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Re: Shark eating dino fossil found in Utah

Good suggestion - potentially important if the fish were getting too large to be swallowed whole. I imagine that a ~1m semiootid could be a bit of a mouthfull for a Dilophosaurus sized animal? Processing food via hands and arms would free the skull from the need to handle food processing forces, potentially allowing the skull to be optimised for prey capture. Or perhaps the forelimbs could play a role in that as well (c.f. the bear and salmon analogy).

Does anyone know how big the armoured catfishes in S. America get. And do caiman ever eat them? Might give you some clues.


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...


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).



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Colin McHenry
School of Environmental and Life Sciences (Geology)
University of Newcastle
Callaghan NSW 2308
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