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Re: Screaming dromaeosaur biplane killers of the air



Headden and others are posting some statements that may mislead the unwary. 

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. 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. There certainly is no reason to 
think that the innermost feathers shortened dramatically as restored in the 
top view illustration, this does not happen in flying  birds. When the wing 
is posed in a normal flight position it has a moderate, fairly typical forest 
bird chord/span ratio, and the span and area/mass ratios plot in the middle 
of the flying avian range, and are similar to Archaeopteryx. The wings were 
therefore fully capable of generating as much lift as modern bird wings, and 
had high thrust potential as well. 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. 

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

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. 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. 

Since the foot feathers could fold up relative to the metatarsus, 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. 

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. 

G Paul