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Re: Moyer et al.: a good study, but not the last word

True, but as Holtz points out, bilateral symmetry (whether dorsal / ventral or 
right / left) would be unlikely in the bacterial case.

Which reminds me -- does asymmetrical pigmentation exist in extant birds? 

On Fri, Mar 7, 2014 9:18 AM EST Dan Chure wrote:

>And of course, some specimens might be bacteria and some might be 
>melanosomes. This is not an all or nothing game.
>On 3/7/2014 5:50 AM, Thomas R. Holtz, Jr. wrote:
> Greetings,
> Just a few notes to add to the comments on the new Moyer et al. paper on 
> bacteria vs. melanosomes:
> There are some good observations in this. However, I think it is fair to say 
> this is not the final word on the subject. I know that
> the UT Austin group that has previously published on melanosomes (including a 
> former student) are hard at work on new studies which
> point to the paleo-examples as being actual melanosomes, and I await news 
> from Jakob Vinther's lab.
> Regardless of the final truth, this is good for science: we have to test our 
> claims!!
> Towards that end, a test I'd like to see. In crystal-level geochemical 
> studies, it is standard operating procedure to publish
> "sample maps" of the crystal being probed, for verification and replication 
> purposes. I do not recall seeing these for the previous
> melanosome studies. That might help to give confidence that a pattern of 
> color was real, and thus probably original rather than
> postmortem bacterial growth. For instance: tracing down and across both left 
> and right "wings" of Anchiornis and find the same
> distribution of supposed-white and supposed-black patterns would increase our 
> confidence in their reality.
> Take care,
> 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
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