Valdosaurus

Valdosaurus ("Weald Lizard") is a genus of bipedal herbivorous iguanodont ornithopod dinosaur found on the Isle of Wight and elsewhere in England. It lived during the Early Cretaceous.

Valdosaurus
Temporal range: Early Cretaceous
Valdosaurus
Referred skeleton of Valdosaurus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Suborder: Ornithopoda
Family: Dryosauridae
Genus: Valdosaurus
Galton, 1977
Species:
V. canaliculatus
Binomial name
Valdosaurus canaliculatus
(Galton, 1975 [originally Dryosaurus])

Discovery and naming

Valdosaurus sp
Valdosaurus sp. ilia, NHM 2150, from the Upper Tunbridge Wells Sandstone 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.

Distribution and material

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 also in Romania (the Cornet Bauxite of Bihor) and Spain. 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.[7]

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 Wealden 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[8]), 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]

In 2016, a new specimen of Valdosaurus was described. 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. [9]

Phylogeny

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.[7]

See also

References

  1. ^ a b Galton, P.M., 1975, "English hypsilophodontid dinosaurs (Reptilia: Ornithischia)", Palaeontology 18(4): 741-752
  2. ^ a b Galton, P.M., 1977. "The Upper Jurassic dinosaur Dryosaurus and a Laurasia-Gondwana connection in the Upper Jurassic", Nature 268(5617): 230-232
  3. ^ Galton, P.M. & P. Taquet, 1982, "Valdosaurus, a hypsilophodontid dinosaur from the Lower Cretaceous of Europe and Africa", Géobios 13: 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, Albuquerque 14: 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. ^ a b 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 Paléobiologie 28(1): 211-273
  7. ^ a b 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.
  8. ^ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 283
  9. ^ 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.
Aralosaurini

Aralosaurini is a tribe of basal lambeosaurine hadrosaurs endemic to Eurasia. It currently contains Aralosaurus (from the Aral sea of Kazakhstan) and Canardia (from Toulouse, Southern France).

Berriasian

In the geological timescale, the Berriasian is an age or stage of the Early Cretaceous. It is the oldest, or lowest, subdivision in the entire Cretaceous. It spanned the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years ago). The Berriasian succeeds the Tithonian (part of the Jurassic) and precedes the Valanginian.

Camptosaurus

Camptosaurus ( KAMP-toh-SAWR-əs) is a genus of plant-eating, beaked ornithischian dinosaurs of the Late Jurassic period of western North America and Europe. The name means 'flexible lizard' (Greek καμπτος/kamptos meaning 'bent' and σαυρος/sauros meaning 'lizard').

Dryosauridae

Dryosaurids were primitive iguanodonts. They are known from Middle Jurassic to Early Cretaceous rocks of Africa, Europe, and North America.

Dryosaurus

Dryosaurus ( DRY-o-SAWR-əs; meaning 'tree lizard', Greek δρυς/drys meaning 'tree, oak' and σαυρος/sauros meaning 'lizard'; the name reflects the forested habitat, not a vague oak-leaf shape of its cheek teeth as is sometimes assumed) is a genus of an ornithopod dinosaur that lived in the Late Jurassic period. It was an iguanodont (formerly classified as a hypsilophodont). Fossils have been found in the western United States (and supposedly the Marnes de Bleville locality in Europe), and were first discovered in the late 19th century. Valdosaurus canaliculatus and Dysalotosaurus lettowvorbecki were both formerly considered to represent species of Dryosaurus.

Edmontosaurini

Edmontosaurini are a tribe of saurolophine hadrosaurs that lived in the Northern Hemisphere during the Late Cretaceous period. It currently contains Edmontosaurus (from the United States and Canada), Ugrunaaluk (from Alaska, U.S.), and Shantungosaurus (from Shandong, China), though Anatosaurus might be a distinct genus. Kerberosaurus and Kundurosaurus from Russia could also be members though are more likely saurolophins.

Elasmaria

Elasmaria is a clade of iguanodont ornithopods known from Cretaceous deposits in South America, Antarctica, and Australia.

Elrhazosaurus

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

Galleonosaurus

Galleonosaurus (meaning "galleon lizard" as the upper jaw bone resembles an upturned galleon) is a genus of basal ornithopod dinosaur from the Wonthaggi Formation of the Gippsland region of Victoria, Australia. The type and only species is G. dorisae, described by Herne et al. in 2019.

Hauterivian

The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous epoch or a stage in the Lower Cretaceous series. It spans the time between 132.9 ± 2 Ma and 129.4 ± 1.5 Ma (million years ago). The Hauterivian is preceded by the Valanginian and succeeded by the Barremian.

Hypsilophodon

Hypsilophodon (; meaning "Hypsilophus-tooth") is an ornithischian 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.

The first remains of Hypsilophodon were found in 1849; the type species, Hypsilophodon foxii, was named in 1869. Abundant fossil discoveries were made on the Isle of Wight, giving a good impression of the build of the species. It was a small bipedal animal with an herbivorous or possibly omnivorous diet. Hypsilophodon reached up to 1.8 metres (5.9 ft) in length, weighed about 20 kg (45 lbs), and was an agile runner. It had a pointed head equipped with a sharp beak used to bite off plant material, much like modern day parrots.

Older studies have given rise to number of misconceptions about Hypsilophodon: that it would climb trees, that its name means "high-rided tooth", was armoured, reached a length of 2.3 metres (7.5 ft), and was also found outside of Wight. During the past decades new research has gradually shown this to be incorrect.

Iguanodontia

Iguanodontia (the iguanodonts) is a clade of herbivorous dinosaurs that lived from the Middle Jurassic to Late Cretaceous. Some members include Camptosaurus, Dryosaurus, Iguanodon, Tenontosaurus, and the hadrosaurids or "duck-billed dinosaurs". Iguanodontians were one of the first groups of dinosaurs to be found. They are among the best known of the dinosaurs, and were among the most diverse and widespread herbivorous dinosaur groups of the Cretaceous period.

Koshisaurus

Koshisaurus is a monospecific genus of basal hadrosauroid from the Kitadani Formation in Japan. The discovery of the genus suggests that hadrosauroids had higher diversity along the eastern margin of Asia in the Early Cretaceous. "Koshi" means an old Japanese regional name including Fukui prefecture where fossils of the genus were discovered.

Lambeosaurini

Lambeosaurini is one of the four lambeosaurine tribes, previously known as Corythosaurini, is a group of hadrosaurid ornithopods known from N. America and Asia. It is defined as all lambeosaurines closer to Lambeosaurus lambei than to Parasaurolophus walkeri (Lambeosaurus lambei>Parasaurolophus walkeri).It currently contains the following genera; Corythosaurus (from the Red Deer River, Canada), Hypacrosaurus (from Alberta, Canada, and Montana, U.S.), Lambeosaurus (also from Canada), Magnapaulia (from Baja California, Mexico), Olorotitan (from the Amur River, Russia), Sahaliyania (also from the Amur river, however in China), and Velafrons (from Coahuila, Mexico). It also may include Angulomastacator (from Rio Grande, Texas), Nipponosaurus (from Sakhalin, Russia), and Amurosaurus (also from the Amur river, again on the Russian side).

Owenodon

Owenodon is a genus of iguanodontian dinosaur known from a partial lower jaw discovered in Early Cretaceous-age rocks of Durlston Bay, Dorset, United Kingdom. The specimen, NHM R2998, comes from the Purbeck Limestone, dating to the middle Berriasian stage (approximately 143 million years ago). It was first described by Richard Owen, who in 1874 assigned it to Iguanodon as the type specimen of the new species I. hoggii, the specific name honouring naturalist A.J. Hogg who had originally collected the fossil in 1860. The bone was damaged during initial preparation but was freed from the surrounding rock matrix by an acid bath between 1975 and 1977. David Norman and Paul Barrett subsequently transferred the species to Camptosaurus in 2002, but this was challenged, and in 2009 Peter Galton assigned the species to the new genus Owenodon. Galton interpreted the genus as an iguanodontoid more derived than Camptosaurus but less derived than Lurdusaurus.

Parasaurolophini

Parasaurolophini is a tribe of derived lambeosaurine hadrosaurids that are native to Asia, N. America, and probably Europe. It is defined as everything closer to Parasaurolophus walkeri than to Lambeosaurus lambei. It currently contains Charonosaurus (from China), Parasaurolophus (from Utah, New Mexico, China and Alberta), and possibly Blasisaurus and Arenysaurus (both from Spain)

Rhabdodontomorpha

Rhabdodontomorpha is a clade of basal iguanodont dinosaurs. This group was named in 2016 in the context of the description, based on Spanish findings, of an early member of the Rhabdodontidae. A cladistic analysis was conducted in which it was found that Muttaburrasaurus was the sister species of the Rhabdodontidae sensu Weishampel. Therefore, Paul-Emile Dieudonné, Thierry Tortosa, Fidel Torcida Fernández-Baldor, José Ignacio Canudo and Ignacio Díaz-Martínez defined Rhabdodontomorpha as a nodal clade: the group consisting of the last common ancestor of Rhabdodon priscus Matheron, 1869 and Muttaburrasaurus langdoni Bartholomai and Molnar, 1981; and all its descendants. Within the clade are included also Zalmoxes and Mochlodon.The group consists of small to large plant eaters from Europe and Gondwana. It must have split from other iguanodont groups during the Middle Jurassic.

Valanginian

In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian stage succeeds the Berriasian stage of the Lower Cretaceous and precedes the Hauterivian stage of the Lower Cretaceous.

Weald Clay

Weald Clay or the Weald Clay Formation is a Lower Cretaceous sedimentary rock underlying areas of South East England. It is part of the Wealden Group of rocks. The clay is named after the Weald, an area of Sussex and Kent. It varies from orange and grey in colour and is used in brickmaking.

The un-weathered form is blue/grey, and the yellow/orange is the weathered form; they have quite different physical properties. Blue looks superficially like a soft slate, is quite dry and hard and will support the weight of buildings quite easily.

Because it is quite impermeable, and so dry, it does not get broken by tree roots. It is typically found at 750mm down below a layer of yellow clay. Yellow, found on the surface, absorbs water quite readily so becomes very soft in the winter.

The two different types make quite different bricks.

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