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Re: four winged Archaeopteryx
Richard Cowen (firstname.lastname@example.org) wrote:
<Nick Longrich says he sees "flight feathers" (his words) on Archaeopteryx and
he infers that it was "four-winged" (his words). However, his whole
interpretative construct depends on his assumption that Archaeopteryx flew
pretty well, and as I've argued too many times, that's highly unlikely.
Archaeopteryx could not lift its arms above horizontal; it did not have the
supracoracoideus structure in the shoulder; the furcula is rigid rather than
flexible; the long bony tail provides a huge amount of drag rather than lift;
the ends of the forelimbs have clawed fingers rather than primary feathers;
> etc. etc. Those feathers on the hind limbs could have been for display, or
for aerodynamic turning in an agile runner and hunter. Longrich documents
*aerodynamic* feathers which may or may not be "flight feathers", and
"four-winged" is so prejudicial a term that it should be struck from any
manuscript. Obviously, this question is going to go on and on until there's a
resolution We still lack a full analysis, and it may have to wait for some new
fossils. Meanwhile, we should go with as uniformitarian an interpretation as
possible: and that says that Archaeopteryx was NOT four-winged."
I agree with some points made in this post, but I cannot agree with the main
premise: It is true that *Archaeopteryx* lacked the structure found in modern
birds and even available to bats and pterosaurs that are productive to powered
flight and the fully developed flight stroke, but it is not actually neccessary
? unless these features are defined as neccessary for "flight" to exist ? for
these features to be present and that a vertebrate such as *Archaeopteryx*
"flew". There is considerable data suggesting that flight preceded "powered"
flight, and that there were aerodynamic and possible "soaring" features present
before the advent of the features Richard Cowen listed above (which occured
WITHIN and not AT the origin of birds) that are conducive to producing lift and
aerodynamic control while the animal is in the air (or running on the ground,
or running up trees, etc.).
I also disagree with Longrich's point that *Archaeopteryx* should be the
focus of origin of flight in birds, since it's apparently likely that flight or
its prerequisites, evolved before the entity "Aves" or even "birds" likely
Jaime A. Headden
"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
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