Valdosaurus

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Valdosaurus
Temporal range: Early Cretaceous, 140–121  Ma
Valdosaurus.png
Assigned skeleton at Dinosaur Isle Museum
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade:† Ornithischia
Clade:† Neornithischia
Clade:† Ornithopoda
Family:† Dryosauridae
Genus:† Valdosaurus
Galton, 1977
Species:
†V. canaliculatus
Binomial name
†Valdosaurus canaliculatus
Galton, 1977 (Galton, 1975)
Synonyms
  • Dryosaurus canaliculatusGalton, 1975
  • Valdosaurus dextrapoda? Blows, 1988

Valdosaurus ("Weald Lizard") 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.

Contents

Discovery and naming

Valdosaurus sp. ilia, NHM 2150, from the Upper Tunbridge Wells Sand of Cuckfield Valdosaurus sp.jpg
Valdosaurus sp. ilia, NHM 2150, from the Upper Tunbridge Wells Sand of Cuckfield

In the nineteenth century Reverend William Darwin Fox collected two small thighbones near Cowleaze Chine on the southwest coast of the Isle of Wight. In 1868 he incorrectly suggested these may have come from the same individual that had in 1848 been uncovered for Gideon Mantell as a fossil of Iguanodon , and which in 1869 would be named as the new genus Hypsilophodon . Regardless, both femora, made part of the collection of the British Museum of Natural History as specimens BMNH R184 and BMNH R185, would be commonly referred to the latter genus.

However, in 1975 Peter Galton named them as a new species of Dryosaurus : Dryosaurus canaliculatus. The specific name means "with a small channel" in Latin, referring to a distinct groove between the condyles of the lower thighbone. [1] In 1977 Galton named a new genus for them: Valdosaurus, the name being derived from Latin Valdus, "Wealden", a reference to the Wealden Group. Its type species, D. canaliculatus, was thus renamed V. canaliculatus. [2] A second species, V. nigeriensis, was described by Galton and Philippe Taquet from younger rocks from Niger in 1982; [3] this has since been transferred to its own genus, Elrhazosaurus .

In 1998 William Blows inadvertently named another species, Valdosaurus dextrapoda , by including this name in a fauna list, [4] but this was an error, and the species has never been supported. [5] [6] Lacking description, it is a nomen nudum .

In 2012, a new specimen of Valdosaurus was discovered, [7] and it was described in 2016. [8] The specimen is the most complete yet found, which was found in articulation and includes a partial dorsal series, an almost complete tail, pelvic material, and both hind limbs. In life, the specimen would have been around 4–5 metres (13–16 ft) long. [8]

Classification

Galton assigned Valdosaurus to the Hypsilophodontidae, [1] [2] but this paraphyletic unnatural group has largely been abandoned. Today Valdosaurus is generally considered a member of the Dryosauridae. [9]

Palaeoenvironment

Restoration of Valdosaurus (lower left) with contemporary dinosaurs Meeting at the river threshold.jpg
Restoration of Valdosaurus (lower left) with contemporary dinosaurs

Having a close European relative of the American form Dryosaurus named led to most of the dryosaurid fossil material of Europe being referred to Valdosaurus. Valdosaurus was seen as not only present in England (the Wessex Formation of the Isle of Wight and the Hastings Beds of West Sussex) but probably also in Spain [ citation needed ]. These rock units were deposited between the Berriasian and Barremian stages, between approximately 145 and 125 million years ago. V. canaliculatus would then be known from thigh bones, extensive additional postcranial elements, partial lower jaws, and teeth. [9]

In 2009 however, Galton critically reviewed the Valdosaurus material. He concluded that no fossils from outside England could be reliably referred to the genus. He thus gave V. nigeriensis its own genus: Elrhazosaurus . Even of many of the English specimens it was uncertain whether they belonged to Valdosaurus, including all cranial elements and teeth. Some hindlimb and pelvis bones from the Upper Weald Clay Formation (late Barremian) were referable to V. canaliculatus. Some material from the earlier Hastings Beds (Valanginian) were referred to a Valdosaurus sp. Galton established that Richard Owen had in 1842 been the first to describe Valdosaurus thighbones, specimens BMB 004297-004300, assigning them to Iguanodon. Galton emphasized that though the type femora were very small, fourteen centimetres long (which has led to estimates of a length of 1.2 metres and a weight of ten kilograms [10] ), these were from a juvenile individual and that an adult would have been a "medium-sized euornithopod", with some thighbones reaching a length of half a metre. [6]

See also

Related Research Articles

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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>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">Dinosaur Isle</span> Dinosaur museum on the Isle of Wight

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

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

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

Neovenator is a genus of carcharodontosaurian theropod dinosaur. It is known from several skeletons found in the Early Cretaceous (Hauterivian-Barremian) Wessex Formation on the south coast of the Isle of Wight, southern England. It is one of the best known theropod dinosaurs from the Early Cretaceous of Europe.

Calamospondylus is a genus of theropod dinosaur. It lived during the Early Cretaceous and its fossils were found on the Isle of Wight in southern England. The type species is C. oweni.

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

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

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

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

Elrhazosaurus is a genus of basal iguanodontian dinosaur, known from isolated bones found in Early Cretaceous rocks of Niger. These bones were initially thought to belong to a species of the related dryosaurid Valdosaurus, but have since been reclassified.

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<i>Riparovenator</i> Genus of baryonychine spinosaur from the Early Cretaceous

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<i>Brighstoneus</i> Genus of hadrosauriform dinosaur

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<i>Vectidromeus</i> Genus of hypsilophodontid dinosaurs

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References

  1. 1 2 Galton, P.M., 1975, "English hypsilophodontid dinosaurs (Reptilia: Ornithischia)", Palaeontology18(4): 741-752
  2. 1 2 Galton, P.M., 1977. "The Upper Jurassic dinosaur Dryosaurus and a Laurasia-Gondwana connection in the Upper Jurassic", Nature268(5617): 230-232
  3. ↑ Galton, P.M. & P. Taquet, 1982, "Valdosaurus, a hypsilophodontid dinosaur from the Lower Cretaceous of Europe and Africa", Géobios13: 147-159
  4. ↑ Blows, W.T., 1998, "A review of Lower and Middle Cretaceous dinosaurs of England", New Mexico Museum of Natural History and Science Bulletin, Albuquerque14: 29-38
  5. ↑ Martill, D.M. and Naish, D., 2001, "Ornithopod dinosaurs." Pages 60-132 in Martill, D.M. and Naish, D. (eds.). Dinosaurs of the Isle of Wight, The Palaeontological Association, London.
  6. 1 2 Galton, P.M., 2009, "Notes on Neocomian (Late Cretaceous) ornithopod dinosaurs from England - Hypsilophodon, Valdosaurus, "Camptosaurus", "Iguanodon" - and referred specimens from Romania and elsewhere", Revue de Paléobiologie28(1): 211-273
  7. ↑ Lockwood, Jeremy A. F.; Martill, David M.; Maidment, Susannah C. R. (2024-12-31). "Comptonatus chasei, a new iguanodontian dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, southern England". Journal of Systematic Palaeontology . 22 (1). Bibcode:2024JSPal..2246573L. doi: 10.1080/14772019.2024.2346573 . ISSN   1477-2019.
  8. 1 2 Barrett, Paul. (2016). A new specimen of Valdosaurus canaliculatus (Ornithopoda: Dryosauridae) from the Lower Cretaceous of the Isle of Wight, England. Memoirs of Museum Victoria. 74. 29-48. 10.24199/j.mmv.2016.74.04.
  9. 1 2 Norman, David B. (2004). "Basal Iguanodontia". In Weishampel, D.B.; Dodson, P.; Osmólska, H. (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 413–437. ISBN   0-520-24209-2.
  10. ↑ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 283
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