Iguanodontia

Skeletal reconstruction of Iguanodon bernissartensis at the Natural History Museum in London

  • Worldwide

The Iguanodontia were herbivorous, quadruped ( four legged ) or biped ( two-legged ) Locomotive dinosaurs that occurred on all continents from the Upper Jurassic to late Cretaceous. The group includes all bird Beck dinosaurs that are more closely related than Edmontosaurus with Thescelosaurus, also known hadrosaur.

Description

Iguanodons were medium to large. The slightly built, bipedal Dryosaurus was about two to three meters long, Iguanodon, after which the whole group was named, reached a length of ten to eleven meters and probably weighed 2500 kg. For the very heavy built Lurdusaurus even a weight is given of 5,000 kg.

The skull of most basal iguanodons was elongated and laterally flattened somewhat. Only Dryosaurus and Zalmoxes had a more compact, shorter skull. The lower cranial window was oval, the orbit round and without reinforcing plates of bone. The nostrils were large. The number of teeth increased from basal to the advanced forms of becoming. Addition, the latter developed a beak on the premaxilla. Tenontosaurus and Zalmoxes had ten to twelve teeth had on the maxilla, at Dryosaurus there were already 13 to 17, 14 to 16 at Camptosaurus Iguanodon came to almost 30 teeth, 33 Eolambia

Basically, all genera or species of Iguanodontia were distinguished by their dentition. Unlike most other dinosaurs, they were able to bite off their plant food to the front part of the muzzle and then to chew with his teeth.

Stratigraphic and geographic distribution

The first is sure to be detected Iguanodont Camptosaurus from the early Kimmeridgian of England and Dryosaurus from the Kimmeridgian of North America and Africa. In the Upper Jurassic, the group in Africa, Europe and North America was widespread. Even older from the Middle Jurassic ( Callovian ) is Callovosaurus, whose exact membership is still not clear properly in the system. However, he shows characteristics that are similar to the later Camptosaurus.

From the Early Cretaceous also finds from Asia, South America and Australia are known. During the mid-Cretaceous ( Albian to Cenomanian ) throughout Laurasia was inhabited by iguanodons. In the latter half of the Late Cretaceous non- hadrosauride iguanodons occurred only in Europe with Rhabdodon and Zalmoxes. On all other continents they have been replaced by Hadrosauriern. All iguanodons died at the end of the Cretaceous period, 65.5 million years with all other dinosaurs. Zalmoxes is the last proven fossil genus.

Internal classification of basal Iguanodontia

  • Iguanodontia Tenontosaurus
  • Rhabdodon
  • Zalmoxes
  • Dryomorpha Dryosauridae? Callovosaurus
  • Dryosaurus
  • Dysalotosaurus
  • Kangnasaurus
  • Planicoxa
  • Valdosaurus
  • Ankylopollexia
  • Camptosaurus
  • Draconyx
Maastrichtian Mya (unit) Ornithopod Corythosaurus Lambeosaurus
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