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Re: Feathering in coelurosaurs



Just to throw my hat in the ring here:

Does anyone know of a large reptile that is brightly colored or even colorful? As far as I know, crocs, large snakes (Anacondas, boids, etc.), Galapagos turtles, and the like are all relatively dull colored animals, even though all of these reptiles see in color (please correct me if I'm wrong). On the avian side of things, ostriches, emus, and other large ground birds are relatively drab as well. I don't pretend to know why this is, but it's interesting. What is it about getting larger in both these groups that seems to dull their colors?

If we use a phylogenetic bracket hypothesis, then, we might be able to say this, if birds and crocodilians represent the living outgroups to dinosaurs: (A) Since both crocs and birds have color vision, that would make it a "primitive" or symplesiomorphic trait for dinosaurs and all ornithodirans; (B) Based on this hypothesis, dinosaurs would have primitively had color vision; (C) This might imply colorful patterns for display or deception, but of course none of this testable. Dinosaurs may have been drab animals when they became larger, if the trend we observe in living avians and crocodilians holds true for all archosaurs. Are there any large archosaurs that are very colorful?

I suppose in the end, if the current relationships between dinosaurs and birds and crocs hold, we can be reasonably sure that dinosaurs were primitively color-seeing animals. What colors they were, or if the large dinos were color-impaired, is at the moment beyond the reach of a direct scientific inquiry. While we're all waiting for cloning to bring back dinosaurs (and Matt Wedel will agree with me that sauropods should be the first to be cloned), maybe an area of investigation would be to study skin coloration in large and small archosaurs and see if there is some integumentary reason for the "color change" with size.

Matt Bonnan
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