Rhynchocephalia

Young Tuatara ( Tuatara )

• Worldwide

The Sphenodontia (Size: Keilzahnige ) or Rhynchocephalia (Lat.: beak heads) are a taxon of lizard- like, diapsider reptiles that lived during the Triassic and Jurassic, and the tuatara ( Sphenodon ) today on some islands off the coast of New Zealand occur. Fossil jaw remains from the Lower Triassic are already assigned to the Sphenodontia. Complete skeletons that are similar to those of extant tuatara, there are from the Upper Triassic. From then on, until the Upper Jurassic, the animals were worldwide, including in Europe, widespread. Fossils from the Cretaceous are rare, from the Cenozoic, there is still no finds.

Features

Sphenodontier were small to medium-sized lizard that Pleurosaurier reached lengths of 75 centimeters in the tuatara, this is the maximum length. The vertebrae are formed amphicoel ( indented on both ends). The construction of the skull is conservative, the cranial windows are particularly large. The akrodonte dentition (teeth sit without root on the upper edge of the jaw) show a varied adaptation to different food sources. The Upper Jurassic Sapheosaurus was toothless.

System

The Rhynchocephalia were once a Sammeltaxon to the many primitive, not more closely related taxa, such as the Rhynchosauria, were counted. Today, they include only two families, the aquatic and the terrestrial Pleurosauridae Sphenodontidae. To avoid confusion with the old meaning of the name Sphenodontia is used today mostly. The Sphenodontia be united with their sister group, the modern Schuppenkriechtieren ( Squamata ) in the taxon Lepidosauria.

• Sphenodontia Pleurosauridae Palaeopleurosaurus
• Pleurosaurus

• Kallimodon
• Homoeosaurus
• Sapheosaurus
• Pamizinsaurus
• Brachyrhinodon
• Polysphenodon
• Clevosaurus
• Sphenodontinae Cynosphenodon
• Eilenodon
• Tuatara ( Sphenodon )
• Zapatadon
• Oenosaurus