RE: oviraptor beaks

[Toby White <mwhite@houston.rr.com>]

One of the odder aspects of the Oviraptor skull is that the eyes are placed 
so close to the mouth.  The arrangement looks extremely dangerous unless 
the dino was hunting nothing more resistant than some kind of Cretaceous 
oatmeal.  It must have been dry oatmeal at that, since anything else would 
have flowed out the sides.  The big beak makes more sense from a safety 
standpoint.  A beak is also consistent with the dicynodont-style slicer. 
 That kind of equipment is very efficient IF the food item is correctly 
fixed in position and oriented.  Otherwise its like trying to slice a 
tomato one-handed -- it just slips away to the side.  The simplest 
mechanical solution is to infer a beak of some kind: cuts off pieces of 
whatever of predictable size, helps keep the juices in the mouth, and 
orients the mouthful for processing while keeping claws, bones, stems, or 
even just dust away from the eyes.

  --Toby White

Vertebrate Notes at
http://dinodata.net and
http://home.houston.rr.com/vnotes/index.htm



On Friday, March 03, 2000 8:04 PM, Stephen Priestley 
[SMTP:sn2192@uniserve.com] wrote:
> Nick Longrich wrote:
>
> > [I think] Cracraft was right...when he compared the lower jaw of
> Chirostenotes
> > (Caenagnathus back then) to the dicynodonts. Big, anteriorly fused
> anterior
> > dentary beak with anteroposteriorly elongate jaw joint for a sliding
> motion
> > of the jaws.
> >     Turns out the rest of the skull fits in pretty well with this. Many
> > dicynodonts also have the extremely short skulls seen in oviraptorids,
> and
> > also if I recall have fused premaxes.
>
> Yes, all but the earliest dicynodonts have fused premaxillae (and 
vomers).
> Does this relate to the beak or to the development of a secondary palate?
>
> > *downwardly vaulted palate*.  As I understand things, the dicynodonts 
are
> > believed to have a  shearing motion of the jaws. So In this sheme,
> > Oviraptorids could have chopped through very tough vegetation like a 
pair
> > of those scissors you see on late-nite TV cuts through a penny.
>
> In dicynodonts, that shearing (or grinding) occurred behind the tusks 
where
> (as Kemp put it) an inverted knife-and-cutting board operated -- ie: a
> sharp, horn-covered dentary blade was drawn back against a flat,
> horn-covered upper plate. Is there anything to indicate that oviraptorids
> may have also used this system?
>
> Stephen Priestley
>
>
>
>
>