3:30PM - 4:00PM
Mr. Arindam Roy Department of Earth Sciences, HKU
Modern birds, the only surviving lineage of dinosaurs are represented by 10,000+ species that inhabit diverse ecological niches. They exhibit an astonishing range of colours and colour patterns which are highly related to their ecology and behaviour. The colour gamut of avian plumage is produced by complex interactions between pigments and feather structure. Preserved melanin pigment has been discovered in fossilised non-avian dinosaurs, paravians, and early bird feathers and scales from a variety of sites around the world and is a leading factor in organic integument preservation in fossils. Vertebrate melanin is typically stored in rod- to sphere-shaped, lysosome-derived, membrane bound vesicles called melanosomes. Black, dark brown, and grey colours are produced by eumelanin and reddish-brown colours are produced by phaeomelanin. Specific morphotypes and nanostructural arrangements of melanosomes and their relation to the keratin matrix in the feathers create the so called ‘structural colours’. The modern relationships between the shape, arrangement, and size of avian melanosomes, melanin chemistry, and feather colour were applied to reconstruct the hues and colour patterns of isolated feathers and plumage of the dinosaurs Anchiornis, Sinosauropteryx, and Microraptor in seminal papers that kick-started the field of palaeocolour reconstruction. Further research has inferred melanin-based colour for more non-avian dinosaurs and early birds, identified countershading camouflage patterns, and informed subsequent predictions on the ecology and behaviour of these extinct animals.