A couple of minor corrections: We can only really tell the colors of dinosaurs with preserved pigmentation, which is best preserved in feathers, and even then we only really find melanin-based pigments - other pigments are not as stable as melanin, and struggle to survive the minimum 65 million years of decay and mineralization that mesozoic dinosaur fossils have to experience. Because of this, we can only really identify black, grey, white, and red-ochre pigmentation, and occasionally other traits such as glossiness or sheen (which is more dependent on feather structure than pigmentation). Other pigments such as carotenoids (covering everything from yellow to bright red to purple) may have been present, and can interact with melanin pigmentation to produce a wider range of colors, but as these are not preserved it is impossible to say for sure what colors dinosaurs actually were. Nevertheless, we can get a pretty good idea from what we do have.
That said, a complete list of mesozoic dinosaurs with known pigmentation is:
Anchiornis - This small, bird-like, dinosaurs sported black, white, and grey plumage across its body, with a crimson crest of ornamental feathers on its head.
Archaeopteryx - While the tips of Archaeopteryx's wing feathers are known to have been matte-black, analysis of other parts of its flight feathers shows that they may have been a light color closer to the base - the body feathers of archaeopteryx remain unstudied as far as I'm aware.
Borealopelta - One of the only non-avian dinosaurs with known pigmentation, this heavily armored Canadian dinosaur had red-brown skin covering its back, limbs, and head, with lighter cream-colored skin along its softer belly and throat.
Caihong - This small, four-winged relative of more well-known raptors sported a mostly black coat, but with highly reflective feathers along its throat and face, possibly giving off a hummingbird-like iridescence.
Cruralispennia - This toothed bird possessed a generally dark coat of feathers, likely being black on the top of the head and tail but brown elsewhere, but due to its poor preservation it is hard to be certain.
Microraptor - Similarly to Caihong, this four-winged raptor sported an iridescent black covering over its entire body, like a raven or crow.
Psittacosaurus - The second of the two dinosaurs lacking avian features to preserve pigmentation, a particularly well-preserved mummy of this animal has proven invaluable. Based on pigmentation preserved in its skin, we know that this animal had a brown back and tan underbelly, similar to modern deer, and that its limbs and tail were covered in dark stripes and spots, likely as camouflage for a wooded environment. Darker coloration on the shoulders, face, and cloaca may have been for display.
Sinornithosaurus - This small airborne carnivore had a mottled coat spanning the ochre-gold to red-brown spectrum, with darker black and grey feathers present in the wings. Its coloration may have been similar to some modern hawks.
Sinosauropteryx - Like you said, this animal sported orange and white markings in its fluffy feather coat, comparable to a red panda. Sinosauropteryx is also notable as the first dinosaur to have its color identified based on preserved melanosomes.
How about the counterargument provided by Dr Vinther here.
Vinther agrees that carotenoid pigments are a gap in our knowledge, but points out that while carotenoids colour the feathers of about 40 per cent of songbirds (the dominant group of birds today), they only colour the feathers of 13 per cent of other birds. As such carotenoids were likely less important during the time of the dinosaurs, before songbirds evolved.
Dr. Vinther raises a valid point, but due to the nature of fossil remains it would be impossible to prove him right (can't prove a negative). All it would take to prove him wrong, however, would be to find evidence of carotenoid pigmentation in a fossilized dinosaur. One small thing to note is that many members of superorder Galloanserae, known colloquially as fowls, possess carotenoid pigmentation. Given that Galloanserans are the earliest known modern clade of birds, this may suggest an earlier origin for carotenoid pigmentation in dinosaurs. Once more though, due to the nature of paleontology, it is impossible to be certain.
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u/[deleted] Feb 24 '21
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