RE: feathers and WWD

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

> -----Original Message-----
> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of 
> evelyn sobielski
> Sent: Tuesday, November 12, 2013 11:29 AM
> To: dinosaur@usc.edu
> Subject: Re: feathers and WWD
> 
> ...but the case of Mammalia shows that the default position is untenable, 
> especially if the metabolic rate of theropods was as high as
> their anatomy indicates. Whether anything heavier than a horse could maintain 
> a thermal insulation by a dense coat of integumentary
> structures (feathers in this case) in the Mesozoic climate (with subtropical 
> conditions almost up to the polar circles) is very
> questionable; phylogenetic reasoning is usually a good approach, but in this 
> case the constraint is basic physics, and physics always
> wins over phylogeny: it's hard to maintain your lineage if you are dead form 
> heatstroke.
>

The specific case asked was about dromaeosaurids. Even the largest 
dromaeosaurids (Utahraptor, Achillobator, etc.) are only horse-mass or smaller.

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

> Thomas R. Holtz, Jr. <tholtz@umd.edu> schrieb am Di, 12.11.2013:
> 
>  Betreff: Re: feathers and WWD
>  An: hammeris1@att.net
>  CC: dinosaur@usc.edu
>  Datum: Dienstag, 12. November, 2013 03:45 Uhr
> 
>  Don't forget: Walking with Dinosaurs
>  came out in 1999, and was being
>  animated in 1998. So at that time the degree of feathering  among  
> coelurosaurs was unknown.
> 
>  At present, every single dromaeosaurid for which integument  is known is  
> fully feathered, as are the outgroups Troodontidae,
> Avialae,  Oviraptorosauria, and Therizinosauria. (And we have feathers  on 
> other,  more distant outgroups).