A lower level may be denoted by adding the prefix " infra ", meaning lower , to the rank. For example, infra order (below suborder) or infra family (below subfamily). Botanical ranks categorize organisms based (often) on their relationships ( monophyly is not required by that clade, which does not even mention this word, nor that of " clade "). They start with Kingdom, then move to Division (or Phylum), Class, Order, Family, Genus, and Species. Taxa at each rank generally possess shared characteristics and evolutionary history. Understanding these ranks aids in taxonomy and studying biodiversity. There are definitions of

455-490: A more recent common ancestor with Tyrannosaurus rex than with neornithean birds . To make the family more exclusive, Thomas Holtz redefined it in 2004 to include all species more closely related to Tyrannosaurus rex than to Ornithomimus velox , Deinonychus antirrhopus or Allosaurus fragilis . Sereno published a new definition in 2005, using Ornithomimus edmontonicus , Velociraptor mongoliensis and Troodon formosus as external specifiers. The Sereno definition

520-399: A new rank at will, at any time, if they feel this is necessary. In doing so, there are some restrictions, which will vary with the nomenclature code that applies. The following is an artificial synthesis, solely for purposes of demonstration of absolute rank (but see notes), from most general to most specific: Ranks are assigned based on subjective dissimilarity, and do not fully reflect

585-459: A particular organism, it is usually not necessary to specify names at ranks other than these first two, within a set of taxa covered by a given rank-based code. However, this is not true globally because most rank-based codes are independent from each other, so there are many inter-code homonyms (the same name used for different organisms, often for an animal and for a taxon covered by the botanical code). For this reason, attempts were made at creating

650-534: A phylogenetic analysis of Tyrannosauroidea which incorporated taxa from the ancient continent of Gondwana (which today consists of the southern hemisphere), such as Santanaraptor and Timimus , whose placement in the group has been controversial. They have found that not only Santanaraptor and Timimus were placed as tyrannosaurs more derived than Dilong , but they have found in their analysis that tyrannosauroids were widespread in Laurasia and Gondwana since

715-558: A prominent ridge on the surangular bone extends sideways from just below the jaw joint, except in the basal Guanlong . Tyrannosauroids had S -shaped necks and long tails, as did most other theropods. Early genera had long forelimbs, about 60% the length of the hindlimb in Guanlong , with the typical three digits of coelurosaurs. The long forelimb persisted at least through the Early Cretaceous Eotyrannus , but

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780-477: A synapomorphy is the marker for the most recent common ancestor of the monophyletic group consisting of a set of taxa in a cladogram. What counts as a synapomorphy for one clade may well be a primitive character or plesiomorphy at a less inclusive or nested clade. For example, the presence of mammary glands is a synapomorphy for mammals in relation to tetrapods but is a symplesiomorphy for mammals in relation to one another—rodents and primates, for example. So

845-576: A taxon in a category above the species level). It should be a natural group (that is, non-artificial, non- polyphyletic ), as judged by a biologist, using all the information available to them. Equally ranked higher taxa in different phyla are not necessarily equivalent in terms of time of origin, phenotypic distinctiveness or number of lower-ranking included taxa (e.g., it is incorrect to assume that families of insects are in some way evolutionarily comparable to families of mollusks). Of all criteria that have been advocated to rank taxa, age of origin has been

910-564: Is also called a binomial , that is, a two-term name. For example, the zoological name for the human species is Homo sapiens . This is usually italicized in print or underlined when italics are not available. In this case, Homo is the generic name and it is capitalized; sapiens indicates the species and it is not capitalized. While not always used, some species include a subspecific epithet. For instance, modern humans are Homo sapiens sapiens , or H. sapiens sapiens . In zoological nomenclature, higher taxon names are normally not italicized, but

975-493: Is derived from the Greek ειδος eidos ('form'). Scientists have commonly understood Tyrannosauroidea to include the tyrannosaurids and their immediate ancestors. With the advent of phylogenetic taxonomy in vertebrate paleontology, however, the clade has received several more explicit definitions. The first was by Paul Sereno in 1998, where Tyrannosauroidea was defined as a stem-based taxon including all species sharing

1040-467: Is not a requirement of the zoological and botanical codes. A classification in which all taxa have formal ranks cannot adequately reflect knowledge about phylogeny. Since taxon names are dependent on ranks in rank-based (Linnaean) nomenclature, taxa without ranks cannot be given names. Alternative approaches, such as phylogenetic nomenclature , as implemented under the PhyloCode and supported by

1105-435: Is now widely used as a fundamental rank, although it is not mentioned in any of the nomenclature codes, and is a synonym for dominion ( Latin : dominium ), introduced by Moore in 1974. A taxon is usually assigned a rank when it is given its formal name. The basic ranks are species and genus. When an organism is given a species name it is assigned to a genus, and the genus name is part of the species name. The species name

1170-402: Is the relative or absolute level of a group of organisms (a taxon ) in a hierarchy that reflects evolutionary relationships. Thus, the most inclusive clades (such as Eukarya and Opisthokonta ) have the highest ranks, whereas the least inclusive ones (such as Homo sapiens or Bufo bufo ) have the lowest ranks. Ranks can be either relative and be denoted by an indented taxonomy in which

1235-622: Is unknown in Appalachiosaurus . Derived tyrannosaurids have forelimbs strongly reduced in size, the most extreme example being Tarbosaurus from Mongolia , where the humerus was only one-quarter the length of the femur . The third digit of the forelimb was also reduced over time. This digit was unreduced in the basal Guanlong , while in Dilong it was more slender than the other two digits. Eotyrannus also had three functional digits on each hand. Tyrannosaurids had only two, although

1300-439: Is usually associated with a certain body plan , which is also, however, an arbitrary criterion. Enigmatic taxa are taxonomic groups whose broader relationships are unknown or undefined. (See Incertae sedis .) There are several acronyms intended to help memorise the taxonomic hierarchy, such as "King Phillip came over for great spaghetti". (See taxonomy mnemonic .) Synapomorphy Examples of apomorphy are

1365-411: Is very tall, blunting the front of the snout, a feature which evolved convergently in abelisaurids . The nasal bones are characteristically fused, arched slightly upwards and often very roughly textured on their upper surface. The premaxillary teeth at the front of the upper jaw are shaped differently from the rest of the teeth, smaller in size and with a D -shaped cross section . In the lower jaw ,

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1430-557: The Ancient Greek words σύν ( sún ), meaning "with, together"; ἀπό ( apó ), meaning "away from"; and μορφή ( morphḗ ), meaning "shape, form". Lampreys and sharks share some features, like a nervous system, that are not synapomorphic because they are also shared by invertebrates . In contrast, the presence of jaws and paired appendages in both sharks and dogs, but not in lampreys or close invertebrate relatives, identifies these traits as synapomorphies. This supports

1495-789: The Botanical Code , the Prokaryotic Code , the Code for Viruses , the draft BioCode and the PhyloCode all recommend italicizing all taxon names (of all ranks). There are rules applying to the following taxonomic ranks in the International Code of Zoological Nomenclature : superfamily, family, subfamily, tribe, subtribe, genus, subgenus, species, subspecies. The International Code of Zoological Nomenclature divides names into "family-group names", "genus-group names" and "species-group names". The Code explicitly mentions

1560-483: The International Society for Phylogenetic Nomenclature , or using circumscriptional names , avoid this problem. The theoretical difficulty with superimposing taxonomic ranks over evolutionary trees is manifested as the boundary paradox which may be illustrated by Darwinian evolutionary models. There are no rules for how many species should make a genus, a family, or any other higher taxon (that is,

1625-558: The PhyloCode , the code of phylogenetic nomenclature , does not require absolute ranks. Taxa are hierarchical groups of organisms, and their ranks describes their position in this hierarchy. High-ranking taxa (e.g. those considered to be domains or kingdoms, for instance) include more sub-taxa than low-ranking taxa (e.g. those considered genera, species or subspecies). The rank of these taxa reflects inheritance of traits or molecular features from common ancestors. The name of any species and genus are basic ; which means that to identify

1690-504: The acetabulum (hip socket), and a huge "boot" on the end of the pubis , more than half as long as the shaft of the pubis itself. These features are found in all known tyrannosauroids, including basal members Guanlong and Dilong . The pubis is not known in Aviatyrannis or Stokesosaurus but both show typical tyrannosauroid characters in the ilium. The hindlimbs of all tyrannosauroids, like most theropods, had four toes, although

1755-427: The fruit fly familiar in genetics laboratories ( Drosophila melanogaster ), humans ( Homo sapiens ), the peas used by Gregor Mendel in his discovery of genetics ( Pisum sativum ), the "fly agaric" mushroom Amanita muscaria , and the bacterium Escherichia coli . The eight major ranks are given in bold; a selection of minor ranks are given as well. Taxa above the genus level are often given names based on

1820-452: The largest land-based predators ever to exist , but most of these later genera had proportionately small forelimbs with only two digits. Primitive feathers have been identified in fossils of two species and may have been present in other tyrannosauroids as well. Prominent bony crests in a variety of shapes and sizes on the skulls of many tyrannosauroids may have served display functions. Tyrannosauroids varied widely in size, although there

1885-472: The sister group of Tyrannosauroidea. The most basal tyrannosauroid known from complete skeletal remains is Guanlong, a representative of the family Proceratosauridae . Other early taxa include Stokesosaurus and Aviatyrannis , known from far less complete material. The better-known Dilong is considered slightly more derived than Guanlong and Stokesosaurus . Dryptosaurus , long a difficult genus to classify, has turned up in several recent analyses as

1950-418: The type genus , with a standard termination. The terminations used in forming these names depend on the kingdom (and sometimes the phylum and class) as set out in the table below. Pronunciations given are the most Anglicized . More Latinate pronunciations are also common, particularly / ɑː / rather than / eɪ / for stressed a . There is an indeterminate number of ranks, as a taxonomist may invent

2015-414: The vestigial metacarpal of the third are preserved in some well-preserved specimens. As in most coelurosaurs, the second digit of the hand is the largest, even when the third digit is not present. Characteristic features of the tyrannosauroid pelvis include a concave notch at the upper front end of the ilium , a sharply defined vertical ridge on the outside surface of the ilium, extending upwards from

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2080-633: The American Ornithologists' Union published in 1886 states "No one appears to have suspected, in 1842 [when the Strickland code was drafted], that the Linnaean system was not the permanent heritage of science, or that in a few years a theory of evolution was to sap its very foundations, by radically changing men's conceptions of those things to which names were to be furnished." Such ranks are used simply because they are required by

2145-465: The Coelurosauria, echoing suggestions first published in the 1920s. Tyrannosaurids are now universally considered to be large coelurosaurs. In 1994, Holtz grouped tyrannosauroids with elmisaurids , ornithomimosaurs and troodonts into a coelurosaurian clade called Arctometatarsalia based on a common ankle structure where the second and fourth metatarsals meet near the tarsal bones, covering

2210-482: The Middle Jurassic. They have proposed new subclade names for Tyrannosaurioidea. The first is Pantyrannosauria referring to all non-proceratosaurid members of the group, while Eutyrannosauria for larger tyrannosaur taxa found in the northern hemisphere such as Dryptosaurus , Appalachiosaurus , Bistahieversor , and Tyrannosauridae. Below is their phylogeographic tree they have recovered, in which displays

2275-619: The Tyrannosaurs to be sister taxa to the Maniraptora with them being closer to birds than Ornithomimosaurs were. He called this group Tyrannoraptora (which in the absence of papers that recover a Tyrannosaur-maniraptoran clade), is a clade which contains most Coelurosaurs. A 2007 analysis found the family Coeluridae , including the Late Jurassic North American genera Coelurus and Tanycolagreus , to be

2340-531: The concept can be understood as well in terms of "a character newer than" ( autapomorphy ) and "a character older than" ( plesiomorphy ) the apomorphy: mammary glands are evolutionarily newer than vertebral column, so mammary glands are an autapomorphy if vertebral column is an apomorphy, but if mammary glands are the apomorphy being considered then vertebral column is a plesiomorphy. These phylogenetic terms are used to describe different patterns of ancestral and derived character or trait states as stated in

2405-432: The family Canidae , which includes dogs, wolves, jackals, and all foxes; the next higher major taxon, Carnivora (considered an order), includes caniforms (bears, seals, weasels, skunks, raccoons and all those mentioned above), and feliforms (cats, civets, hyenas, mongooses). Carnivorans are one group of the hairy, warm-blooded, nursing members of the class Mammalia , which are classified among animals with notochords in

2470-461: The family Tyrannosauridae, its ancestry has been the subject of much debate. For most of the twentieth century, tyrannosaurids were commonly accepted as members of the Carnosauria , which included almost all large theropods. Within this group, the allosaurids were often considered to be ancestral to tyrannosaurids. In the early 1990s, cladistic analyses instead began to place tyrannosaurids into

2535-405: The first toe (the hallux ) did not contact the ground. Tyrannosauroid hindlimbs are longer relative to body size than almost any other theropods, and show proportions characteristic of fast-running animals, including elongated tibiae and metatarsals . These proportions persist even in the largest adult Tyrannosaurus , despite its probable inability to run. The third metatarsal of tyrannosaurids

2600-599: The following ranks for these categories: The rules in the Code apply to the ranks of superfamily to subspecies, and only to some extent to those above the rank of superfamily. Among "genus-group names" and "species-group names" no further ranks are officially allowed, which creates problems when naming taxa in these groups in speciose clades, such as Rana . Zoologists sometimes use additional terms such as species group , species subgroup , species complex and superspecies for convenience as extra, but unofficial, ranks between

2665-464: The following taxonomic categories in the International Code of Nomenclature for Cultivated Plants : cultivar group , cultivar , grex . The rules in the ICN apply primarily to the ranks of family and below, and only to some extent to those above the rank of family. (See also descriptive botanical name .) Taxa at the rank of genus and above have a botanical name in one part (unitary name); those at

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2730-584: The gigantic Tyrannosaurus . Fossils of tyrannosauroids have been recovered on what are now the continents of North America, Europe and Asia, with fragmentary remains possibly attributable to tyrannosaurs also known from South America and Australia. Tyrannosauroids were bipedal carnivores , as were most theropods, and were characterized by numerous skeletal features , especially of the skull and pelvis . Early in their existence, tyrannosauroids were small predators with long, three-fingered forelimbs. Late Cretaceous genera became much larger, including some of

2795-480: The gradational nature of variation within nature. These problems were already identified by Willi Hennig , who advocated dropping them in 1969, and this position gathered support from Graham C. D. Griffiths only a few years later. In fact, these ranks were proposed in a fixist context and the advent of evolution sapped the foundations of this system, as was recognised long ago; the introduction of The Code of Nomenclature and Check-list of North American Birds Adopted by

2860-434: The hierarchy of taxa (hence, their ranks) does not necessarily reflect the hierarchy of clades . While older approaches to taxonomic classification were phenomenological, forming groups on the basis of similarities in appearance, organic structure and behavior, two important new methods developed in the second half of the 20th century changed drastically taxonomic practice. One is the advent of cladistics , which stemmed from

2925-510: The hypothesis that dogs and sharks are more closely related to each other than to lampreys. The concept of synapomorphy depends on a given clade in the tree of life. Cladograms are diagrams that depict evolutionary relationships within groups of taxa. These illustrations are accurate predictive device in modern genetics. They are usually depicted in either tree or ladder form. Synapomorphies then create evidence for historical relationships and their associated hierarchical structure. Evolutionarily,

2990-496: The level of indentation reflects the rank, or absolute, in which various terms, such as species , genus , family , order , class , phylum , kingdom , and domain designate rank. This page emphasizes absolute ranks and the rank-based codes (the Zoological Code , the Botanical Code , the Code for Cultivated Plants , the Prokaryotic Code , and the Code for Viruses ) require them. However, absolute ranks are not required in all nomenclatural systems for taxonomists; for instance,

3055-485: The lineage. An immature Eotyrannus was over 4 meters (13 feet) in length, and a subadult Appalachiosaurus was estimated at more than 6 meters (20 feet) long, indicating that both genera reached larger sizes. The Late Cretaceous tyrannosaurids ranged from the 9 meters (30 feet) Albertosaurus and Gorgosaurus to Tyrannosaurus , which exceeded 12 meters (39 feet) in length and may have weighed more than 6,400  kilograms (7  short tons ). A 2010 review of

3120-490: The literature concluded that tyrannosaurs were "small- to mid-sized" for their first 80 million years but were "some of the largest terrestrial carnivores to ever live" in their last 20 million years. Skulls of early tyrannosauroids were long, low and lightly constructed, similar to other coelurosaurs, while later forms had taller and more massive skulls. Despite the differences in form, certain skull features are found in all known tyrannosauroids. The premaxillary bone

3185-405: The most basic (or important) is the species, but this opinion is not universally shared. Thus, species are not necessarily more sharply defined than taxa at any other rank, and in fact, given the phenotypic gaps created by extinction, in practice, the reverse is often the case. Ideally, a taxon is intended to represent a clade , that is, the phylogeny of the organisms under discussion, but this

3250-409: The most frequently advocated. Willi Hennig proposed it in 1966, but he concluded in 1969 that this system was unworkable and suggested dropping absolute ranks. However, the idea of ranking taxa using the age of origin (either as the sole criterion, or as one of the main ones) persists under the name of time banding, and is still advocated by several authors. For animals, at least the phylum rank

3315-413: The phylogenetic relationships of the taxa as well as the continents those taxa have been found. Guanlong wucaii [REDACTED] Proceratosaurus bradleyi [REDACTED] Taxonomic rank In biology , taxonomic rank (which some authors prefer to call nomenclatural rank because ranking is part of nomenclature rather than taxonomy proper, according to some definitions of these terms)

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3380-479: The phylum Chordata , and with them among all animals in the kingdom Animalia . Finally, at the highest rank all of these are grouped together with all other organisms possessing cell nuclei in the domain Eukarya . The International Code of Zoological Nomenclature defines rank as: "The level, for nomenclatural purposes, of a taxon in a taxonomic hierarchy (e.g. all families are for nomenclatural purposes at

3445-492: The presence of erect gait , fur , the evolution of three middle ear bones , and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles , which have retained their ancestral traits of a sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. The word synapomorphy —coined by German entomologist Willi Hennig —is derived from

3510-455: The rank of species and above (but below genus) have a botanical name in two parts ( binary name ); all taxa below the rank of species have a botanical name in three parts (an infraspecific name ). To indicate the rank of the infraspecific name, a "connecting term" is needed. Thus Poa secunda subsp. juncifolia , where "subsp". is an abbreviation for "subspecies", is the name of a subspecies of Poa secunda . Hybrids can be specified either by

3575-653: The rank-based codes; because of this, some systematists prefer to call them nomenclatural ranks . In most cases, higher taxonomic groupings arise further back in time, simply because the most inclusive taxa necessarily appeared first. Furthermore, the diversity in some major taxa (such as vertebrates and angiosperms ) is better known that that of others (such as fungi , arthropods and nematodes ) not because they are more diverse than other taxa, but because they are more easily sampled and studied than other taxa, or because they attract more interest and funding for research. Of these many ranks, many systematists consider that

3640-1298: The right is a cladogram of Eutyrannosauria from a 2020 study by Jared T. Voris and colleagues on the genus Thanatotheristes : Juratyrant [REDACTED] Stokesosaurus [REDACTED] Dilong Guanlong [REDACTED] Proceratosaurus Sinotyrannus [REDACTED] Yutyrannus [REDACTED] Xiongguanlong [REDACTED] Aniksosaurus Fukuiraptor Australovenator [REDACTED] Orkoraptor [REDACTED] Dryptosaurus [REDACTED] Bistahieversor Tyrannosauridae [REDACTED] Dryptosaurus aquilunguis [REDACTED] Appalachiosaurus montgomeriensis [REDACTED] Bistahieversor sealeyi Gorgosaurus libratus [REDACTED] Albertosaurus sarcophagus Qianzhousaurus sinensis Alioramus remotus Alioramus altai [REDACTED] Teratophoneus curriei Dynamoterror dynastes Lythronax argestes [REDACTED] Nanuqsaurus hoglundi Thanatotheristes degrootorum Daspletosaurus torosus [REDACTED] Daspletosaurus horneri Zhuchengtyrannus magnus Tarbosaurus bataar [REDACTED] Tyrannosaurus rex [REDACTED] In 2018 authors Rafael Delcourt and Orlando Nelson Grillo published

3705-468: The same rank, which lies between superfamily and subfamily)." Note that the discussions on this page generally assume that taxa are clades ( monophyletic groups of organisms), but this is required neither by the International Code of Zoological Nomenclature nor by the Botanical Code , and some experts on biological nomenclature do not think that this should be required, and in that case,

3770-485: The subgenus and species levels in taxa with many species, e.g. the genus Drosophila . (Note the potentially confusing use of "species group" as both a category of ranks as well as an unofficial rank itself. For this reason, Alain Dubois has been using the alternative expressions "nominal-series", "family-series", "genus-series" and "species-series" (among others) at least since 2000. ) At higher ranks (family and above)

3835-487: The third metatarsal when viewed from the front. Basal tyrannosauroids like Dilong , however, were found with non- arctometatarsalian ankles, indicating that this feature evolved convergently. Arctometatarsalia has been dismantled and is no longer used by most paleontologists, with tyrannosauroids usually considered to be basal coelurosaurs outside Maniraptoriformes . While many place tyrannosauroids as basal coelurosaurs, Paul Sereno in his 1990s analysis of theropods would find

3900-727: The works of the German entomologist Willi Hennig . Cladistics is a method of classification of life forms according to the proportion of characteristics that they have in common (called synapomorphies ). It is assumed that the higher the proportion of characteristics that two organisms share, the more recently they both came from a common ancestor. The second one is molecular systematics, based on genetic analysis , which can provide much additional data that prove especially useful when few phenotypic characters can resolve relationships, as, for instance, in many viruses , bacteria and archaea , or to resolve relationships between taxa that arose in

3965-464: Was a general trend towards increasing size over time. Early tyrannosauroids were small animals. One specimen of Dilong , almost fully grown, measured 1.6 meters (5.2 feet) in length, and a fully grown Guanlong measured 3 meters (9.8 feet) long. Teeth from Lower Cretaceous rocks (140 to 136 million years old) of Hyogo , Japan , appear to have come from an approximately 5 metres (16 ft) long animal, possibly indicating an early size increase in

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4030-548: Was adopted in a 2010 review. Some studies have suggested that the clade Megaraptora , usually considered to be allosauroids , are basal tyrannosauroids. However, other authors disputed the placement of megaraptorans within Tyrannosauroidea, and a study of megaraptoran hand anatomy published in 2016 caused even the original scientists suggesting their tyrannosauroid relationships to at least partly reject their prior conclusion. While paleontologists have long recognized

4095-469: Was named by Henry Fairfield Osborn in 1905, along with the family Tyrannosauridae. The name is derived from the Ancient Greek words τυραννος tyrannos ('tyrant') and σαυρος sauros ('lizard'). The superfamily name Tyrannosauroidea was first published in a 1964 paper by the British paleontologist Alick Walker . The suffix -oidea , commonly used in the name of animal superfamilies,

4160-430: Was originally described as an early tyrannosaurid, but is usually considered a carnosaur today. Iliosuchus has a vertical ridge on the ilium reminiscent of tyrannosauroids and may in fact be the earliest known member of the superfamily, but not enough material is known to be sure. Below on the left is a cladogram of Tyrannosauroidea from a 2022 study by Darren Naish and Andrea Cau on the genus Eotyrannus , and on

4225-511: Was pinched at the top between the second and fourth, forming a structure known as the arctometatarsus . The arctometatarsus was also present in Appalachiosaurus but it is unclear whether it was found in Eotyrannus or Dryptosaurus . This structure was shared by derived ornithomimids , troodontids and caenagnathids , but was not present in basal tyrannosauroids like Dilong paradoxus , indicating convergent evolution . Tyrannosaurus

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