Living reconstruction of Paradapedon
|249.7 to 199.6 million years|
|Osborn , 1903|
The Rhynchosauria are an extinct group of herbivorous reptiles from the Triassic . They have been found in Europe, North America, Brazil, India, and East and South Africa, among others.
The plump, short-legged animals were characterized by reduced dentition in the front jaw and by tooth plates in the rear jaw. The intermaxillary bone, the foremost bone in the upper jaw, was toothless and formed a hook-shaped, protruding "beak". In the back of the jaw, the individual teeth sat on large bone plates. The worn teeth on the front edge were replaced with newly formed teeth on the rear edge of the bone plate.
In the course of evolution , the Rhynchosauria's skull became wider and wider, and in the later forms it is wider than it is long. The original upper temporal opening of the diapsids widened enormously in the rhynchosaurs to provide space for the large adductors of the jaw muscles. The largest Rhynchosauria reached lengths of up to 2.5 meters.
The first Rhynchosauria, the genera Rhynchosaurus , Mesosuchus and Howesia , appeared in the Lower Triassic. In these forms, the intermaxillary bone still has some teeth. Later species lost these teeth, the head became increasingly broader and the animals larger.
In the Middle Triassic , the rhynchosauria were among the most common larger terrestrial vertebrates in South America, India and East Africa. Only a few closely related genera remained in the Upper Triassic (including Scaphonyx , Paradapedon and Hyperodapedon ).
At the end of the Triassic, the group died out.
The Rhynchosauria were earlier because of a superficial similarity in the skull anatomy and the dentition together with the (today so called) Sphenodontia ( bridge lizards and extinct relatives) as Rhynchocephalia to the scale lizards (Lepidosauria).
It was later recognized that the anatomy of the skull only has primitive features in common and that the dentition is clearly different. Today they are placed in the trunk line of the Archosauria to the Archosauromorpha .
This is followed by a generic list according to Benton and Hone (2008) and Langer et al. (2010):
- Mesodapedon (probably synonym of Stenaulorhynchus )
- Paradapedon (probably synonymous with Hyperodapedon )
- Scarphonyx (probably synonymous with Hyperodapedon )
- Robert L. Carroll : Paleontology and Evolution of the Vertebrates. Thieme, Stuttgart et al. 1993, ISBN 3-13-774401-6 .
- Martin Sander : Reptiles. 220 individual representations (= Haeckel library. Vol. 3). Enke, Stuttgart 1994, ISBN 3-432-26021-0 .
- ^ David WE Hone, Michael J. Benton : A new genus of Rhynchosaur from the Middle Triassic of South-West England. In: Palaeontology. Vol. 51, No. 1, 2008, pp. 95-115, doi : 10.1111 / j.1475-4983.2007.00739.x .
- ^ Max C. Langer, Felipe C. Montefeltro, David E. Hone, Robin Whatley, Cesar L. Schultz: On Fodonyx spenceri and a new rhynchosaur from the Middle Triassic of Devon. In: Journal of Vertebrate Paleontology. Vol. 30, No. 6, 2010, pp. 1884-1888, doi : 10.1080 / 02724634.2010.521901 .
- ^ David M. Dilkes: The Early Triassic rhynchosaur Mesosuchus browni and the interrelationships of basal archosauromorph reptiles. In: Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences. Vol. 353, No. 1368, 1998, pp. 501-541, doi : 10.1098 / rstb.1998.0225 .
- Mikko's Phylogeny Archive Rhynchosauria
- Palaeos.com Rhynchosauria
- The Taxonomicon Order † Rhynchosauria