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Post by ningishzida on Dec 15, 2008 20:55:27 GMT
We usually envision theropod dinosaurs with rows of visible sharp teeth, but the best evidence suggests you would never see those teeth, and that virtually all of the so-alled 'scientifcally accurate models and artwork are wrong.
It is quite logical that most theopods, with their narrow serrated teeth, probably had very similar mouth structures to varanid lizards , like the Komodo dragon, that have almost identical, narrow and serrated teeth.
But when we look at a Komodo Dragon, do we see rows of gleaming sharp teeth? No. And in all liklihood we would not see these in most carnivorous dinosaurs either.
Even when a Komodo has its mouth open, only the very tips of the teeth are seen. The rest are concealed in thick fleshy sheathes that retract depending on how much pressure the lizard exerts. If the komodo is snapping up a small animal, only the tips are used to hold the prey. If it is a large aimal like a buffalo, then the whole cutting edge of the teeth are exposed to slice through hide and flesh. Given the itentical type teeth, almost certainly, carnivorous dinosaurs would have had the identical types of gums, and you would not see the teeth , even with the mouth open.
Moreover, the komodo also has lips that extend well beyond the jawbone, which create an airtight seal so it can breath through its nostrils. Dinosaurs would certainly have these 'lips' too, so that they could seal their mouths, and provof of this are the holes in the jawbone for blood vessels to supply all of the flesh out side of the jaws. There would be no point for these holes if the dinosaurs did not have lips.
The reality of the situation then is that most theopods would have very different heads. A T-Rex then would probably have a good six inches of fleshy scale covered 'lips' beyond the actual jawbones. Accordiingly, you would have all of this extra flesh on the skull as well, so it would not look like a dessicated 'zombie' dino with a thin sheet of parchment like skin stretched over its skull.
So the heads of virtually all theropod dinosaurs would be larger and look much like a lizard's. When the mouth is closed, no teeth could be seen as all.
There is only one possible exception and these are the spinosaurids, who have round teeth like crocodiles, and probably a similar aquatic lifetyle. They probably did not have the gum sheaths and lips of other theropods, but skulls much like crocodilians. Models and artwork of these dinosaurs, without lips and like crocodilians are probably accurate, and are likely the only reasonably accurate reconstructions of the heads of theropod dinosaurs..
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Post by kuni on Dec 15, 2008 21:08:57 GMT
Interesting stuff. It'll be tough to ever know for sure, since there's a lot of phylogenetic distance between dinos and squamates. It would still be cool to see some artwork done in this style, though...
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Post by sid on Dec 15, 2008 21:14:05 GMT
Naah...That could be possible for Dromeosaurids and other small-medium sized theropods...But for animals with BIG upper teeth like Tyrannosaurids,Tetanurans and Ceratosaurids having bigass lips,sorry,that's NOT realistic They probably had lips,but not as prominent as in Varanids and other lizards. So,according to this theory,even Smilodon probably had a pair of big,fleshy lips to hide his "swords" ;D ;D
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Post by ningishzida on Dec 15, 2008 21:26:28 GMT
Naah...That could be possible for Dromeosaurids and other small-medium sized theropods...But for animals with BIG upper teeth like Tyrannosaurids,Tetanurans and Ceratosaurids having bigass lips,sorry,that's NOT realistic They probably had lips,but not as prominent as in Varanids and other lizards. So,according to this theory,even Smilodon probably had a pair of big,fleshy lips to hide his "swords" ;D ;D It is very realistic. Same kind of teeth in both types of animals, very similar behavior, etc. Proportionately to its skull, T-Rex doesn not have teeth larger than an Varanid. And then there is the mtter of the holdes for blood vessels. They only make sense if there is a lot of flesh outside of the jaws, exactly as we seen in varanid lizards. To prove this, take a komodo dragon skull, and give it a typical dino reconstruction of a thing coating of skin over the skull, and all those exposed teeth. It will look like the typical theropod dino reconstruction. But we KNOW it doesn't look like this because these animals are still living. Accurate reconstructions of theropods would have heads like varanid lizards and you would not see their teeth.
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Post by [][][]cordylus[][][] on Dec 15, 2008 21:33:42 GMT
Hmmm.... Instead of comparing theropod dinosaurs to squamates(The two aren't closely related at all), why don't we compare them to crocodilians.... No big gums there, right? It's a nice theory though.
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Post by [][][]cordylus[][][] on Dec 15, 2008 21:34:39 GMT
Naah...That could be possible for Dromeosaurids and other small-medium sized theropods...But for animals with BIG upper teeth like Tyrannosaurids,Tetanurans and Ceratosaurids having bigass lips,sorry,that's NOT realistic They probably had lips,but not as prominent as in Varanids and other lizards. So,according to this theory,even Smilodon probably had a pair of big,fleshy lips to hide his "swords" ;D ;D It is very realistic. Same kind of teeth in both types of animals, very similar behavior, etc. Proportionately to its skull, T-Rex doesn not have teeth larger than an Varanid. And then there is the mtter of the holdes for blood vessels. They only make sense if there is a lot of flesh outside of the jaws, exactly as we seen in varanid lizards. To prove this, take a komodo dragon skull, and give it a typical dino reconstruction of a thing coating of skin over the skull, and all those exposed teeth. It will look like the typical theropod dino reconstruction. But we KNOW it doesn't look like this because these animals are still living. Accurate reconstructions of theropods would have heads like varanid lizards and you would not see their teeth. I'm pretty sure those big "holes" were for making the skull lighter.
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Post by ningishzida on Dec 15, 2008 21:39:16 GMT
Hmmm.... Instead of comparing theropod dinosaurs to squamates(The two aren't closely related at all), why don't we compare them to crocodilians.... No big gums there, right? It's a nice theory though. Of course not, because crocodilians are largely fish eaters as their round teeth betray. If you read the OP, that was taken into account, and why I said the only accurate models are those of the Spinosaurids. There should be a reason why varanid and typical theropod teeth are virtually identical, and why there are holes in theropod jaws to supply blood to those huge 'lizard lips'.
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Post by ningishzida on Dec 15, 2008 21:41:47 GMT
It is very realistic. Same kind of teeth in both types of animals, very similar behavior, etc. Proportionately to its skull, T-Rex doesn not have teeth larger than an Varanid. And then there is the mtter of the holdes for blood vessels. They only make sense if there is a lot of flesh outside of the jaws, exactly as we seen in varanid lizards. To prove this, take a komodo dragon skull, and give it a typical dino reconstruction of a thing coating of skin over the skull, and all those exposed teeth. It will look like the typical theropod dino reconstruction. But we KNOW it doesn't look like this because these animals are still living. Accurate reconstructions of theropods would have heads like varanid lizards and you would not see their teeth. I'm pretty sure those big "holes" were for making the skull lighter. No, they are holes for blood vessels, exactly like every other animal that has lips and flesh covering their jaws.
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Post by [][][]cordylus[][][] on Dec 15, 2008 21:58:55 GMT
Could you please post a picture of what holes you are talking about? I am confused.
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Post by [][][]cordylus[][][] on Dec 15, 2008 21:59:47 GMT
Hmmm.... Instead of comparing theropod dinosaurs to squamates(The two aren't closely related at all), why don't we compare them to crocodilians.... No big gums there, right? It's a nice theory though. Of course not, because crocodilians are largely fish eaters as their round teeth betray. If you read the OP, that was taken into account, and why I said the only accurate models are those of the Spinosaurids. There should be a reason why varanid and typical theropod teeth are virtually identical, and why there are holes in theropod jaws to supply blood to those huge 'lizard lips'. I thought crocs and gators ate many land animals, and it was the babies who ate the little things like bugs and fish...
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Post by ningishzida on Dec 15, 2008 22:08:50 GMT
Could you please post a picture of what holes you are talking about? I am confused. I am referring to the row of holes just a little below the tooth line, which are for blood vessels. Crocs do not have these because their aquatic lifestyle does not require them to have lips like virtually all terrestrial reptiles have. Here is a link to a typical T-Rex skull where you can see this. www.uky.edu/KGS/education/t_rex_skull.pdf
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Post by crazycrowman on Dec 15, 2008 22:12:12 GMT
"Same kind of teeth in both types of animals, very similar behavior, etc." Besides assuming that theropods were cursorial predators, we can not accurately say that they had "very similar behavior" to varanids, or any modern animal, and the only time where we can even make "solid" statements about their behavior is where that behavior has been recorded in the fossil record (trackways, dead packs, nesting animals preserved atop nests) "Accurate reconstructions of theropods would have heads like varanid lizards and you would not see their teeth." This seems to be a matter similar to that of feathered T -rexes - An article about therpod "lips" scienceinsociety.northwestern.edu/content/articles/2008/medill-reports/june/dino-art/paleoartists-see-bones-and-make-dinosaursAnd even one about beaks. news.bbc.co.uk/1/hi/sci/tech/184387.stm
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Post by Dinotoyforum on Dec 15, 2008 23:27:58 GMT
The JP raptors were right! ;D
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Post by crazycrowman on Dec 15, 2008 23:46:08 GMT
I thought crocs and gators ate many land animals, and it was the babies who ate the little things like bugs and fish... Depends entirely on the species, but as a whole, they are NOT all fish specialists. As juveniles, many of them eat whatever they can overpower, but some species, especially the slender snouted species, are fish specialists, and in the wild, although they will eat carrion and small animals as well, some like the African Slender Snouted Crocodile, Gharial prey predominantly on fish. Some caiman, even though they are generalist feeders for the most part, like the Spectacles and Yacare, often base their diets as adults off fish if they live in a habitat with a great amount of piscine diversity. The Nile and Indo pacific Crocodiles do become "large game" specialists, and as adults prey very heavily on large macropods/hoofed mammals in some parts of their range. In other areas they live off of smaller fare. They are generalists, though will often tackle very large prey one on one. The American Alligator eats all different sorts of foods, though turtles, crabs and snakes are up among the top prey choices, (they have wider crushing jaws with very pillar like teeth to demolish hard prey) followed by waterfowl/herons/stork/other birds. They will and do eat fish, but are not fish specialists.
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Post by bolesey on Dec 15, 2008 23:51:00 GMT
We usually envision theropod dinosaurs with rows of visible sharp teeth, but the best evidence suggests you would never see those teeth, and that virtually all of the so-alled 'scientifcally accurate models and artwork are wrong. Reptillian tooth-covering lips were pretty much the standard in dinosaur illustration for years. I remember when that Witmer study made the news, and I've read other bits and pieces. I dunno, I need to read up on it again. If they ever find a skull with good skin impressions, it might put the matter to rest.
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Post by ningishzida on Dec 16, 2008 1:02:56 GMT
The JP raptors were right! ;D Yes, on the matter of lips covering the teeth, but probably not about their exaggerated intellect. That image is probably representative of the basic look of most theropods with their mouth's closed, with the probable exception of the Spinosaurids.
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Post by [][][]cordylus[][][] on Dec 16, 2008 1:22:50 GMT
I thought crocs and gators ate many land animals, and it was the babies who ate the little things like bugs and fish... Depends entirely on the species, but as a whole, they are NOT all fish specialists. Thought so.
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Post by therizinosaurus on Dec 16, 2008 1:27:41 GMT
I don't see any evidence for the lips. Here's how I see the train of thought: T-Rex had big teeth. Squamates have big teeth and lips. Therefore, T-rex had big lips. You could apply that way of thinking to prove that any extinct animal had any physical feature, for example: Sabre-tooth cats are large felines. Leopards are large felines with spots. Therefore sabre-tooth cats had spots.
Just my 2 cents...
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Post by [][][]cordylus[][][] on Dec 16, 2008 1:33:44 GMT
But not ALL felines of today have spots...
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Post by therizinosaurus on Dec 16, 2008 1:35:46 GMT
/\ But not all squamates have gums
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