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Re: FEATHERS 2



At 11:39 AM 10/30/96 -0500, Jeff Martz wrote:

>     One more little thing...if feathers were really very widespread among 
>dinosaurs, isn't it a remarkable coincidence that the ONLY feather 
>impressions to date JUST HAPPEN to come from that one little dinosaur 
>group most closely related to birds?

Compsognathus-grade coelurosaurs are not particularly close to the origin of
birds: more so than Carnosauria, for example, but less so than
dromaeosaurids, oviraptorosaurs, etc.

There is currently a sample size of 1 for non-avian feathers.  Any questions
of statistics (such as "remarkable coincidence") must take into account the
nature of statistics from a sample size of 1.

There are no good specimens of ornithischians, sauropodomorphs, ceratosaurs,
"megalosaurs", or carnosaurs found in such fine-grained sediments.  These
are all fairly big animals; not the sort of critter normally found in
lithographic limestones of any age.

To be fair, though, using the Lagerstatt modifier of Witmer's "Phylogenetic
Bracket" method, this discovery supports the idea that coelurosaurs were
feathered ancestrally, but leaves as ambiguous the integumentary character
of dinosaurs outside this clade.

Still, it is a way cool discovery.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661

"There are some who call me...  Tim."
-- Tim the Enchanter, "Monty Python and the Holy Grail"
---------- subtitle --[Monty Python ik den Holy Grailen]

"Tim?!?  They called me TIM?!?!"
-- Tom the Paleontologist, on seeing "The Ultimate Guide to T. rex" :-)