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Grooves to Tubes

Mitchell, J.S, A.B. Heckert & H-D. Sues 2010 'Grooves to tubes: evolution of 
the venom delivery 
system in a Late Triassic ?reptile?'. Naturwissenschaften (2010) 97:1117?1121


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

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Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj