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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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