[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Deinonychus Morphological Variations within Ontogeny

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.

On Fri, Apr 17, 2015 at 10:38 PM, Tim Williams <tijawi@gmail.com> wrote:
> Jason Brougham <jaseb@amnh.org> wrote:
>> Senter, 2006, is grossly in error.
>> Dromaeosaurs had a glenoid orientation that does not even resemble that
>> depicted by Senter.
> Fantastic!  If deinonychosaurs and basal avialans (archaeopterygids,
> confuciusornithids and the like) were capable of even a rudimentary
> flight stroke, it opens up a great many more scenarios for the origin
> of flight in birds.  This includes those scenarios that entail
> flapping (rather than just "passive" gliding), such as wing-assisted
> incline running (WAIR) and controlled flapping descent (CFD).
> Nevertheless, the hypothesis that aerial locomotion in these taxa
> primarily consisted of gliding is consistent with the feather
> morphology of these same taxa (e.g., Feo et al., 2015).  But this
> doesn't rule out some role for flapping, if the shoulder anatomy
> allowed it.  This debate on the aerial abilities of
> non-ornithothoracean pennaraptorans has a long way to go.
> Cheers
> Tim

Jaime A. Headden
The Bite Stuff: http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth" - P. B. Medawar (1969)