shichahn: (Feets!)
[personal profile] shichahn
So, as most of you probably know, one of the latest advances in dinosaur reconstruction is identifying their coloration. We can do this by looking at the microscopic structures in dinosaur feathers, called melanosomes, in which certain melanosome shapes yield specific colors in the resulting feather. Previously, we had identified the colors of three dinosaurs: Sinosauropteryx, Anchiornis, and Archaeopteryx.

The latest addition is the coloration of Microraptor gui, which struck paleontologists as particularly remarkable when it was discovered - this dinosaur has four wings, rather than two. The front limbs as well as the back limbs are winged, giving it an unusual, biplane-like appearance. It is suspected that the surface area added by the lower/rear wings aided this animal in gliding from branches, rather than being used for powered, flapping flight like in modern birds.

But there's something else we should take from this image, the latest artistic rendering of Microraptor, as released yesterday by the American Museum of Natural History: the line between dinosaur and bird gets ever-fuzzier with each new discovery.



Microraptor had iridescent black plumage like Archaeopteryx, and like modern crows and blackbirds. That particular plumage coloration is usually for feather strength. Black feathers are more resistant to sun wear than other colors, so for birds that spend a lot of time in edge or open habitats, this is important for keeping feathers in good condition. Learning the coloration of Microraptor tells us that this dinosaur lived in relatively open areas, while its gliding style suggests that there was some kind of structure in those habitats as well - so a wooded edge, perhaps, or shrubland, or even the forest canopy, might have been where Microraptor lived. Its size - about that of a pigeon - and sharp teeth and talons suggest that it ate small vertebrate prey, and some Microraptor skeletons have small mammal and dinosaur/bird bones in the stomach. Around 300 fossils of this animal have been found, which is a rather incredible number. It was likely very common in ancient China, which makes it again very similar to today's blackbirds. Each little piece of information informs us further about its lifestyle - remarkable for something that has been extinct for nearly 120 million years.

I keep looking at that picture, above. And I want to show it to anyone who still believes that birds are not dinosaurs. Not that dinosaurs and birds are related, no - because that is a fairly well-established scientific fact by now, and anyone who still supports the ancestral archosaur hypothesis probably lives under a rock. But beyond that, birds are dinosaurs. If we can look at the skeleton of a Microraptor, or an Anchiornis or even a Sinosauropteryx and call it a dinosaur, and then look at the skeleton of a chicken or a hawk or an ostrich, the only thing that separates these animals is time. Yes, birds today are toothless, and many of them have strong flight muscles. But we have found toothless, beaked dinosaurs. Not the plant-eating kind, but the carnivorous birdlike Limusaurus. We also have a number of modern birds without strong flight muscles - think kiwis, cassowaries, emus, ostriches, and many others. So that does not separate birds and dinosaurs either. Birds are part of a long, continuous line of theropod dinosaurs which survived the mass extinction at the K-T boundary. They have evolved and rapidly diversified since then, but that does not make them not dinosaurs. It makes them survivors.
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