Valdosaurus Temporal range: Early Cretaceous, | |
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Assigned skeleton at Dinosaur Isle Museum | |
Scientific classification | |
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 | |
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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.
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]
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]
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]
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.
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.
The Isle of Wight is one of the richest dinosaur localities in Europe, with over 20 species of dinosaur having been recognised from the early Cretaceous Period, some of which were first identified on the island, as well as the contemporary non-dinosaurian species of crocodile, turtle and pterosaur.
Weald Clay or the Weald Clay Formation is a Lower Cretaceous sedimentary rock unit underlying areas of South East England, between the North and South Downs, in an area called the Weald Basin. It is the uppermost unit of the Wealden Group of rocks within the Weald Basin, and the upper portion of the unit is equivalent in age to the exposed portion of the Wessex Formation on the Isle of Wight. It predominantly consists of thinly bedded mudstone. The un-weathered form is blue/grey, and the yellow/orange is the weathered form, it is used in brickmaking.
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'.
Hypsilophodontidae is a traditionally used family of ornithopod dinosaurs, generally considered invalid today. It historically included many small bodied bipedal neornithischian taxa from around the world, and spanning from the Middle Jurassic until the Late Cretaceous. This inclusive status was supported by some phylogenetic analyses from the 1990s and mid 2000s, although there have also been many finding that the family is an unnatural grouping which should only include the type genus, Hypsilophodon, with the other genera being within clades like Thescelosauridae and Elasmaria. A 2014 analysis by Norman recovered a grouping of Hypsilophodon, Rhabdodontidae and Tenontosaurus, which he referred to as Hypsilophodontia. All other analyses from around the same time have instead found these latter taxa to be within Iguanodontia.
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.
Calamosaurus was a genus of small theropod dinosaur from the Barremian-age Lower Cretaceous Wessex Formation of the Isle of Wight, England. It is based on two cervical vertebrae, collected by Reverend William Fox.
Lurdusaurus is a genus of massive and unusually shaped iguanodont dinosaur from the Elrhaz Formation in Niger. It contains one species, L. arenatus. The formation dates to the Early Cretaceous, roughly 112 million years ago. Lurdusaurus has a highly atypical body plan for an iguanodont, with a small skull, long neck, rotund torso, and powerful forelimbs and claws, somewhat reminiscent of a ground sloth. Its metacarpals are fused and reinforced into a large block, and the thumb spike is remarkably enormous. These would have allowed the hand to have functioned almost like a ball-and-chain flail. Lurdusaurus is estimated to have been 7–9 m (23–30 ft) long and 2 m high when on all-fours, but its stomach would have been only 70 cm off the ground. It may have weighed 2.5–5.5 t, conspicuously heavy for an iguanodontid this size.
Laosaurus is a genus of neornithischian dinosaur. The type species, Laosaurus celer, was first described by O.C. Marsh in 1878 from remains from the Oxfordian-Tithonian-age Upper Jurassic Morrison Formation of Wyoming. The validity of this genus is doubtful because it is based on fragmentary fossils. A second species from the Morrison Formation, L. gracilis, and a species from the late Cretaceous Allison Formation of Alberta, Canada, Laosaurus minimus, are also considered dubious.
Nanosaurus is the name given to a genus of neornithischian dinosaur that lived about 155 to 148 million years ago, during the Late Jurassic-age. Its fossils are known from the Morrison Formation of the south-western United States. The type and only species, Nanosaurus agilis, was described and named by Othniel Charles Marsh in 1877. The taxon has a complicated taxonomic history, largely the work of Marsh and Peter M. Galton, involving the genera Laosaurus, Hallopus, Drinker, Othnielia, and Othnielosaurus, the latter three now being considered to be synonyms of Nanosaurus. It had historically been classified as a hypsilophodont or fabrosaur, types of generalized small bipedal herbivore, but more recent research has abandoned these groupings as paraphyletic and Nanosaurus is today considered a basal member of Neornithischia.
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.
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, and possibly also Romania and Spain. The specimen, NHM R2998, comes from the Purbeck Limestone, dating to the middle Berriasian stage. 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, meaning "Owen's tooth", named after Sir Richard Owen. Galton interpreted the genus as an iguanodontoid more derived than Camptosaurus but less derived than Lurdusaurus.
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.
Wightia is a genus of tapejarid pterosaur recovered from the Lower Cretaceous (Barremian) aged Wessex Formation of the Isle of Wight of England, from which it gets its name. The only species within this genus is W. declivirostris.
Ceratosuchops is a genus of spinosaurid from the Early Cretaceous (Barremian) of Britain.
Brighstoneus is a genus of hadrosauriform dinosaur from the Early Cretaceous Wessex Formation of the Isle of Wight, England. The genus contains a single species, Brighstoneus simmondsi, known from a partial skeleton.
Vectidromeus is an extinct genus of hypsilophodontid ornithopod dinosaur from the Early Cretaceous Wessex Formation of England. The genus contains a single species, V. insularis, known from a partial skeleton belonging to a juvenile individual.
Comptonatus is a genus of ornithopod dinosaur from the Early Cretaceous epoch. Its remains are known from the Wessex Formation in England. The type and only species is C. chasei.