Sphenodontia

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Sphenodontia
Young Bridge Lizard (Tuatara)

Young Bridge Lizard (Tuatara)

Temporal occurrence
Ladinium (Upper Middle Triassic ) until today
242 to 0 million years
Locations
  • Worldwide
Systematics
Amniotes (Amniota)
Sauropsida
Diapsida
Lepidosauromorpha
Scale lizards (Lepidosauria)
Sphenodontia
Scientific name
Sphenodontia
Williston , 1925

The Sphenodontia ( size for wedge-toothed ones ) or Rhynchocephalia (size for beak heads ) are a taxon of lizard-like, diapsid reptiles . They flourished in the Triassic and Jura . With the bridge lizard ( Sphenodon punctatus ) they still occur today on some islands off the coast of New Zealand . The earliest evidence of a sphenodontic animal comes from the Upper Middle Triassic of Germany.

features

Sphenodontier were small to medium-sized lizards, the pleurosaurs reached lengths of 75 centimeters, with the bridge lizards this is the maximum length. The vertebrae are amphicoel shaped (indented at both ends). The construction of the skull is conservative, the skull windows are particularly large. The acrodontic dentition (teeth sit on the upper edge of the jaw without a tooth root) show a varied adaptation to different food sources. The Upper Jurassic Sapheosaurus was toothless.

Systematics and fossil record

The Rhynchocephalia were once a collective taxon, to which many "primitive", not closely related taxa, e.g. B. also the Rhynchosauria , were counted. In the system currently used, only two families are assigned to them: the aquatic , exclusively fossil Pleurosauridae and the terrestrial Sphenodontidae. To avoid confusion with the old concept of Rhynchocephalia, many authors only use the name "Sphenodontia" for these two families. The Sphenodontia are united with their sister group , the scale creeping animals (Squamata), in the taxon scale lizards (Lepidosauria).

Fossil of the aquatic Sphenodontier Pleurosaurus goldfussi in the Berlin Museum of Natural History
Life picture of Brachyrhinodon taylori from the Upper Triassic of Scotland, one of the oldest known Sphenodont animals

The oldest known remains of Sphenodonti (as of 2015) are in the form of isolated jaws (cf.  Diphydontosaurus  sp.) And come from the lower Keuper ( Erfurt Formation , uppermost Middle Triassic ) of Vellberg in Baden-Württemberg. More complete skeletons, similar to those of recent bridge lizards, are known from the early Upper Triassic . From the Upper Triassic to the Upper Jurassic , sphenodontics are widespread worldwide. Cretaceous fossils are rare, and there are few finds from the Cenozoic either , all of which are limited to New Zealand and the genus Sphenodon .

literature

  • Robert L. Carroll: Paleontology and Evolution of the Vertebrates . Thieme, Stuttgart 1993, ISBN 3-13-774401-6
  • K. Deckert, Gisela Deckert , GE Freytag, G. Peters, G. Sterba: Urania animal kingdom, fish, amphibians, reptiles. Urania-Verlag, 1991, ISBN 3-332-00376-3 .

Web links

Commons : Sphenodontia  - collection of images, videos and audio files

Individual evidence

  1. ↑ Marc EH Jones, Cajsa Lisa Anderson, Christy A. Hipsley, Johannes Müller, Susan E. Evans, Rainer R. Schoch: Integration of molecules and new fossils supports a Triassic origin for Lepidosauria (lizards, snakes, and tuatara). BMC Evolutionary Biology. Vol. 13, No. 1, 2013, Item No. 208, doi : 10.1186 / 1471-2148-13-208 (Open Access)
  2. ↑ Marc EH Jones, Alan JD Tennyson, Jennifer P. Worthy, Susan E. Evans, Trevor H. Worthy: A sphenodontine (Rhynchocephalia) from the Miocene of New Zealand and palaeobiogeography of the tuatara (Sphenodon). Proceedings of the Royal Society B. Vol. 282, 2009, pp. 1385-1390, doi : 10.1098 / rspb.2008.1785