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Re: Archaeopteryx feathers (Re: Feathers on Bloody Everything)



Toby White wrote:

> Are you sure about this?

No, not 100%.  I am sure that I have seen what appear to me to be the preserved
traces of fibers on the body and legs of the Berlin _Archaeopteryx_ as depicted 
in
early and contemporary photographs and illustrations and in casts of this
specimen.  All of these sources I mention reveal the same basic details which 
are
consistent with my interpretation that the specimen may reveal such fiber
impressions, and that these impressions I reference, unlike the well known
impressions of advanced feathers on the wings and tail of the fossil, do not 
show
any evidence of modern avian contour feather morphology that I can see.

I have a cast of my own which I believe shows good detail, and I can assure you
that the apparent fiber impressions I refer to are not an optical illusion of 
the
matrix.  The arrangement and direction of each apparent fiber impression is
consistent with the hypothesis that these shapes were formed by fibers which 
made
up the animal's integument.  I may not be able to prove that these are in fact
fiber impressions, but I am at a loss as to a more likely explanation for these
features.

Gregory S. Paul states on page 123 of _Predatory Dinosaurs of the World_: "Only 
one
of six _Archaeopteryx_ specimens show the soft body contour feathers we are 
looking
for in other dinosaurs, and _Compsognathus_ may have had even softer, less
preservable feathers."

>   Finally, how can we differentiate between faintly preserved protofeathers 
> and
> the plumaceous portion of a contour feather in this context?

I do not mean to position myself as an authority in interpreting this fossil, 
and I
welcome the opinions of biologists and paleontologists on this matter.  Would 
that
the fossil preserved microscopic details of these features.  Wonderful as this
celebrated fossil is, it provides a limited amount of information.

The contour feathers of Mesozoic birds may represent a key topic to inquiries
intended to heighten our understanding of the origin and evolution of feathers.
One would expect a protofeather to be simpler than the remiges of a modern 
flying
bird, which represent a derived state.  One would think that, if this earliest
known bird, _Archaeopteryx_, exhibited both "modern" avian wing and tail 
feathers
and simpler filamentous structures adorning the remainder of the body -- on the
very same specimen -- that these simpler structures on the body might represent 
a
retention of the basal "protofeather" morphology.  It has been postulated that 
the
evolution of derived avian cranial anatomy, for example, seems to have lagged
behind the development of essentially modern avian flight adaptations in 
Mesozoic
birds.  I am confident that paleontologists are carefully studying the 
morphology
of the body feathers of the earliest birds in an attempt to tease just such
information from them.

> Staring at a few jpegs for a couple of minutes is not the same as studying
> actual specimens, so I can't really claim to have an informed opinion.

Speaking for myself, I am no expert either, but I have carefully examined my 
cast
of the specimen in question.  On the other hand, I cannot claim to have studied 
the
original specimen, which is securely locked in a vault at the Humboldt Museum 
fur
Naturkunde (as it should be).  I welcome the input of anyone who has actually
viewed the Berlin specimen, or who has read what leading authorities have had to
say on this matter, no matter what their conclusions.

And, yes, dinosaur lovers, I am pursuing this discussion because the topic holds
implications for our interpretation of the preserved integument of non-avian
dinosaurs.

-- Ralph W. Miller III       gbabcock@best.com

(Cowering in anticipation of the next feathered bombshell from China...)