RE: Making Lip of It

[Jaime Headden <qi_leong@hotmail.com>]

The fisher idea is certainly useful, and gives us a good framework to test the 
dietary elements. I note elsewhere on my blog 
(http://qilong.wordpress.com/2011/08/12/incredulous-teeth-i-with-twin-crests/) 
that Manabu Sakamoto has presented data that, like crocodilians, dilophosaur 
jaws have a very strong posterior bite force component, much higher in relation 
to that of a large majority of other theropods, meaning it exterts a lot of 
force generally in the posterior portions of the jaw, and less so gradually 
along the jaw. The same model may be just as applicable to other "croc-snouted" 
theropods and similar jaw types in a variety of archosaurs such as 
*Riojasuchus*, but of course that remains to be tested.

  I think for the most part the "fisher" model tends to work in relation as 
alluded to in the pdf to the long and thinness of the dentition, but this 
should not necessarily be true as the teeth are recurved, mediolaterally 
strongly compressed, and finely serrated, features that tend[*] to occur in 
more macropredatory, terrestrial carnivores. I'd like to think this gives 
*Dilophosaurus* a relatively standard terrestrial carnivore profile, with just 
longer teeth. Note that similar dentition, albeit relatively smaller, exists in 
some short-faced abelisaurids, so I suspect the models for diet should run 
similarly.

[*] waffling

Cheers,

  Jaime A. Headden
  The Bite Stuff (site v2)
  http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
Backs)


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> Date: Mon, 19 Sep 2011 09:37:12 -0600
> From: JAMESKIRKLAND@utah.gov
> To: Vert.Paleo.Mailing.List@listproc.usc.edu; dinosaur@usc.edu; 
> VRTPALEO@usc.edu
> Subject: Re: Making Lip of It
>
>
>
>
>
> James I. Kirkland Ph. D.
> State Paleontologist
> Utah Geological Survey
> 1594 West North Temple, Suite 3110
> P.O. Box 146100
> Salt Lake City, UT 84114-6100
>
> (801) 537-3307 FAX (801) 537-3400
> jameskirkland@utah.gov
> http://members.networld.com/kirkland/>>> Jaime Headden <qi_leong@hotmail.com> 
> 9/18/2011 2:19 AM >>>
>
> I'm going out on a limb and posting my (sometimes) controversial opinion in 
> regards to that perennial problem of dinosaur lips. In this, I will 
> temporarily gush over Larry Witmer's biology work while at the same time 
> taking an aim at a cherished childhood icon, "Crash" McCreery's 
> "velociraptors" from _Jurassic Park_. The conclusions are anything but, but I 
> had a lot of fun making the art. Check it out at my blog, or follow the 
> direct link: http://qilong.wordpress.com/2011/09/18/making-lip-of-it/ . At 
> over 3,500 words, it's my largest single piece written exclusively online, 
> and represents the culmination of a few lines of data regarding jaw structure 
> and soft-tissue analogies. As I state in the post, I'm an amateur and would 
> appreciate positive criticism.
>
> Interesting stuff Jamie;
>
> Since, I think Dilophosaurus often ate fish , I tend to think croc jaws make 
> more sense.
>
> http://geology.utah.gov/surveynotes/snt39-3.pdf
>
> Certainly all the articulated skulls I have looked at with closed jaws have 
> the upper teeth extending to base of the dentary, so I figure they would be 
> visible in part.
>
> Also I see going from a croc-like pattern to a beak as being more straight 
> forward, than from an animal with fleshy lips.
>
> But, then again my background is geology, so what do I know.
>
> Jim Kirkland