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.