89-516: Neornithischia ("new ornithischians") is a clade of the dinosaur order Ornithischia . It is the sister group of the Thyreophora within the clade Genasauria . Neornithischians are united by having a thicker layer of asymmetrical enamel on the inside of their lower teeth. The teeth wore unevenly with chewing and developed sharp ridges that allowed neornithischians to break down tougher plant food than other dinosaurs. Neornithischians include
178-534: A clade (from Ancient Greek κλάδος (kládos) 'branch'), also known as a monophyletic group or natural group , is a grouping of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree . In the taxonomical literature, sometimes the Latin form cladus (plural cladi ) is used rather than the English form. Clades are
267-520: A rib . In 2007, Gregory S. Paul split I. atherfieldensis into a new, separate genus, Mantellisaurus which has been generally accepted. In 2009 fragmentary iguanodontid material was described from upper Barremian Paris Basin deposits in Auxerre , Burgundy . While not definitively diagnosable to the genus/species level, the specimen shares "obvious morphological and dimensional affinities" with I. bernissartensis. In 2010, David Norman split
356-479: A "ladder", with supposedly more "advanced" organisms at the top. Taxonomists have increasingly worked to make the taxonomic system reflect evolution. When it comes to naming , this principle is not always compatible with the traditional rank-based nomenclature (in which only taxa associated with a rank can be named) because not enough ranks exist to name a long series of nested clades. For these and other reasons, phylogenetic nomenclature has been developed; it
445-623: A clade can be described based on two different reference points, crown age and stem age. The crown age of a clade refers to the age of the most recent common ancestor of all of the species in the clade. The stem age of a clade refers to the time that the ancestral lineage of the clade diverged from its sister clade. A clade's stem age is either the same as or older than its crown age. Ages of clades cannot be directly observed. They are inferred, either from stratigraphy of fossils , or from molecular clock estimates. Viruses , and particularly RNA viruses form clades. These are useful in tracking
534-517: A combination of alcohol , arsenic , and 390 kilograms of shellac . This combination was intended to simultaneously penetrate the fossils (with alcohol), prevent the development of mold (with arsenic), and harden them (with shellac). The fossils entered a third round of conservation from 2003 until May 2007, when the shellac, hide glue and gelatine were removed and impregnated with polyvinyl acetate and cyanoacrylate and epoxy glues. Modern treatments of this problem typically involve either monitoring
623-463: A final layer of tin foil . Damage was repaired with papier-mâché . This treatment had the unintended effect of sealing in moisture and extending the period of damage. In 1932 museum director Victor van Straelen decided that the specimens had to be completely restored again to safeguard their preservation. From December 1935 to August 1936 the staff at the museum in Brussels treated the problem with
712-460: A firm creationist , opposed the early versions of evolutionary science (" transmutationism ") then being debated and used what he would soon coin as dinosaurs as a weapon in this conflict. With the paper describing Dinosauria, he scaled down dinosaurs from lengths of over 61 metres (200 feet), determined that they were not simply giant lizards, and put forward that they were advanced and mammal-like, characteristics given to them by God ; according to
801-478: A giant crocodile . In 1821 Mantell mentioned the find of herbivorous teeth and began to consider the possibility that a large herbivorous reptile was present in the strata. However, in his 1822 publication Fossils of the South Downs he as yet did not dare to suggest a connection between the teeth and his very incomplete skeleton, presuming that his finds presented two large forms, one carnivorous ("an animal of
890-667: A giant herbivore. In a new edition that year of his Recherches sur les Ossemens Fossiles Cuvier admitted his earlier mistake, leading to an immediate acceptance of Mantell, and his new saurian, in scientific circles. Mantell tried to corroborate his theory further by finding a modern-day parallel among extant reptiles. In September 1824 he visited the Royal College of Surgeons but at first failed to find comparable teeth. However, assistant-curator Samuel Stutchbury recognised that they resembled those of an iguana he had recently prepared, albeit twenty times longer. In recognition of
979-587: A lifelike pose could be achieved during the mounting process. This specimen, along with several others, first opened for public viewing in an inner courtyard of the palace in July 1883. In 1891 they were moved to the Royal Museum of Natural History , where they are still on display; nine are displayed as standing mounts, and nineteen more are still in the Museum's basement. The exhibit makes an impressive display in
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#17327906754821068-606: A name for the fossil creature. The letter was read to members of the Society at a meeting on 17 December, and a report was published in the Hampshire Telegraph the following Monday, 20 December, which announced the name, misspelled as "Iguanadon". Mantell formally published his findings on 10 February 1825, when he presented a paper on the remains to the Royal Society of London . A more complete specimen of
1157-645: A new genus Delapparentia was named for a specimen in Spain that was originally thought to belong to I. bernissartensis . The previous identification was subsequently reaffirmed in a new analysis of individual variation in the Belgian specimens, finding that the Delapparentia specimen was within the range of I. bernissartensis . In 2015 a new species of Iguanodon , I. galvensis , was named based on material including 13 juvenile ( perinate ) individuals found in
1246-480: A quadruped, the animal's hands would have been held so that the palms faced each other, as shown by iguanodontian trackways and the anatomy of this genus's arms and hands. The three-toed pes ( foot ) of Iguanodon was relatively long, and when walking, both the hand and the foot would have been used in a digitigrade fashion (walking on the fingers and toes). The maximum speed of Iguanodon has been estimated at 24 km/h (15 mph), which would have been as
1335-422: A revised taxonomy based on a concept strongly resembling clades, although the term clade itself would not be coined until 1957 by his grandson, Julian Huxley . German biologist Emil Hans Willi Hennig (1913–1976) is considered to be the founder of cladistics . He proposed a classification system that represented repeated branchings of the family tree, as opposed to the previous systems, which put organisms on
1424-546: A rhinoceros. Though the very next day Cuvier retracted, Lyell reported only the dismissal to Mantell, who became rather diffident about the issue. In 1824 Buckland described Megalosaurus and was on that occasion invited to visit Mantell's collection. Seeing the bones on 6 March he agreed that these were of some giant saurian—though still denying it was a herbivore. Emboldened nevertheless, Mantell again sent some teeth to Cuvier, who answered on 22 June 1824 that he had determined that they were reptilian and quite possibly belonged to
1513-587: A rough margin that was likely covered and lengthened by a keratinous material to form a cropping beak for biting off twigs and shoots . Its food gathering would have been aided by its flexible little finger, which could have been used to manipulate objects, unlike the other fingers. Exactly what Iguanodon ate with its well-developed jaws is not known. The size of the larger species, such as I. bernissartensis , would have allowed them access to food from ground level to tree foliage at 4–5 metres (13–16 ft) high. A diet of horsetails , cycads , and conifers
1602-457: A similar animal was discovered in a quarry in Maidstone , Kent , in 1834 (lower Lower Greensand Formation), which Mantell soon acquired. He was led to identify it as an Iguanodon based on its distinctive teeth. The Maidstone slab (NHMUK PV OR 3791) was used in the first skeletal reconstructions and artistic renderings of Iguanodon , but due to its incompleteness, Mantell made some mistakes,
1691-429: A suffix added should be e.g. "dracohortian". A clade is by definition monophyletic , meaning that it contains one ancestor which can be an organism, a population, or a species and all its descendants. The ancestor can be known or unknown; any and all members of a clade can be extant or extinct. The science that tries to reconstruct phylogenetic trees and thus discover clades is called phylogenetics or cladistics ,
1780-683: A topic of study as new species are named or long-standing ones reassigned to other genera. In 1878 new, far more complete remains of Iguanodon were discovered in Belgium and studied by Louis Dollo . These were given the new species I. bernissartensis. In the early 21st century it became understood that the remains referred to as Iguanodon in England belonged to four different species (including I. bernissartensis ) that were not closely related to each other, which were subsequently split off into Mantellisaurus , Barilium and Hypselospinus . It
1869-509: A variety of basal forms historically known as " hypsilophodonts ", including the Thescelosauridae . As these taxa do not all form a monophyletic clade, the term 'small-bodied early diverging ornithischian' (SBEDO) has been used to refer to these as a collective group. In addition, there are derived forms classified in the groups Marginocephalia and Ornithopoda . The former includes clades Pachycephalosauria and Ceratopsia , while
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#17327906754821958-752: Is a genus of iguanodontian dinosaur . While many species found worldwide have been classified in the genus Iguanodon , dating from the Late Jurassic to Early Cretaceous , taxonomic revision in the early 21st century has defined Iguanodon to be based on one well-substantiated species: I. bernissartensis , which lived during the Barremian to early Aptian ages of the Early Cretaceous in Belgium , Germany , England , and Spain , between about 126 and 122 million years ago. Iguanodon
2047-499: Is also used with a similar meaning in other fields besides biology, such as historical linguistics ; see Cladistics § In disciplines other than biology . The term "clade" was coined in 1957 by the biologist Julian Huxley to refer to the result of cladogenesis , the evolutionary splitting of a parent species into two distinct species, a concept Huxley borrowed from Bernhard Rensch . Many commonly named groups – rodents and insects , for example – are clades because, in each case,
2136-674: Is estimated to have measured about 9 metres (30 feet) long as an adult, with some specimens possibly as long as 13 metres (43 feet), although this is likely an overestimate, given that the maximum body length of I. bernissartensis is reported to be 11 m (36 ft). Although Gregory S. Paul suggested a body mass of 3.08 metric tons (3.40 short tons) on average, constructing a 3D mathematical model and employing allometry -based estimate suggests an I. bernissartensis close to 8 m (26 ft) long (smaller than average) weighs close to 3.8 metric tons (4.2 short tons) in body mass. Specimens of relatively large individuals have been reported in
2225-476: Is in turn included in the mammal, vertebrate and animal clades. The idea of a clade did not exist in pre- Darwinian Linnaean taxonomy , which was based by necessity only on internal or external morphological similarities between organisms. Many of the better known animal groups in Linnaeus's original Systema Naturae (mostly vertebrate groups) do represent clades. The phenomenon of convergent evolution
2314-417: Is not conclusive, though. Whatever its exact diet, due to its size and abundance, Iguanodon is regarded as a dominant medium to large herbivore for its ecological communities . In England, this included the small predator Aristosuchus , larger predators Eotyrannus , Baryonyx , and Neovenator , low-feeding herbivores Hypsilophodon and Valdosaurus , fellow "iguanodontid" Mantellisaurus ,
2403-494: Is not on display. The fossil arrived in New Zealand following the move of Gideon Mantell's son Walter there; after the elder Mantell's death, his fossils went to Walter. Only two species assigned to Iguanodon are still considered to be valid. One of the first details noted about Iguanodon was that it had the teeth of a herbivorous reptile, although there has not always been consensus on how it ate. As Mantell noted,
2492-617: Is one of the first dinosaur genera to have been named, numerous species have been assigned to it. While never becoming the wastebasket taxon several other early genera of dinosaurs (such as Megalosaurus ) became, Iguanodon has had a complicated history, and its taxonomy continues to undergo revisions. Although Gregory Paul recommended restricting I. bernissartensis to the famous sample from Bernissart, ornithopod workers like Norman and McDonald have disagreed with Paul's recommendations, except exercising caution when accepting records of Iguanodon from France and Spain as valid. I. anglicus
2581-515: Is responsible for many cases of misleading similarities in the morphology of groups that evolved from different lineages. With the increasing realization in the first half of the 19th century that species had changed and split through the ages, classification increasingly came to be seen as branches on the evolutionary tree of life . The publication of Darwin's theory of evolution in 1859 gave this view increasing weight. In 1876 Thomas Henry Huxley , an early advocate of evolutionary theory, proposed
2670-489: Is still controversial. As an example, see the full current classification of Anas platyrhynchos (the mallard duck) with 40 clades from Eukaryota down by following this Wikispecies link and clicking on "Expand". The name of a clade is conventionally a plural, where the singular refers to each member individually. A unique exception is the reptile clade Dracohors , which was made by haplology from Latin "draco" and "cohors", i.e. "the dragon cohort "; its form with
2759-651: Is the most diverse clade within Neornithischia. The name "Cerapoda" is a portmanteaux of "Ceratopsia" and "Ornithopoda". As the name suggests, the clade is divided into two groups: Ornithopoda ("bird-foot") and Marginocephalia ("fringed heads"). The latter group includes the Pachycephalosauria ("thick-headed lizards") and Ceratopsia ("horned faces"). The following taxonomy follows Richard J. Butler , Paul Upchurch and David B. Norman , 2008 (and Butler et al. , 2011) unless otherwise noted. Cerapoda
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2848-669: The Camarillas Formation near Galve, Spain. In 2017 a new study was done of I. galvensis, with further evidence of distinctiveness from I. bernissartensis including several new autapomorphies . It was also found that the Delapparentia holotype (which is also from the Camarillas Formation) was not distinguishable from either I. bernissartensis or I. galvensis . Iguanodon were bulky herbivores that could shift from bipedality to quadrupedality . The only well-supported species, I. bernissartensis ,
2937-734: The Royal Belgian Institute of Natural Sciences , in Brussels . A replica of one of these is on display at the Oxford University Museum of Natural History and at the Sedgwick Museum in Cambridge. Most of the remains were referred to a new species, I. bernissartensis , a larger and much more robust animal than the English remains had yet revealed. One specimen, IRSNB 1551, was at first referred to
3026-647: The Valanginian species I. dawsoni and I. fittoni into Barilium and Hypselospinus respectively. After Norman 2010, over half a dozen new genera were named off English " Iguanodon" material. Carpenter and Ishida in 2010 named Proplanicoxa, Torilion and Sellacoxa while Gregory S. Paul in 2012 named Darwinsaurus , Huxleysaurus and Mantellodon and Macdonald et al. in 2012 named Kukufeldia . These species named after Norman 2010 are not considered valid and are considered various junior synonyms of Mantellisaurus , Barilium and Hypselospinus. In 2011,
3115-401: The armoured herbivore Polacanthus , and sauropods like Pelorosaurus . Early fossil remains were fragmentary, which led to much speculation on the posture and nature of Iguanodon . Iguanodon was initially portrayed as a quadrupedal horn-nosed beast. However, as more bones were discovered, Mantell observed that the forelimbs were much smaller than the hindlimbs. His rival Owen was of
3204-402: The hyoid bones that supported the tongue are heavily built, implying a muscular, non-prehensile tongue used for moving food around in the mouth. The giraffe-tongue idea has also been incorrectly attributed to Dollo via a broken lower jaw. The skull was structured in such a way that as it closed, the bones holding the teeth in the upper jaw would bow out. This would cause the lower surfaces of
3293-482: The 2020s: a specimen referred to as I. cf. galvensis was measured up to 9–10 m (30–33 ft) in length, while a new specimen of I. bernissartensis from the upper Barremian of the Iberian Peninsula was measured up to 11 m (36 ft) in length. Such large individuals would have weighed approximately 4.5 metric tons (5.0 short tons). The arms of I. bernissartensis were long (up to 75%
3382-549: The 20th century as World Wars and the Great Depression enveloped Europe. A new species that would become the subject of much study and taxonomic controversy, I. atherfieldensis , was named in 1925 by R. W. Hooley , for a specimen collected at Atherfield Point on the Isle of Wight . Iguanodon was not part of the initial work of the dinosaur renaissance that began with the description of Deinonychus in 1969, but it
3471-511: The Early Jurassic taxon Lesothosaurus diagnosticus from Southern Africa as the most basal known member of Neornithischia – a position previously held by Stormbergia dangershoeki (a taxon considered by the authors to be an adult form of Lesothosaurus and therefore a junior subjective synonym). However, Baron et al. go on to state that this result is only poorly supported and that future studies will be needed in order to better resolve
3560-565: The Lizard Tribe of enormous magnitude"), the other herbivorous. In May 1822 he first presented the herbivorous teeth to the Royal Society of London but the members, among them William Buckland , dismissed them as fish teeth or the incisors of a rhinoceros from a Tertiary stratum. On 23 June 1823 Charles Lyell showed some to Georges Cuvier , during a soiree in Paris , but the famous French naturalist at once dismissed them as those of
3649-508: The Renaissance would be another re-thinking of how to reconstruct the animal. A major flaw with Dollo's reconstruction was the bend he introduced into the tail . This organ was more or less straight, as shown by the skeletons he was excavating, and the presence of ossified tendons. In fact, to get the bend in the tail for a more wallaby or kangaroo -like posture, the tail would have had to be broken. With its correct, straight tail and back,
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3738-407: The advent of cladistic analyses , Iguanodontidae as traditionally construed was shown to be paraphyletic , and these animals are recognised to fall at different points in relation to hadrosaurs on a cladogram , instead of in a single distinct clade. Essentially, the modern concept of Iguanodontidae currently includes only Iguanodon . Groups like Iguanodontoidea are still used as unranked clades in
3827-449: The animal would have walked with its body held horizontal to the ground, arms in place to support the body if needed. In the 21st century, Iguanodon material has been used in the search for dinosaur biomolecules . In research by Graham Embery et al., Iguanodon bones were processed to look for remnant proteins . In this research, identifiable remains of typical bone proteins, such as phosphoproteins and proteoglycans , were found in
3916-458: The animals in this areally restricted find appear to have been killed by flash floods . At least 15 individuals, from 2 to 8 metres (6 ft 7 in to 26 ft 3 in) long, have been found here, most of the individuals belong to the related Mantellisaurus (described as I. atherfieldensis , at that time believed to be another species of Iguanodon ). but some are of I. bernissartensis. One major revision to Iguanodon brought by
4005-628: The base of the ornithischian tree. Pyrodontia was named by André O. Fonseca and colleagues in 2024 to unite the members of Thescelosauridae and Cerapoda . It's name translates to "fire teeth" in reference to the rapid diversification of this clade during the Middle Jurassic. The clade is formally defined in the PhyloCode as "the smallest clade containing Ceratops montanus , Iguanodon bernissartensis , Pachycephalosaurus wyomingensis , and Thescelosaurus neglectus . Cerapoda
4094-568: The best-known members of the clade include Dryosaurus , Camptosaurus , Ouranosaurus , and the duck-bills, or hadrosaurs . In older sources, Iguanodontidae was shown as a distinct family . This family traditionally has been something of a wastebasket taxon , including ornithopods that were neither hypsilophodontids or hadrosaurids. In practice, animals like Callovosaurus , Camptosaurus , Craspedodon , Kangnasaurus , Mochlodon , Muttaburrasaurus , Ouranosaurus , and Probactrosaurus were usually assigned to this family. With
4183-399: The bones was being oxidized to iron sulphate , accompanied by an increase in volume that caused the remains to crack and crumble. When in the ground, the bones were isolated by anoxic moist clay that prevented this from happening, but when removed into the drier open air, the natural chemical conversion began to occur. To limit this effect, De Pauw immediately, in the mine-gallery, re-covered
4272-525: The dinosaurs became that seen by the public for decades. With Benjamin Waterhouse Hawkins , he had nearly two dozen lifesize sculptures of various prehistoric animals built out of concrete sculpted over a steel and brick framework; two iguanodonts (based on the Maidstone specimen), one standing and one resting on its belly, were included. Before the sculpture of the standing iguanodont
4361-431: The dug-out fossils with wet clay, sealing them with paper and plaster reinforced by iron rings, forming in total about six hundred transportable blocks with a combined weight of a hundred and thirty tons. In Brussels after opening the plaster he impregnated the bones with boiling gelatine mixed with oil of cloves as a preservative . Removing most of the visible pyrite he then hardened them with hide glue , finishing with
4450-409: The first of the teeth later named Iguanodon . Other later authors agree that the story is not certainly false. It is known from his notebooks that Mantell first acquired large fossil bones from the quarry at Whitemans Green in 1820. Because also theropod teeth were found, thus belonging to carnivores, he at first interpreted these bones, which he tried to combine into a partial skeleton, as those of
4539-484: The first teeth of an Iguanodon in the strata of Tilgate Forest in Whitemans Green , Cuckfield , Sussex , England , in 1822 while her husband was visiting a patient. However, there is no evidence that Mantell took his wife with him while seeing patients. Furthermore, he admitted in 1851 that he himself had found the teeth, although he had previously stated in 1827 and 1833 that Mrs. Mantell had indeed found
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#17327906754824628-451: The fundamental unit of cladistics , a modern approach to taxonomy adopted by most biological fields. The common ancestor may be an individual, a population , or a species ( extinct or extant ). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over
4717-546: The group consists of a common ancestor with all its descendant branches. Rodents, for example, are a branch of mammals that split off after the end of the period when the clade Dinosauria stopped being the dominant terrestrial vertebrates 66 million years ago. The original population and all its descendants are a clade. The rodent clade corresponds to the order Rodentia, and insects to the class Insecta. These clades include smaller clades, such as chipmunk or ant , each of which consists of even smaller clades. The clade "rodent"
4806-559: The hand is relatively immobile, with the three central fingers grouped together, bearing hoof -like phalanges , and able to hyperextend . This would have allowed them to bear weight. The wrist is also relatively immobile, and the arms and shoulder bones robust. These features all suggest that the animal spent time on all fours. Furthermore, it appears that Iguanodon became more quadrupedal as it got older and heavier; juvenile I. bernissartensis have shorter arms than adults (60% of hindlimb length versus 70% for adults). When walking as
4895-403: The holotype of a separate species Mantellodon carpenteri by Paul (2012), but this is considered dubious and it is generally considered a specimen of Mantellisaurus At the same time, tension began to build between Mantell and Richard Owen , an ambitious scientist with much better funding and society connections in the turbulent worlds of Reform Act -era British politics and science. Owen,
4984-409: The humidity of fossil storage, or, for fresh specimens, preparing a special coating of polyethylene glycol that is then heated in a vacuum pump, so that moisture is immediately removed and pore spaces are infiltrated with polyethylene glycol to seal and strengthen the fossil. Dollo's specimens allowed him to show that Owen's prehistoric pachyderms were not correct for Iguanodon . He instead modelled
5073-590: The last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic . Some of the relationships between organisms that the molecular biology arm of cladistics has revealed include that fungi are closer relatives to animals than they are to plants, archaea are now considered different from bacteria , and multicellular organisms may have evolved from archaea. The term "clade"
5162-518: The latter term coined by Ernst Mayr (1965), derived from "clade". The results of phylogenetic/cladistic analyses are tree-shaped diagrams called cladograms ; they, and all their branches, are phylogenetic hypotheses. Three methods of defining clades are featured in phylogenetic nomenclature : node-, stem-, and apomorphy-based (see Phylogenetic nomenclature§Phylogenetic definitions of clade names for detailed definitions). The relationship between clades can be described in several ways: The age of
5251-662: The latter typically includes Hypsilophodon and the more derived Iguanodontia . Neornithischia was first named by Cooper in 1985 and defined as "all genasaurians more closely related to Parasaurolophus walkeri than to Ankylosaurus magniventris or Stegosaurus stenops ". In 2021, Neornithischia was given a formal definition under the PhyloCode : "The largest clade containing Iguanodon bernissartensis and Triceratops horridus but not Ankylosaurus magniventris and Stegosaurus stenops ." A 2017 study by Matthew G. Baron, David B. Norman , and Paul M. Barrett recovered
5340-463: The length of the legs) and robust, with rather inflexible hands built so that the three central fingers could bear weight. The thumbs were conical spikes that stuck out away from the three main digits. In early restorations, the spike was placed on the animal's nose. Later fossils revealed the true nature of the thumb spikes, although their exact function is still debated. They could have been used for defense, or for foraging for food. The little finger
5429-525: The line to the flat-headed hadrosaurines , and Ouranosaurus on the line to the crested lambeosaurines , but his proposal has been rejected. The cladogram below follows an analysis by Andrew McDonald, 2012. Rhabdodontidae Tenontosaurus Dryosauridae Camptosaurus Uteodon Hippodraco Theiophytalia Iguanacolossus Lanzhousaurus Kukufeldia Barilium Iguanodon Hadrosauroidea (including Mantellisaurus , and Xuwulong ) Because Iguanodon
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#17327906754825518-468: The living animal, including feeding, movement, and social behaviour. As one of the first scientifically well-known dinosaurs, Iguanodon has occupied a small but notable place in the public's perception of dinosaurs, its artistic representation changing significantly in response to new interpretations of its remains. The discovery of Iguanodon has long been accompanied by a popular legend . The story goes that Gideon Mantell 's wife, Mary Ann , discovered
5607-452: The mine for palaeontology, and Otto Jaekel was sent from Berlin to supervise. Just as the first fossiliferous layer was about to be uncovered, however, the German army surrendered and had to withdraw. Further attempts to reopen the mine were hindered by financial problems and were stopped altogether in 1921 when the mine flooded. Research on Iguanodon decreased during the early part of
5696-597: The most famous of which was the placement of what he thought was a horn on the nose. The discovery of much better specimens in later years revealed that the horn was actually a modified thumb. Still encased in rock, the Maidstone skeleton is currently displayed at the Natural History Museum in London . The borough of Maidstone commemorated this find by adding an Iguanodon as a supporter to their coat of arms in 1949. This specimen has become linked with
5785-503: The name I. mantelli , a species named in 1832 by Christian Erich Hermann von Meyer in place of I. anglicus , but it actually comes from a different formation than the original I. mantelli / I. anglicus material. The Maidstone specimen, also known as Gideon Mantell's "Mantel-piece", and formally labelled NHMUK 3741 was subsequently excluded from Iguanodon . It is classified as cf. Mantellisaurus by McDonald (2012); as cf. Mantellisaurus atherfieldensis by Norman (2012); and made
5874-433: The name suggests, but much larger and more closely packed. Unlike hadrosaurids, which had columns of replacement teeth, Iguanodon only had one replacement tooth at a time for each position. The upper jaw held up to 29 teeth per side, with none at the front of the jaw , and the lower jaw 25; the numbers differ because teeth in the lower jaw are broader than those in the upper. Because the tooth rows are deeply inset from
5963-493: The nebulous, gracile I. mantelli , but is currently referred to Mantellisaurus atherfieldensis . The skeletons were some of the first complete dinosaur skeletons known. Found with the dinosaur skeletons were the remains of plants, fish, and other reptiles, including the crocodyliform Bernissartia . The science of conserving fossil remains was in its infancy, and new techniques had to be improvised to deal with what soon became known as " pyrite disease". Crystalline pyrite in
6052-476: The opinion it was a stumpy creature with four pillar-like legs. The job of overseeing the first lifesize reconstruction of dinosaurs was initially offered to Mantell, who declined due to poor health, and Owen's vision subsequently formed the basis on which the sculptures took shape. Its bipedal nature was revealed with the discovery of the Bernissart skeletons. However, it was depicted in an upright posture, with
6141-568: The outside of the jaws, and because of other anatomical details, it is believed that, as with most other ornithischians, Iguanodon had some sort of cheek -like structure, muscular or non-muscular, to retain food in the mouth. Iguanodon gives its name to the unranked clade Iguanodontia , a very populous group of ornithopods with many species known from the Middle Jurassic to the Late Cretaceous . Aside from Iguanodon ,
6230-1199: The previous analyses of Boyd and Herne and colleagues, with thescelosaurids outside Ornithopoda and heterodontosaurids outside Neornithischia, while other aspects of relationships, like the placement of Changmiania or the grouping within Ornithopoda were novel results. Their equal-weights results are below. Asilisaurus Lutungutali Silesaurus Technosaurus Kwanasaurus Eucoelophysis Pisanosaurus Heterodontosauridae Eocursor Laquintasaura Lesothosaurus Emausaurus Scutellosaurus Scelidosaurus Yuxisaurus Jakapil Eurypoda Agilisaurus Hexinlusaurus Sanxiasaurus Minimocursor Yandusaurus Nanosaurus Zephyrosaurus Orodromeus Oryctodromeus Albertadromeus Koreanosaurus Yueosaurus Changmiania Haya griva RTMP 2008.045.0002 Changchunsaurus Jeholosaurus Parksosaurus Thescelosaurus Kulindadromeus Pachycephalosauria Ceratopsia Hypsilophodontidae Rhabdodontomorpha Clade In biological phylogenetics ,
6319-430: The remains he was working with were unlike any modern reptile, especially in the toothless, scoop-shaped form of the lower jaw symphysis , which he found best compared to that of the two-toed sloth and the extinct ground sloth Mylodon . He also suggested that Iguanodon had a prehensile tongue which could be used to gather food, like a giraffe . More complete remains have shown this to be an error; for example,
6408-552: The resemblance of the teeth to those of the iguana, Mantell decided to name his new animal Iguanodon or 'iguana-tooth', from iguana and the Greek word ὀδών ( odon , odontos or 'tooth'). Based on isometric scaling , he estimated that the creature might have been up to 18 metres (59 feet) long, more than the 12-metre (39 ft) length of Megalosaurus . His initial idea for a name was Iguana-saurus ('Iguana lizard'), but his friend William Daniel Conybeare suggested that that name
6497-412: The scientific literature, though many traditional iguanodontids are now included in the superfamily Hadrosauroidea . Iguanodon lies between Camptosaurus and Ouranosaurus in cladograms, and is probably descended from a camptosaur-like animal. At one point, Jack Horner suggested, based mostly on skull features , that hadrosaurids actually formed two more distantly related groups, with Iguanodon on
6586-454: The skeletal mounts after the cassowary and wallaby , and put the spike that had been on the nose firmly on the thumb . His reconstruction would prevail for a long period of time, but would later be discounted. Excavations at the quarry were stopped in 1881, although it was not exhausted of fossils, as recent drilling operations have shown. During World War I , when the town was occupied by German forces , preparations were made to reopen
6675-454: The skeletons and in 1882 Louis Dollo reconstructed them. At least 38 Iguanodon individuals were uncovered, most of which were adults. In 1882, the holotype specimen of I. bernissartensis became one of the first ever dinosaur skeletons mounted for display. It was put together in a chapel at the Palace of Charles of Lorraine using a series of adjustable ropes attached to scaffolding so that
6764-523: The spread of viral infections . HIV , for example, has clades called subtypes, which vary in geographical prevalence. HIV subtype (clade) B, for example is predominant in Europe, the Americas and Japan, whereas subtype A is more common in east Africa. Iguanodon bernissartensis Iguanodon ( / ɪ ˈ ɡ w ɑː n ə d ɒ n / i- GWAH -nə-don ; meaning ' iguana - tooth '), named in 1825,
6853-440: The tail dragging along the ground, acting as the third leg of a tripod. During his re-examination of Iguanodon , David Norman was able to show that this posture was unlikely, because the long tail was stiffened with ossified tendons. To get the tripodal pose, the tail would literally have to be broken. Putting the animal in a horizontal posture makes many aspects of the arms and pectoral girdle more understandable. For example,
6942-491: The understanding of the time, they could not have been "transmuted" from reptiles to mammal-like creatures. In 1849, a few years before his death in 1852, Mantell realised that iguanodonts were not heavy, pachyderm -like animals, as Owen was putting forward, but had slender forelimbs. However, since his passing left him unable to participate in the creation of the Crystal Palace dinosaur sculptures , Owen's vision of
7031-460: The upper jaw teeth to rub against the upper surface of the lower jaw's teeth, grinding anything caught in between and providing an action that is the rough equivalent of mammalian chewing . Because the teeth were always replaced, the animal could have used this mechanism throughout its life, and could eat tough plant material. Additionally, the front ends of the animal's jaws were toothless and tipped with bony nodes, both upper and lower, providing
7120-430: Was a large, bulky herbivore , measuring up to 9–11 metres (30–36 ft) in length and 4.5 metric tons (5.0 short tons) in body mass. Distinctive features include large thumb spikes, which were possibly used for defense against predators , combined with long prehensile fifth fingers able to forage for food. The genus was named in 1825 by English geologist Gideon Mantell , based on fossil specimens found in England and
7209-724: Was also found that the originally described type species of Iguanodon, I. anglicus is now a nomen dubium , and not valid. Thus the name " Iguanodon " became fixed around the well known species based primarily on the Belgian specimens. In 2015, a second valid species, I. galvensis , was named, based on fossils found in the Iberian Peninsula. Scientific understanding of Iguanodon has evolved over time as new information has been obtained from fossils . The numerous specimens of this genus, including nearly complete skeletons from two well-known bone beds , have allowed researchers to make informed hypotheses regarding many aspects of
7298-505: Was completed, he held a banquet for twenty inside it. The largest find of Iguanodon remains to that date occurred on 28 February 1878 in a coal mine at Bernissart in Belgium , at a depth of 322 m (1,056 ft), when two mineworkers, Jules Créteur and Alphonse Blanchard, accidentally hit on a skeleton that they initially took for petrified wood . With the encouragement of Alphonse Briart , supervisor of mines at nearby Morlanwelz , Louis de Pauw on 15 May 1878 started to excavate
7387-630: Was elongated and dextrous, and could have been used to manipulate objects. The phalangeal formula is 2-3-3-2-4, meaning that the innermost finger (phalange) has two bones, the next has three, etc. The legs were powerful, but not built for running, and each foot had three toes. The backbone and tail were supported and stiffened by ossified tendons , which were tendons that turned to bone during life (these rod-like bones are usually omitted from skeletal mounts and drawings). These animals had large, tall but narrow skulls, with toothless beaks probably covered with keratin , and teeth like those of iguanas , as
7476-733: Was first named by Sereno in 1986 and defined by him as " Parasaurolophus walkeri Parks, 1922, Triceratops horridus Marsh, 1889, their most recent common ancestor and all descendants". A similar clade Neornithopoda was tentatively proposed by David B. Norman to unite ceratopsians with advanced ornithopods in a 1984 paper. In 2021, Cerapoda was given a formal definition under the PhyloCode : "The smallest clade containing Iguanodon bernissartensis Boulenger in Beneden, 1881, Pachycephalosaurus wyomingensis (Gilmore, 1931), and Triceratops horridus Marsh, 1889." The phylogenetic study of Fonseca and colleagues in 2024 recovered results similar to
7565-421: Was given the species name I. anglicus. Iguanodon was the second type of dinosaur formally named based on fossil specimens, after Megalosaurus . Together with Megalosaurus and Hylaeosaurus , it was one of the three genera originally used to define Dinosauria . The genus Iguanodon belongs to the larger group Iguanodontia , along with the duck-billed hadrosaurs. The taxonomy of this genus continues to be
7654-487: Was more applicable to the iguana itself, so a better name would be Iguanoides ('Iguana-like') or Iguanodon . He neglected to add a specific name to form a proper binomial , but one was supplied in 1829 by Friedrich Holl: I. anglicum , which was later emended to I. anglicus . Mantell sent a letter detailing his discovery to the local Portsmouth Philosophical Society in December 1824, several weeks after settling on
7743-479: Was not neglected for long. David B. Weishampel 's work on ornithopod feeding mechanisms provided a better understanding of how it fed, and David B. Norman 's work on numerous aspects of the genus has made it one of the best-known dinosaurs. In addition, a further find of numerous disarticulated Iguanodon bones in Nehden, Nordrhein-Westphalen , Germany , has provided evidence for gregariousness in this genus, as
7832-465: Was suggested by David Norman, although iguanodonts in general have been tied to the advance of angiosperm plants in the Cretaceous due to the dinosaurs' inferred low-browsing habits. Angiosperm growth, according to this hypothesis , would have been encouraged by iguanodont feeding because gymnosperms would be removed, allowing more space for the weed -like early angiosperms to grow. The evidence
7921-595: Was the original type species , but the lectotype was based on a single tooth and only partial remains of the species have been recovered since. In March 2000, the International Commission on Zoological Nomenclature changed the type species to the much better known I. bernissartensis , with the new holotype being IRSNB 1534. The original Iguanodon tooth is held at Te Papa Tongarewa , the national museum of New Zealand in Wellington , although it
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