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

Re: Deinonychus Morphological Variations within Ontogeny



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