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Re: Brachiosaur flexibility and face-shape



On 28 September 2011 17:12,  <GSP1954@aol.com> wrote:
> It is not entirely certain that the B altithorax coracoid actually belongs
> to the holotype because it's awfully big compared to the ilium (as can be
> seen in Riggs original same scale figure), and to G. brancai coracoids.

Really?  Check out Taylor (2009:fig 4), which can be seen here;
        http://www.miketaylor.org.uk/dino/brachio/extras.html

I showed same-sclaed limb-girdle elements Brachiosaurus (FMNH P25107)
and Giraffatitan (coracoid from HMN SII, ilium from Aa 13 but scaled
to SII size).  The Brachiosaurus coracoid looks _a little_ larger than
that of Giraffatitan, but nothing outstanding.

> I cannot easily fit it on the skeletal restoration. And I suspect the 
> laterally
> facing glenoid is due to poor ossification.

My guess would be, rather, that if it's not a genuine distinguishing
feature, it's due to _excess_ ossification, as with the Kentrosaurus
ulna figured by Mallison (2010b:fig. 3B-D).  That's rather an exciting
prospect, since if it's true then it tells us something about the
cartilaginous extent of the glenoid in sauropods generally.

> It is not possible to accurately restore the exact posture and action of
> long necks from the bones

These eighteen words should be tatooed on the insides of the eyelids
of everyone who works on sauropods.


REFERENCES

Mallison, Heinrich.  2010b.  The digital Plateosaurus II: An assessment
of the range of motion of the limbs and vertebral column and of
previous reconstructions using a digital skeletal mount.  Acta
Palaeontologica Polonica 55(3):433-458.  doi:10.4202/app.2009.0075
        http://www.app.pan.pl/archive/published/app55/app20090075.pdf

Taylor, Michael P.  2009a.  A re-evaluation of Brachiosaurus altithorax
Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from
Giraffatitan brancai (Janensch 1914).  Journal of Vertebrate
Paleontology 29(3):787-806.
        
http://www.miketaylor.org.uk/dino/pubs/taylor2009/Taylor2009-brachiosaurus-and-giraffatitan.pdf