Re: Shark eating dino fossil found in Utah

[Tim Williams <twilliams_alpha@hotmail.com>]

> From the article:

> Anatomical features and track marks linked to the dinosaur suggest it 
> specialized in eating and catching fish, including sharks and huge bony 
> fish that, when consumed, would have been "like biting through chain mail," 
> Utah State paleontologist James Kirkland told Discovery News.

I wonder if being a biped actually helped in this case.  The theropod in 
question could have grabbed the fish with its procumbent front teeth, in the 
same manner as rhamphorhynchids and many sauropterygians and crocodyliforms. 
 Once caught, the theropod could then use its hands to help prise off the 
armored skin so the fish could be easily dealt with by the jaws.


Dann Pigdon wrote:

> "The only other meat-eating dinosaurs with teeth worn like that are the 
> spinosaurs Spinosaurus and Suchimimus from North Africa where large...fish 
> dominated," said Kirkland.
>
> I wonder if the teeth of *Masiakasaurus* show a similar wear pattern?

The papers that have dealt with _Masiakosaurus_ (Sampson et al., 2001; 
Carrano et al., 2002) do seem open to the idea that _Masiakasaurus_ was 
piscivorous.  The procumbent front teeth could have been used to clasp fish, 
and the more typically theropod recurved teeth behind could process the 
prey.  Based on the dentition, these studies also raise other possibilities 
for _Masiakasaurus_'s dietary habits - such as eating fruit or small prey 
(like insects), or both.

Piscivory has been proposed for spinosaurs, based on the crocodilian-like 
morphology of the jaws (although Sues et al. [2002] disagree) and the 
discovery of partially digested fish scales inside the _Baryonyx_ skeleton 
(Charig and Milner (1986, 1997).  However, the same skeleton also has 
partially digested bones of a small ornithopod (not sure if it would still 
be categorized as _Iguanodon_), and  spinosaurs are known to have fed on 
pterosaurs (Buffetaut et al., 2004).  Spinosaurs obviously had diverse 
diets, and the same is probably true of other fish-eating theropods.  Just 
how dedicated thet were to piscivory is unclear; but then there's this 
intriguing idea...

http://dml.cmnh.org/1998Nov/msg00418.html

Basal oviraptorosaurs (_Caudipteryx_, _Protarchaeopteryx_, _Incisivosaurus_) 
also have procumbent teeth.  These critters might have included arthropod 
prey in their diet.  One idea of mine (completely untestable, and so not 
worth a jot) is that these theropods used their wings and feathered tails to 
flush insects out of small trees into the open, like some birds do today 
(wagtails, etc).

Cheers

Tim

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