Feather Color Revealed in Dinosaurs

Wednesday, January 27, 2010 at 8:11 PM Bookmark and Share
Unrelated to my previous post, news came today from the journal Nature that a group of scientists have used SEM techniques to reveal color patterns from some well preserved dinosaur feathers -- cool stuff!

Here's a figure from the paper, showing some of the melanosomes (pigment containing structures within cells).


"Melanosomes in the integumentary filaments of 
the dinosaur Sinornithosaurus (IVPP V12811). 
a, Optical photographs of part of the holotype and SEM samples (insets). 
b, Mouldic phaeomelanosomes.
c, Aligned eumelanosomes preserved as solid bodies (at arrows). 

d, Strongly aligned mouldic eumelanosomes. 
Scale bars: a, main panel, 50mmand inset, 5 mm; b–d, 2 mm." 


In addition to the coloration details, this paper also gets into other aspects of feather structure confirming that these structures are indeed feathers:
Our results demonstrate conclusively that the integumentary filaments of non-avian theropod dinosaurs are epidermal structures. In birds, melanin is synthesized endogenously in specialized pigment producing cells, melanocytes, that occur primarily in the dermis; the melanocytes migrate into the dermal pulp of the developing feather germ, where the melanin is packaged into melanosomes and then those melanosomes are transferred to keratinocytes for deposition into developing feathers. In various avian species melanin granules also form, and are apparently retained, in dermal melanocytes; melanin granules can form a discrete layer in the dermis, but below, and not as part of, the collagen layer. The occurrence of melanosomes embedded inside the filaments of Jehol non-avian dinosaurs thus confirms that these structures are unequivocally epidermal structures, not the degraded remains of dermal collagen fibres, as has been argued recently. Our work confirms that these filaments are probably the evolutionary precursors of true feathers, and it will be interesting to determine whether any fossil filaments might relate to other kinds of epidermal outgrowths in modern birds.

For further discussion of the paper, see...

0 comments:

Post a Comment