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Re: FISH-EATING THEROPODS



On Wed, 6 Nov 1996, Darren Naish wrote:

> The whole perception of these dinosaurs as salmon-eating bear analogues is yet
> another demonstration of the Power of Art. It's hard to find a restoration of
> _Baryonyx_ where it isn't gaffing or grabbing a fish. Fact is, the impact of
> artistic restorations is so great that nice, early, accessible pictures
> influence just about all of the artists that attempt restorations thereafter.
> Examples are the so-oft repeated colour scheme of _Phorusrhacos_ (following
> Burian's pampas scene), the plumed head of _Syntarsus_ you can see in many
> illustrations (following Bakker's drawing in his famous _Sci. Am._ article) 
> and
> the many recent dinosaur pics where the colour schemes are identical to those
> created by John Sibbick for Norman's _Illustrated Encyclopedia of Dinosaurs_
> (e.g. _Euoplocephalus_ with green armour). 

        Yes, I will agree with that. 
        On the other hand, I think
there is *good* evidence to argue for a high degree of piscivory in
Spinosaurus and Baryonyx. Both have extremely high tooth counts, the only
higher found in Pelicanimimus polyodon. Having lots of teeth is a
piscovoran trait (look at porpoise skulls, gharials, etc.). The teeth are
also conical- built for puncturing and gripping, not for slicing, the meat
they bit into. (Again, crocs, porpoises) Also the terminal "rosette" of
teeth is somewhat reminiscent of what we see in crocodilians. Finally, at
least in Spinosaurus, the terminal pair of teeth in the dentary actually
point *forward*. While this is not as extreme as what we see in
Rhamphorhynchus or various plesiosaurs, it is quite unlike what we see in
carnivores like snakes or T. rex, where the teeth point backwards towards
the gullet. All these features, along with the fact that digested scales
were found in Baryonyx's gullet, convince me that these things may have
eaten a lot of fish. Are there modern animals that live this way? No, and
it's damn puzzling, but this seems to be where the evidence points. But,
then, there are no 4-5 tonne mammalian land carnivores, either.  
        Exclusive piscivores, probably not, animals in general have a
broader diet than we usually give them credit for. But heavily, even
primarily, piscivorous? That seems very possible. Certainly they did not
hunt in a manner like Allosaurus or Tyrannosaurus, whatever they hunted. 
        By the way, what kind of depositional environment were these
things found in?
        Nick L.