RE: Eodromaeus, new basal theropod from Triassic in Argentina

[Erik Boehm <erikboehm07@yahoo.com>]

I thought there were skin impressions of sauropods, hadrosaurs (indeed, a near 
complete "mummified" hadrosaur), and theropods that showed a covering of scales.

I also didn't think that the bristles such as found only on the psittacosaurus 
tails were homologous with the maniraptor "fuzz" or feathers.

Of course, there are good reasons why semi-aquatic crocs, large dinos, etc, 
would lose fuzz.
But to my limited knowledge, the most parsimonious hypothesis is that the 
maniraptor fuzz was not ancestral, and neither were the bristles seen on some 
Ornithischia.

--- On Fri, 1/14/11, Jaime Headden <qi_leong@hotmail.com> wrote:

> From: Jaime Headden <qi_leong@hotmail.com>
> Subject: RE: Eodromaeus, new basal theropod from Triassic in Argentina
> To: "Jason" <pristichampsus@yahoo.com>, "Dinosaur Mailing List" 
> <dinosaur@usc.edu>
> Date: Friday, January 14, 2011, 10:32 PM
> 
>   The argument for non-squamous integument is not a
> fanciful one when dealing with any basal dinosaur. The issue
> with regards to *Tianyulong* especially evokes an integument
> much akin to that of *Sinosauropteryx*, preferring then an
> argument of parsimony: It is easier to conceive that
> integument shifted from scales to "fuzz" once than it is to
> assume it did so repeatedly throughout Dinosauria. Whether
> parsimony forms the better argument over any other is to be
> seen; the next contravening hypothesis, which I assume
> Jura/Jason may prefer for the moment, is that all Dinosauria
> should be seen to be squamous (like crocs and other
> archosaurs for which integument is known) unless proven
> otherwise, but this is not the null-hypothesis. Instead,
> based evenly on Phylogenetic Bracketing and historical
> assumption, we can i
> 
>   This inference becomes greater than 50% in favor of
> "fuzz" when pterosaurs are placed between birds and crocs on
> the avian lineage, or even between Archosauria and the base
> of Archosauropmorpha. In the latter scenario, with the
> presence of feathers at one end, "fuzzy" taxa along that
> lineage, and "fu
ithout contradicting evidence, "fuzz" would be the likelier
> inference, including for stem-crocs. This is based solely
> upon Phylogenetic Bracketing. Placing pterosaur4s closer to
> birds than crocs should only increase the likelihood for one
> lineage of -- rather than the whole of -- Archosauria, but
> weighs greater preponderance on the argument that "fuzz" is
> the null hypothesis of integument.
> 
> Cheers,
> 
> Jaime A. Headden
> The Bite Stuff (site v2)
> http://qilong.wordpress.com/
> 
> "Innocent, unbiased observation is a myth." --- P.B.
> Medawar (1969)
> 
> 
> "Ever since man first left his cave and met a stranger with
> a
> different language and a new way of looking at things, the
> human race
> has had a dream: to kill him, so we don't have to learn his
> language or
> his new way of looking at things." --- Zapp Brannigan
> (Beast With a Billion Backs)
> 
> 
> 
> 
> 
> ----------------------------------------
> > Date: Fri, 14 Jan 2011 07:56:57 -0800
> > From: pristichampsus@yahoo.com
> > To: dinosaur@usc.edu
> > Subject: RE: Eodromaeus, new basal theropod from
> Triassic in Argentina
> >
> > --- On Fri, 1/14/11, Jeff Hecht  wrote:
> >
> > > At 2:55 PM +0000 1/14/11, David Howlett wrote:
> > > >Interesting how the pop culture image of
> small
> > > predatory dinosaurs is slowly beginning to shift
> - did
> > > anyone else notice that the illustration in that
> article
> > > included a fuzzy layer of down? Obviously there
> is no
> > > evidence in the slightest for this, but it does
> demonstrate
> > > that the concept of feathered dinosaurs is
> becoming
> > > ubiquitous - amazing considering that even a
> decade ago
> > > there was still a lot of resistance to the idea
> in the
> > > mind's eye of the public!
> >
> > +++++++++++++++++++++++++++++++++++
> >
> > *Ugh* yeah, it's annoying as crap. I don't think the
> illustration is a sign of the public's increasing acceptance
> of fuzz on dinosaurs. I believe it has more to do with the
> paleoart community, with many (if not most) of the high
> pr
e.
> >
> > Jason
> >
> >
> >
>     
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>   
>