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Post by schnautzr on Sept 13, 2009 3:15:30 GMT
Well, I've always gone against that current that says Archaeopteryx was a bird...ever since I first read about it as a kid. I've always found it difficult to accept that something that flies but doesn't look like a bird at all could possibly be a bird. Archaeopteryx has always just been a flying reptile to me, even though I never once thought it very closely related to the pterosaurs. From that judgement alone, I guess that's how I've come to decide what's a bird and what's a reptile.
So anyway, now that I have said what I call a bird and you have said what you call a bird, I guess now we can discuss whether birds "stopped being dinosaurs", as I suggest, or "are still dinosaurs" as you suggest.
Let's go back to fish for a moment. Fish and amphibians. I love mudskippers. A few months ago I saw my first live mudskippers at the aquarium in Newport, KY. They appear rather amphibian, don't they? But we call them fish. When did fish become amphibians? One might suggest it was when they left the water, but there are land-dwelling fish and there are amphibians who spend most of their lives in the water. However, we don't (or I should say I don't) refer to amphibians as fish.
Back to the theropods and birds. Eventually, birds diverged. Whether it was Archaeopteryx as you and most scientists claim or Confuciusornis as I and smaller minority of scientists claim, it happened. Suddenly a theropod had become a bird.
What truly defines a theropod? "Beast foot" doesn't quite do the trick... that could easily include elephants and alligators. Originally, Theropoda consisted of all carnivorous dinosaurs. It contained carnosaurs and coelurosaurs. Raptors were discovered and the definition had to be revised several times...indicating error already. Now theropods include anything saurischian with hollow bones, a wishbone, three toes, and egg broods.
Birds definitely meet the immediately listed requirements, but do they fit into the parent taxa?
Saurischia: No. Birds fit better within Ornithischia, even though they descended from Saurischia. This is called convergent evolution. So while birds may be theropod-like, they don't fit the requirements for being a theropod due to the more highly developed hip structure.
As for whether birds are still dinosaurs... Dinosauria: Dinosaur synapomorphies include an elongated crest on the humerus, or upper arm bone, to accommodate the attachment of deltopectoral muscles; a shelf at the rear of the ilium, or main hip bone; a tibia, or shin bone, featuring a broad lower edge and a flange pointing out and to the rear; and an ascending projection on the astragalus, one of the ankle bones, which secures it to the tibia. Um...grabbed that list of synapomorphies from Wikipedia. Wish I knew more about anatomy. I'm not sure whether birds exhibit any of these characteristics. Do you know?
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mantooth02
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Dieter the Saurornitholestes [F4:ManTooth02]
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Post by mantooth02 on Sept 13, 2009 22:12:20 GMT
Well, I've always gone against that current that says Archaeopteryx was a bird...ever since I first read about it as a kid. I've always found it difficult to accept that something that flies but doesn't look like a bird at all could possibly be a bird. Archaeopteryx has always just been a flying reptile to me, even though I never once thought it very closely related to the pterosaurs. From that judgement alone, I guess that's how I've come to decide what's a bird and what's a reptile. I cannot imagine archeopteryx not looking like a bird to anyone. feathers and the ability to fly are all characteristics that for the longest time were thought to have belonged solely to birds. Amphibians include the common ancestors of all living amphibians and all their descendants. Amphibians also metamorphose from a water breathing form, to an air breathing form, fishes do not. Mudskippers though able to move about on land did not descend from the common ancestor of amphibians. Without getting technical mudskippers are Perciformes fishes due to their spiny and soft rayed fins. They belong to the Goby family and like all other gobies have fused pelvic fins that form a sort of sucker. According to Cladistics (which is something I support, you don't appear to) all tetrapods are Sarcopterygii fishes, so amphibians in that sense never did stop being fishes. Fishes are difficult to classify, they aren't a monophyletic taxon. When I took ichthyology in college my professor made it a point to point out that we humans are more closely related to salamanders than lamprey are to walleye. Again I suggest reading that "Fishes: A Slippery Subject" article. It states the following "The sarcops are most notably characterized by having jaws with fixed teeth, a bony skeleton, a skull with sutures, a type of scale known as '"cosmoid", and heavy, lobe-like paired fins (pectoral and pelvic) supported by stout bones. For this reason, sarcops are informally known as the lobe-finned fishes. As their name suggests, lungfishes actually have primitive lungs and breathe not water, but air. Consider that the tetrapods, too, have jaws with fixed teeth, a bony skeleton, a skull with sutures, and heavy, paired appendages. As we have seen, scales are not at all a defining character of fishiness, nor is breathing by way of gills. Therefore, based on many structural and physiological synapomorphies, the tetrapods not only share a common ancestor with the lobe-finned fishes, but are derived from them. The tetrapods are now generally believed to represent a subclass within the Sarcopterygii." Read the entire article here. Actually, it kinda does. Beast foot refers to the anatomy of the feet not that they were literally "beast feet", birds share this same anatomy. Truthfully birds don't actually have bird hips, they have derived lizard hips that merely resemble the hips of Ornithischia. You can read about this here (I hope for the sake of this conversation you are checking these articles out). The best list I could find is this. In terms of structure dinosaurs and birds share the following. # A pubis (one of the three bones making up the vertebrate pelvis) shifted from an anterior to a more posterior orientation and bearing a small distal "boot." # Elongated arms and forelimbs and clawed manus (hands). # Large orbits (eye openings in the skull). # Flexible wrist with a semi-lunate carpal (wrist bone). # Hollow, thin-walled bones. # 3-fingered opposable grasping manus (hand), 4-toed (foot); but supported by 3 main toes. # Reduced, posteriorly stiffened tail. # Elongated metatarsals (bones of the feet between the ankle and toes). # S-shaped curved neck. # Erect, digitgrade (ankle held well off the ground) stance with feet postitioned directly below the body. # Similar eggshell microstructure. # Teeth with a constriction between the root and the crown. # Functional basis for wing power stroke present in arms and pectoral girdle (during motion, the arms were swung down and forward, then up and backwards, describing a "figure-eight" when viewed laterally). # Expanded pneumatic sinuses in the skull. # Five or more vertebrae incorporated into the sacrum (hip). # Straplike scapula (shoulder blade). # Clavicles (collarbone)fused to form a furcula (wishbone). # Hingelike ankle joint, with movement mostly restricted to the fore-aft plane. # Secondary bony palate(nostrils open posteriorly in throat). # Possibly feathers...this awaits more study. Small, possibly feathered dinosaurs were recently found in China. It appears that many coelurosaurs were cloaked in an external fibrous covering that could be called "protofeathers." SOURCE: 8e.devbio.com/article.php?ch=16&id=161I might also add that though they aren't apparent to you there is a good reason the overwhelming majority of scientists consider birds to be living dinosaurs. I'm not a professional so I can only share what I know but keep in mind that they know a whole lot more. I'm not generally one who questions professionals on things I know little about. Just because you don't want to think of birds as dinosaurs does not make it so, that is the beauty of science.
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Post by schnautzr on Sept 14, 2009 0:21:35 GMT
I will definitely take a look at those articles. That list of theropod characteristics is much easier to understand, thank you.
As for "how anyone could possibly not view Archaeopteryx as a bird"...
Archaeopteryx was first presented to me in an old 90s issue of Zoobooks. I may even still have that copy...I might check if I have a moment later. I don't remember the specifics at the moment, but the illustration "clearly" (to me, anyway) looked like a small dinosaur with sparse plumage. The head was portrayed in such a way that it didn't scream "BIRD!"...instead it screamed "DINOSAUR WITH FEATHERS!" But like I said, that was more than 10 years ago when I was first exposed to it. I'll definitely see if I can find the illustration and possibly send a photo of it.
Time for supper, then I'll read your articles and look for that "ancient wing".
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Post by schnautzr on Sept 14, 2009 1:33:39 GMT
Back...I did not find the old Zoobooks magazine, but I'll do my best to describe to you what the illustration looked like. It appears I have made the same error Mr. Seeley made when naming the two orders of dinosaurs. That article was an interesting read. The fish information is by no means new to me, although this is the first time I've actually stopped to reflect upon which class of fish tetrapods evolved from. Sarcopterygii makes the most sense, as the essay suggests. Back to the illustration I referred to... The Archaeopteryx illustrated in the old Zoobooks magazine portrayed the creature as having a head similar to a snake, only elongated (I can't say I've seen the actual shape in any other creature...the first hint that it could be wrong). The arms were decorated with two or three rows of feathers, but the arms were still visible. The tail had feathers going down both sides, similar to a fern. These were the features I recognized instantly as reptilian. I have never once viewed the creature as the first bird, only as a potential predecessor. More recently I was introduced to Confuciusornis, and I was hesitant at first to call it a bird, but ultimately decided it was indeed a very primitive bird. I did manage to find an image which conveys the basic principles I'm discussing: mac122.icu.ac.jp/biobk/archaeopteryx.jpgI am not saying that I am correct or that anyone is incorrect, I am only explaining how I see things. I really appreciate your cool attitude as we discuss this...it would be very difficult if one of us was hostile or completely didn't care.
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mantooth02
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Dieter the Saurornitholestes [F4:ManTooth02]
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Post by mantooth02 on Sept 14, 2009 2:05:36 GMT
It's a difficult topic to cover, especially for non-professionals plus I like talking about it and not many people want to hear it so doing it here is a nice alternative. Here is an image illustrating how I view archeopteryx from the recent book "Feathered Dinosaurs: The Origin of Birds" by John Long. Much more bird like than the illustration you showed me. My professor told us that Sarcops became amphibians because they were bad at being fish, the rest went on to become the fishes we have today. That statement has stuck with me. It is important to remember when looking at something like a bass that they are not our ancestors, the fishes we have today have had millions of years to improve their own design. The same is true for birds, they spit from dinosaurs millions of years ago. They may not seem like dinosaurs but they've had an additional 65 million years to evolve that other dinosaurs have not.
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Post by schnautzr on Sept 14, 2009 4:28:17 GMT
That's quite a pic you've got there. If that were my first view of Archaeopteryx, I'd DEFINITELY think "BIRD!" as soon as I saw it. I don't like to sound stubborn, but I do think that image is rather liberal with the modern feathers...reminds me of today's waterfowl. I'd like to think Archaeopteryx was rather somewhere in between the two illustrations we've presented-- possibly a more pronounced "beak", although as I understand it, the beak didn't develop until the Cretaceous-- but most likely with a cruder and less full plumage. Unless you've got anything else to say, I'm quite satisfied with the discussion and have nothing left to say myself. Can't wait to participate in another great debate. Edit: I just noticed...You referenced Poling several times, and I just referenced an illustration of his!
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mantooth02
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Dieter the Saurornitholestes [F4:ManTooth02]
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Post by mantooth02 on Sept 14, 2009 19:31:54 GMT
That's quite a pic you've got there. If that were my first view of Archaeopteryx, I'd DEFINITELY think "BIRD!" as soon as I saw it. I don't like to sound stubborn, but I do think that image is rather liberal with the modern feathers...reminds me of today's waterfowl. I'd like to think Archaeopteryx was rather somewhere in between the two illustrations we've presented-- possibly a more pronounced "beak", although as I understand it, the beak didn't develop until the Cretaceous-- but most likely with a cruder and less full plumage. That isn't the first picture I ever saw of Archeopteryx, I honestly don't remember what was, it just happens to be my favorite. Another good one is Luis Rey's which you'll probably like. Huh, so you did. The artist is actually Joe Tucciarone and honestly I'm not much a fan of his work. I'm not sure how Poling is involved with it. Here is his web site. That archeopteryx looks "cartoony" to me. www.joetucciarone.com/joe.html
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Post by schnautzr on Sept 14, 2009 20:06:03 GMT
Yes, it does look rather cartoony. Zoobooks would never have included such a cartoony illustration as that one; it was simply the closest I could find to it.
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mantooth02
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Dieter the Saurornitholestes [F4:ManTooth02]
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Post by mantooth02 on Sept 14, 2009 20:15:04 GMT
Though I never subscribed I did used to have a few Zoobooks, the artwork was pretty good as I recall.
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Post by schnautzr on Sept 14, 2009 20:46:28 GMT
We had a subscription for several years. Easily had a few hundred of them. By using this handy but incomplete list, I can pinpoint that our subscription began in March of 91 (yes, I distinctly remember the first time I saw a Zoobooks magazine it was about gorillas). That was back when the title was very boring-looking. All caps, black and white. Big color picture of a gorilla (grayish black) with a red border around the cover. Made for one of the blandest covers I've ever seen on a magazine. The hummingbirds cover was a little better...even though the hummingbird pictured was quite distasteful, the aqua border helped make up for the lack of color. Eventually they adopted the logo you see today (although it was black and white and 2-dimensional). Later they made each letter in the title a different color for a rainbow effect, but it still had that single-colored border going around the picture, much like National Geographic. Looking at the Zoobooks website today, I wouldn't recognize today's magazine as Zoobooks if I didn't read the word "Zoobooks". I remember feeling ripped off when they issued the ones like "The Deer Family", "City Animals", "The Skunk Family", "Big Cats", "Whales and Dolphins", and "Endangered Species". That meant that there would be less information per animal. I even felt ripped off when they issued "Dinosaurs", even though there was a four or six page double-sided foldout. Yup, used to love those magazines. That was back when I watched Wild America (with Marty Stouffer), too, and got really excited if Nova came on while I was watching TV. We're talking Sesame Street age...you know, sunny days sweeping the clouds away.
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mantooth02
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Dieter the Saurornitholestes [F4:ManTooth02]
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Post by mantooth02 on Sept 14, 2009 22:35:19 GMT
The first magazine I ever recall getting was "My Big Backyard" followed by "Ranger Rick" and then "International Wildlife" and the "Smithsonian" and "Birder Magazine". Now I get "National Geographic" and 'Tropical Fish Hobbyist". I didn't really get the benefit of "Wild America" until my early teens when I was given a box VHS set which I watched and re-watched constantly. I mostly watched "Wild Discovery", that came out in 1995. I don't recall what wildlife program I watched before that.
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Post by schnautzr on Sept 14, 2009 23:04:03 GMT
Three cheers for "My Big Backyard" and "Ranger Rick"!
My TV shows included Wild America (Marty Stouffer), Bill Nye the Science Guy (Bill Nye), Kratt's Creatures (Chris & Martin Kratt), Really Wild Animals (Dudley Moore), and Eyewitness (Martin Sheen). Unfortunately, I don't believe any of those shows still air today. I didn't watch much of Nature (George Page) -- I said Nova earlier and meant Nature. George Page has an awesome voice...I envy him.
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mantooth02
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Dieter the Saurornitholestes [F4:ManTooth02]
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Post by mantooth02 on Sept 14, 2009 23:19:52 GMT
Oh yeah, I remember some of those. I also remember watching Mr. Wizard on Nickelodeon but mostly I just watched whatever was on Discovery or TLC back when TLC was worth watching of course. TLC used to have good shows such as "PaleoWorld" and "Alien Invasion Week". Great stuff. On Discovery I remember really loving "Arthur C. Clarke's Mysterious World/Universe" I still watch those on YouTube and those I have taped, really takes me back.
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Post by jadeelf on Oct 11, 2009 19:50:19 GMT
synapsid reptiles are the forerunners of mammals not dinosaurs or birds.
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mantooth02
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Dieter the Saurornitholestes [F4:ManTooth02]
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Post by mantooth02 on Oct 11, 2009 22:53:13 GMT
I'm not seeing where anyone suggested that? I think I do remember schnautzr suggesting it though. Nice Papo allosaurus.
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