OMNIVOROUS DINOSAURS

[darren.naish@port.ac.uk]

T. Michael Keesey wrote:

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Apart from modern birds, there is no proof of omnivory in 
any dinosaur. But here is a list of some groups for which 
omnivory has been suggested: - basal _Dinosauria_ 
(including basal theropods, sauropodomorphs, and 
ornithischians) - _Oviraptorosauria_ - _Therizinosauria_ - 
_Troodontidae_ (which are supposed to have similar 
dentition to _Pachycephalosauria_....) - _Omnivoropteryx_ 
(obviously) and many other avian taxa
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In response Tim wrote....

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Omnivory has also been suggested for the Aussie 
ornithopod _Muttaburrasaurus_.
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Well, Mike did say ornithischians (thus covering the bases), 
but if we're going to get specific...

I suppose it's possible to find pretty much anything in the 
literature depending on (1) how hard you look and (2) what 
you're willing to consider 'literature', but omnivory has been 
suggested for far more specific kinds of dinosaurs than 
those listed above. The following have also, at one time or 
another, been suggested to be omnivorous...

Ornithomimosaurs, diplodocids and other sauropods, 
_Stegosaurus_ and other stegosaurs, basal ornithopods 
(hypsilophodontids and kin), heterodontosaurs, 
pachycephalosaurs, and ceratopsians (including 
psittacosaurids, basal neoceratopsians and ceratopsids).

Off the top of my head I can't recall any suggestion of 
omnivory among ankylosaurs - the myrmecophagous 
versions of Nopsca and Maryanska notwithstanding. Of 
course if predatory theropods occasionally ate leaves (Paul 
1988) then they were part-time omnivores too, but only in 
the same way that cats might be.

'Accidental' omnivory (where a strict herbivore accidentally 
swallows a caterpillar, maggot or little mammal) is likely in 
all lineages of herbivores, living and extinct, but 'active' 
omnivory has specifically been suggested for the dinosaurs 
I list above. Yes there really are suggestions in the literature 
that stegosaurs and diplodocids picked at carcasses.

-- 
Darren Naish
School of Earth & Environmental Sciences
University of Portsmouth UK, PO1 3QL

email: darren.naish@port.ac.uk
tel: 023 92846045