Owenodon

Last updated

Owenodon
Temporal range:
Early Cretaceous, Berriasian
Owenodon hoggii lateral.tif
Holotype NHMUK PV R 2998 in lateral view
Owenodon hoggii medial.tif
Holotype NHMUK PV R 2998 in medial view
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade:† Ornithischia
Clade:† Neornithischia
Clade:† Ornithopoda
Clade:† Iguanodontia
Clade:† Dryomorpha
Genus:† Owenodon
Galton, 2009 [1]
Species:
†O. hoggii
Binomial name
†Owenodon hoggii
Synonyms
  • Iguanodon hoggii
    Owen, 1874 [2]
  • Camptosaurus hoggii
    (Owen, 1974) Norman & Barrett, 2002 [3]

Owenodon is a genus of iguanodontian dinosaur known from a partial lower jaw discovered in Early Cretaceous-age rocks of Dorset, United Kingdom, and possibly also Romania and Spain. The first and only definitive specimen was found in the Lulworth Formation of the Purbeck Limestone Group, dating to the middle Berriasian stage. It was first described by Richard Owen as a species Iguanodon , I. hoggii, honouring naturalist A.J. Hogg who had originally collected the fossil. Owen described the mandible as it was, partially embedded in a limestone block, but it was given to the Natural History Museum, London where it was accessioned as NHMUK PV R 2998 and further prepared. Some damage occurred to a tooth crown and part of the bone while stored in the collections. Redescription of I. hoggii by David Norman and Paul Barrett subsequently transferred the species to Camptosaurus in 2002, as well as tentatively referring other camptosaur-like material from the Purbeck beds to the species. The identity of the species was questioned, with Kenneth Carpenter and Yvonne Wilson, and Greg Paul, separating "C." hoggi from Camptosaurus as an intermediate ornithopod, until Peter Galton named the new genus Owenodon for it in 2009. Galton removed the material assigned by Norman and Barrett from Owenodon, but referred isolated teeth from the Bauxite of Cornet, Romania, and the El Castellar Formation of Spain to O. hoggii. The taxon, believed by Galton to be intermediate between Camptosaurus and Iguanodon, is of uncertain relationships, with the limited material preventing clear understanding of its position within ornithopod evolution. Phylogenetic studies have found Owenodon to be more primitive, equivalent to, or more derived than Camptosaurus, but it is often excluded to improve results.

Contents

History of naming

Holotype of Iguanodon hoggii (now Owenodon) as originally figured by Owen in 1874 Owenodon.jpg
Holotype of Iguanodon hoggii (now Owenodon) as originally figured by Owen in 1874

A partial mandible discovered in the middle Purbeck Formation by A. J. Hogg was described in 1874 by British palaeontologist Sir Richard Owen. The fossil was found in a hard limestone known as "Under Feather", 1.2–1.5 m (4–5 ft) below the "Cinder Beds" which contain many shells of Ostrea distorta . At the time of its discovery, it was considered the first definitive material of Iguanodon from the Purbeck Formation, only preceded by a single large bone of the hand described by British palaeontologist William Buckland which likely washed out of the cliffs dividing the Greensand from the Purbeck. The mandible is a partially complete dentary bearing ten teeth, which show stronger primary and secondary ridges but weaker tertiary ridges than the teeth of larger Iguanodon material from the Wealden Formation, and as such Owen gave the mandible the new binomial name Iguanodon hoggii (often misspelled as I. hoggi [4] ). However, in the caption where the dentary was figured, Owen instead labelled the mandible as a young specimen of Iguanodon mantelli . [2] The specimen was presented by Hogg to the British Museum of Natural History (now the Natural History Museum) in December of 1901, where it was acquired and given the specimen number NHMUK PV R 2998. [5] Owen's description of the specimens provenance suggests it was collected in the Cherty Freshwater Beds of the middle Purbeck where it was found in Durlston Bay, which is middle Berriasian in age as part of the Tirnovella occitana zone. While it was originally described based on the partially-prepared inner surface of the mandible embedded in limestone, the mandible was fully prepared in 1975 using acetic acid and is cleared of matrix, but was damaged between 1977 and 1998 breaking one tooth crown and a part of the rear margin. [3] The "Under Feather" locality from which the specimen was found is now called the Cherty Freshwater Member of the Lulworth Formation, part of the Purbeck Limestone Group. [6]

Redescription of Iguanodon hoggii by British palaeontologists David B. Norman and Paul M. Barrett in 2002 found that I. hoggii was a species of Camptosaurus instead, creating the new combination Camptosaurus hoggii. This referral was made as the dentary of I. hoggii showed similarities to Camptosaurus dispar and Camptosaurus prestwichii in the count of teeth and the structure of tooth ridges, while the species Iguanodon atherfieldensis had a much greater number of teeth and consistent fluting around the crowns despite overall similarities in tooth ridges. Norman and Barrett also considered other material from the Purbeck to possible belong to C. hoggii (as cf. C. hoggii). From Dorset was referred the partial femur Cambridge University Sedgwick Museum specimen X.29337, the dorsal centrum of a juvenile NHMUK 46785, the foot phalanx NHMUK PV R 2942, and the crushed limb bone Dorset Museum specimen G.350, from Buckinghamshire was referred the foot phalanx Buckinghamshire County Museum specimen 467/22, and from Yorkshire was referred the femur, tibia , fibula , and astragalus NHMUK PV R 8676. All referrals were based on general similarities to ornithopods and Camptosaurus , to which C. hoggii was the closest species in geography and age. However, the systematic position of C. hoggii was considered provisional as the type mandible was not very diagnostic and related genera were of uncertain phylogenetic placement. [3]

The referral of Iguanodon hoggii to Camptosaurus was challenged by American palaeontologists Kenneth Carpenter and Yvonne Wilson in 2008, who described the new species Camptosaurus aphanoecetes and found it more similar to C. dispar than Camptosaurus hoggii was. As a result, they removed Iguanodon hoggii from Camptosaurus and left it as an unnamed euornithopod, "Camptosaurus" hoggii. [7] In 2008 American palaeontologist Greg Paul also removed Iguanodon hoggii from Camptosaurus, as it was too incomplete. Paul recommended that I. hoggi was considered an undiagnostic nomen dubium , and an indeterminate species of Ornithopoda or Camptosauridae. [4] American palaeontologist Peter Galton redescribed NHMUK PV R 2998 in 2009 in a review of Lower Cretaceous ornithopods from England, where differences that prevented referral to both Iguanodon in the teeth and Camptosaurus in the dentary were identified, and as such Galton gave the new genus name Owenodon for the species. Owenodon hoggii was considered to be intermediate between Camptosaurus and iguanodontoids, likely referrable to the clade Styracosterna. Galton also reevaluated the referred material of Norman and Barrett, considering the femur CAMSM X.29337 to be an iguanodontoid separate from Owenodon, the dorsal centrum (NHMUK 46785) to be an undiagnostic euornithopod, and the partial hindlimb NHMUK PV R 8676 was referred to the species Iguanodon hollingtoniensis . However, material from a Berriasian to Valanginian fissure fill of Bauxite of Cornet in Romania showing intermediate anatomy between Camptosaurus and iguanodontoids was tentatively referred to Owenodon sp., which includes teeth, a maxilla , frontal , braincase , vertebrae, humerus , carpals and a metacarpal , and a partial femur. [1]

Further review of English and Belgian iguanodontian taxa by Norman in 2012 included a discussion of Owenodon and a rediagnosis of the taxon. The taphonomic crushing of the dentary caused some features thought to be unique to Owenodon, though its depth and the arch of the tooth row were likely anatomical. Norman considered the taxonomic status of Owenodon to be provisional, with the separation of Owenodon as its own genus being a subjective decision based more on stratigraphy and geography than anatomy. [8] Galton also reviewed small ornithopods of England and Europe in 2012, removing the all the Romanian material except for maxillary and dentary teeth from Owenodon, but added a tooth from the Hauterivian to Barremian El Castellar Formation of Spain to Owenodon sp., expanding the geographic range of the genus. [9]

Classification

Originally named as a species of Iguanodon, Owenodon hoggii was associated with the various iguanodont species from southern England, which are now classified among the genera Iguanodon, Mantellisaurus , Barilium , and Hypselospinus . [8] Camptosaurus, where O. hoggii was also referred, is a more primitive ornithopod than the iguanodonts, but still on the branch of ornithopods leading to hadrosaurs. [1] As its own species and genus, Owenodon hoggii is a taxon of inconsistent and uncertain classification, but it shows similarities to the camptosaur and iguanodont areas of ornithopod evolution. [8] In the first edition of The Dinosauria in 1990, Norman and David B. Weishampel retained I. hoggi (misspelled) within Iguanodon as a member of Iguanodontidae, [10] but the second edition in 2004 had Norman place I. hoggi (misspelled) in Camptosaurus as one of two ornithopods within Ankylopollexia but outside Iguanodontoidea. [11] Carpenter and Wilson moved "I." hoggi into Euornithopoda in 2008, [7] while Paul considered it Ornithopoda or Camptosauridae incertae sedis the same year. [4] In naming Owenodon, Galton classified it as a tentative member of Styracosterna less derived than Lurdusaurus , Equijubus , and Iguanodontoidea. [1]

The onset of phylogenetics in ornithopod studies have at points incorporated Owenodon as an operational taxon, though it has also been removed from analyses after running in order to improve the resolution of relationships. The phylogenetic analyses of American palaeontologist Andrew T. McDonald and colleagues from 2010 to 2017 on have found Owenodon to be an early member of Ankylopollexia, either slightly closer to Iguanodon and Hadrosauridae than Camptosaurus but in an unresolved position with respect to Uteodon (alternatively Camptosaurus aphanoecetes) and Cumnoria (alternatively Camptosaurus prestwichii), in an unresolved position with respect to C. dispar but further from Iguanodon and Hadrosauridae than Uteodon and Cumnoria, or have had to remove Owenodon to achieve useful resolution. [12] [13] [14] [15] [16] Alternatively, Owenodon was added to the analysis of Australian palaeontologist Matthew C. Herne and colleagues in 2019 where it was further from Iguanodon than Camptosaurus, either in an unresolved result between Ankylopollexia and Dryosauridae, or closer to Ankylopollexia. [17] The phylogenetic analysis of Brazilian palaeontologist André O. Fonseca and colleagues in 2024 incorporated the analyses of McDonald and Herne together, and found Owenodon to be a clear member of Styracosterna more derived than Camptosaurus, Uteodon and Cumnoria, in a polytomy with or slightly more primitive than Hippodraco . [18] The results of the analysis by American palaeontologist Karen E. Poole in 2022 found similar results, with the maximum parsimony results placing Owenodon more derived than Camptosaurus and Dakotadon and more primitive than Lanzhousaurus and later iguanodonts, in a polytomy with Theiophytalia and Iguanacolossus , while bayesian results had Owenodon as the sister to Iguanacolossus in a basal styracosternan clade alongside Theiophytalia and Dakotadon. [19]

Skeleton of former Camptosaurus species Uteodon aphanoecetes Camptosaurus aphanoecetes - IMG 0673.jpg
Skeleton of former Camptosaurus species Uteodon aphanoecetes
Skeleton of former Iguanodon species Mantellisaurus atherfieldensis Hul - Mantellisaurus atherfieldensis - 2.jpg
Skeleton of former Iguanodon species Mantellisaurus atherfieldensis

Palaeoecology

Environment of the Purbeck beds including the mammals Durlstodon (left), Durlstotherium (center and right) and the theropod Nuthetes Purbeck lagoon.jpg
Environment of the Purbeck beds including the mammals Durlstodon (left), Durlstotherium (center and right) and the theropod Nuthetes

The Purbeck Group is a distinctive sequence of evaporites, thin sandstones and shelly limestones interbedded with marl and shales. Sedimentology shows they were deposited in a fluctuation of freshwater, brackish, hypersaline and quasi-marine environments. Flora and fauna are indicative of variable terrestrial, lacustrine, saline and lagoonal associations. The climate of the early Purbeck Group was likely similar to the modern Mediterranean and became wetter towards the end of the Berriasian. [20] While the Purbeck Group was originally known as the informal Purbeck Beds, it can now be divided into the upper Durlston Formation and the lower Lulworth Formation. The "Upper Purbeck Beds" and a majority of the "Middle Purbeck Beds" are contained within the Durlston Formation, the oldest deposit of which is the Cinder Beds of the Stair Hole Member. [21] The Cinder Beds have, at times, been considered the Jurassic-Cretaceous Boundary, which would result in the entire Lulworth Formation being latest Jurassic, Tithonian, in age. [22] However, despite the uncertainties about the age of the beds because of a lack of correlation through fauna or dating, it is generally accepted that the Purbeck Group is entirely earliest Cretaceous in age, with the Lulworth Formation being early Berriasian. [22] [20] [23] The Purbeck Group is visibly underlain by the Late Jurassic Portland Group in Durlston Bay and has a transitional but locally obscured boundary with the overlying Wealden Group at Peveril Point. [20]

There is a great deal of uncertainty as to the location of the specimens collected from the Lulworth Formation; the only definitive way to test would be to analyse the matrix of each specimen to determine its salinity. [21] The Purbeck Group has the most diverse ornithischian fauna of any deposit in Dorset, and is one of few Berriasian deposits globally, but is limited almost entirely to cranial or dental material, and tracks. Echinodon becklesii is the only other named ornithischian from the beds, and is a heterodontosaurid known from multiple partial jaws and teeth. A femur and dorsal of an intermediate hadrosauriform is also known, along with intermediate ornithopods and ankylosaurs known both from body fossils and from footprints. [6] Beyond ornithischians, the Lulworth Formation also contains the theropod Nuthetes , amphibians, turtles, lizards, snakes, mammals and crocodilians, and varieties of invertebrates. [21] [24] [25] Amphibians from the Lulworth Formation include the salamanders Apricosiren and an intermediate batrachosauroidid, the albanerpetontid Celtedens and the frog Sunnybatrachus . [24] Four taxa of turtles are known, the cryptodires Dorsetochelys , Helochelydra , Hylaeochelys and Pleurosternon . [26] [27] The Purbeck is one of the most diverse Early Cretaceous deposits globally for lepidosaurians. [28] The genera Becklesius , Dorsetisaurus , Durotrigia , Paramacellodus , Pseudosaurillus , Parasaurillus , Purbicella , Saurillus , Parviraptor and three unnamed tooth morphologies represent the known squamates, [29] and fossils referred to the rhynchocephalians Homoeosaurus and Opisthias have also been found. [30]

The diverse mammal assemblage includes the small eutherians Durlstodon and Durlstotherium ; [20] the non-eutherian peramurans Peramus , Peramuroides , Magnimus and Kouriogenys ; [31] [32] the non-eutherian symmetrodonts Spalacotherium , Tinodon and Thereuodon ; [33] [34] the non-eutherian dryolestoids Achyrodon , Amblotherium , Dorsetodon , Chunnelodon and Phascolestes ; [35] [36] [37] the non-eutherian multituberculates Albionbaatar , Bolodon , Gerhardodon , Plagiaulax and Sunnyodon ; [38] [39] [40] the non-eutherian eutriconodonts Trioracodon and Triconodon , the non-mammalian morganucodontan Purbeckodon ; [41] and the non-mammalian docodont Peraiocynodon . [42] Crocodilians from within the Lulworth deposits include Goniopholis gracilidens , Theriosuchus pusillus , Pholidosaurus purbeckensis , dubious remains previously known as Goniopholis tenuidens , [21] and the dubious taxon Macellodus brodiei . [29] Specific sites within the formation also preserve the primitive snipe flies Simulidium and Pseudosimulium , [25] and the nematoceran flies Eoptychoptera , Brodilka and Eucorethrina . [23]

Related Research Articles

<i>Iguanodon</i> Ornithopod dinosaur genus from Early Cretaceous period

Iguanodon, named in 1825, 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 was a large, bulky herbivore, measuring up to 9–11 metres (30–36 ft) in length and 4.5 metric 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.

<i>Lesothosaurus</i> Extinct genus of ornithischian dinosaur

Lesothosaurus is a monospecific genus of ornithischian dinosaur that lived during the Early Jurassic in what is now South Africa and Lesotho. It was named by paleontologist Peter Galton in 1978, the name meaning "lizard from Lesotho". The genus has only one valid species, Lesothosaurus diagnosticus. Lesothosaurus is one of the most completely-known early ornithischians, based on numerous skull and postcranial fossils from the Upper Elliot Formation. It had a simpler tooth and jaw anatomy than later ornithischians, and may have been omnivorous in some parts of the year.

<i>Hypsilophodon</i> Extinct genus of dinosaurs

Hypsilophodon is a neornithischian dinosaur genus from the Early Cretaceous period of England. It has traditionally been considered an early member of the group Ornithopoda, but recent research has put this into question.

<span class="mw-page-title-main">Ornithopoda</span> Extinct suborder of dinosaurs

Ornithopoda is a clade of ornithischian dinosaurs, called ornithopods. 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, before they were wiped out by the Cretaceous–Paleogene extinction event along with all other non-avian dinosaurs. Members are known worldwide.

<i>Valdosaurus</i> Extinct genus of dinosaurs

Valdosaurus is a genus of bipedal herbivorous iguanodont ornithopod dinosaur found on the Isle of Wight and elsewhere in England, Spain and possibly also Romania. It lived during the Early Cretaceous.

<i>Leaellynasaura</i> Extinct genus of dinosaurs

Leaellynasaura is a genus of small herbivorous ornithischian dinosaurs from the late Aptian to early Albian stage of the Early Cretaceous, around 118-110 million years ago. It was first discovered in Dinosaur Cove, Australia. The only known species is Leaellynasaura amicagraphica. It was described in 1989, and named after Leaellyn Rich, the daughter of the Australian palaeontologist couple Tom Rich and Patricia Vickers-Rich who discovered it. The specific name, amicagraphica, translates to "friend writing" and honours both the Friends of the Museum of Victoria and the National Geographic Society for their support of Australian paleontology.

<i>Camptosaurus</i> Extinct genus of dinosaurs

Camptosaurus is a genus of plant-eating, beaked ornithischian dinosaurs of the Late Jurassic period of western North America and possibly also Europe. The name means 'flexible lizard'.

<i>Echinodon</i> Extinct genus of dinosaurs

Echinodon is a genus of heterodontosaurid dinosaur that lived during the earliest Cretaceous of southern England and possibly western France in the Berriasian epoch. The first specimens were jaw bones named Echinodon becklesii by Sir Richard Owen in 1861, and since their original description only additional teeth have been discovered. The specific name honours collector Samuel Beckles who discovered the material of Echinodon and many other taxa from across England, while the genus name translates as "prickly tooth" in reference to the dental anatomy of the taxon.

<i>Cumnoria</i> Extinct genus of dinosaurs

Cumnoria is a genus of herbivorous iguanodontian dinosaur. It was a basal iguanodontian that lived during the Late Jurassic period in what is now Oxfordshire, United Kingdom.

<i>Nuthetes</i> Extinct genus of dinosaurs

Nuthetes is the name given to a genus of coelurosaurian theropod dinosaur, either a dromaeosaurid or a tyrannosauroid, known only from fossil teeth and jaw fragments found in rocks of the middle Berriasian age in the Cherty Freshwater Member of the Lulworth Formation in England and also the Angeac-Charente bonebed in France. If it was a dromaeosaurid, Nuthetes would have been a small predator.

<i>Theiophytalia</i> Extinct genus of dinosaurs

Theiophytalia is a genus of herbivorous iguanodontian dinosaur from the lower Cretaceous period of Colorado, USA. It contains a single species, T. kerri.

<i>Mantellisaurus</i> Extinct genus of dinosaurs

Mantellisaurus is a genus of iguanodontian dinosaur that lived in the Barremian and early Aptian ages of the Early Cretaceous Period of Europe. Its remains are known from Belgium (Bernissart), England, Spain and Germany. The type and only species is M. atherfieldensis. Formerly known as Iguanodon atherfieldensis, the new genus Mantellisaurus was erected for the species by Gregory Paul in 2007. According to Paul, Mantellisaurus was more lightly built than Iguanodon and more closely related to Ouranosaurus, making Iguanodon in its traditional sense paraphyletic. It is known from many complete and almost complete skeletons. The genus name honours Gideon Mantell, the discoverer of Iguanodon.

<span class="mw-page-title-main">Dryosauridae</span> Extinct family of dinosaurs

Dryosauridae was a family of primitive iguanodonts, first proposed by Milner & Norman in 1984. They are known from Middle Jurassic to Early Cretaceous rocks of Africa, Europe, and North America.

<i>Dakotadon</i> Extinct genus of dinosaurs

Dakotadon is a genus of iguanodont dinosaur from the Barremian-age Lower Cretaceous Lakota Formation of South Dakota, USA, known from a partial skull. It was first described in 1989 as Iguanodon lakotaensis, by David B. Weishampel and Philip R. Bjork. Its assignment has been controversial. Some researchers suggest that "I." lakotaensis was more basal than I. bernissartensis, and related to Theiophytalia, but David Norman has suggested that it was a synonym of I. bernissartensis. Gregory S. Paul, working on a revision of iguanodont species, gave "I." lakotaensis its own genus (Dakotadon) in 2008. He measured its length at 6 metres (20 ft) and body mass at 1 metric ton.

<span class="mw-page-title-main">Ankylopollexia</span> Extinct clade of dinosaurs

Ankylopollexia is an extinct clade of ornithischian dinosaurs that lived from the Late Jurassic to the Late Cretaceous. It is a derived clade of iguanodontian ornithopods and contains the subgroup Styracosterna. The name stems from the Greek word, “ankylos”, mistakenly taken to mean stiff, fused, and the Latin word, “pollex”, meaning thumb. Originally described in 1986 by Sereno, a most likely synapomorphic feature of a conical thumb spine defines the clade.

<span class="mw-page-title-main">Elasmaria</span> Extinct clade of dinosaurs

Elasmaria is a clade of ornithopods known from Cretaceous deposits in South America, Antarctica, and Australia that contains many bipedal ornithopods that were previously considered "hypsilophodonts".

<span class="mw-page-title-main">Lulworth Formation</span>

The Lulworth Formation is a geologic formation in England. It dates from the late Tithonian to the mid Berriasian. It is a subunit of the Purbeck Group. In Dorset, it consists of three members, which are in ascending order, the Mupe Member, the Ridgway Member, and the Warbarrow Tout Member. The Mupe Member is typically 11 to 16 m thick and largely consists of marls and micrites with interbeds of calcareous mudstone. The Ridgeway Member is about 3 to 7 m thick and consists of in its western portion carbonaceous muds, marls and micrites, in the east the muds are replaced by micritic limestone. The Warbarrow Tout Member is 17 to 39 m thick and consists of limestone at the base and micrite and mudstone for the rest of the sequence, this member is the primary source of the vertebrate fossils within the formation. Elsewhere the unit is undifferentiated.

References

  1. 1 2 3 4 Galton, P.M. (2009). "Notes on Neocomian (Late Cretaceous) ornithopod dinosaurs from England – Hypsilophodon, Valdosaurus, "Camptosaurus", "Iguanodon" – and referred specimens from Romania and elsewhere" (PDF). Revue de Paléobiologie. 28 (1): 211–273.
  2. 1 2 Owen, R. (1874). "Monograph on the Fossil Reptilia of the Wealden and Purbeck Formations. Supplement No. V. Dinosauria (Iguanodon). [Wealden and Purbeck]". Monographs of the Palaeontological Society. 27 (124): 1–18. doi:10.1080/02693445.1874.12113258.
  3. 1 2 3 Norman, D.B.; Barrett, P.M. (2002). "Ornithischian dinosaurs from the Lower Cretaceous (Berriasian) of England". Special Papers in Palaeontology. 68: 161–189.
  4. 1 2 3 Paul, G.S. (2008). "A revised taxonomy of the iguanodont dinosaur genera and species" (PDF). Cretaceous Research. 29 (2): 192–216. Bibcode:2008CrRes..29..192P. doi:10.1016/j.cretres.2007.04.009.
  5. ↑ "PV R 2998". Data Portal. Natural History Museum. Retrieved 24 August 2024.
  6. 1 2 Barrett, P.M.; Maidment, S.C.R. (2011). "Dinosaurs of Dorset: Part III, the ornithischian dinosaurs (Dinosauria, Ornithischia) with additional comments on the sauropods". Proceedings of the Dorset Natural History and Archaeological Society. 132: 145–163.
  7. 1 2 Carpenter, K.; Wilson, Y. (2008). "A new species of Camptosaurus (Ornithopoda: Dinosauria) from the Morrison Formation (Upper Jurassic) of Dinosaur National Monument, Utah, and a biomechanical analysis of its forelimb". Annals of the Carnegie Museum. 76 (4): 227–263. doi:10.2992/0097-4463(2008)76[227:ansoco]2.0.co;2. S2CID   86197297.
  8. 1 2 3 Norman, D.B. (2012). "Iguanodontian Taxa (Dinosauria: Ornithischia) from the Lower Cretaceous of England and Belgium". In Godefroit, P. (ed.). Bernissart Dinosaurs, and Early Cretaceous Terrestrial Ecosystems. Indiana University Press. pp. 175–212. ISBN   978-0-253-35721-2.
  9. ↑ Galton, P.M. (2012). "Hypsilophodon foxii and Other Smaller Bipedal Ornithischian Dinosaurs from the Lower Cretaceous of Southern England". In Godefroit, P. (ed.). Bernissart Dinosaurs, and Early Cretaceous Terrestrial Ecosystems. Indiana University Press. pp. 225–282. ISBN   978-0-253-35721-2.
  10. ↑ Norman, D.B.; Weishampel, D.B. (1990). "Iguanodontidae and Related Ornithopods". In Weishampel, D.B.; Osmólska, H.; Dodson, P. (eds.). The Dinosauria. University of California Press. pp. 510–533. ISBN   0-520-24209-2.
  11. ↑ Norman, D.B. (2004). "Basal Iguanodontia". In Weishampel, D.B.; Osmólska, H.; Dodson, P. (eds.). The Dinosauria (2nd ed.). University of California Press. pp. 413–437. ISBN   0-520-24209-2.
  12. ↑ McDonald, A.T.; Kirkland, J.I.; DeBlieux, D.D.; Madsen, S.K.; Cavin, J.; Milner, A.R.C.; Panzarin, L. (2010). "New Basal Iguanodonts from the Cedar Mountain Formation of Utah and the Evolution of Thumb-Spiked Dinosaurs". PLOS ONE. 5 (11): e14075. Bibcode:2010PLoSO...514075M. doi: 10.1371/journal.pone.0014075 . PMC   2989904 . PMID   21124919.
  13. ↑ McDonald, A.T.; Barrett, P.M.; Chapman, S.D. (2010). "A new basal iguanodont (Dinosauria: Ornithischia) from the Wealden (Lower Cretaceous) of England". Zootaxa. 2569: 1–43. doi:10.11646/zootaxa.2569.1.1.
  14. ↑ McDonald, A.T. (2012). "Phylogeny of Basal Iguanodonts (Dinosauria: Ornithischia): An Update". PLOS ONE. 7 (5): e36745. Bibcode:2012PLoSO...736745M. doi: 10.1371/journal.pone.0036745 . PMC   3358318 .
  15. ↑ McDonald, A.T.; Espílez, E.; Mampel, L.; Kirkland, J.I.; Alcalá, L. (2012). "An unusual new basal iguanodont (Dinosauria: Ornithopoda) from the Lower Cretaceous of Teruel, Spain". Zootaxa. 3595: 61–76. doi:10.11646/zootaxa.3595.1.3.
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