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RE: Deinonychus Morphological Variations within Ontogeny



Yes. There are many papers that came to the opposite conclusion. Unenlagia, for 
instance, is said to have been capable of "extensive forelimb elevation" (Novas 
and Puerta (1997) New Evidence Concerning Avian Origins from the Late 
Cretaceous of Patagonia. Nature: 391) and Velociraptor is said (and 
demonstrated) to have a lateral - facing glenoid in Norell, Mackovicky (1999) 
Important Features of the Dromaeosaurid Skeleton II. Many specimens discovered 
since then confirm this: Linheraptor and Citipati IGM 100/1004 are good 
examples.

I can demonstrate further that IGM 100/976 is preserved collapsed from its life 
position, although that is actually already obvious in Senter, Figure 1 (unless 
one accepts that Velociraptor's torso was dorsoventrally flattened to be twice 
as wide as it was tall).

In fact, Senter unwittingly suggests a large degree of dorsal elevation for the 
humerus in Archaeornithomimus and Bambiraptor. Look at his Figure 2, B and C. 
In both cases he shows the scapula rotated ~90 degrees from life position. If 
one rotates the figures clockwie so that the scapulae are vertical (lie on the 
dorsolateral surface of the rib cage, as in life) the ranges of humeral 
elevation figured are large. If one does not the coracoids can't really 
articulate with the sternum.

See for yourself. In each case, determine where the coracoids should articulate 
with the sternum. Senter's orientations of the coracoids dislocate them from 
the sternal plates.

Furthermore, I was so confused by Senter's papers that I went back and 
manipulated models myself, to try to achieve the orientations he published. I 
posted the results on my blog here: 
http://jasonbrougham.com/2012/08/31/a-shoulder-to-cry-on/ 

________________________________________
From: owner-DINOSAUR@usc.edu [owner-DINOSAUR@usc.edu] on behalf of Augusto Haro 
[augustoharo@gmail.com]
Sent: Sunday, April 19, 2015 6:05 PM
To: Tim Williams; Dinosaur Mailing List
Subject: Re: Deinonychus Morphological Variations within Ontogeny

Is there a paper indicating the error in Senter's (2006) orientation of the
paravian glenoid?

Dr. Augusto Haro
Museo de Paleontología
Universidad Nacional de Córdoba
CONICET
Vélez Sársfield 249
X5000JJC
Córdoba, Argentina
TE: +54 351 4332098, int. 256

2015-04-19 0:01 GMT-03:00 Tim Williams <tijawi@gmail.com>:

> Jaime Headden <jaimeheadden@gmail.com> wrote:
>
> > Note that for many joint reconstructions, cartilage and other tissues
> > influence limitations and permissions that differ from the shapes of
> > the bone articular surfaces. In the case of some joints, this can be
> > much higher than otherwise seems. In the shoulder and hip, especially,
> > in crocs and some birds these joints are very, VERY different in form
> > from their bony portions. This matters.
>
>
> Certainly.  Irrespective of this crucial consideration, it nonetheless
> seems that the glenoid orientation was very different between
> dromaeosaurs and crown birds.  Even if dromaeosaurs (and
> non-ornithothoracean birds) were capable of some form of flapping, the
> evidence still points to powered flight arising quite late in bird
> evolution - maybe close to the most recent common ancestor of
> Enantiornithes and Ornithuromorpha.  So even after the impact of 'soft
> anatomy' is factored into joint reconstructions, I'm highly skeptical
> of any dromaeosaur (juvenile or otherwise) being capable of powered
> flight.
>
>
>
>
>
> Cheers
> Tim
>