Re: Coelurosauria

[Jamie Stearns <stearns5@cox.net>]

I seem to have made some rather big mistakes on tyrannosaurs, so I'll have 
to redo much of the basal part of that clade. As for Dryptosaurus, how 
derived is it, exactly? I'm thinking probably somewhere near Alioramus and 
Appalachiosaurus at this point.

> > > Ornithomimus closer to Struthiomimus than Dromiceiomimus.
> > > From what I'd read, Dromiceiomimus had longer forelimbs and a shorter 
> > > torso
> > than either of the other two.
>
> Ah, but are long arms and a short torso primitive characters for 
> ornithomimids?  I would think not, but haven't checked.
> Makovicky et al. (2004) synonymized Dromiceiomimus brevitertius with 
> Ornithomimus edmontonicus, since they found Russell's proportional 
> differences to be invalid once a larger sample was measured.  Kobayashi 
> and Barsbold (2005) found them to be sister taxa, to the exclusion of 
> Struthiomimus.
Guess the differences were simply due to variation between individuals then.

As for dromaeosaurs, yes, Deinonychus's skull is longer and lower in profile 
than Bambiraptor's. I'm still not certain as to the placement of 
Achillobator, though. It may be basal to Dromaeosauridae+Troodontidae.

I don't really know much about Adasaurus, as I can't seem to find any 
pictures of the skeleton. Utahraptor may have been placed too close to 
Deinonychus by mistake, as it seems the reconstruction I've seen was likely 
inspired by that monstrosity from Jurassic Park, at least judging from the 
shape of the skull.

I've also heard that Utahraptor and Dromaeosaurus may form a clade and that 
Adasaurus may also be in that clade, but I'm not sure exactly what supports 
this. Something in the teeth? Anyway, if this checks out, the tree would end 
up looking like this:

`---Achillobator
..`---Troodontidae
....`--+---Buitreraptor
......|...`---Unenlagia
......|....`---Rahonavis
......`--+---Utahraptor
........|...`---Adasaurus
........|.....`---Dromaeosaurus
........`--+---Deinonychus
..........|...`---Saurornitholestes
..........|.....`---Velociraptor
..........`---Bambiraptor
............`---Sinornithosaurus
..............`---Microraptor
................`---Archaeopteryx
..................`---All other birds

I have, however, heard rumors of Archaeopteryx actually being a more basal 
dromaeosaur or even a troodontid lately rather than the sister taxon to all 
other birds, as conventional wisdom would have it. How well-supported are 
these ideas, and are things like Microraptor actually closer to birds than 
Archaeopteryx is?