[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Velociraptor scavenged azhdarchid pterosaur



>>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?

Healed wounds on articulated, un-scavenged herbivorous dinosaur
skeletons which can be demonstrated to have been inflicted by teeth or
claws could be taken as evidence of predation. Footprint evidence of
pursuits / combat events would be better still.

I think scavenging could be inferred when the size difference between
predator and prey item is massive - finding an adult sauropod phalanx
in the belly of an Ornitholestes (I doubt it could have swallowed one
whole, but lets assume it could), for example. I wonder how many
Ornitholestes it would take to take down an adult Camarasaurus (or to
screw in a lightbulb, for that matter...).

Do these sound reasonable?

On Sun, Mar 4, 2012 at 7:32 AM, Habib, Michael <MHabib@chatham.edu> 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
>



--
Dr. Stephen Poropat

Postdoctoral Research Fellow
Uppsala University
Villavägen 16
SE-752 36 Uppsala
Sweden

Research Associate
Australian Age of Dinosaurs
PO Box 408
Winton 4735
Australia