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Re: No Subj. (long feathers)



On Fri, 22 Nov 1996 DPterosaur@aol.com wrote:

> In a message dated 11/22/1996 9:12:45 AM, longrich@stardot.com (Nick
> Longrich) wrote:
> 
> <<it [super-long bird feather] could concievably be aerodynamic, a double
> version of the rhamphorhynch tail. >>
> 
> Or visa versa, the rhamph tail could be decorative, a sign of sexual maturity
> (it did change shape with increased size). The aerodynamic theory is an old
> paradigm recently upset by work using bipedal lizards showing the long thin
> stiff tail of early pterosaurs was a terrestrial adaptation that quickened
> the stride rate.

        On Archaeopteryx, the tail is flexible at the base and stiffened 
along its length by extensions of the chevrons fore and aft. The new 
Madagascar bird has this and extensions of the postzygaphophases or 
whatever the heck they're called (the things sticking off the back). In 
Archaeopteryx, the aerofoil is held horizontally. In Rhamphorhynchus, the 
tail vane is held vertically. In Archaeopteryx the tail is highly 
flexible in the vertical plane, in Rhamphorhynchus, through the horizonal 
plane. 
 Wellnhofer shows  five different rhamph tails but he also attributes 
them to five different species of Rhamphorhnychus. 

         I should mention that GSP's drawing of Parksosaurus 
shows long vertebral extensions/ossified tendons (don't know which they 
are here). I also noticed something else looking at the Velociraptor for 
comparison with this:
        Dromies have really big, long, coracoids. Really unlike what you see 
in ornithomimes/ T. rex compsognathus. Or any of the other dinosaurs I 
could find, like Parksosaurus.
        I can't compare w/ oviraptor 'cause I can't find PDW (grumble 
grumble). 
        Now everybody, what do we find large, long  coracoids on?? All 
together now: "pterosaurs and birds". 
        Now everyone: what do we find large sterna on? What do we 
sometimes find stiffened tails flexible at the base on? What do we find 
lots of thoracic stiffening on?