Stump the Paleontology Major!

[Katrina Rix]

Fire away with your best prehistory questions. I'll find the answer to anything I don't know, or ask one of the older, wiser paleontologists. ;D I'll also post any cool facts I feel like sharing here.

Cool fact #1 - The first tetrapods (four legged animals like amphibians, reptiles, birds, and mammals) had more then five fingers on each limb. Take a moment to observe your modified lobe fin now. Appreciate your ability to type with said lobe fin. See those little rays holding up a fish's fin? Those are your digits, and our early tetrapod ancestors probably had eight or so of them on each hand. Ain't life cool?

[aric]

IIRC, one of the arguments some people use to say that birds aren't direct descendants of dinosaurs is that the fingers in a birds wings aren't simply modified therapod fingers. I think they said they were different fingers from different parts of the hand. Is this true? And if so, how do paleontologists who propose that birds are descendants of dinosaurs handle the digit issue?

I'm not up to speed on the dissidents' issues when it comes to dinosaur physiology and how it realtes to avian physiology. I may have completely mangled their position.

- Aric

[Christopher]

What sound does a diabetic brachiosaur make, when trying to play a flute made out of tin cans?

[Kiva]

*rolls on floor laughing hysterically*
Chris, I don't think those were the questions she was talking about.

Although, now that you mention it... I'm rather curious to hear the answer. ;D

[Katrina Rix]

aric - Well, the studies on which digits correspond to which has been done on bird embryos. As I understand it, the digits that are supposed to be in birds are ones that were lost during the evolution of the theropod hand.

My personal rebuttal - digits are very difficult to differentiate in embryos. This could just be poorly read data. Feathers are very complicated tissue, and assuming they evolved twiced is a stretch. Anatomically speaking, aside from the possible digit question, birds and derived maniraptorans seem to be the same thing. A wealth of evidence points to birds being theropods. Besides, I've only seen that one study, and it got stomped on pretty badly. Since it doesn't seem to have been repeated, and no one can observe the development of theropod embryos (which could have done the exact same thing), I'm sticking with chickens being derived maniraptors.


Anon. - Wargh! of course. Maybe Warghtoodledo, if said brachiosaur prefers traditional flute music.

[Christopher]

Ha! The right answer was 329! I win! *Dances* *Gives Rix choccy for trying*

[aric]

Ah, excellent. I didn't hear that the digit idea got crushed.

What about the lizard-hip thing for theropods? Sometimes, they bring up the alleged ridiculousness of birds coming from lizard-hipped therapod dinosaurs.

- Aric

[Katrina Rix]

Aric - That's just from people who haven't done their research, just gone on the names. It's a rather old division, back from good old Owen's days. The ornithschians (I think that's spelled right), which are the bird hipped dinosaurs, have both bones of the hip pointing backward. The saurischians have the bones in a little V shape. However, in some of the more derived theropods (which are saurischians), the bones of the hip are moving back, like a bird's. Dromaesaurids, for instance, have the same hip configuration as modern birds.