Re: flexible horizontal ridge in dino restorations, and Baryonyx pic

["Gigi Babcock or Ralph Miller III" <gbabcock@best.com>]

Bill  wa105@mead.anglia.ac.uk writes:
 
> I remember seeing in a few dinosaur pictures (I'm afraid I can't cite any
specific ones) a 
> horizontal ridge running from shoulder to hip.  I have a jigsaw with a
sauropod showing one of 
> these very clearly.  It goes wavy when the foreleg is pointing back and
the hindleg forward, so 
> it must be flexible but not stretchy.
 
> What is this?  A tendon?  A fold of skin, like the vertical ones in Asian
rhinos?  A seriously 
> vulnerable major vein?  What is the evidence for the existence of this
structure? I cannot think 
> of any living animals with a prominent line in this position.

I am no authority on dinosaur reconstruction, but I've read a thing or two.
 Assuming we're seeing the same feature, I believe that we're just dealing
here with a fold of skin.  You see this sort of simple adornment on the
_Triceratops_ by Charles Knight as it confronts the _Tyrannosaurus_ in the
classic Field Museum of Natural History mural.  I think of it as an
expedient shorthand textural detail used by Knight so many years ago, and
duplicated time and time again by subsequent artists because Knight put it
there.  Like the artists of today, Knight was basing his restorations in
part on modern animals.  I suppose he was basing the skin fold on the skin
folds of modern reptiles.  Some reptiles have something like this, but
usually reptiles have a much more complex pattern of wrinkles which is much
more interesting in appearance.

Stephen Czerkas is perhaps the leading expert on dinosaur skin, and has
taken pains to study dinosaur skin impressions in order to make his highly
realistic dinosaur sculptures (assisted by his wife, Sylvia Czerkas).  Some
of his work is on view in the books _The Rise and Fall of the Dinosaur_,
_Dinosaurs All Around_, _Dinosaurs: A Global View_, _Dinosaurs Past and
Present_, and the new Currie & Padian volume, _The Encyclopedia of
Dinosaurs_.  The latter book includes a Czerkas article on dinosaur skin
(which I've not yet seen).  Based on studies of the marvelous
_Edmontosaurus_ and _Carnotaurus_ skin impressions as well as scrappier
fossil remains of various other dinosaur integuments, Czerkas has come to
the conclusion that (for the larger dinosaurs at least) the evidence points
to tubercle-studded skins that have lots of wrinkles.  You see a similar
interpretation in the restorations of Mark Hallett and Gregory S. Paul
(among others), although these artists (unlike Stephen Czerkas) may favor
the use of feathers or proto-feathers on small theropods.  Any
reconstructions are limited by available data, but at least these folks are
doing their best to keep up with the latest finds.  That's my opinion, for
what it's worth.

I have not seen simple, singular, flexible horizontal ridges per se in any
of the more up-to-date sculptures and illustrations, but I'm sure that they
will continue to show up from time to time until people bury all the older
artwork, which, hopefully, will never happen.
Best of luck,

Ralph Miller III <gbabcock@best.com>