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Re: Additional material on the Sinornthosaurus venom report



You also have some mammals with sulci and without venom, including
baboons, if I do not recall badly about a paper indicating that the
sulci are present in many non-venomous mammals, regarding a hypothesis
on the possibility of a venom-delivering system in certain Mesozoic
mammals. "Labyrinthodonts" also have many sulci per tooth, but they do
not look like needing venom for subduing prey they can swallow at once
(are there examples of living non-amniote sarcopterygians with
venomous bites?). In any case, absence of a venomous bite for extant
archosars suggests venom was not present in non-avian dinosaurs.

2009/12/22 Michael Mortimer <mickey_mortimer111@msn.com>:
>
> Denver Fowler wrote-
>
>> there's a slightly better image of the teeth here:
>>
>> http://www.sciencedaily.com/releases/2009/12/091221212630.htm
>>
>> Mmm... almost certainly hanging out of their sockets. Is this another case 
>> of PNAS not having reviewed papers? It's not at all unusual to find 
>> depressed areas such as this in theropod tooth roots.
>
> I agree, those are quite common.  And even real grooves on the crown aren't 
> uncommon in theropods- Ceratosaurus, baryonychines, Paronychodon, etc.. 
>  Since it's written by Martin and Burnham, I wouldn't be surprised if they 
> didn't know what they were talking about.  The only depressions on the 
> maxilla ("for a venom gland") are the antorbital fossa and the fossa within 
> it around the promaxillary fenestra, both odd places to put a venom gland. 
>  The lateral ridge below the antorbital fossa doesn't connect with either 
> fossa or the teeth themselves except perhaps via the neurovascular foramina. 
>  Next thing you know, troodontids will be venomous because of their deep 
> labial dentary groove with foramina. ;)  Suppose we'll see the paper soon 
> enough.
>
> Mickey Mortimer
> The Theropod Database- http://home.comcast.net/~eoraptor/Home.html
>