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David Marjanovic referred to:
"Gerard Gierlinski: Feather-like Impressions in a
Theropod Resting Trace from the Lower Jurassic of Massachusetts"...
Several years ago when I first came across
this paper, I was thrilled at the thought that a Theropod had left impressions
of down or feathers that are preserved from the early Jurassic. I held
this enthusiasm for Gierlinksi's interpretation of the dinosaur body impressions
for several years, even after I met Dr. Paul Olsen, probably the world's most
experienced researcher on tracks from the Newark Supergroup, in Philadelphia at
Dinofest '98. When I brought up the subject of Gierliski's paper, to
Olsen, he told me that he has studied the ichnite carefully and that the shapes
interpreted by Gierlinski as probable feather or down impressions definitely
are NOT any such thing. He had examined them very carefully and at
length.
Frankly, at the time I was a bit taken
aback and even slightly offended. Olsen, I felt, was just too skeptical
and most likely wrong. Being the outspoken person that I am, I
flatly told him so!
Within the next year, however, a friend
brought some Newark Supergroup dinosaur ichnites to my home. One of them
-- much to my astonishment -- was covered with (all around, and any and
everywhere beyond, a theropod footprint) precisely (yes, identical in every
characteristic) the kind of traces that Gierlinski interprets as probable
feather or down-like imprints. What is clear, however, is that these are
not impressions made by a body covering of any sort. To my eye, the most
probably cause was some type of plant material having been dragged across the
wet or damp, very fine-grained substrate by action of shallow water, wind, or
both.
Now I have no doubt -- having seen this
(and the slab in now in my collection) -- that Paul Olsen's interpretation of
Hitchcock's item AC1/7 is the correct one, and Gierlinski's is incorrect.
After all, Olsen -- unlike Gierlinski -- has spent many years (beginning in his
youth) studying Newark Supergroup ichnites, and his experienced opinion should
carry considerable weight in evaluating Gierlinski's paper.
Of course, I would be delighted to be
provided with evidence that both Dr. Olsen and I are
wrong, but because of what I have now seen (the Newark Supergroup ichnite now in
my collection) it seems well advised to stick with the more conservative
interpretation of AC 1/7.
But, please, let no one mis-read my
intention here. I am not passing any judgement whatsoever as to whether
some Early Jurassic Theropod(s) may or may not have had either fiberous or
feathery covering. I am asserting, however, that AC1/7 offers no evidence
of such, whatsoever.
Perhaps it is to Gierlinslki's credit that
he was observant enough to notice the interesting texture of AC 1/7, and that he
was scientifically venturesome enough to publish his interpretation,
but that interpretation seems now a bit too far out in left
field.
My two bits worth. Please don't
crucify (i.e. 'flame') the messenger.
Ray Stanford
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