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Re: Screaming dromaeosaur biplane killers of the air



Greg Paul (GSP1954@aol.com) wrote:

<In the type C. pauli and M. gui (probably the same species) the distal 
primaries (folded over the femur in C. pauli, not to be confused with the 
more distal tibia based feathers) are actually quite long, indeed they are
 longer relative to the hand in both specimens, and in that sense are
closer to the modern avian condition than is Archaeopteryx.>

  I did not measure *C. volans*, given that the slab is underlit in the
Czerckas publication and it is not apparently possible, as least with the
scans I have, to see integument in much light. The photo of the LPM type
in Norell et al. does not show how these are perfectly and fully
preserved, and I do not trust Czerckas' allusion of lengths given tyhe
conflation of the leg feathers to arm feathers. If anyone has better
pictures of these regions, I would love to see them. However, my
measurements for *M. gui* and *Archaeopteryx* stand, as they were made
from the scales figured in their respective papers and, of all things,
Greg Paul's _Dinosaurs of the Air_. The longest preserved feather of *M.
gui* is shorter than the arml measured from glenoid to the tip of the
second finger's claw.

<The most proximal preserved ulna feathers are also long, about as long as
the ulna, maybe  longer - it being difficult to be exact from the photos,
and there are badly placed sediment breaks in both specimens.>

  In *M. gui*, the secondaries wrap around the ulna on the right side, and
it is not likely there was a vacent space inboard of the elbow.

<When the wing is posed in a normal flight position it has a moderate,
fairly typical forest bird chord/span ratio,>

  Considering I measured the chord and span from the given figure, and now
again from the photo, I get a anspect ratio of around 5.25, lower than in
forest birds.

<The wings were therefore fully capable of generating as much lift as
modern bird wings, and had high thrust potential as well.>

  This statement must be based on a mechanical analysis, not how wing
shape and aspect are similar to flying birds today or the assumption that
*Archaeopteryx* was a fully capable flapping flyer, a similarity I note
throughout _Dinosaurs of the Air_. Very few biomechanical analyses have
been made on fossil birds in this regard, and its about time we start.
Well, get the ones that aren't published finished and published, anyway.

<The large size of the wings is readily apparent in the articulated type
M. gui. To consider these enormous, fully refined arm wings merely
maneuvering control surfaces, or compare them the dinky little,
symmetrical, frayed edged feather arrays on the wee arms of Caudipteryx,
is absurd.>

  I really doubt they were frayed. The entire skeleton of the specimens of
those that have the best preserved wings are nearly wholly disarticulated,
often lacking all of the dorsals, the hips are disarticulated, and the
legs hardly in their natural positions (this is especially true of the
holotype), which argues that the "fraying" is evidence of dessication and
trauma to the animal postmortem. The vanes of the wings of better
articulated specimens, such as BPM 0001, do not show this "fraying" and
the rachis, unlike the type NGMC specimen has curvaceous rachi, hardly a
natural condition. As for the "enormous" wings of *M. gui*, what is the
comparison based on?

<As I detail in DA, the Johel dromaeosaurs have a large set of arm,
pectoral girdle, and trunk adaptations for advanced flight not present in 
Archaeoptryx, which itself was probably a competent powered flier, not
just a glider. In no regard are the flight adaptations of the
dromaeosaurs'  forelimbs inferior (read the descriptions of the various
Johel coracoids and study the illustrations carefully).>

  These birds lacked a sternal keel, humeral elevator, reduced lateral
coracoid edge, lower coracoid tubercle, unfused uncinates to ribs, fused
carpus, broadened proximal digits of the fingers, vennate alulae
(previously referred, I will fill this in in my reply to Jim).... This
data seems to have been ignored. This makes them "not so good flyers", not
power flyers, which is still assumptive of *Archaeopteryx* as well, which
has a smaller sternal surface as far as is known than birds or basal
dromaeosaurs, or even oviraptorosaurs. The idea that *Archaeopteryx* was a
good flyer, and therefore animals with similar anatomy to Archaeopteryx,
upon the assumption that Archaeopteryx was basal to these forms, were
better at "flying" ... there are too many assumptions here, and not enough
data.

<The spherical femoral head of the type Sinornithosaurus is pictured in
the Nature description, my hi-res photos verify it.>

  I would really like to see this, if you would care to share it, as my
photos show an unelevated humeral caput that would have prevented lateral
extension of the femur. Not even birds can spread their femora dorsally in
the lateral direction.

<Combined with the splayed out hindlegs of the completely articulated
spread eagled sinornithosaur later described in Nature and the presence of
well developed leg wings, the burden is upon those who wish to challange
the ability of Johel dormaeosaur legs to sprawl. Citing the condition on
later dromaeosaurs and troodonts is not pertinent since these are more
derived, smaller armed, flightless forms that had no need for sprawling,
spherical femoral heads. It is called evolution, in this case reversal
(probably genetically simple) to the ancestoral condition due to a return
to the ancestoral, nonvolant lifestyle.>

  Contrary to these data, it seems the data I presented was overlooked a
tad. NGMC 91 lacks known humeral proximal ends, which however articulated
the rest of the body, goes along with the missing pelvic material. Despite
all this, the large, terrestrial *Bagaraatan* has a spherical and elevated
femoral caput that surpases the height of the trochanteric crest, unlike
either *Sinornithosaurus* or *Microraptor*. When the trochanteric crest
contacts the ilium, dorsal elevation is no longer possible, and this is
the first reason why the above quoted conclusion is erroneous. Another is
preservational: Even *Confuciusornis* is preserved on its side, a datum
used to determine avian affinity by some, and the reverse of the
"spread-eagle" pattern (also seen in *Confuciusornis*) with a high
trochanteric crest, a femoral caput more medial than dorsal as in the
other dinosaurs named including *Archaeopteryx*. And despite all this,
*Confuciusornis* in "spread-eagle" preservation along with other
dino-birds in this position, the femora are disarticulated. I still see no
evidence for laterally-extending femora.
 
<In all modern birds large, strongly asymmetrical distal primaries with
trim edges are always used for flight, display is at best a secondary
function. Since this form applies to the distal leg feathers the only
logical scientific conclusion is that they evolved primarily for flight,
and that display was at most a secondary use.>

  Yet there is no consideration of a display-exapted use for the original
leg feathers that enlarged them from a basal smaller, assymetry for air
foils? No. It seems *Microraptor* _must_ have flown.

<If the dromaeosaur's leg feathers were the same size yet symmetrical then
it could only be concluded that they were for display. But this is not the
case, ergo arguing that aerodynamic feathers were mainly for display is
not logical of scientific.>

  Greg Paul bring to light many features in non-flying animals, such as
long pennate feathers in *Caudipteryx*, or large sterna in oviraptorosaurs
and dromaeosaurids, which must have been for flight, precluding that they
must be evidence for loss of flight. Unfortunately, possible evidence of
leg display feathers and a small tail airfoil with small wings in a
possible glider or flapper (which as I pointed out would be limited, not
"power flapping") seems to have been dismissed. Still, is the idea of a
flying and flapping *Microraptor* too much to look at other possible
conditions for the feathers. In the Hopp and Orsen hypothesis, these
feathers would also be in the perfect place for a brooding umbrella, and I
fail to see evidence of true flight.
 
<Since the foot feathers could fold up relative to the metatarsus,>

  What? I missed the muscular analysis showing the attachement of the
calamus to special dermal muscles (unknown in any other animal, as far as
I know) that would have controlled these feathers.

<I'm not so sure they would have hindered movement on the ground - indeed
it seems to be an adaptation for allowing ground locomotion which most
fast moving climbing animals are capable of. So does not contradict the
arboreal adaptations of the Johel dromaeosaurs.>

  No, it enhances it. And I don't think anyone has doubted *Microraptor*
was arboreal, not even Feduccia -- except for claims of extraordinary
forgery, disproved based on the nearly perfect fit of all slabs (oddly
enough, on the type slab of *M. gui*, a subslab with perfectly arranged
feathers was foudn to be unfitted and not pertaining to the type slab ...
this lies just below the feet and rearward of the left preserved manus).
But you don't have a arctometatarsalian pes in a branch clamberer,
especially coupled with an unreversed hallux, so the data is equivocal
regarding arboreality ... but this too seems to be ignored on the basis of
assumptions about similarities to *Archaeopteryx*. The phylogeny of Paul
in 2000 would support that *Microraptor* would be more derived than
*Archaeopteryx* as a post-urvögel, predecessor to *Sinornithosaurus*,
without need to making it a flyer of any repute. In fact, as a glider, it
seems to be perfectly situated between the successively more terrestrial
dromaeosaurids.

<Biplane, for those having trouble with basic etymology, means two(bi) 
wings(planes). The arrangment of the wings is not definitive. There are
tandem biplanes, staggered biplanes, and so forth.>

  The term was "biplane" ... it was used by Paul onlist without the term
"tandem" or "staggered" attached when first used. I was refuting the use
of "biplane" alone. Tandem biplanes and the models I've seen show a
proximal smaller set than a rear, larger set, essentially variable
positions for canards, which replace tails. Few except Jim it seems have
suggested that the rear legs may have converged next to the tail, and this
would form a "convential" aeronautic design. No need for special designs
and circumstances, I think.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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

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