Sphenodontidae

Sphenodontidae is a family within the reptile group Rhynchocephalia, comprising taxa most closely related to the living tuatara (Sphenodon punctatus). 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 adaptation 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]

Sphenodontidae
Temporal range:
Tuatara (Sphenodon punctatus)
Skeleton of Sphenofontis, a sphenodontine from the Late Jurassic of Germany
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Rhynchocephalia
Suborder: Sphenodontia
Family: Sphenodontidae
Cope, 1870 (conserved name)
Type species
Hatteria punctata
Gray, 1842
Subgroups
Synonyms
  • 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 Navajosphenodon in lateral view, showing closed temporal bar (bottom right)

References


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