Editor's Summary

2 February 2006

A sting in the tale

Conventional wisdom has it that among reptiles, venom delivery systems have evolved in only two lineages, advanced snakes and the helodermatid lizards, the latter represented by the Gila monster and beaded lizard, sole survivors of an ancient group of predators called the Monstersauria. A new study reveals that two additional major lineages of lizards — the varanids and iguanians — also produce venom toxins, and that iguanian lizards even have the signs of venom glands. This suggests that snakes and lizards are much more closely related than was thought, the snakes evolving from relatively advanced lizards, rather than as a separate evolutionary radiation.

Letter: Early evolution of the venom system in lizards and snakes

Bryan G. Fry, Nicolas Vidal, Janette A. Norman, Freek J. Vonk, Holger Scheib, S. F. Ryan Ramjan, Sanjaya Kuruppu, Kim Fung, S. Blair Hedges, Michael K. Richardson, Wayne. C. Hodgson, Vera Ignjatovic, Robyn Summerhayes and Elazar Kochva

doi:10.1038/nature04328

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