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secondarily flightlessness (sick) (was "Flightless Birds")



Hey - there's a strange charm to your prose, Headden:  "While tyrannosaurs totally forgot they were more birdy than *Coelophysis*, . ."  . . has it ever been better put?!
 
While reading your 5th Aug "Flightless Birds" piece, it all suddenly clicked for me - maybe because it could be close to what you were saying.  Are you ready for it?  Right . . . there now follows an account of my new position (except for viewers in Cladland who have their own program). . .
 
Just recently, I have become totally and utterly convinced that proper feathers *did not exist prior to _Archaeopteryx_* (or something very close).   _Sinosauropteryx_ was an important clue.  No flightless bird has ever been shown to have completely lost the feather structure.  Lost asymmetry - yes.  Lost neat, ultra smooth low drag contours, in exchange for long thin, and also "explosive" untidy feathers giving a shaggy hairdo look?  Yes.  But never lost to the extraordinary extent of _Sinosauropteryx_.  Ratites, which have not flown for something like 60 mill yrs or more still have proper feathers to some extent.  _Protarchaeopteryx_ & _Caudipteryx_ had feathers so good you had to check the skeleton to see if they were flightless or not.
 
_Sino.._ would have had to have lost its feathers a lot earlier than 60 mill yrs previously - and it couldn't have done because of the post-Archae explosion which shows the effect the feather revolution had.  Pre Archae: absolutely no feathers found.  Post Archae: blam - it all happens.  No.  For me the proper feather was the key to the birds' success and radiation more massive than most people appreciate.
 
BUT -
 
. . . early dinos had some hollowed-out bones, and progressively more robust thoraxes.  They must have been doing *something*.  Clubbing their prey is a non-starter (sorry Kevin) since [claws and "hands"] like that are totally unsuitable for heavy strikes.  Yet they couldn't have been flying either, since they only had fur and usually no skin flaps.  They must have been shinning up trees (which encouraged strengthening arms and chest bones), and gliding/parachuting on hair, maybe long, stiffened hair, growing from the arms, tail and possibly elsewhere.  At this point the peculiar backward-folding wrists might have become useful, when trying to miss tree trunks.
 
That's it - now I'm happy.  Predictions?  No feathers to appear pre-Archae; especially no feathers on _Coelophysis_, _Protoavis_ or other such "too earlies".  They all had fur like _Sino..._ (...unless they were huge; some/most big dinos developed scales).
 
Hair-for-gliding would have been incompatible with cold-bloodedness.  Warm-bloodedness, hair and gliding would have developed together.
 
(As usual, I will not be answering objections of a cladistic nature, which I regard as seriously flawed.)
 
Bits:
 
One good reason for dinos becoming steadily more bird-like is that after extinction events, small forms are more likely to survive, and tree-capable types are more likely to be small, which doesn't require that birdliness is superior in any other way (though it may have been).
 
Archie would have had little difficulty climbing *up*; climbing down backwards might have been a different matter though.
 
By the way chaps, a flightless modern bird with useless arms and no teeth is a *totally different animal* to one with claws and teeth; so much so that a great many comparisons of the type that are currently being made are totally redundant.
 
Also, I do hope it's only a series of misprints that is making at least three people say "secondarily flightlessness" instead of "secondary flightlessness"!
 
 
John V Jackson    jjackson@interalpha.co.uk
 
(Wannabeasaurus   beecee-effia (sort of) - & proud of it!  )
 
 

"(contary to viewpoints expressed variously by Padian and Chiappe 1998, the claws
of _Allosaurus_ and _Tyrannosaurus_ do not equate well with climbers).  " 
 
That's reassuring!!