[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Diplodocus tooth occlusion

Happy New Year Jordan! For quite some time I've been
asking these questions myself regarding diplodocid and
other sauropod jaw mechanics, and here is what I
believe the main consensus is on diplodocids like
Diplodocus, based on the most recent work by Barrett &
Upchurch in Hans-Dieter Sues' Origins of Herbivore
Herbivory (Cambridge U. Press, 2000). To begin with,
diplodocoids have an antero-posteriorly elongate
glenoid fossa, which means that there was a lot of
forward-backward jaw movement(propaliny). This, and
the fact that the main jaw muscle attachments were
situated at a low angle to the mandible, suggests to
these workers that diplos were employing a "seize and
pull" motion to the jaws as opposed to the more
cropping and side-to-side tearing motion thought to
characterize macronarians like Camarasaurus. Diplos
are also highly unique among other sauropods in having
paired, thin extensions of bone arising from the
dentaries and the maxillae, effectively creating bony
"cheeks" which could have helped retain cropped food,
as well as the more acute angle to which the occiput
of the skull articulates with the atlas. All these
features, along with the distinctive bevelling along
the labial margins of the teeth, suggests that the
"raking" scenario is the most likely one for these
sauropods, and I think most probably in harvesting
conifer leaflets and fruiting bodies. The teeth met
along an occlusal surface in a "neutral" jaw position,
but it may have been likely that a food mass was held
and stabilized by either the upper or lower set while
the second tooth row was brought against it, at the
same time the head was pulled backwards (hope I'm
making sense). This was most likely the mechanism for
harvesting food. Best Wishes, Mark Hallett    
--- Jordan Mallon <j_mallon@hotmail.com> wrote:
> G'day, eh...
> I'm just curious as to how the teeth of Diplodocus
> occlude.  Do the 
> mandibular teeth fit neatly within the upper jaw
> like in most theropods, or 
> vice versa?  Do the teeth slot between one another? 
> Could the jaw close at 
> all?  This is a question for which I DEMAND AN
> ANSWER!!!  (Pretty please 
> with a cherry on top.)
> Best,
> Jordan Mallon
> Undergraduate Student, Carleton University
> Vertebrate Paleontology & Paleoecology
> Paleoart website:
> http://www.geocities.com/paleoportfolio/
> AIM: jslice mallon
> The new MSN 8: advanced junk mail protection and 2
> months FREE*  

Do you Yahoo!?
Yahoo! Hotjobs: Enter the "Signing Bonus" Sweepstakes