Re: fossil fish colouration

[HPB1956@aol.com]

Dann Pigdon wrote:
>>
This only applies to creatures that exhibit metallic colouration (fish 
scales, peacock feathers, etc). In the case of the fossil fish, the scales 
had been preserved in sediment so fine grained that electron microscope 
images revealed the original minute striations on the scale surfaces. The 
colour of light reflected by these tiny ridges repends on their distance 
appart (there is a direct correlation between distance between ridges and the 
wavelength of the light reflected). Hence by measuring the distance between 
the minute striations it was possible to determine what colour light they 
would have reflected.
<<

Point taken. But according to a report in Earth Magazine (1998/2) there was 
more to it than just this kind of colouration. 
Quote from Earth Magazine "True Colors":
>>
... Biophysicist Andrew Parker at the Australian Museum in Sidney took a 
magnified look at 370ma old fish called placoderms.
... He noticed cells cells which contain microscopic structures called 
diffraction gratings. These split light into ist rainbow of colors, ... , and 
produce a silvery reflection.
... Much to his surprise he also found cells containing clumps of either red 
or black pigment granules. By mapping the distribution of color cells of one 
particularly well preserved placoderm, he came up with a color model of the 
creature: red on top and silver on bottom.
<<

Theoretically this method could be used also for fossils of dinosaurs.
But I think there's one additional problem: if dinosaurs had some kind of 
"fluffy" integument covering their body, the naked skin underneath wouldn't 
(IMHO) show any sign of a colour pattern (e.g. stripes). Just think of an 
plucked chicken.
But there may have been some naked patches of coloured skin especially at the 
head and neck which could be examined with this method.