In order to grasp to what extent we can reliably interpret the animal colour from the fossil record, first it must be established how such colour is generated, with an understanding of the taphonomic processes resulting in its preservation consequently being equally crucial.
When examining extant species, the mechanisms through which colours are produced can be roughly split into two categories; colours produced through pigmentation, and those produced through structural means, with considerable overlap occurring between the two.
Pigmentation is achieved through the absorption of particular wavelengths of visible light (the wavelengths visible light being between 380 and 750nm) by chromophores, regions of organic molecules responsible for colour. The wavelengths that are not absorbed by chromophores are consequently reflected, resulting in the distinctive colour of the pigment. Containing either metal complexes or conjugated π-bonds, chromophores comprise vacant electron orbitals, which are filled when electrons are excited from their ground-state. This ‘jump’ in energy
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Melanin is a recalcitrant, heavily cross-linked, inert polymer. Similarly to the vast majority of pigments, the generation of colour is only one of the many roles that melanin fills. For example, as well as imparting red-brown to black tones in organisms, melanin also provides mechanical strength to the keratinous tissues found in beaks and feathers, and is a crucial component of the invertebrate immune system. Synthesized as two distinct chemical forms; eumelanin and phenomelanin, eumelanin provides black to dark brown pigmentation, whereas phenomelanin provides red-brown to buff. Eumelanin occurs within oblong, rod-like eumelanosomes, between 900 and 1100nm in length. Phenomelanin is found to occur in sub-spherical phenomelanosomes, which are much smaller at around 500nm in