Evidence birds did not evolve from dinosaurs?

http://www.sciencedaily.com/releases/2009/06/090609092055.htm

I don't think so.

John Ruben is a well known BANDit. BAND = birds are not dinosaurs. This is allied to ABSRD (pronounced "absurd"), or anything but a small running dinosaur.

Membership of these groups is comprised of people who "know" that birds could not have evolved from dinosaurs, and are on a ceaseless quest to try and find evidence to support this "knowledge."

They "know" that feathers had to have evolved for flight directly and that flight evolved from the trees down, not the ground up.

But these are a priori beliefs, not facts established by evidence.

They are also a salutary lesson that clever and well educated people, experts in their own way and in their own fields, can also be very wrong about things and almost wilfully so.

On any reckoning of the available evidence, the case that birds are highly derived theropod dinosaurs is overwhelming. (Theropods were the two-legged carnivorous dinosaurs. A group ranging from the immense T rex to the tiny microraptor.)

It is now absolutely clear that feathers did evolve in the context of becoming volent, but were exapted for that purpose. Exaptation is where a character that originally fulfilled another function is put to another use.

While we can never be certain about these things, (the Deep Time problem makes this impossible), it does seem that primitive filamentous feathers, akin (but probably not exactly the same) to those found on Kiwis evolved with the Theropoda long before the first theropod became the first bird, and probably for the purpose of insulation.

We now have numerous fossils of what are clearly dinosaurs covered in this "dino-fuzz." But even more astounding, (and how the BANDits reconcile this with their views is simply beyond me), we have many fossils now of again unequivocal dinosaurs not only covered in this fuzz, but also with modern looking feathers adorning their arms and tails. Other than being symmetrical rather than asymmetrical (for those on the arms), they are identical to the flight and body feathers found on modern birds.

Now, these are mostly maniraptorans. Velociraptor was such a creature, as was oviraptosaurus and its kin.

However, one of the very first of the animals discovered in China covered in dino-fuzz, Sinosauropteryx prima, was not a maniraptoran.

It was a primitive compsognathid dinosaur. A "living fossil," (yes I know the term is very suspect, but you get my drift), even in its own day. This would indicate that feathers or their antecedents evolved much earlier on and further back along the dinosaur family tree than people had previously imagined, and that such structures were widespread amongst several lineages within the Theropoda.

You really would think that this would close the case on this question. But never underestimate people's ability to believe what they want to believe and build elaborate houses of cards to support it.

It's not just UFO enthusiasts or 9/11 conspiracy cranks who do this.

So the BANDits start looking further back in time to search for any poorly preserved reptile that has some vaguely avian characteristic which they then cite as a possible contender as an ancestor to birds. And at times by vague, I really do mean vague. A somewhat triangular skull is put forward as indicating possible avian affinities.

That some of these reptiles don't appear to be anywhere near to the archosaurs, the group of diapsid reptiles that birds, (along with crocodilians and dinosaurs), clearly belong to, doesn't seem to faze them.

That they can't give a plausible evolutionary line from said primitive reptile to birds supported by any fossil evidence, doesn't seem to faze then either. The argument runs something like this - "this Triassic reptile has some vague similarity to modern birds and somehow, we don't know how though, may have given rise to them.

"We just know however that birds didn't evolve from theropod dinosaurs and therefore something like this must have been the ancestor."

Not a particularly strong argument I'd suggest.

Here are some artists' interpretation of the modern understanding of maniraptoran dinosaurs, oviraptosaurs in this case:

These are dinosaurs.

Posted via email from Garth's posterous