Field of Science

New Species of the Late Triassic Venomous Archosauriform Uatchitodon

Mitchell, J. S., Heckert, A. B., and H.-D. Sues. 2010. Grooves to tubes: evolution of the venom delivery system in a Late Triassic “reptile”. Naturwissenschaften, online first. DOI 10.1007/s00114-010-0729-0

Abstract - Venom delivery systems occur in a wide range of extant and fossil vertebrates and are primarily based on oral adaptations. Teeth range from unmodified (Komodo dragons) to highly specialized fangs similar to hypodermic needles (protero- and solenoglyphous snakes). Developmental biologists have documented evidence for an infolding pathway of fang evolution, where the groove folds over to create the more derived condition. However, the oldest known members of venomous clades retain the same condition as their extant relatives, resulting in no fossil evidence for the transition. Based on a comparison of previously known specimens with newly discovered teeth from North Carolina, we describe a new species of the Late Triassic archosauriform Uatchitodon and provide detailed analyses that provide evidence for both venom conduction and document a complete structural series from shallow grooves to fully enclosed tubular canals. While known only from teeth, Uatchitodon is highly diagnostic in possessing compound serrations and for having two venom canals on each tooth in the dentition. Further, although not a snake, Uatchitodon sheds light on the evolutionary trajectory of venom delivery systems in amniotes and provide solid evidence for venom conduction in archosaur-line diapsids.

Supplemental data available here.


  1. Out of curiosity, do the remains of the new species contain anything other than the teeth mentioned in the article? Descriptions of Uatchitodon have revolved around its teeth for so long due to its potentially venomous nature that it makes one wonder what the actual living animal looked like.

  2. Both species are only known from teeth. Other bones of these taxa have probably been collected but cannot be recognized without a direct association. This is also what happened with Revueltosaurus and is probably common for tooth taxa.

  3. BTW...past experiences demonstrate that the possibilities of what the living animal of Uatchitodon may have looked like are wide open.


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