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RE: Question - problem in Senter 2006?



I agree with your assessment.  I'd wonder if the pectoral girdle portion was 
accidentally rotated if not for the fact the prior figure is labeled lateral 
but is actually dorsal, as you say.  Good catch on the whole thing.

Mickey Mortimer

----------------------------------------
> Date: Mon, 25 Jul 2011 11:52:45 -0400
> From: jaseb@amnh.org
> To: dinosaur@usc.edu; gareth.dyke@ucd.ie; dwe_hone@yahoo.com
> Subject: Question - problem in Senter 2006?
>
> I have a question for experts on Senter (2006) Comparison of Forelimb 
> Function Between Deinonychus and Bambiraptor (Theropoda: Dromaeosauridae) JVP 
> 26 (4):897-906.
>
> I've been working on a Microraptor anatomical model using Senter 2006 as a 
> primary source for a few weeks now.
>
> I noticed some anomalies in Senters discussion of Bambiraptor but just this 
> moment the full magnitude of the possible error dawned on me. I ask experts 
> on the DML to confirm my understanding.
>
> In the text Senter notes that the humerus can be elevated to a nearly 
> horizontal position, and that this result largely agrees with Gishlick 2001.
>
> In Senter's Figure 1, the second figure, labeled cranial view, the humerus 
> position marked e (e for elevated humerus) seemed to me to show the humerus 
> at 80 degrees above horizontal, considering the orientation of the coracoid 
> and scapula. The figure appears to be turned on its side to fit on the page. 
> Just now I realized that Senter has presented this figure as a life position, 
> not turned on its side.
>
> In other words, he has placed the glenoid pointing straight down ventrally, 
> and the sternal process of the coracoid turned to point medially. Thus the 
> scapula lies ventrolateral, not dorsal, to the coracoid.This explains why, in 
> the figure to the left of this, the coracoid stands dorsally to and high 
> above the scapula.
>
> In fact the sternal process of the coracoid should point ventrally, and 
> articulates with the coracoid groove of the sternal plate along the anterior 
> sternal margin, as in IGM 100/985 (fig 3 in Norell& Makovicky (1997). The 
> ventrally pointing sternal process of the coracoid is confirmed by the 
> configuration of dromaeosaur coracoids and sterna in Norell&Makovicky (1999), 
> Jasinoski et al. (2006), Godfrey&Currie (2004) and many deinonychosaur 
> specimens found in articulation.
>
> If we turn Senter's figure 1 so that the sternal process points ventrally 
> then he has, in fact, found a range of motion for the humerus that shows an 
> elevation of the humerus at 80 degrees ABOVE horizontal! He has also found 
> that the humerus can't be depressed much below the horizontal. Also, the 
> figure to the left, previously called lateral view must now be considered a 
> dorsal view.
>
> Can anyone tell me if I've made any mistakes in my interpretation of Senter 
> here?
>
> Thank You,
>
>
> Jason Brougham
> Senior Principal Preparator
> American Museum of Natural History
> jaseb@amnh.org
> (212) 496 3544
>
>