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Temporal range: Late Triassic–Recent
Tuatara (Sphenodon punctatus)
Skeleton of Sphenofontis, a sphenodontine from the Late Jurassic of Germany
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Rhynchocephalia
Suborder: Sphenodontia
Family: Sphenodontidae
Cope, 1870 (conserved name)
Type species
Hatteria punctata
Gray, 1842
  • Hatteriidae
    Cope, 1864 (rejected name)
  • Rhynchocephalidae
    Hoffmann, 1881 (rejected name)
Skeleton of Navajosphenodon from the Early Jurassic of North America, one of the oldest sphenodontines.
Illustration of the skull of Navajospenodon in lateral view, showing closed temporal bar (bottom right)

Sphenodontidae is a family within the reptile group Rhynchocephalia, comprising taxa most closely related to the living tuatara of the genus Sphenodon. Historically the taxa included within Sphenodontidae have varied greatly between analyses, and the group has lacked a formal definition.[2] Cynosphenodon from the Early Jurassic of Mexico has consistently been recovered as a close relative of the tuatara in most analyses, with the clade containing the two often called Sphenodontinae.[2] The herbivorous Eilenodontinae, otherwise considered part of Opisthodontia, is also sometimes considered part of this family as the sister group to Sphenodontinae. Sphenodontines first appeared during the Early Jurassic, and are characterised by a complete lower temporal bar caused by the fusion of the quadrate/quadratojugal and the jugal, which was an adaption for reducing stress in the skull during hard biting.[3] Like modern tuatara, members of Sphenodontinae were likely generalists with a carnivorous/insectivorous diet.[4]


  1. ^ Apesteguia RO, Rougier GW (2012). "A basal sphenodontian (Lepidosauria) from the Jurassic of Patagonia: new insights on the phylogeny and biogeography of Gondwanan rhynchocephalians". Zoological Journal of the Linnean Society. 166 (2): 342–360. doi:10.1111/j.1096-3642.2012.00837.x. [R. Benson/R. Benson]
  2. ^ a b Simões TR, Caldwell MW, Pierce SE (December 2020). "Sphenodontian phylogeny and the impact of model choice in Bayesian morphological clock estimates of divergence times and evolutionary rates". BMC Biology. 18 (1): 191. doi:10.1186/s12915-020-00901-5. PMC 7720557. PMID 33287835.
  3. ^ Simões, Tiago R.; Kinney-Broderick, Grace; Pierce, Stephanie E. (2022-03-03). "An exceptionally preserved Sphenodon-like sphenodontian reveals deep time conservation of the tuatara skeleton and ontogeny". Communications Biology. 5 (1): 1–19. doi:10.1038/s42003-022-03144-y. ISSN 2399-3642. PMID 35241764.
  4. ^ Villa, Andrea; Montie, Roel; Röper, Martin; Rothgaenger, Monika; Rauhut, Oliver W. M. (2021-05-03). "Sphenofontis velserae gen. et sp. nov., a new rhynchocephalian from the Late Jurassic of Brunn (Solnhofen Archipelago, southern Germany)". PeerJ. 9: e11363. doi:10.7717/peerj.11363. ISSN 2167-8359. PMC 8101455. PMID 33987027.