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Re: Velociraptor scavenged azhdarchid pterosaur



Things do not always go smoothly for predators, especially when feeding on prey their size and larger. Injuries may not be uncommon.

Seriously, I am interested in whatever evidence you might have in interpreting the Protoceratops-Velociraptor specimen as something other than an attempted predation event (maybe going badly for the predator) preserved in progress. If there are alternative explanations for that specimen other than predation and the evidence is such that we cannot choose between the alternatives, then the topic of predation in dinosaurs should probably just be abandoned as a research effort. If we cannot figure out what the hell is going on in such a spectacular specimen as that of the V-P, then why spend any time with tooth marks, bone fragments within rib cages, or any other such material.

Dan






On 3/3/2012 11:32 PM, Habib, Michael wrote:
True, but that assumes that the "fighting dinosaurs" preserves a one-on-one 
predation attempt, which I personally doubt (actually, it may not be a predation attempt 
at all - consider that the Velociraptor appears to have been in the process of being 
mangled badly).  Incidentally, the 9kg mass for the azhdarchid in the new paper is 
probably too low by a fair margin (9kg is about the mass of a large albatross).  In any 
case, we cannot absolutely rule out predation, but it would still seem that scavenging 
would be the preferred hypothesis in this case.

This discussion/debate brings up an interesting question: what evidence should 
we, as paleontologists, require before tentatively accepting a scavenging 
hypothesis for a given preserved feeding event?  And conversely, what evidence 
should be required to tentatively accept a predation hypothesis?

--Mike Habib


On Mar 4, 2012, at 12:54 AM, Tim Williams wrote:

Mickey Mortimer<mickey_mortimer111@msn.com>  wrote:

Scavenging's certainly possible, but since the closely related Deinonychus is 
generally accepted as predating Tenontosaurus (which is about as heavy
compared to Deinonychus as Quetzelcoatlus is compared to Velociraptor), I don't 
see how we can favor one hypothesis over another.  Sure I'm assuming
that the Velociraptor was found singly, but if Roach and Brinkman (2007) are 
correct that Deinonychus did not live in packs but merely aggregated to kill,
then a lone dromaeosaurid with parts of a large animal in its belly is just 
what we'd expect.


There's also the famous "fighting dinosaurs": _Velociraptor_ preserved
in combat with _Protoceratops_.  The _Velociraptor_ (an adult) is
estimated to have have weighed around 24 kg, the _Protoceratops_ at
least that much.


For the Hone&c study, the _Velociraptor_ was a sub-adult estimated to
have tipped the scales at 13 kg.  The pterosaur is estimated to have
weighed at least 9 kg.  So IMHO the contest between _Velociraptor_ and
pterosaur would be less daunting than _Velociraptor_ vs
_Protoceratops_.  Also, pterosaurs (even azhdarchids) were less adept
on the ground than velociraptorines.  Would it really have been
prohibitively difficult for a  _Velociraptor_ to attack an azhdarchid
of comparable (or even lesser) body mass?  Even if the pterosaur
weighed substantially more than the _Velociraptor_, predation still
seems to be well within the realm of possibility.





Cheers

Tim
Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
mhabib@chatham.edu
(443) 280-0181




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