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RE: Sinosauropteryx protofeathers



Thomas Holtz said:

>Some facts, first:
>A) We do not *AT THIS TIME* know much about the structure of the
>integumentary fibers of _Sinosauropteryx_.  In fact, that would be the
>safest thing to call them: integumentary fibres.  Not feathers, not
>protofeathers, etc.

>>Here's what I'm fishing for: are there defined characteristics that would
>>identify a structure AS a protofeather (as opposed to a feather).  I know
>>this has been hit on before, BUT - is there some characteristic and/or
>>structure of
>>a feather that DEFINES it as a "true" feather?

As you mentioned earlier and as I am partly familier with, feathers come in
all forms. From a morphological viewpoint, therefore, the _Sinosauropteryx_
integumentary fibers cannot be compared to a "typical" feather because
there isn't one to begin with. Or should we rely on the image of a feather
with a quill, rachis, vanes, etc.? I remember that old Scientific American
article (1975) about _Longisquama_ having large, overlapping scales and
those eloangted dorsal appendages. If I recall correctly, the author said
that these scales could represent a stage in the evolution of feathers. At
that time, that was about as close as you can get to having protofeathers.

>From a chronological perspective, anything resembling a "true" feather that
predates it might well be called a protofeather. Just how closly it has to
resemble the flight or contour feather (since it is the feather laymen are
most familiar with, thanks in part to its use as a pen) is an open
question. Would it need to have the beginning of a rachis?

For that matter, out of curiosity, what IS the name (if any) for the
pterosaur body covering?
Raymond Thaddeus C. Ancog
Mines and Geosciences Bureau
Philippines