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

Re: Gigantoraptor stuff

Pedro Andrade wrote:

Even if Gigantoraptor is not Deinocheirus,

In the most recent analysis, _Deinocheirus_ came out as a gigantic ornithomimosaur, close to _Harpymimus_.

this thing
bugs me: is there any special reason why Late
Cretaceous maniraptoriforms in Mongolia grew so large?
Apart from Gigantoraptor and Deinocheirus there's also
giant therizinosaurids and Achillobator.

Yeah, it bugs me too. Maniraptoriforms appear to have radiated into the "large herbivore" role dominated by sauropodomorphs and ornithischians. In Iren Dabasu, for example, there are plenty of theropods, a few runty hadrosaurs, but no sauropods (AFAIK - if I'm wrong on this, please let me know). Derived therizinosauroids appear to have been herbivores, and the same might be true of at least some oviraptorosaurs (hence my previous comparison of _Gigantoraptor_ to _Dinornis_). I don't know about _Deinocheirus_ - although its placement among basal ornithomimosaurs suggests that it was perhaps not a ferocious predator... but I wouldn't want to go too far with that. Somebody had the intriguing suggestion that _Deinocheirus_ was specialized for digging up small ornithopods from their burrows (which, if nothing else, would make for a great illustration).

But _Achillobator_ was certainly a predator. It had plenty of big herbivores to go after.

Why did this happen in Mongolia and not say, North America?

It might have - especially if tyrannosauroids are maniraptoriforms. North America also had large dromaeosaurs (e.g., _Utahraptor_), some therizinosauroids, and at least one large oviraptorosaur (undescribed; and not as humongous as _Gigantoraptor_).

Hope that helped.



Who's that on the Red Carpet? Play & win glamorous prizes. http://club.live.com/red_carpet_reveal.aspx?icid=REDCARPET_hotmailtextlink3