A question about Archaeopteryx

talkorigins states that there are several reasons for archaeopteryx being classifed as a bird:1) Feathers
2) A furcula
3) Opposable hallux
4) Pubis elongate and directed backward.My question is about the opposable hallux. A little while ago, there was a lot of interest in a tenth Archaeopteryx specimen that popped up. It didn't have a reversed hallux, which is present in most perching birds today. Is 'opposable hallux' and 'reversed hallux' the same thing?If that is the case, it appears that three out of four of the avian traits that talkorigins listed is either shared between dinosaurs (feathers and furculae) or not possessed by Archaeopteryx (the opposable hallux).Why then is Archaeopteryx still classified as a bird?Thank you.

Thread moved here from the Proposed New Topics forum.

Archy is classified by scientists as both dinosaur and bird--not just bird. It displays defining avian features (bird) while also displaying defining features of coelurosaurs (dinosaur).The new wrinkle is that birds as a group are coming to be classified as dinosaurs. New discoveries reveal many non-avian species of coelurosaurs possessed features once diagnostic of birds: hollow bones, feathers, wishbone, even behaviors like sleeping under a wing/arm. One result of such discoveries is that the number of features we can call 'unique to birds' is shrinking. The realization is emerging that birds are really a specialized line of dinosaurs that happened to survive the K-T event. Birds are coelurosaurs.Archy is an avian dinosaur. Classic model._Edited by Archer Opterix, : Detail.Edited by Archer Opterix, : Clarity.Edited by Archer Opterix, : Typo.

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ArcherAll species are transitional.

Thank you Archer Opterix. Judging by your name, I've come to the right person. So when creationists try to wave Archaeopteryx off by saying that it is just a bird, not only are they wrong because Archaeopteryx is transitional between dinosaurs and birds, they are also wrong because being a bird means you're a dinosaur anyway!If it is too much to ask, could you list a few avian features of Archaeopteryx? I know about the backward facing pubis, but many therapod dinosaurs have a very similar sort of hip structure. The hips are themselves transitional!Edited by Hongi, : No reason given.

Thanks, but I'm hardly the best person for this. We have some excellent science-heads available to us here.I recommend taking this to the thread 'Early Birds had Dino Feet'. It's a natural.
_Edited by Archer Opterix, : Added link.

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ArcherAll species are transitional.

all birds are dinosaurs.

talk origins is not the best source on archaeopteryx.indeed, many dinosaurs had feathers, most post-mid-jurassic theropods seemed to have furculae, and all dienonychosaurs have their pubis bones elongated and directed backwards. and archaeopteryx doesn't have the opposible halux. on t.o's work alone, we'd assume that archaeopteryx is simply not a bird at all -- it has by far more and more obvious dinosaurian characteristics.but let's not forget some basic facts here -- birds are dinosaurs, so all birds will have dinosaurian characteristics. and talk origins is not the end-all, be-all of scientific research. there are things that make paleontologists and biologists group archie with bird, as "the first bird." they're just a little more technical:Dinosauria On-Line

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I did say as much. Three times.Serves me right. Next time I'll remember to put everything in my first sentence where people can read it.

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ArcherAll species are transitional.

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there are things that make paleontologists and biologists group archie with bird, as "the first bird." they're just a little more technical

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Thank you arachnophilia. This is what I was looking for.I found it a bit odd that Archaeopteryx was assigned to bird-status based on only a handful of traits. I know now that's not true.I'll follow up on this link. Very useful.

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but let's not forget some basic facts here -- birds are dinosaurs, so all birds will have dinosaurian characteristics.

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One more question regarding this above quote. As I understand it, evolution is modification upon modification. Contrary to creationist belief's, a cat will not evolve into a dog. No organism will never evolve to be fundamentally different. e.g whales are still modified mammals, snakes are still modified tetrapods.So when you say that birds still possess dinosaurian characteristics, can we can see those dinosaur traits today in any bird skeleton, albeit in a modified way? For example, do birds still have the perforate acetabulum that was present in their long ago ancestors?Edited by Hongi, : No reason given.

eh, ignore me i was just being nitpicky in that there is no class of animals that are "just a bird" and not dinosaurs as well.

yeah, i had found it a bit odd too. personally, if the totally arbitrary point about where "bird" begins were up to me, i'd have probably picked a different point. yes. here, for example, you can see a diagram of the hip bones of sauropod, theropod, ornithstician, maniraptorian (and archie), and a modern bird hip. birds do indeed still have a perforate acetabulum.i'd like to mention, though, as a word of caution, that it's quite possible that certain "dinosaur" characteristics may have been modified to such an extent that they've lost the particular quality people are looking for -- but the bones themselves are still homologous. for instance, we could say that theropod dinosaurs have three digits on their hands, that end in curved claws. birds do not, but the formation of their carpometacarpus is homologous to the three digits -- it's formed of those three digits, which have been fused together.

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i'd like to mention, though, as a word of caution, that it's quite possible that certain "dinosaur" characteristics may have been modified to such an extent that they've lost the particular quality people are looking for -- but the bones themselves are still homologous. for instance, we could say that theropod dinosaurs have three digits on their hands, that end in curved claws. birds do not, but the formation of their carpometacarpus is homologous to the three digits -- it's formed of those three digits, which have been fused together.

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And I'm also pretty sure that cladistics classifies on evolutionary relationships, not on the abscence or presence of traits. e.g, a mammalian descendent will still be put under the mammal clade if they lost their lactating ability.Once again, a big thanks for helping me.

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yes, something like that. but i'm not the person to ask about cladistics. everytime i make a point about it, someone says either "cladistics is not based on features" or "cladistics is not based on evolutionary relationships." which i've never been able to figure out.

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