* Vidal, N.; Delmas, A.-S.; David, P.; Cruaud, C.; Couloux, A.; Hedges, S.B. 2007: The phylogeny and classification of caenophidian snakes inferred from seven nuclear protein-coding genes. C.R. Biologies, 330: 182–187. PDF
Xenophidia (Caenophidia) is a superfamily of the suborder Serpentes (snakes) that contains cobras, vipers, sea snakes and the majority of snake species. Almost all venomous snakes belong to this superfamily. Additionally, the broad belly scales and rows of dorsal scales correspond to the vertebrae in Caenophidians, while they do not in Henophidians or Scolecophidians.
Caenophidia contains most of the diversity of extant snakes, with over 3,000 species. They are believed to be a recent evolutionary radiation, having evolved in the mid-Cenozoic.
* Atractaspididae (mole vipers).
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