Nova: The Four Winged Dinosaur
Posted on February 27th, 2008 by blue collar scientist
Microraptor fossil. The image is from Wikimedia Commons, where it is licensed under the Creative Commons Attribution ShareAlike 2.5 license. Unfortunately, no author name is provided.
I’ve just finished watching the latest Nova, which aired last night (all praise be to TIVO). The episode was about Microraptor.
The early part of the documentary set up some controversy by contrasting the ideas of Larry Martin with those of various AMNH paleontologists and staff, and their collaborators at other institutions. Martin proposes that the development of flight from ground-dwelling dinosaurs1 doesn’t make much sense, without really giving any compelling reasons. He also says that this model is necessary for the evolution of birds from dinosaurs, and again, I don’t fully understand why he thinks that. As I’m fond of saying here, just because you say something doesn’t make it true. I’m unable to think of a reason that arboreal dinosaurs developing flight means that birds can’t have evolved from dinosaurs.
He did make a reproduction of Microraptor which featured splayed femurs. The documentary covered pretty convincingly why the reproduction was not plausible - even I could see that Martin’s pelvis was flatter than a pancake. The documentary covered the similarity of the splayed rear-limb model to lizard anatomy, but I don’t think I really understood why Martin believed - even if everything else he said was true, which I wasn’t convinced of - that Microraptor could not have secondarily splayed rear limbs.
Anyone?
The AMNH team certainly seemed to be doing the better science from what Nova presented. Not only was their model constructed with some pretty rigorous methods, they recruited a multidisciplinary team of experts in various fields and hiked out to a wind tunnel to test it. It made Martin’s approach look a bit parochial. The latter half of the documentary seemed to abandon any further coverage of Martin’s work.
The wind tunnel scene was pretty interesting. I’ve been part of similar groups of scientists trying out and testing new ideas, and what Nova showed is pretty much how scientists act - on the whole very competitive, but very collegial and with few exceptions willing to admit it when the data proves them wrong. As usual, Nova was well worth watching.
- the “ground-up” model, as he puts it, which for some reason has me picturing dinosaurs flying into airplane propellers end ending up as ingredients in my hamburger [↩]
Tags: dinosaur, feather, flight, flying, fossil, Microraptor, Nova, PBS, raptor, theropod
February 27th, 2008 at 5:16 pm
It’s always possible that Microraptor’s hindlimbs splayed secondarily, but that’s a long shot, especially given how close it is to basal Paravians. And with more than two dozen specimens of Microraptor now known, it’s pretty clear from looking at all the fossils that Microraptor’s femoral articulation wasn’t any different from its cousins.
I thought it was a well-done documentary, although I would have liked to see Martin’s comical model thrown in the wind tunnel. A recent paper about Microraptor’s hypothesized flight posture suggests that the splayed out wings would actually inhibit lift, and the animal would have gone into a downward spiral (or something similarly alarming).
Martin also made the terrible argument that if Microraptor was arboreal, the dinosaur theory of bird origins is wrong. That’s not true at all. He implies that dinosaurs were NOT and never were, arboreal. Well, we know that’s not the case. Microraptor was. Sinornithosaurus shows arboreal adaptations. Epidendrosaurus was arboreal. Basal paravians in general probably were.
February 27th, 2008 at 8:13 pm
(And how would Martin know no dinosaur was arboreal, anyway? Has he a time machine stashed somewhere and footage of no dinosaurs ever in trees?)
I didn’t see the special, but I did play with the flash interactive thingy on NOVA’s website. Very interesting. The simulator indicates that the greatest lift:drag combo can be achieved by tucking the hindwings all the way backwards. While interesting, it’s not very likely, given the feather asymmetry. No primaries in any living animal point away from the direction of wind (as they would have had to in the simulation).
Additionally, the feathers attached to the metatarsals are apparently stronger than the primaries (per Gregory S. Paul on the DML). This leads me to believe that the only possible orientation in flight was short-edge first, as would be the case in all flighted birds.
Gotta say, Microraptor is pretty non-boring, for a theropod. It’s my favorite theropod of all time (which probably isn’t saying much).
February 27th, 2008 at 9:47 pm
“Additionally, the feathers attached to the metatarsals are apparently stronger than the primaries (per Gregory S. Paul on the DML)”
Guh. I need a brain editor. First, it was David Marjanovic, and he was saying that the foot feathers are even more asymmetrical than the primaries.
Carry on.
March 6th, 2008 at 6:55 pm
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