Re: Venomous archosaurs

[Phillip Bigelow <bh162@scn.org>]

A footnote on the subject of fossil teeth with venom injection
characteristics: 

Figure 2 in Sues (1996) shows a classic example of a venom canal orifice
situated on the side of the tooth, rather than on the tip.  This
"orifice-on-side" morphology is seen in some exant venomous reptiles that
struggle with their prey.  Apparently, having the orifice on the tip of
the tooth (ala pit vipers) makes the tooth much weaker, and much more
likely to snap off during a struggle.  Also note in Figure 2 how robust
the _?Uatchitodon_ tooth is compared to that on pit vipers. 

Pit vipers don't struggle with their prey and therefore they can get away
with having teeth shaped like hypodermic needles.  Whatever _?Uatchitodon_
(or whatever the critter in Figure 2 was), my guess (speculative as it is)
is that the animal likely used a prolonged bite when it attacked its prey. 

                    <pb>

> >The reference is:
> >
> >Sues, H.-D. 1996. A reptilian tooth with apparent
> >venom canals from the Chinle Group (Upper Triassic)
> >of Arizona. Journal of Vertebrate Paleontology 16(3):571-572.