Re: Wing Feather Arrangement in Archaeopteryx and Anchiornis

[Matthew Martyniuk <martyniuk@gmail.com>]

On Thu, Nov 22, 2012 at 2:03 AM, Tim Williams <tijawi@gmail.com> wrote:
> Also, Figure 4. highlights just how large the space was between the
> wing and the body, with apparently no tertials to fill the gap.  This
> is another major difference between the wings of _Archaeopteryx_ and
> non-avialans compared to the modern/neornithean wing.

This assumes that the humerus was extended when the wing was deployed,
which is not even the case in many modern birds. Take a look at this
photo of an owl in flight:
http://www.brendanbody.co.uk/flight_tutorial/images/owl_wing_position_small.jpg

The tertials are that ragged little patch of dark feathers in the
'armpit', and the humerus is held almost flush with the contour
feathers. And even still, there can often be a gap in the wing between
the secondaries and the contours that the tertials do not completely
fill. See for example:
http://www.photographyblogger.net/wp-content/uploads/2010/08/birds3.jpg

It's only in soaring birds like vultures that the humerus is held
extended to maximize wing length and where the tertials become a
well-developed part of the wing surface. There's no reason to think a
sizable gap would exist in primitive birds even without any tertials.

Matt