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Raptors and Stuff
Oh wow, quite a bit of news from SVP.
Well, for one, there was a paper presented that argued that
Nanotyrannus exhibited features that were in fact most consistent with
those of a juvenile T. rex, including a general lack of fusion, smooth
nasals, and some more technical characters; this was met with a vocal
interrogation from some freaky, hairy person in the audience ;), who
argued that the number of teeth in Nanotyrannus was different from the
number in T. rex.
Aforementioned freaky, hairy person gave a very good lecture on how
Allosaurus is a sabre-tooth, citing the fact that it has a simply massive
jaw articulation allowing the jaw to be opened to great distances, muscle
articulation so as to allow this opening, and muscle attachments with the
neck that allow a powerful downward slash with the upper jaw to be
inflicted, using the tooth rows on the upper jaw to create two giant
slashing blades. He compared the animal to the saber-toothed cats in the
muscle attachment and jaw joints.
On Thursday, Horner gave a talk on how the internal bone texture of
Maisaura revealed that in fact it WAS poorly ossified stuff, comparable
to altricial hatchlings, with Orodromeus more like precocial birds in the
texture of the bone. Good mother, bad mother, good mother again?
The snout of spinosaurus resembles very much the skull of Baryonyx,
only a heck of a lot bigger. Turns out, interestingly enough, the *very*
front lower teeth actually point -forward-, if you remember, this is a
piscivorous trait (elasmosaurus, rhamphorhynchus, etc. have it,
Sampson et. al.
Majungatholus (presumed Madagascan pachycephalosaur) turns out to be
the same thing as a Majungasaurus. Majungasaurus, it has been found, is
actually a theropod- and not just any theropod, an *abelisaur* as a matter
of fact! A bone-headed abelisaur.
Wrobelewski argued that the evidence was not in fact consistent with a
sealevel regression causing North American dino extinctions- he
showed estuarine sediments present in Wyoming up to and through the K-T,
and argued that theropods did not really experience a decrease in
diversity, although in the latest Cretaceous conditions for preservation
did become kind of bad. He argued that the extinction did in fact appear
to have been geologically rapid.
>From Novas et. al
There is some interesting material from Patagonia, including a 35
cm second pedal ungual similar in general shape to that of Deinonychus.
Presumably it would be somewhat larger with a horn sheath covering the
claw. Diet probably consisted of terrified _Utahraptor_.
Witmer and Maxwell:
New skull material from Deinonychus settles old questions. Turns out
the nasals are not concave as in Velociraptor, but rather convex,
compared in general appearance to Dromaeosaurus by the authors. It also
turns out that Deinonychus has a methesmoid bone: an interorbital bone
septum, which it would now appear Archaeopteryx had as well.
More from Madagascar:
Forster et. al. Report on Vorona. They also had a second very
interesting little bird- turns out it has an interesting tail. It is flexible
at the base. The backward processes of the top of the vertebrae-
postzygapophesis, maybe, I'm not that up on terminology- are relatively
long, maybe a third or half the length of the vertebrae themselves. The
chevrons are very elongate fore and aft. Hm, now why does that sound
familiar? Turns out the second toe is robust, sickle-clawed, with a large
joint extending to the dorsal surface of the metatarsal.This, is, of
course, the sickle-clawed bird we've been waiting for.
When I get around to it, I'll try to start an argu- er, discussion-
on dromaeosaurs and the evolution of flight, which ought to keep us going
for a while ;).