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Ornithopoda

January 01, 1970

Ornithopoda (/ˌɔːrnəˈθɒpədə/)[2] is a clade of ornithischian dinosaurs, called ornithopods (/ˈɔːrnəθəˌpɒdz, ɔːrˈnɪθ-/).[3][4] They represent one of the most successful groups of herbivorous dinosaurs during the Cretaceous. The most primitive members of the group were bipedal and relatively small-sized, while advanced members of the subgroup Iguanodontia became quadrupedal and developed large body size. Their major evolutionary advantage was the progressive development of a chewing apparatus that became the most sophisticated ever developed by a non-avian dinosaur, rivaling that of modern mammals such as the domestic cow. They reached their apex of diversity and ecological dominance in the hadrosaurids (colloquially known as 'duck-bills'), before they were wiped out by the Cretaceous–Paleogene extinction event along with all other non-avian dinosaurs. Members are known from all seven continents, though they are generally common in the Southern Hemisphere.

Ornithopods
Temporal range: Middle Jurassic - Late Cretaceous, 164–66 Ma
Mounted skeleton of Parasaurolophus cyrtocristatus, Field Museum of Natural History
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: †Ornithischia
Clade: †Cerapoda
Clade: †Ornithopoda
Marsh, 1881
Subgroups
Synonyms[1]

History of research edit

In 1870, Thomas Henry Huxley listed Iguanodontidae (coined by Cope a year earlier[5]) as one of his three families of dinosaurs (alongside Megalosauridae and Scelidosauridae), including within it the genera Iguanodon, Hypsilophodon, and Hadrosaurus, in addition to Cetiosaurus and tentatively Stenopelix.[6] The term Ornithopoda was erected by Othniel Charles Marsh in 1881 as part of his then still ongoing investigation of the classification of Dinosauria. It was considered one of the four definite orders of dinosaurs, the others being Theropoda, Sauropoda, and Stegosauria (Hallopoda was considered a possible fifth). He subdivided the order into three families: Camptonotidae, Iguanodontidae, and Hadrosauridae; the former was a new name, whereas the latter two were carried over from the nomenclatures of Huxley and Edward Drinker Cope respectively. Within Camptonotidae he included the European Hypsilophodon and three American taxa he named himself, Camptonotus, Laosaurus, and Nanosaurus.[7] Camptonotus was in 1885 renamed to Camptosaurus, as the original name was pre-occupied by a cricket; the associated family followed suit, becoming Camptosauridae.[8] In Iguanodontidae, only found in Europe, he included Iguanodon and Vectisaurus. In Hadrosauridae, he included Hadrosaurus, Cionodon, and tentatively Agathaumas.[7]

Description edit

 
Three-toed feet of Iguanodon

Ornithopoda means "bird feet", from the Greek ornithos, ornis ("bird") and pous, podos ("feet"); this is in reference to members’ characteristic birdlike feet.[9] They were also characterized as lacking in body armour, not developing a horny beak, having an elongated pubis (that eventually extended past the ilium), and having a missing hole in the lower jaw (a Mandibular fenestra). A variety of ornithopods, and related cerapods, had thin cartilaginous plates along the outside of the ribs; in some cases, these plates mineralized and were fossilized. The function of these intercostal plates is unknown. They have been found with Hypsilophodon, Othnielosaurus, Parksosaurus, Talenkauen, Thescelosaurus,[10] and Macrogryphosaurus to date.[11]

The early ornithopods were only about 1 metre (3 feet) long, but probably very fast. They had a stiff tail, like the theropods, to help them balance as they ran on their hind legs. Later ornithopods became more adapted to grazing on all fours; their spines curved, and came to resemble the spines of modern ground-feeders, such as the bison. As they became more adapted to eating while bent over, they became facultative quadrupeds; still running on two legs, and comfortable reaching up into trees, but spending most of their time walking or grazing on all fours. The taxonomy of dinosaurs previously ascribed to the Hypsilophodontidae is problematic. The group previously consisted of all non-iguanodontian bipedal ornithischians, but a phylogenetic reappraisal has shown such species to be paraphyletic. As such, the hypsilophodont family is currently represented only by Hypsilophodon.[12]

Later ornithopods became larger, but never rivalled the incredible size of the long-necked, long-tailed sauropods that they partially supplanted. The very largest, such as Shantungosaurus, were as heavy as medium-sized sauropods (up to 23 metric tons/25 short tons), but never grew much beyond 15 metres (50 feet).

Classification edit

 
Size of a variety of numerous ornithopods
 
An artist's interpretation of Diluvicursor, an elasmarian
 
Restoration of Muttaburrasaurus, an early iguanodont
 
Skeleton of Dysalotosaurus, a dryosaurid ornithopod from the Jurassic
 
Life restoration of Iguanacolossus, a styracosternan
 
Life restoration of Corythosaurus, a lambeosaurine hadrosaur, and one of the last ornithopods

Historically, most indeterminate ornithischian bipeds were lumped in as ornithopods. Most have since been reclassified.[citation needed]

Taxonomy edit

Ornithopoda is usually given the rank of Suborder, within the order Ornithischia. While ranked taxonomy has largely fallen out of favour among dinosaur paleontologists, some researchers have continued to employ such a classification, though sources have differed on what its rank should be. Benton (2004) placed it as an infraorder within the suborder Cerapoda (originally named as an unranked clade), while others, such as Ibiricu et al. 2010, have retained it at its traditional ranking of suborder.[13]

Phylogeny edit

In 2021, Ornithopoda was given a formal definition under the PhyloCode: "The largest clade containing Iguanodon bernissartensis but not Pachycephalosaurus wyomingensis and Triceratops horridus."[1] The cladogram below follows a 2017 analysis by Madzia et al.:[14]

References edit

  1. ^ a b Madzia, D.; Arbour, V.M.; Boyd, C.A.; Farke, A.A.; Cruzado-Caballero, P.; Evans, D.C. (2021). "The phylogenetic nomenclature of ornithischian dinosaurs". PeerJ. 9: e12362. doi:10.7717/peerj.12362. PMC 8667728. PMID 34966571.
  2. ^ "Ornithopoda". Merriam-Webster.com Dictionary.
  3. ^ . Lexico UK English Dictionary. Oxford University Press. Archived from the original on December 13, 2021.
  4. ^ "ornithopod". Merriam-Webster.com Dictionary.
  5. ^ Cope, Edward D. (1969). "Synopsis of the extinct batrachia, reptilia and aves of North America". Transactions of the American Philosophical Society. 14 (1): 91. doi:10.5962/bhl.title.60499.
  6. ^   Huxley, Thomas H. (1870). "On the Classification of the Dinosauria, with observations on the Dinosauria of the Trias". Quarterly Journal of the Geological Society of London. Vol. 26. pp. 32–51. doi:10.1144/gsl.jgs.1870.026.01-02.09 – via Wikisource.
  7. ^ a b Marsh, O. C. (1882). "Classification of the Dinosauria". American Journal of Science. 23 (133): 81–86. Bibcode:1882AmJS...23...81M. doi:10.2475/ajs.s3-23.133.81. S2CID 130836648.
  8. ^ Marsh, Othniel C. (1885). "Names of extinct reptiles" (PDF). American Journal of Science. 29: 169.
  9. ^ Colbert, Edwin H. (Edwin Harris); Knight, Charles Robert (1951). The dinosaur book: the ruling reptiles and their relatives. New York: McGraw-Hill. p. 152.
  10. ^ Butler, Richard J.; Galton, Peter M. (August 2008). "The 'dermal armour' of the ornithopod dinosaur Hypsilophodon from the Wealden (Early Cretaceous: Barremian) of the Isle of Wight: a reappraisal". Cretaceous Research. 29 (4): 636–642. Bibcode:2008CrRes..29..636B. doi:10.1016/j.cretres.2008.02.002.
  11. ^ Calvo, J. O.; Porfiri, J. D.; Novas, F. E. (2007). "Discovery of a new ornithopod dinosaur from the Portezuelo Formation (Upper Cretaceous), Neuquén, Patagonia, Argentina". Arquivos do Museu Nacional. 65 (4): 471–483.
  12. ^ Weishampel, D. B. & Heinrich, R. E. (1992). "Systematics of Hypsilophodontidae and basal Iguanodontia (Dinosauria: Ornithopoda)" (PDF). Historical Biology. 6 (3): 159–184. doi:10.1080/10292389209380426.
  13. ^ Ibiricu, Lucio M.; Martínez, Rubén D.; Lamanna, Matthew C.; Casal, Gabriel A.; Luna, Marcelo; Harris, Jerald D.; Lacovara, Kenneth J. (2010). "A Medium-Sized Ornithopod (Dinosauria: Ornithischia) from the Upper Cretaceous Bajo Barreal Formation of Lago Colhué Huapi, Southern Chubut Province, Argentina". Annals of Carnegie Museum. 79: 39–50. doi:10.2992/007.079.0103. S2CID 53407321.
  14. ^ Madzia, Daniel; Boyd, Clint A.; Mazuch, Martin (2017). "A basal ornithopod dinosaur from the Cenomanian of the Czech Republic". Journal of Systematic Palaeontology. 16 (11): 967–979. doi:10.1080/14772019.2017.1371258. S2CID 90008574.

External links edit

  • GEOL 104 dinosaurs: a Natural history, ornithopoda: beaks, bills & crests, by Thomas R. Holtz Jr.

January 01, 1970
ornithopoda, ɔːr, clade, ornithischian, dinosaurs, called, ornithopods, ɔːr, ɔːr, they, represent, most, successful, groups, herbivorous, dinosaurs, during, cretaceous, most, primitive, members, group, were, bipedal, relatively, small, sized, while, advanced, . Ornithopoda ˌ ɔːr n e ˈ 8 ɒ p e d e 2 is a clade of ornithischian dinosaurs called ornithopods ˈ ɔːr n e 8 e ˌ p ɒ d z ɔːr ˈ n ɪ 8 3 4 They represent one of the most successful groups of herbivorous dinosaurs during the Cretaceous The most primitive members of the group were bipedal and relatively small sized while advanced members of the subgroup Iguanodontia became quadrupedal and developed large body size Their major evolutionary advantage was the progressive development of a chewing apparatus that became the most sophisticated ever developed by a non avian dinosaur rivaling that of modern mammals such as the domestic cow They reached their apex of diversity and ecological dominance in the hadrosaurids colloquially known as duck bills before they were wiped out by the Cretaceous Paleogene extinction event along with all other non avian dinosaurs Members are known from all seven continents though they are generally common in the Southern Hemisphere OrnithopodsTemporal range Middle Jurassic Late Cretaceous 164 66 Ma PreꞒ Ꞓ O S D C P T J K Pg N Mounted skeleton of Parasaurolophus cyrtocristatus Field Museum of Natural History Scientific classification Domain Eukaryota Kingdom Animalia Phylum Chordata Clade Dinosauria Clade Ornithischia Clade Cerapoda Clade OrnithopodaMarsh 1881 Subgroups Ampelognathus Burianosaurus Changmiania Convolosaurus Gideonmantellia Elasmaria Hypsilophodontidae Iguanodontia Synonyms 1 Clypeodonta Norman 2014 Euornithopoda Sereno 1986 Hypsilophodontia Cooper 1985 Contents 1 History of research 2 Description 3 Classification 3 1 Taxonomy 3 2 Phylogeny 4 References 5 External linksHistory of research editIn 1870 Thomas Henry Huxley listed Iguanodontidae coined by Cope a year earlier 5 as one of his three families of dinosaurs alongside Megalosauridae and Scelidosauridae including within it the genera Iguanodon Hypsilophodon and Hadrosaurus in addition to Cetiosaurus and tentatively Stenopelix 6 The term Ornithopoda was erected by Othniel Charles Marsh in 1881 as part of his then still ongoing investigation of the classification of Dinosauria It was considered one of the four definite orders of dinosaurs the others being Theropoda Sauropoda and Stegosauria Hallopoda was considered a possible fifth He subdivided the order into three families Camptonotidae Iguanodontidae and Hadrosauridae the former was a new name whereas the latter two were carried over from the nomenclatures of Huxley and Edward Drinker Cope respectively Within Camptonotidae he included the European Hypsilophodon and three American taxa he named himself Camptonotus Laosaurus and Nanosaurus 7 Camptonotus was in 1885 renamed to Camptosaurus as the original name was pre occupied by a cricket the associated family followed suit becoming Camptosauridae 8 In Iguanodontidae only found in Europe he included Iguanodon and Vectisaurus In Hadrosauridae he included Hadrosaurus Cionodon and tentatively Agathaumas 7 Description edit nbsp Three toed feet of Iguanodon Ornithopoda means bird feet from the Greek ornithos ornis bird and pous podos feet this is in reference to members characteristic birdlike feet 9 They were also characterized as lacking in body armour not developing a horny beak having an elongated pubis that eventually extended past the ilium and having a missing hole in the lower jaw a Mandibular fenestra A variety of ornithopods and related cerapods had thin cartilaginous plates along the outside of the ribs in some cases these plates mineralized and were fossilized The function of these intercostal plates is unknown They have been found with Hypsilophodon Othnielosaurus Parksosaurus Talenkauen Thescelosaurus 10 and Macrogryphosaurus to date 11 The early ornithopods were only about 1 metre 3 feet long but probably very fast They had a stiff tail like the theropods to help them balance as they ran on their hind legs Later ornithopods became more adapted to grazing on all fours their spines curved and came to resemble the spines of modern ground feeders such as the bison As they became more adapted to eating while bent over they became facultative quadrupeds still running on two legs and comfortable reaching up into trees but spending most of their time walking or grazing on all fours The taxonomy of dinosaurs previously ascribed to the Hypsilophodontidae is problematic The group previously consisted of all non iguanodontian bipedal ornithischians but a phylogenetic reappraisal has shown such species to be paraphyletic As such the hypsilophodont family is currently represented only by Hypsilophodon 12 Later ornithopods became larger but never rivalled the incredible size of the long necked long tailed sauropods that they partially supplanted The very largest such as Shantungosaurus were as heavy as medium sized sauropods up to 23 metric tons 25 short tons but never grew much beyond 15 metres 50 feet Classification edit nbsp Size of a variety of numerous ornithopods nbsp An artist s interpretation of Diluvicursor an elasmarian nbsp Restoration of Muttaburrasaurus an early iguanodont nbsp Skeleton of Dysalotosaurus a dryosaurid ornithopod from the Jurassic nbsp Life restoration of Iguanacolossus a styracosternan nbsp Life restoration of Corythosaurus a lambeosaurine hadrosaur and one of the last ornithopods Historically most indeterminate ornithischian bipeds were lumped in as ornithopods Most have since been reclassified citation needed Taxonomy edit Ornithopoda is usually given the rank of Suborder within the order Ornithischia While ranked taxonomy has largely fallen out of favour among dinosaur paleontologists some researchers have continued to employ such a classification though sources have differed on what its rank should be Benton 2004 placed it as an infraorder within the suborder Cerapoda originally named as an unranked clade while others such as Ibiricu et al 2010 have retained it at its traditional ranking of suborder 13 Phylogeny edit In 2021 Ornithopoda was given a formal definition under the PhyloCode The largest clade containing Iguanodon bernissartensis but not Pachycephalosaurus wyomingensis and Triceratops horridus 1 The cladogram below follows a 2017 analysis by Madzia et al 14 Clypeodonta Hypsilophodon Cerapoda Marginocephalia Ornithopoda Gideonmantellia Elasmaria Burianosaurus Iguanodontia Rhabdodontomorpha Muttaburrasaurus Rhabdodontidae Tenontosaurus Dryomorpha Dryosauridae Ankylopollexia Camptosaurus Styracosterna Iguanodon HadrosauroideaReferences edit a b Madzia D Arbour V M Boyd C A Farke A A Cruzado Caballero P Evans D C 2021 The phylogenetic nomenclature of ornithischian dinosaurs PeerJ 9 e12362 doi 10 7717 peerj 12362 PMC 8667728 PMID 34966571 Ornithopoda Merriam Webster com Dictionary ornithopod Lexico UK English Dictionary Oxford University Press Archived from the original on December 13 2021 ornithopod Merriam Webster com Dictionary Cope Edward D 1969 Synopsis of the extinct batrachia reptilia and aves of North America Transactions of the American Philosophical Society 14 1 91 doi 10 5962 bhl title 60499 nbsp Huxley Thomas H 1870 On the Classification of the Dinosauria with observations on the Dinosauria of the Trias Quarterly Journal of the Geological Society of London Vol 26 pp 32 51 doi 10 1144 gsl jgs 1870 026 01 02 09 via Wikisource a b Marsh O C 1882 Classification of the Dinosauria American Journal of Science 23 133 81 86 Bibcode 1882AmJS 23 81M doi 10 2475 ajs s3 23 133 81 S2CID 130836648 Marsh Othniel C 1885 Names of extinct reptiles PDF American Journal of Science 29 169 Colbert Edwin H Edwin Harris Knight Charles Robert 1951 The dinosaur book the ruling reptiles and their relatives New York McGraw Hill p 152 Butler Richard J Galton Peter M August 2008 The dermal armour of the ornithopod dinosaur Hypsilophodon from the Wealden Early Cretaceous Barremian of the Isle of Wight a reappraisal Cretaceous Research 29 4 636 642 Bibcode 2008CrRes 29 636B doi 10 1016 j cretres 2008 02 002 Calvo J O Porfiri J D Novas F E 2007 Discovery of a new ornithopod dinosaur from the Portezuelo Formation Upper Cretaceous Neuquen Patagonia Argentina Arquivos do Museu Nacional 65 4 471 483 Weishampel D B amp Heinrich R E 1992 Systematics of Hypsilophodontidae and basal Iguanodontia Dinosauria Ornithopoda PDF Historical Biology 6 3 159 184 doi 10 1080 10292389209380426 Ibiricu Lucio M Martinez Ruben D Lamanna Matthew C Casal Gabriel A Luna Marcelo Harris Jerald D Lacovara Kenneth J 2010 A Medium Sized Ornithopod Dinosauria Ornithischia from the Upper Cretaceous Bajo Barreal Formation of Lago Colhue Huapi Southern Chubut Province Argentina Annals of Carnegie Museum 79 39 50 doi 10 2992 007 079 0103 S2CID 53407321 Madzia Daniel Boyd Clint A Mazuch Martin 2017 A basal ornithopod dinosaur from the Cenomanian of the Czech Republic Journal of Systematic Palaeontology 16 11 967 979 doi 10 1080 14772019 2017 1371258 S2CID 90008574 External links editGEOL 104 dinosaurs a Natural history ornithopoda beaks bills amp crests by Thomas R Holtz Jr Portal nbsp Dinosaurs Retrieved from https en wikipedia org w index php title Ornithopoda amp oldid 1220649212, wikipedia, wiki, book, books, library,

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