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Oz dromaeosaurs(Re: Megaraptor)
>Firstly, only north Africa and Australia seem to see dromaeosaur
>fossils, and even those are doubtful, and could belong to a sister
>branch of the "raptors," or to dinosaurs similar to *Noasaurus*.
>Secondly, I recall that *Baryonyx* was touted as being a super raptor 20
>ft+ long before Utahraptor was discovered, even while the spinosaurid's
>skeleton was being unearthed, which in the '90's (I believe) was
>something of a shock to myself when I first saw the bones in a
>children's book on dinosaurs -- Eyewitness.
>diagnostic. I'm not saying for sure they weren't raptors, but Laurasia
>seems to be where all the valid dromaeosaurids have been found, and the
>troodontids, so I am having difficulty believing in Gondwanan raptors:
>the African, Australian, and South American "raptors" could all be
>spinosauroid, and England _was_ a part of North Africa at one point, as
>was half of Europe, then drifted north.
You are right in that the Australian dromaeosaur material is based solely
on teeth (over 30 teeth known from Dinosaur Cove and Flat Rocks in
Victoria) However the teeth of spinosaurs (Baryonyx, Irritator) are
extremely distinctive in being slender,conical structures with no
serrations visible to the naked eye and would have been immediately
recognised as such.
It should also be noted that the Early Cretaceous (Aptian/Albian) aussie
dromaeosaurs are associated with other forms previously only known from
Late Cretaceous Laurasia (oviraptorosaurs, Timimus (?ornithomimid),
protoceratopsians etc*). So there is little ground to discount the
possibility of Australian dromaeosaurs (though yes, it would be nice if we
had more than teeth to work with...)
* see: Currie et.al 1996 Possible oviraptorosaur specimens..., Alcheringa
Rich & Rich 1994, Neoceratopsians & ornithomimosaurs..., Nat.
Geographic Research & Exploration 10: 129-131.