Snake fangs (was Re: Vampire-osaurs?)

[Nick Pharris <npharris@umich.edu>]

Quoting Phil Bigelow <bigelowp@juno.com>:

> On highly-derived injection mechanisms (such as rattlesnake fangs), is a
> living pulp cavity still present?

I believe so, but it would be in the edge of the tooth, not the middle (see
below).

> Evolving an internal venom channel from a primitive lateral fossa doesn't
> seem too complicated, but then you have to re-plumb the output of the
> venom sac (from draining into the mouth, to draining into the inside of
> the tooth).

Not if the sides of the channel simply grow together to create a hollow tube, as
indeed seems to be what happened--see
http://members.iinet.net.au/~bush/onfangs.html
http://www.amonline.net.au/factsheets/snake_fangs.htm
http://www.zoobooks.com/newFrontPage/animals/virtualZoo/animals/s/snakes/fangs.html
for details.

Nick Pharris
Department of Linguistics
University of Michigan