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Toen in 1842 de Dinosauria door Richard Owen voor het eerst benoemd werden, werd Iguanodon met Megalosaurus en Hylaeosaurus in deze groep geplaatst.
In 1878 werden in de steenkoolmijnen van Bernissart skeletten gevonden van de dinosauriërgeslacht Iguanodon. Deze vondst is vrij uniek in de wereld: 30 complete en enkele onvolledige skeletten werden teruggevonden. Het was de eerste keer dat zoveel en zo’n volledige resten van dinosauriërs werden teruggevonden en zijn momenteel te bezichtigen in het Koninklijk Belgisch Instituut voor Natuurwetenschappen. De soort kreeg de naam Iguanodon bernissartensis, wat wil zeggen Iguanodon van Bernissart. Het is nog steeds niet duidelijk hoe het komt dat zoveel skeletten op dezelfde plaats bewaard zijn maar algemeen neemt men aan dat de vindplaats een natuurlijke moerassige bezinkingsput was. De kadavers konden zich er gedurende vele jaren opeenstapelen en fossiliseerden. De steenkool uit het bekken van Bergen waarnaar gedolven werd, stamt uit het Carboon, de iguanodons uit het Jura, een latere periode. De dinosauriërs zijn gevonden doordat hun resten door een onderaardse verschuiving, een “cran”, in oudere lagen terecht zijn gekomen.
Iguanodon May 17, 2011
One of the first dinosaurs to be found, Iguanodon had strong back legs with three-toed feet and hoof-like nails.
Iguanodon usually walked on all fours but sometimes got about on just its hind legs. It weighed as much as an elephant.
Famed as being one of the first dinosaurs to be scientifically recognized, Iguanodon became something of a wastebasket taxon over the years. It was thought to have been a four-footed, rhinoceros-like animal until complete skeletons were found in a mine in Belgium in the 1880s. Thereafter, it was restored in a kangaroo-like pose. Now it is largely regarded as a four-footed animal once more.
Factbox //Name: Iguanodon, meaning ’iguana tooth’Size: up to 10m long and 5m highFood: plants and leavesLived: about 120-110 million years ago in the Early Cretaceous Period in Europe, Mongolia, North Africa
Iguanodon is the archetypal ornithopod. Its head is narrow and beaked, with tough, grinding teeth. Its hands consist of three weight-bearing fingers with hooves. It has a massive spike on the first finger used for defence or gathering food, and a prehensile fifth finger that works like a thumb. The hind legs are heavy and the three toes are weight-bearing. The long, deep tail balanced the animal as it walked.
Although Iguanodon was found and named by Mantell in 1825, the description was based only on teeth. In 2000 the International Commission on Zoological Nomenclature ruled the type species to be I. bernissartensis described in 1881, based on complete skeletons from Belgium.
Scientists speculate that Iguanodon probably walked on its toes, like a cat or dog. When chased by a predator, it could run at speeds of 35km/h. Iguanodon’s tail was stiff and flat, and this helped it to keep its balance.
Several skeletons of Iguanodon have been found close together. This is a clue to the fact that they lived in groups or herds. Iguanodon was the second dinosaur to be named (after Megalosaurus), in 1825.
Iguanodon had very strange hands. These had four fingers and a pointed thumb that resembled a spike. Iguanodon could only move this spike from side to side and used it as a weapon to defend itself. Iguanodon was a herbivore and used its fourth finger to hook down branches for food.
Most of Iguanodon’s day was probably spent searching for food and then chewing it up. It had no teeth at the front of its jaws but used its bony beak to bite off leaves. its back teeth were like an iguana’s, but much larger. There were about a hundred of them.
In 1878, in the small town of Bernissart in Belgium, miners working 322m down a shaft struck a mass of fossil bones. They had dug right through the skeleton of an Iguanodon. Finally, the bones of 39 Iguanodon were discovered there, and were put together. The complete skeletons can still be seen in the Royal Institute of Natural Sciences in Belgium.
Mantellisaurus atherfieldensis Iguanodon atherfieldensis
Leguanentand van Atherfield
- I. atherfieldensis, described by R.W. Hooley in 1925, was smaller and less robust than I. bernissartensis, with longer neural spines. It was renamed Mantellisaurus atherfieldensis in 2007.
Deze iguanodonsoort was kleiner en slanker dan Iguanodon bernissartensis; kijk maar naar de schedel en de voorpoten. Hij liep meestal op twee poten. Net als andere iguanodons had deze dinosoort puntige duimstekels om zich te verdedigen. Ooit werd gedacht dat deze ‘hoorns’ op de snuit van de iguanodons stonden, zoals bij een neushoorn! Naast de groep Iguanodon bernissartensis die in het Belgische mijndorp Bernissart werd gevonden, werd ook één heel goed bewaard skelet van Iguanodon atherfieldensis gevonden.
Deze dino leefde 135-110 miljoen jaar geleden. Paleontologen vonden hem in Groot-Brittanië, België, Duitsland, Spanje, Frankrijk en Mongolië
Iguanodon atherfieldensis is very similar to Iguanodon bernissartensis, but is smaller and more gracile and has some other osteological differences. Differences between these two species can be explained as ontogenetic, sexual, or individual (ecological) variations. Despite these possibilities, it is still considered that these are two different species.
Early, inaccurate sketch of two Iguanodon
1. Buckland, William. “Notice on the Megalosaurus or great Fossil Lizard of Stonesfield,” in: Transactions of the Geological Society of London, series. 2, vol. 1 (1824), pp. 390-396.
2. Mantell, Gideon. “Notice on the Iguanodon, a newly discovered fossil reptile, from the sandstone of Tilgate Forest, in Sussex,” in: Philosophical Transactions of the Royal Society of London, vol. 115 (1825), pp. 179-186.
3. Mantell, Gideon. The Wonders of Geology. London: Relfe and Fletcher, 1838.
4. Owen, Richard. “Report on British fossil reptiles. Part II,” in: Report of the Eleventh Meeting of the British Association for the Advancement of Science, held at Plymouth, July 1841, pp. 66-204.
5. Hawkins, Benjamin Waterhouse. “On visual education as applied to geology,” in: Journal of the Society of Arts, vol. 2 (1854), pp. 444-449.
6. Owen, Richard. Geology and Inhabitants of the Ancient World. London: Crystal Palace Library, and Bradbury & Evans, 1854.
7. Goodrich, Samuel Griswold. Illustrated Natural History of the Animal Kingdom. New York: Derby & Jackson, 1859
Incisivosaurus, Gabriel Lio.jpg
This image of Incisivosaurus, by Portia Sloan, was released to the press by the IVPP.
Incisivosaurus (“incisor lizard”) was a basal oviraptorosaurian theropod dinosaur from the Lower Cretaceous Period of what is now the People’s Republic of China. The holotype, a skull, mandible, and an incomplete cervical vertebra, was collected from the lowermost levels (fluvial beds) of the Yixian Formation (Jehol Group, Barremian) in the Sihetun area, near Beipiao City, in western Liaoning Province. The most significant, and highly unusual, characteristic of this theropod is it apparent adaptation to an herbivorous or False Doctrinevorous lifestyle. The genus was named for its prominent and rodent-like incisiform premaxillary teeth, which exhibit wear patterns common to plant-eating dinosaurs. The species name honors Dr. Jacques Gauthier. The skull, which measures approximately 10 cm, preserves the most complete dentition known for any oviraptorosaurian. A cladistic analysis published by Xu et al. (2002) indicates that Incisivosaurus is the basalmost of the Oviraptorosauria, below Caudipteryx + the Caenagnathoidea polytomy.
Osmolska et al. (2004) describe Incisivosaurus gauthieri as follows: “The long preorbital region is approximately half the length of the skull. The pterygoid has an accessory ventral flange that contacts its fellow on the midline. The mandible is slender with a reduced coronoid bone and a long external fenestra. The upper jaws and mandible bear a heterodont dentition; the first premaxillary tooth is mesiodistally compressed and greatly enlarged, while the second through fourth premaxillary teeth are much small and subconical. The nine maxillary teeth and eight or nine dentary teeth are small and lanceolate.” The skull also possesses a vertically oriented ectopterygoid, a fused dentary symphysis, a long and shallow posteroventral process of the dentary, large mandibular fenestra, a strap-like splenial, and long retroarticular process. All these traits are shared with more typical oviraptorosaurs.
However, the skull of Incisivosaurus lacks the following traits generally used to unite oviraptorosaurs and derived avialians: toothless jaws, abbreviated nasal, elongate parietals, quadrates with lateral cotyles for the quadratojugal, a rodlike jugal bar, a long maxillary process of the palatine, an absence of a subsidiary palatine fenestra, an ectopterygoid that articulates primarily with the lacrimal and maxilla laterally, absence of a jugal hook on the ectopterygoid. In most of these particular instances, Incisivosaurus more closely resembles therizinosaurs than birds.
Incisivosaurus is assumed to have been feathered like most other maniraptoran theropods and may have been secondarily flightless. Its total body length has been estimated at just under a meter.
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