RE: Archaeopteryx not the first bird, is the earliest known (powered) flying dinosaur

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

Tim Williams (twilliams_alpha@hotmail.com) wrote:

<Furthermore, studies on living primates show that while a subspherical femoral
head certainly increases femoral abduction, a more cylindrical femoral head
allows for better landings.>

  Indeed, the studies in question have been to focus on the evolution of
leaping behavior and climbing in "prosimians" such as *Tarsius* and fossils of
omomyoids and others and the origins of the Simia. Tim ealier expounded on this
(http://dml.cmnh.org/2003Jun/msg00033.html and
http://dml.cmnh.org/2004May/msg00084.html) and primatologists and
paleoanthropologists are well-versed in these distinctions. This data tends to
allow us to show that while birds are advantageously aided by a spherical
femoral head, the femur is held at a greater protraction and walking is focused
at the knee, rather than the hip joint. Conversely, more terrestrial taxa show
a sub-vertical femur with comparatively lesser cnemial excursion during the
stride phase, and also possess cylindrical femoral capiti.

  Also brought up has been the more spherical femoral capiti of large bodied
theropods such as *Bagaraatan* (allied with tyrannosauroids?) and
ornithomimosaurs, as well as oviraptorids, which as in *Ingenia* shows a
laterally everted femur with subspherical, yuet still cylindrical, caput. No
one has used the femoral anatomy to argue these taxa were lateral sprawlers as
has been suggested for *Microraptor*.

  Cheers,

Jaime A. Headden

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


                
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