Re: WING FEATHER ATTACHMENT

["Jaime A. Headden" <qilongia@yahoo.com>]

  For ease of understanding, David, it might be wise to include
the name of who you are replying to (in this case, me).

I wrote:

<<Not so ... take a closer look. I also hope you've seen Hopp
and Orsen's work on the subject, as they show in step-wise
addition of feather development how oviraptorids with nesting
posture do not have appresed humeri to the back. This and
personal observation should indicate the actual posture.>>

David Marjanovic (david.marjanovic@gmx.at) wrote:

<These illustrations, the reconstructions as well as the
drawings of the fossil, show the forearms and hands diverging
from the sides of the trunk and the humeri lying nearly parallel
to it. The little gap that there is between humerus and ribs
must have been filled by the soft tissue of the upper arm along
with the contour/protofeathers, there's not enough space for
remiges or even tertials, and Hopp & Orsen didn't draw any in
their figures.>

  Take a good long look at the fossil, David. There is a
considerable angle between humerus and the proposed midline of
the trunk given the position of pectoral girdle and furcula to
pelvic elements. This angle (discussed on the list, including by
Tom Hopp, Dinogeorge, myself, and many others -- wistfulness,
that was years ago! :) ) is a real condition of the fossil, now
referred to *Ciripati osmolskae* (Clark et al., 2001).

  I, too, may not have drawn tertials ... I see none in ratites,
large-bodied non-volant birds that retain virtually not
aerodynamic condition to the wings save struthioniforms, which
still flap when running! Hopp and Orsen propose that the
aerodynamic function of the wing was a secondary feature in the
evolution of the wing; this coincides with Hartman's work on the
aerodynamic ability of the distally feathered arms and tail, and
serve to add to the hypothesis that flight was a secondary
feature in most of the evolution of the avian wing, and that
even the aerodynamic form of the feathers occured while the
animals were more or less landbound, or bounding about in trees
(a possible second stage -- or just a diversion in the blink of
God's eye).

  However, the actual fossil of GI (SPS) 100/979 (nesting
oviraptorid we're all so familiar with) shows a considerable
space even between humerus and trunk (the ribs are dislocated,
so this is speculation as to the degree of space) and in an
animal trying to cover or enwrap it's nest within a hot desert,
this is a critical space, and survival would have adapted the
animals to survive given the persistence of such an arm when
used in brooding (see Hopp and Orsen, I know you got it, David).

<In living (flying) birds this gap (which is pretty large when
the wings are extended) is completely filled by long contour
feathers originating from the upper arm (tertials) and the
sides. The books of Feduccia (1996) and Shipman (1998) contain
reconstructions (copied from elsewhere) of wings without
tertials.> 

  In no living bird that can fly, however, are tertials absent.
They are even present in hoatzin chicks, albeit incipiently.
Re-evaluate the import of the reconstructions and what they
serve to acheive (diagrams? evolutionary scenario?) and so forth.

=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

__________________________________________________
Do You Yahoo!?
Make international calls for as low as $.04/minute with Yahoo! Messenger
http://phonecard.yahoo.com/