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Melanosomes and ancient coloration re-examined



Ben Creisler
bcreisler@gmail.com


A new paper:

Mary H. Schweitzer, Johan Lindgren and Alison E. Moyer (2015)
Melanosomes and ancient coloration re-examined: A response to Vinther
2015 (DOI 10.1002/bies.201500018).
BioEssays (advance online publication)
DOI: 10.1002/bies.201500061
http://onlinelibrary.wiley.com/doi/10.1002/bies.201500061/abstract

Round to elongate microbodies associated with fossil vertebrate soft
tissues were interpreted as microbial traces until 2008, when they
were re-described as remnant melanosomes – intracellular,
pigment-containing eukaryotic organelles. Since then, multiple claims
for melanosome preservation and inferences of organismal color,
behavior, and physiology have been advanced, based upon the shape and
size of these microstructures. Here, we re-examine evidence for
ancient melanosomes in light of information reviewed in Vinther
(2015), and literature regarding the preservation potential of
microorganisms and their exopolymeric secretions. We: (i) address
statements in Vinther's recent (2015) review that are incorrect or
which misrepresent published data; (ii) discuss the need for caution
in interpreting “voids” and microbodies associated with degraded
fossil soft tissues; (iii) present evidence that microorganisms are in
many cases an equally parsimonious source for these “voids” as are
remnant melanosomes; and (iv) suggest methods/criteria for
differentiating melanosomes from microbial traces in the fossil
record.

***
News release:

https://news.ncsu.edu/2015/10/schweitzer-color/


==============

Response to:

(apparently not yet mentioned on the DML...)

Jakob Vinther (2015)
A guide to the field of palaeo colour.
Melanin and other pigments can fossilise: Reconstructing colour
patterns from ancient organisms can give new insights to ecology and
behaviour.
BioEssays 37(6): 643–656
DOI: 10.1002/bies.201500018
http://onlinelibrary.wiley.com/doi/10.1002/bies.201500018/abstract

Melanin, and other pigments have recently been shown to preserve over
geologic time scales, and are found in several different organisms.
This opens up the possibility of inferring colours and colour patterns
ranging from invertebrates to feathered dinosaurs and mammals. An
emerging discipline is palaeo colour: colour plays an important role
in display and camouflage as well as in integumental strengthening and
protection, which makes possible the hitherto difficult task of doing
inferences about past ecologies, behaviours, and organismal
appearance. Several studies and techniques have been presented in the
last couple of years that have described ways to characterize pigment
patterns. Here, I will review the available methods and the likely
applications to understand past ecologies. A golden age of colourized
dinosaurs and other animals is now dawning upon us, which may
elucidate the nature of ancient predator prey interactions and display
structures.