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Re: [GSP1954@aol.com: Re: dinosaur endothermy (long)]



Nick Longrich wrote:

> In Sinosauropteryx there are clearly visible dark patches of
> hairlike insulatory structures, these run along the top of the neck,
> back, and in broken clumps along the top and bottom of the
> tail. However, reconstructions showing feathers only in these areas
> are, I believe, incorrect.  The reason why is because when I looked
> at the photos I saw what I took to be the imprints of these
> structures on the underside of the neck.

As you say, this in an incredible fossil.  I don't know which photo(s) you
have seen, but in the one we have the structures in question don't look
particularly hair-like or feather-like--in fact they seem to be
superficially similar to the dorsal crest on a basilisk lizard.  To refer to
them as "insulatory" seems to be a stretch since they only appear on the
dorsal surface of the fossil.  As you point out "having a mostly bald animal
(of this size) doesn't make a heck of a lot of sense."   The preserved dark
tissue below the tail is clearly segmental (i.e., it runs between the hemal
arches) and not at all like feathers, hairs, or scales.  The only visible
structures on the ventral surface of the animal are apparently gastralia.
There is also soft tissue preserved in the abdomen and in the eye, yet
nothing with definite feather-like morphology is visible.  Like nearly
everyone else in the world I have just some photos to go by.  Until a
description of this fossil is published (from rumors I hear it won't be too
far off in the future), I think it's safer to err on the side of
caution--it's much better than having to choke down crow later.  

TDJ
:-{)
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    Terry D. Jones                             Voice:  541/737-6120       |
    Oregon State University              Fax:      541/737-0501          
    Dept. of Zoology                         JONEST@bcc.orst.edu
    3029 Cordley Hall
    Corvallis, OR  97331-2914
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