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

Re: Arms into wings

Dinogeorge wrote:

<Roadrunners are already quite capable fliers, so the point is moot:
In this instance, flight did indeed come first. What you want is a
bird that exhibits this kind of behavior but whose lineage is entirely
flightless (not just secondarily flightless)--and there is no such
bird extant. No, because extant birds use flight feathers (as defined
by their aerodynamic properties) for brooding, not brooding feathers
for flight. I'm quite sure that many, many more birds use their wings
for flying than for brooding. So it is much more straightforward to
regard brooding as a flight exaptation rather than flight as a
brooding exaptation.>

  Because extant birds use one behavior apparently primary to another
does not presume that an ansestral bird did so. One for whom brooding
or flight is not immediately testable, and one for which neither can
be proven over the other as being _first_. Brooding _or_ flight could
have come first, but feathers were there before either, so what were
feathers being used for before either? And then the next question.
Struthioniforms and allies certainly don't lean into the wind when
running, being partially indifferent to it. Wind doesn't matter when
you're a ground animal. Feathers (being of seconady flightless origin)
are used _only_ for display and brooding (and at least in males, for
whapping each other in sparring -- ostriches, of course).

  Simple as this, *Caudipteryx* has few flight related structures
(feathers, broad sternum, acromial process), the pectoral girdle was
primitive in construction, relative to "eumaniraptorans," and the
forelimbs are short and virtually identical to non-flight animals,
oviraptorosaurs. By series represented in the fossils (I know! Damn MJ
formations!) we see what seems to be a very rapid differentiation
among the Solhofen--Sihetun fauna and both being very close to being
of the same age. Feather-like structures that may have been brachiated
but certainly could have been streamlined but with short arms;
symmetrically-vaned plumage with broad sternma but still short arms;
asymmetrical plumage with long arms but no keel or triosseal canal or
supracoracoidius lifting action; asymmetrical plumage with triosseal
canal, long arms, keeled sterna, etc.. All at nearly the same time. It
is these sites, I would think, that need to be investigated further
for any evidence that mihgt settle this.

- Often, it is the man who is brought
  down the path to the end who does
  not see his own steps. -

Jaime A. Headden

Qilong, the website, at:
Get your free @yahoo.com address at http://mail.yahoo.com