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thoughts on the dinobirds exhibit



Dear List

I'm back (for a little while). I've just been to see the wonderfull
dinobird exhibit in London. It is a great exhibit and certainly an
unmissable experience. Although seeing dave for the first time is about
as close as you can get to a religious experience in dinosaur science,
the animal I spent the most time on was that poor relation among the
feathery dinosaurs, the one and only (and badly beat-up) 
Protarchaeopteryx. I will say at the outset I came away fairly convinced
that Protarchaeopteryx is the closest known sister group of, if not an
actual synonym of, Incisivosaurus, as has been suggested by Rutger
Jansma on this list. The skull is extremely badly crushed but some
details are plain. These include a relatively large and deep premaxilla
with a dorsally placed external naris. It is also clear that there was
only one pair of large premaxillary teeth at the front of the jaws. They
apper widely sepparated but I suspect this is because the left and right
premaxillaries have sepparated. Each large tooth is followed by three or
four much smaller teeth. It is true that the anterior (as they currently
lie)  large pmx tooth does not have the incisor like wear facet (the tip
of the other is busted off) but I notice it is a little smaller than its
companion, so I am suggesting it is a new, replacement tooth that was
just coming through and thus had not become worn. Other points of
similarity include the leaf-like shape of the other teeth, the fact that
the dentary row of teth is very short and that the symphyseal region is
edentulous. There is also an indication of a large external mandibular
fenestra and a long slender retroarticular process. Also intriguing is
that amongst the general ruin that is the main part of the skull is a
nicely preserved and easily recognised ectopterygoid that looks a lot
like that of Incivosaurus. In short I am convinced Protarchaeopteryx is
a basal oviraptorosaur (as indeed a number of postcranial characters
suggest) and think a special relationship with Incisivosaurus is very
likely. Another point is that there is clearly a large pennaceous
feather extending from the right forearm, indicating weakly developed
'wings' were present.

Other highlights included the ability to flit between NGMC 64 and the
holotype of Sinosauropteryx - and yes I agree that they are almost
certainly different taxa.

Well i could burble on for ages but I really should be getting back to
my sauropodomorphs - only two months of postdoc left and so many papers
to write.

cheers

Adam Yates