Sphenodontia

Sphenodonts
Temporal range: Late Triassic - Recent
Sphenodon
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Subclass: Diapsida
Infraclass: Lepidosauria
Order: Sphenodontia
(Williston, 1925)
Families

Sphenodontia is an order of lizard-like reptiles that includes only one living genus, the tuatara (Sphenodon), and only two living species. Despite its current lack of diversity, the Sphenodontia at one time included a wide array of genera in several families, and represents a lineage stretching back to the Mesozoic Era.

Contents

Systematics

Sphenodontia, once a wastebin taxon containing a diverse array of unrelated reptiles (notably the rhynchosaurs), today consists of three families: the possibly paraphyletic Gephyrosauridae, the Pleurosauridae, and the Sphenodontidae. Sphenodontidae is the family which contains all modern tuatara, as well as a number of extinct subfamilies.

Taxonomy

Classification follows Wu (1994),[1] Evans et al. (2001),[2] and Apesteguia & Novas (2003).[3][4]

Phylogeny

The following is a cladogram of Sphenodontia after Wu (1994),[5] Evans et al. (2001),[6] and Apesteguia & Novas (2003).[7][8]

SPHENODONTIDA
unnamed

Gephyrosaurus


Sphenodontia
unnamed

Diphydontosaurus



unnamed

Planocephalosaurus


Pleurosauridae
unnamed

Palaeopleurosaurus


unnamed

Pleurosaurus



Sphenodontidae
unnamed

Rebbanasaurus


"Clevosaurinae"
unnamed

Polysphenodon



Brachyrhinodon



Clevosaurus



Sphenodontinae
unnamed

Homoeosaurus



Kallimodon


unnamed
unnamed

Sapheosaurus


unnamed

Ankylosphenodon



Opisthodontia
unnamed

Pamazinsaurus


unnamed
unnamed
unnamed

Zapatadon



Theretairus



Sphenovipera


Sphenodontini
unnamed

Cynosphenodon


unnamed

Sphenodon (Tuatara)







unnamed

Opisthias


Eilenodontini
unnamed

Toxolophosaurus


unnamed
unnamed

Priosphenodon


unnamed

Eilenodon










References

  1. ^ Wu, X-C. 1994: Late Triassic-Early Jurassic sphenodontians from China and the phylogeny of the Sphenodontia. in Fraser, N. C. & Sues, H-D. 1994: In the Shadow of the Dinosaurs. Cambridge University Press, New York. 1994
  2. ^ Evans, S. E., Prasad, G. V. R. & Manhas, B. K., 2001: Rhynchocephalians (Diapsida: Lepidosauria) from the Jurassic Kota Formation of India. Zoological Journal of the Linnean Society: Vol. 133, #3, pp. 309-334
  3. ^ Apesteguia, S. & Novas, F. E., 2003: Large Cretaceous sphenodontian from Patagonia provides insight into lepidosaur evolution in Gondwana. Nature: Vol. 425, pp. 609-612
  4. ^ Mikko's Phylogeny Archive
  5. ^ Wu, X-C. 1994: Late Triassic-Early Jurassic sphenodontians from China and the phylogeny of the Sphenodontia. in Fraser, N. C. & Sues, H-D.. 1994: In the Shadow of the Dinosaurs. Cambridge University Press, New York. 1994
  6. ^ Evans, S. E., Prasad, G. V. R. & Manhas, B. K., 2001: Rhynchocephalians (Diapsida: Lepidosauria) from the Jurassic Kota Formation of India. Zoological Journal of the Linnean Society: Vol. 133, #3, pp. 309-334
  7. ^ Apesteguía S, Novas FE (2003) Large Cretaceous sphenodontian from Patagonia provides insight into lepidosaur evolution in Gondwana. Nature, 425:609–612
  8. ^ "Sphenodontida". http://www.helsinki.fi/~mhaaramo/metazoa/deuterostoma/chordata/reptilia/lepidosauromorpha/sphenodontida.html. Retrieved May 3, 2010. 

External links