RE: Epidexipteryx

[Tim Williams <twilliams_alpha@hotmail.com>]

Mike Keesey wrote:


> Or just among maniraptorans in general. Not many avians are
> hypercarnivorous, either. 


Yes, true.  But archaeopterygids may have been, so I thought I'd limit my 
generalization to non-avian maniraptorans.  


> And the sister group group of maniraptorans,
> _Ornithomimosauria_, was also noncarnivorous, so it's more or less a
> maniraptoriform trend.


Again true.  I avoided citing "noncarnivory" as a maniraptoriform trend because 
some phylogenetic analyses recover predatory theropods such as _Ornitholestes_, 
compsognathids, and even tyrannosaurids inside Maniraptoriformes (i.e., closer 
to birds than ornithomimosaurs are).  And with _Deinocheirus_ close to - or 
even at - the base of the Ornithomimosauria, you have to wonder now 
ornithomimosaurs started out.


> Never thought of that -- the feathered clade is just a little bit
> larger than the multi-dieted clade.


It's something I've been thinking about for a while...   ;-)


Evelyn Sobielski wrote:


>> Or just among maniraptorans in general. Not many avians are
>> hypercarnivorous, either.
>
> There are of course some borderline taxa like _Enaliornis_ and _Gansus_ which 
> fall in the "large invertebrate - small vertebrate" feeding guild. But avian 
> raptors - Falconiformes or not (_Enantiornis_ makes for a reasonably 
> convincing predator of smaller vertebrates too) do not appear until the Late 
> Cretaceous.


There's _Boluochia_ of Early Cretaceous (Barremian) age, which had a hooked 
beak and so might have been predatory.


Tom Holtz wrote:


> This was an important aspect of Lindsay Zanno's Romer Prize session talk at
> SVP, and I have alluded to this before as well. Of course, what we really
> need are very basal (Middle Jurassic, for instance) ornithomimosaurs,
> therizinosaurs, alvarezsaurs, and oviraptorosaurs to see if these guys
> inherited or convergently evolved their non-hypercarnivory.


Darn, wish I'd seen Lindsay's talk.  (Sadly, I wasn't at SVP either, but 
Bristol is looking promising.)  Anyway, in the case of troodontids, if these 
were non-hypercarnivorous, this was probably secondary given that _Sinovenator_ 
(the most basal known troodontid) was most like dromaeosaurids in its 
ecomorphology.  An omnivorous diet for _Troodon_ was proposed by... darn, who 
was it?... oh that's right...


Holtz, T.R., Jr., Brinkman, D.L. and Chandler, C.L. (1998).  Denticle 
morphometrics and a possibly omnivorous feeding habit for the theropod dinosaur 
_Troodon_.  Gaia 15: 159-166.


;-)


Cheers

Tim



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