ARCHAEOPTERYX FLIGHT

["Matthew Troutman" <m_troutman@hotmail.com>]

Alas, a new thread.....

ARCHAEOPTERYX

Chris Nedin wrote:
<<<So,  as you see,  the furcula of Archaeopteryx is built to hold a 
large wing depresser muscle.>>>

<<This has little bearing on what I wrote, namely that the some tendon 
structures amongst others ( e.g. M.supracoracoideus) of Archae implies 
that it was not capable of power flight (flapping flight, yes) and so 
was probably not on the direct line to birds with the ability to power 
fly. FWIW I accept that Archae was capable of flapping flight, but not 
power flight.>>

"Power flight"?  If you are using the term as a way to define the strong 
way that modern birds fly I would agree with you.  To a point......

Actually, Archaeopteryx, with its large pectoralis,  was probably 
capable of strong flight function.  Though the supracoracoideus was not 
high enough to allow a complete upstroke.  However, what bearing this 
has on "power flight" is debatable; remember Max Sy's experiments where 
he cut the supracoracoidus of pigeons and crows and the birds were 
capable of flight, just not from level ground.  The supracoracoideus 
contributes little to the actual flight of a bird other than the 
upstroke, which is not a necessary part of flight, just a convience.  

There is a lot of evidence that suggests Archaeopteryx was a strong 
flier.  The furcula for one is great evidence of strong flight.  As I 
had noted eariler, the furcula in Archaeopteryx and the enantiornithines 
is adapted as the major site of the M.pectoralis.  It also contributes 
as a brace since it is incapable of flexion due to its thin, flat 
cross-section.  The single, ossified sternum is also good evidence of 
strong muscles and strong flight capabilities.  You see, flight is a 
very stressful activity and everything in the body has to either be 
fused and changed to prevent injury to the body during flight.  The 
single sternal unit (opposed to the two plates seen ancestrally in 
theropods) is more structurally stable during flight.  Why would an 
animal need such bracing?  The obvious answer is that the muscles were 
exerting alot of stress.  That means that Archaeopteryx was a strong 
flier and had strong flight muscles.  Another indicator of strong flight 
muscles is the coracoid.  In Archaeopteryx the coracoid, though lacking 
the pronounced acrocoracoid process and several other features, is a 
prototype of the modern avian coracoid; it is beginning to show a 
strutlike shape.  The strutlike shape allows an interlocking mechanism 
into the sternum, where it serves as a brace for preventing the collaspe 
of the anterior thorax by strong compressive forces.  Where do the 
strong compressive forces come from?  The only obvious ( and most 
parsimonous ) answer is from strong flight muscles. 

Though the flight muscles of Archaeopteryx were probably not as 
developed as the typical modern bird, it can be said that the evidence 
from the osteology of the pectoral region of Archaeopteryx suggests that 
Archaeopteryx had strong flight muscles and was a strong flier.  

MORRISON MULTITUBERCULATES AND HUNTERIA

Does anybody have a copy of the Bakker et al. 1990 paper where 
Zofiabataar is discussed and described?  Any information on this paper 
and where I can get some more information on Hunteria (I'm getting to 
review my Bakker literature) would be appreciated by anybody on this 
list.  

Thanks in advance,

Matt Troutman

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