Evidence of melanin - pigments found in skin, hair, feathers and eyes - in a fossil fish eye from the early Eocene, is reported in a study published in Nature Communications this week. Supposed fossil organelles containing melanin have previously been reported and have led to claims about the possible colour of ancient species but, because their shape and size are similar to those of bacteria, conclusive evidence is required to confirm their identity.
Fossil feathers, hairs and eyes can be preserved as carbonised traces of micrometre-sized structures, which were thought to be the remains of bacteria. However, these structures have now also been interpreted as melanosomes - colour-bearing organelles containing melanin - opening up the possibility to reconstruct fossil plumage colour patterns. A clear identification of the source of these organelles is therefore crucial.
Johan Lindgren and colleagues used ion mass spectroscopy study microbodies isolated from a fossil fish eye from the early Eocene of Denmark. They found a presence of molecularly preserved melanin in association with melanosome-like microbodies. The work helps expand our knowledge of pigments in fossil material.