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Post by paleofreak on Feb 25, 2011 15:04:05 GMT
Had Sinornithosaurus been found in 1980, Dromaeosauridae would become a synonim of Archaeopterygidae, and raptors would be birds (...) Also, had Archaeopteryx been discovered after Dromaeosaurs, it would be classified as a dromaeosaur. Why? Even in a non cladistic world, scientists would pay attention to slight differences in morphology, make arbitrary boundaries and create a lot of distinct taxa.
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Post by Griffin on Feb 25, 2011 16:11:28 GMT
"Raptor" is any predatory bird? I always was under the impression it just meant things with a hooked beak and talons. falconiformes and strigiformes.
So under this logic would a great blue heron be a raptor? barn swallow? woodpecker?... So many birds are technically predators as well.
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Post by sid on Feb 25, 2011 19:21:11 GMT
Modern (and prehistoric) birds are "just" a type of theropod dinosaurs, not the other way around, so Velociraptor is a dinosaur and, say, a heron is a dinosaur too.
Saying that dromaeosaurids are birds would be like saying a mouse is a human because both are mammals ;D
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Post by Horridus on Feb 25, 2011 19:30:16 GMT
Saying that dromaeosaurids are birds would be like saying a mouse is a human because both are mammals ;D It wouldn't really be in any case as dromaeosaurs are birds' closest relatives. However, it may be stretching the word 'bird' beyond usefulness to include dromaeosaurs. In the traditional sense of a bird being any animal with feathers then they certainly are. On the other hand, limiting it to taxa within Aves means they aren't. But people disagree about the taxonomy, as ever. Since dromaeosaurs almost certainly evolved from Archaeopteryx-like ancestors, and Archaeopteryx has traditionally been classed as a bird, there is definitely an argument for dromaeosaurs being birds. It just depends on where you draw the line in the end...it's arbitrary.
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Post by paleofreak on Feb 25, 2011 20:56:56 GMT
Since dromaeosaurs almost certainly evolved from Archaeopteryx-like ancestors According to my info, the most probable scenario is dromaeosaurids, troodontids and birds descendingd from a small, "four winged" creature, more similar to Anchiornis or Microraptor than to Archaeopteryx.
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Post by Horridus on Feb 25, 2011 21:22:49 GMT
Although Archaeopteryx did have long feathers on its legs...
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Post by Griffin on Feb 25, 2011 21:24:04 GMT
"Modern (and prehistoric) birds are "just" a type of theropod dinosaurs, not the other way around, so Velociraptor is a dinosaur and, say, a heron is a dinosaur too."
Trust me i know all that. I just don't think its normal to say any bird that kills other animals for food deserves the title "raptor".
About this whole "dromaeosaurs are birds" argument. Personally I always considered them dinosaurs and not birds mainly because I never thought of it that hard. But like Horridus said there is def an argument there. Depends on what you consider a bird.
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Post by eriorguez on Feb 25, 2011 21:53:50 GMT
And if Sinornithosaurus was discovered in the 80's, it would be classified as an Archaeopterygiform, and all Deinonychosaurs would end up classified in Class Aves. Then cladistics would rise, and the tree would look the same, but Deinonychosaurs would be called birds.
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Post by Horridus on Feb 25, 2011 21:58:11 GMT
As long as you're not advocating the idea that dromaeosaurs are birds and therefore aren't dinosaurs, we can all get along
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Post by dinoguy2 on Feb 26, 2011 0:42:02 GMT
Had Sinornithosaurus been found in 1980, Dromaeosauridae would become a synonim of Archaeopterygidae, and raptors would be birds (...) Also, had Archaeopteryx been discovered after Dromaeosaurs, it would be classified as a dromaeosaur. Why? Even in a non cladistic world, scientists would pay attention to slight differences in morphology, make arbitrary boundaries and create a lot of distinct taxa. No, in a pre-cladistic world, class-level classification was based on major differences in morphology, not slight ones. If it had feathers, it was a bird. That's why Archaeopteryx was called a bird. Heck, the holotype of Archaeopteryx itself is *just* a feather, no skeleton at all. The fact that it was a feather led it to be classified as a bird. After cladistics, feathers no longer make the bird. But they did up until the 80s. And they will again, I imagine, because everyone from Gautheir to Tom Holtz is now classifying Aves as only modern birds. So either Aves does not equal bird, or Hesperornis is not bird. So what is a bird? Why not go back to the older, sensible definition of bird = something with feathers? Oh, right... because that would make dromaeosaurs birds, and we can't have that... Seriously though. I would challenge anybody to create a definition for the word "bird" that both makes logical sense and doesn't include Microraptor.
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Post by paleofreak on Feb 26, 2011 1:37:12 GMT
No, in a pre-cladistic world, class-level classification was based on major differences in morphology, not slight ones. humm... not always. Just subtle differences between mammals and their close relatives, that were classified as non mammal reptiles. You are right here. But this doesn't imply that, after Archaeopteryx, all newly discovered feathered creatures would be classified as birds. When more fossils are found and the limits of the classes became fuzzy, non cladistic taxonomists make an arbitrary boundary. And that boundary could be the presence of feathers, or some other characters. Everyone? no, I don't think so. The cladistic definitions of Aves that include Archaeopteryx are much widely used. I can have that. No problem, but I'd like some scientific consensus first... Bird: a member of the clade Aves, which is commonly defined as the most recent common ancestor of Archeopteryx and the Neornithes, plus all its descendants.
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Post by dinoguy2 on Feb 26, 2011 2:30:15 GMT
"Commonly defined" is the clincher. PhyloCode defines Aves = Neornithes. And why is Archaeopteryx logically a better choice of definition than, say, Anchiornis?
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Post by foxilized on Feb 26, 2011 4:34:07 GMT
Why is it so important to decide how to name the thing? What does it change? --It's not a retoric question, I am actually asking that for real--. Is it because the debate to decide if birds are direct theropod descendants is still active? Really? Thought that was a consensus actually. If so, why is it so important to decide if velociraptor is "a bird" or "a dinosaur", what's the point in practical terms? I am also thinking that if we are really logical, the first step before this would be redefining what exactly is a "Dinosaur". Seems we give a lot of importance to decide if very close animals like a Troodon and an Eagle should be catalogued the same, but on the other hand we do catalogue the same as "Dinosaurs" to an Iguanodon and a Velociraptor. Shoudln't we be more worried on drawing a much greater line between ornithopods/theropods rather than in theropods/birds? All these animals have in common is a very very very old common ancestor and erect limbs. Is that really enough to label them the same?
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Post by paleofreak on Feb 26, 2011 9:31:36 GMT
"Commonly defined" is the clincher. PhyloCode defines Aves = Neornithes Well, the PhyloCode is a controversial classification proposal. In the future, perhaps most paleontologists will follow it, but at the present... It's arbitrary. It's not a matter of logic. And Archaeopteryx is a super-famous fossil, an milestone in the History of Science.
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Post by paleofreak on Feb 26, 2011 12:04:50 GMT
Thought that was a consensus actually. There is a scientific consensus, but it has not already arrived to all internet forums ;D Yes, of course. They are also labeled "vertebrates" toghether with humans, frogs and fish, and their super-ultra-very old common ancestor No problem at all with labels for old and diverse groups.
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Post by Horridus on Feb 26, 2011 20:19:06 GMT
Seems we give a lot of importance to decide if very close animals like a Troodon and an Eagle should be catalogued the same, but on the other hand we do catalogue the same as "Dinosaurs" to an Iguanodon and a Velociraptor. Shoudln't we be more worried on drawing a much greater line between ornithopods/theropods rather than in theropods/birds? There was a time when Ornithischia and Saurischia were thought to have arisen from different ancestors, making 'Dinosauria' an unnatural grouping. However it was demonstrated that the two groups shared many characters even if, for example, Velociraptor and Ankylosaurus look dramatically different. As for the first part of what you said - it's mostly just dogma stopping people from referring to birds as 'dinosaurs', not classfication. Birds have always been 'special' and dinosaurs have always been scaley dead things. Some perceptions can be hard to overturn.
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Post by lio99 on Feb 26, 2011 21:09:16 GMT
I am pretty shore that the raptors had feathers. Ok
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Post by stoneage on Feb 27, 2011 0:52:59 GMT
As long as you're not advocating the idea that dromaeosaurs are birds and therefore aren't dinosaurs, we can all get along ;D Birds evolved from non-dinosaurion archosaurs, so most species once called theropods would not now be classified as dinosaurs.
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Post by eriorguez on Feb 27, 2011 4:20:06 GMT
And, which ones are the non dinosaurian ones? Are you saying Oviraptors have nothing to do with Alvarezsaurs? Alvarezsaurs with Therizinosaurs? Therizinosaurs with Ornithomimosaurs? Ornithomimosaurs with Tyrannosaurs? Tyrannosaurs with Compsognathids? Compsognathids with other tetanureans?
The fact that you belive that just shows your lack of knowledge of theropods AND archosaurs.
No really, that issue is bad.
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Post by paleofreak on Feb 27, 2011 20:23:21 GMT
And, which ones are the non dinosaurian ones? The feathered ones. That's what some few fringe scientists say... without any evidence.
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