[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
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, email@example.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
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
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?