Sphenodontia

Tuatara Sphenodon punctatus with a prion chick, photographed by Paddy Ryan.

Belongs within: Lepidosauria.

The Sphenodontia are a clade of lizard-like reptiles that were abundant in the Triassic and Jurassic. They subsequently declined, and are represented in the modern fauna only by the tuatara Sphenodon species of New Zealand. Many extinct sphenodontians would have closely resembled the modern species, but Pleurosaurus from the Late Jurassic of Europe was an elongate aquatic reptile.

Synapomorphies (from Evans 1988): lacrimal bone absent; alternating acrodont teeth, seven or fewer premaxillary teeth on each side.

<==Sphenodontia [Sphenodontida]
    |  i. s.: Ankylosphenodon AN03
    |         Godavarisaurus S05
    |         *Sigmala sigmala S05
    |         Tingitana S05
    |--Diphydontosaurus Whiteside 1986 AN03, D07
    |    `--D. avonis AN03
    `--+--Planocephalosaurus robinsonae E88, NB17
       `--+--Homoeosaurus AN03
          `--Sphenodontidae S05
               |  i. s.: Piocormus E88
               |--+--Brachyrhinodon Huene 1910 AN03, D07
               |  |    `--B. taylori D07
               |  `--Clevosaurus Swinton 1939 AN03, S05
               |       |--*C. hudsoni Swinton 1939 S05
               |       |--C. bairdi Sues et al. 1994 S05
               |       |--C. convallis Säilä 2005 S05
               |       |--C. mcgilli Wu 1994 S05
               |       |--C. minor Fraser 1988 S05
               |       |--C. petilus Wu 1994 S05
               |       `--C. wangi Wu 1994 S05
               `--+--+--Palaeopleurosaurus AN03
                  |  `--Pleurosaurus Meyer 1831 E88, D07
                  |       |--P. ginsburgi D07
                  |       `--P. goldfussi N85
                  `--+--+--Kallimodon AN03 [incl. Leptosaurus E88]
                     |  `--Sapheosaurus AN03
                     `--+--Pamizinsaurus AN03
                        `--+--Sphenodontinae AN03
                           |    |--Zapatadon AN03
                           |    `--+--Cynosphenodon AN03
                           |       `--Sphenodon AN03
                           |            |--S. guntheri Buller 1877 WH02
                           |            `--S. punctatus (Gray 1842) WH02
                           `--Opisthodontia AN03
                                |--Opisthias AN03 [incl. Theretairus E88]
                                |    `--O. rarus AN03
                                `--Eilenodontinae AN03
                                     |--Toxolophosaurus AN03
                                     `--+--Eilenodon robustus AN03
                                        `--Priosphenodon Apesteguia & Novas 2003 AN03
                                             `--*P. avelasi Apesteguia & Novas 2003 AN03

*Type species of generic name indicated

REFERENCES

[AN03] Apesteguia, S., & F. E. Novas. 2003. Large Cretaceous sphenodontian from Patagonia provides insight into lepidosaur evolution in Gondwana. Nature 425: 609–612.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[E88] Evans, S. E. 1988. The early history and relationships of the Diapsida. In: Benton, M. J. (ed.) The Phylogeny and Classification of the Tetrapods vol. 1. Amphibians, Reptiles, Birds pp. 221–260. Clarendon Press: Oxford.

[NB17] Nesbitt, S. J., R. J. Butler, M. D. Ezcurra, P. M. Barrett, M. R. Stocker, K. D. Angielczyk, R. M. H. Smith, C. A. Sidor, G. Niedźwiedzki, A. G. Sennikov & A. J. Charig. 2017. The earliest bird-line archosaurs and the assembly of the dinosaur body plan. Nature 544: 484–487.

[N85] Norman, D. 1985 (reprinted 2000). The Illustrated Encyclopedia of Dinosaurs. Salamander Books: London.

[S05] Säilä, L. K. 2005. A new species of the sphenodontian reptile Clevosaurus from the Lower Jurassic of south Wales. Palaeontology 48 (4): 817–831.

[WH02] Worthy, T. H., & R. N. Holdaway. 2002. The Lost World of the Moa: Prehistoric life of New Zealand. Indiana University Press: Bloomington (Indiana).

Last updated: 9 August 2017.