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Re: Dinosaur Revolution Review



How the dinosaur mummified skin and skin impression are distributed on
the phylogenetic tree?

[]s,

Roberto Takata

On Thu, Sep 15, 2011 at 2:11 PM, Thomas R. Holtz, Jr. <tholtz@umd.edu> wrote:
>> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]
>> On Behalf Of Scott Hartman
>> Sent: Thursday, September 15, 2011 12:55 PM
>> To: Jura
>> Cc: dinosaur@usc.edu
>> Subject: Re: Dinosaur Revolution Review
>>
>> I've often disagreed with how Jason applies some of the
>> evo-devo findings to feather distribution, but I want to go
>> on the record as agreeing with him in part: there really
>> isn't a known mechanism for dermal types to shift after
>> ovo/utero within an individual's lifetime.
>>  That's not to say I don't believe in the possibility of
>> fuzzy juveniles, but they would have to work within known
>> developmental mechanisms.
>
> [snipped a lot of good stuff: go back to the original to read]
>
> It think the error here is the appropriate level at which to look at the 
> "feathers-back-to-scale" issue. Almost certainly it is
> impossible to "go back" **at the follicle level**: once a follicle is 
> dedicated to one of those modes, it is probably dedicate for
> life (or simply turns off).
>
> But we are dealiing with organisms here that in some cases increase their 
> surface areas by many many many many orders of magnitude,
> while scale size (for instance) increases at no where near that rate. Almost 
> certainly there was the appearance of new follicles
> during ontogeny: the developmental process in these has (so far as I know) 
> not been explored in great detail.
>
> 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
>
>