Re: Dinosaur skin revisited

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

 From: Ralph W. Miller III at gbabcock@best.com

 Some time back there was a brief exchange on the subject of dinosaur skin
(i.e. could a mosquito penetrate it?)...  I now have some questions of my
own on this topic.  

Has anyone got any information on <Herrerasaurus> skin impressions?  I
recall reading a small blurb on the subject (Was it in Dinosaur
Discoveries?) stating that a <Herrerasaurus> fossil skin impression had
been discovered, and I seem to recall that it reportedly displayed
osteoderms or at least some large, conspicuous tubercles.  The animal is
more primitive than a true theropod, but could be informative, considering
the rarity of carnivorous dinosaur integument fossils available.  Prior to
this, I had only heard of impressions of <Carnotaurus>, <Tyrannosaurus>,
<Pelicanimimus>, and <Compsognathus prima> (crest of fibers).

Speaking again of <Compsognathus prima>, does anyone have a response to
Larry Martin's suggestion that the fibers would have supported a frill such
as you see on marine iguanas or basilisk lizards?  Perhaps the appearance
of a frill that covers not only the length of the spine dorsally, but also
much of its tail ventrally, would suggest an aquatic lifestyle, but then a
ventral frill on a terrestrial theropod dinosaur (which did not drag its
tail as lizards do) might also make sense as a mere display, if the fibers
did indeed support a frill.  Considering the alternative, the
"protofeather" explanation for these fibers, could someone explain to me
why fossilization would favor preservation of these fibers only in the
plane of the rock but not elsewhere on the animal (as Nick Longrich has
suggested)?

On July 19, 1997 The San Francisco Examiner reported the finding of  one
square foot of remarkably detailed 70 million year old hadrosaur fossil
skin impressions in New Mexico which shows more than 60 tubercles with
grooves and ridges which originate at the top, then radiate downward toward
the base of the tubercle.  Kewl!  The scientists mentioned in the article
were Brian Anderson of the Mesa Southwest Museum in Mesa, Arizona and Dan
Chure at Dinosaur National Monument.  Has anybody here seen these
impressions or any refs?  Alas, my brief article has no photos. 

For those who, like me, want to know more about dinosaur skin, there will
be an article on the subject by Stephen Czerkas in Currie and Padian's
"Encyclopedia of Dinosaurs."  In the mean time, I highly recommend the
restorations of Stephen Czerkas, Gregory S. Paul, and Mark Hallett for
their authentic skin textures (though obviously limited by current
availability of fossil impression material).  And at present there is "The
Ultimate Dinosaur Book" by David Lambert, which features a few photos of
fossil dinosaur skin impressions.  

Ralph W. Miller III
email: gbabcock@best.com