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

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:

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 

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
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
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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