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Mei example
Reading the description of Mei I am struck by how so many characters once
thought to be exclusively avian and linking Archaeopteryx and birds above all
other theropods are showing up in basal dromaeosaurs, troodonts,
oviraptorosaurs
etc. Also how the latter basal forms are much more avian than the once better
known later members of their groups.
So basal deinonychosaurians appear to be birdy in lacking a postorbital bar*
and contact between the squamosal and quadratojugal, and having a small
antorbital fenestra, saddle-shaped cervical articulations, large ventral
projections
at the neck base, and a short femur. The presence of these features in basal
sickel-claws and their subsequent loss in flightless forms is fully compatible
with the . neoflightless hypothesis, and leaves Archaeopteryx with little if
anything to place it closer to modern birds than the above dinosaurs. Instead
deinonychosaurians had avian features not found in Arch including loss of the
ectopterygoid process*, big sternal plates, ossified sternal ribs and
uncinates, flattened central fingers, and longer primary feathers. If anything
the
sickle-clawed dinosaurs were more derived and better fliers than earlier
Archaeopteryx. Ergo the presence of well developed flight feathers and other
avian
attributes such as the tucked in sleeping posture did not appear deep in
theropods and well before the advent of flight. Instead the supposed
exaptations for
flight are adaptations for flight, latter retained or modified for nonflight
purposes by later avepectorans. Why researchers continue to insist that
Archaeopteryx and birds form a clade above deinonychosaurs, oviraptorosaurs etc
escapes me.
* As I note in DA, it has yet to demonstrated that Archaeopteryx lacked a
postorbital bar, although this is certainly possible. What is certain is that
Archaeopteryx lacked the avian pterygoid-quadrate articulation reported by
Elzanowski and in the Milner et al Nature paper on the braincase etc of the
London
specimen. If the pterygoid and quadrate are articulated in the manner they
suggest then the normal archosaurian quadrate ramus of the pterygoid present in
the Eichstatt and Munich specimens cannot articulate with the equally big
pterygoid ramus plate of the quadrate, and instead projects well posterior to
the
quadrate shaft - an anatomical impossiblity and absurdity! The supposed
quadrate
articulation described by Elzanowski is actually the ectopterygoid process of
the pterygoid, as I detail in DA.