RE: Dinosaur Revolution Review

["Thomas R. Holtz, Jr." <tholtz@umd.edu>]

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> On Behalf Of Neil Taylor
> Sent: Thursday, September 15, 2011 4:00 AM
> To: Dinosaur List
> Subject: Re: Dinosaur Revolution Review
> 
> On 15/09/2011 01:49, Thomas R. Holtz, Jr. wrote:
> > On Wed, September 14, 2011 6:14 pm, Jura wrote:
> >> Not to get this thing started again, but do keep in mind that the 
> >> majority of dinosaur skin impressions show that they were scaly. 
> >> Filamentous integument is the exception, not the rule.
> >>
> > Let us keep in mind that what the data shows is that big 
> sections of 
> > the majority of dinosaur skin was scaly. But that they also 
> show that 
> > when you have relatively complete coverage of the individual 
> > (Psittacosaurus, Juravenator, more to come soon) you get 
> bodies which 
> > are mostly scaly but with isolated patches/lines of 
> filamentous integument.
> >
> 
> doesn't it actually show that big sections of dinosaur 
> corpses were eventually buried and fossilized without feathers.
> 
> I recall a number of experiments involving rolling corpses 
> around showing that integument (hair/feathers) is easily 
> stripped before final burial - plus, not all sediments are 
> fine enough to record filaments, even if able to show scale imprints.
> 
I should have clarified: the specimens I referred to were explicity those with 
scale impressions, not the ones that had lost the
integument altogether.

And yes, absolutely: anything of very fine silt upwards in coarseness will be 
incapable of recording the presence of feathers, fuzz,
etc.

To turn this into a statement that the cladistically-minded can appreciate: in 
dinosaurs for the presence or absence of filamentous
or other feather, we can confidently record a "1", we can confidently record a 
"?", but we have practically no confidence in
recording a "0" when we now have positive presence of said structures in 
Tianyulong and copious theropods. Them's the breaks, folks.
Deal. (And uncertainty continues to reign in steps immediately baseward, due to 
lack of knowledge of the condition in basal
dinosauriforms and the question of the homologies of pycnofibers in pterosaurs).

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA