Re: Extinct venomous mammals

[David Marjanovic <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Phil Bigelow" <bigelowp@juno.com>
Sent: Wednesday, June 22, 2005 5:26 PM

> Is the venom conductor a longitudinal fossa alongside the exterior side
> of the canine (primitive), or is it a (more evolved) internal channel?

It is a V- to C-shaped fossa.

The paper mentions that the (still) living *Solenodon* also has such a venom 
delivery system -- a similar groove on each 2nd lower incisor --, and it 
illustrates a mammalian lower canine from another late Paleocene site that 
is much bigger than the (upper!) canines of *Bisonalveus* and _also_ has a 
venom groove! Must have been fashionable. That makes _three_ cases of 
independent evolution of a venom delivery system in mammals, not counting 
the spurs of monotremes and several clades of Mesozoic mammals. :-o

I remember to have read a paper several months ago that found a single 
origin of venom in snakes, pointing out that many colubroid snakes that are 
not venomous according to the earlier literature are in fact venomous.