Forum Topic
Gavin
MemberTyrannosaurus RexAug-20-2013 10:00 AMAs with any self respecting geek or nerd I have been a Dinosaur fan since I was a little boy; I even had (once upon a time) quite a collection of Dinosaur books, mostly written in the 70's and 80's. Despite these old books affirmations by their respective "experts" that the Dinosaurs where not wiped out by a large asteroid and that Dinosaurs did not evolve into birds, I kept an open mind. And with a lot of recent scientific discoveries proving the aforementioned "experts" wrong. It got me thinking.
[u]Dinosaurs - Birds: A No Brainer[/u]
How the experts of yesteryear could deny the possibility that many small to medium sized Theropod Dinosaurs evolved in to birds defies logical belief, even the books I read as a child, written by these so-called "experts" referred to Ornithischian Hipped Dinosaurs as "Bird-Hipped" Dinosaurs. Looking at the two comparison pictures below...
[center][img]http://i.imgur.com/J3l7QQP.jpg[/img]
[i]Procompsognathus (left), Grey Egret (right)[/i]
[img]http://i.imgur.com/xRQKLZn.jpg[/img]
[i]Gallimimus (left), Ostrich (Right)[/i][/center]
[u]Feathered Dinosaurs Though, Really[/u]
Well if small to medium Theropod Dinosaurs evolved in to prehistoric and then modern day Birds, then yeah Dinosaurs would have developed feathers as part of the evolutionary process for sexual displays, warmth and inevitably (though not in all cases) flight.
[u]But Dinosaurs Where Reptiles, Birds are Warm Blooded[/u]
Yes Birds are warm blooded creatures whose only scales, if they can be called scales, are found on their feet. And no Birds are not reptiles. So one could (and in cases some scientists do) argue that birds did not evolve from Theropod Dinosaurs, for that very reason.
Or one could instead argue that the presumption that Dinosaurs (latin for Terrible Lizard) were reptiles is actually incorrect. But before you call me crazy, take a look at the following comparison image...
[center][img]http://i.imgur.com/ftMrUP6.jpg[/img]
[i](Top Left-Right) Giant Tortoise, Alligator, Komdodo Dragon.
(Bottom Left-Right) Tyrannosaurus Rex, Stegosaurus, Brachiosaurus.[/i][/center]
Notice the top 3 images, all of which are reptiles have their limbs spreading out from their sides, a common reptilian trait that allows them to remain low to the ground to absorb heat from the environment to warm their blood - all reptiles share this anatomical feature.
Yet in the lower three pictures our Dinosaurs are stood upright, much like mammals, birds and other warm blooded animals. What if Dinosaurs were actually warm blooded, and thus not Reptiles.
[u]But Didn't Dinosaurs have scales like modern day Reptiles[/u]
Well the only evidence we have to go off are a few very rare and vague fossilized impressions of Dinosaur skin, which could be scales or could be somthing entirely different.
Not all mammals are covered in fur/hair, take the Elephant, Rhinoceros, Hippopotamus, Aramdillo etc. It is possible that Dinosaurs could have had leathery, bumpy skin instead of scales, which more suits the image we have of Dinosaurs such as the Tyrannosaurus Rex, Brachiosaurus and Triceratops.
But this of course opens another can of worms - are Birds the only ancestors of Dinosaurs alive today. Maybe not. Take a look at the next comparison picture...
[center][img]http://i.imgur.com/hZ6gqWy.jpg[img]
[i]Triceratops (left), Rhinoceros (right).[/i][/center]
Lose the bone frill, shorten the tail, add a horn, and add some fat and its quite viable that Dinosaur favorite the Triceratops may have evolved into the modern day Rhinoceros.
So if Dinosaurs weren't cold blooded, of which the physical evidence seems to suggest, and if their skin was leathery instead of scaled, and as such they were not reptiles, what where they.
Well unless the scientific community wants to create a new genus for them, they were mammals. Think of the Plesiosaur, a marine reptile according to the Dinosaur rulebook, yet it possessed a smooth skin similar to that of a hippopotamus or Dolphin, and breathed air. In Fact take a look at the next comparison picture...
[center][img]http://i.imgur.com/RfYINoa.jpg[/img]
[i]Did the Ichthyosaurus (left) evolve into the Dolphin (right)[/i][/center]
Where Dinosaurs Reptiles or Mammals, or something else? What do you think? And while your at it take a look at this final image...
[center][img]http://i.imgur.com/5gyd8JH.jpg[/img]
[i]Which animal is the drawing emulating?[/i][/center]
The top image is a drawing of an animal in which the head and tail have been erased, but is it a drawing of an Elephant (bottom left) or a Brachiosaurus (bottom right), look carefully, very carefully before answering - I will reveal the answer in due course.
19 Replies
Rex Fan 684
MemberCompsognathusAug-20-2013 10:23 AMMy Theory and Opinion
Dinosaurs are reptiles. While modern reptiles are not warm-blooded, the crocodilians have 4 chambered hearts, like a bird or mammal. Dinosaurs were probably warm-blooded and had 4 chambered hearts. This is how I break up the reptile family tree...
Reptiles-
"Basic" Reptiles-
Turtles/Tortoises
Lizards/Snakes(Mosasaurs were a kind of monitor lizard)
Archosaurs-
Crocodillians
Dinosaurs(birds)
Pterosaurs
Sea Reptiles
A very rough break down I will admit.
Most dinosaurs probably had a covering of primarily scales. The dinosaur mummy Leonardo, a Brachylophosaurus, proves this.
[img]http://static.ddmcdn.com/gif/dinosaur-images-086-resize.jpg[/img]
[img]http://www.wikinoticia.com/images/espaciociencia.com/espaciociencia.com.wp-content.image24.png[/img]
Leonardo
Small-Medium size theropods probably had a covering of feathers, the advanced ones that is, with scaly heads, feet, hands, etc.
[img]http://www.ucmp.berkeley.edu/diapsids/saurischia/velociraptor1_skrep.jpg[/img]
Large theropods like Tyrannosaurus probably had feathers as juveniles and lost them when they reached sexual maturity.
[img]http://1.bp.blogspot.com/-lXITA9_Sa2M/TpJL0EWbBiI/AAAAAAAAACw/mbVDBASA2Cg/s1600/t-rex-hatchling-fuzz-feathers-dinosaurs-color_12392_600x450.jpg[/img]
With a few exceptions, like Yutyrannus.
Herbivores would have had mostly scales, with a few quill like feathers.
[img]http://dic.academic.ru/pictures/wiki/files/84/Triceratops_liveDB.jpg[/img]
Because I classify dinosaurs and their contemporaries(sea reptiles, pterosaurs, and birds) as reptiles, they did not evolve into any mammal species. Mammals began to appear at the same time as dinosaurs, so it's basically impossible for dinosaurs to have evolved into mammals.
"Men like me don't start the wars. We just die in them. We've always died in them, and we always will. We don't expect any praise for it, no parades. No one knows our names."
―Alpha-98
t-rex90
MemberCompsognathusAug-20-2013 3:45 PMBoth of you guys make good points. And you know, part of me did kinda wonder if a Rhino evolved from a Triceratops and the body of an elephant always did look kind of sauropod like to me but then again dinosaurs were reigning supreme at the time, mammals did'nt start to take over until after they became extinct, perhaps mammals evolved from reptiles then? but then why would reptiles be around today? same thing could be told about us humans evolving from apes but that's another story. Dinosaurs always seemed lizard like to me so I'm gonna keep thinking of them as reptiles even though they weren't actually lizards, plus I read that an alligator and crocodile are related to the t-rex in terms of the bite force and jaw power goes (I can see the resemblance too). smaller theropods turning into birds, that makes sense. Have'nt there been mummified dinosaur remains found though? I remember they uncovered a hadrosaur once and it's skin was made up of scales.
Rex Fan 684
MemberCompsognathusAug-20-2013 9:07 PMYes. A fair amount of Edmontosaurus mummies have been found along with some other hadrosaurs. Carnotaurus skin has also been found and other species as well.
"Men like me don't start the wars. We just die in them. We've always died in them, and we always will. We don't expect any praise for it, no parades. No one knows our names."
―Alpha-98
t-rex90
MemberCompsognathusAug-20-2013 11:02 PMThought so, so that pretty much confirms that MOST dinosaurs did have entire bodies covered in scale then, thus making them reptiles. As well as some of the bone structure too.
Gavin
MemberTyrannosaurus RexAug-21-2013 6:35 AMScales or no scales, were all Dinosaurs cold-blooded. Their posture and lifestyles would suggest not. Also remember that the distinction between reptile or mammal is not as clear cut as you would at first presume.
If you are familiar with your Dinosaurs you will have heard of this guy...
[center][img]http://i.imgur.com/4NciBmJ.jpg[/img][/center]
Dimetrodon was what is referred to as a Para-Mammal, a mammalian-like reptile, of which their are many as can be seen [url=http://en.wikipedia.org/wiki/Paramammal][b]HERE[/b][/url] - some of which even had fur, which shows that it is possible for reptiles to evolve into mammals, not unlike how reptiles evolved into birds, one would say.
Thus my crazy theory suddenly seems less crazy and suddenly more plausible -and remember scales does not always mean reptile. Fish have scales, as do we humans, our skin is composed of minute scales and we are mammals. Hmmm the plot thickens.
Rex Fan 684
MemberCompsognathusAug-21-2013 9:12 AMThe theory of evolution, which could be wrong itself, that's up to debate as well, states that mammals did evolve from reptiles. But not dinosaurs. The first true mammals showed up at the same time as the first true dinosaurs. They continued to overlap until non-avian dinosaurs went extinct 65 million years ago and there was a sudden explosion in mammal population and diversity. Dinosaurs continued to hold the role of top predator in some locations until the final Ice Age in the form of Terror Birds.
"Men like me don't start the wars. We just die in them. We've always died in them, and we always will. We don't expect any praise for it, no parades. No one knows our names."
―Alpha-98
Deltadromeus
MemberCompsognathusAug-21-2013 9:16 PMMy theory is that dinosaurs are dinosaurs. They evolved into birds, but aren't birds. There are some reptile-mammal crossovers from the Permian and before and I think they evolved into mammals. Reptiles have been around since ancient times, before the Triassic, ie crocodiles and turtles. The ichthyosaurs were sea reptiles by name, but I do think they evolved into whales and dolphins. Th Petrasaurs evolved from reptiles and then died out. And another thing, I think the dinosaurs where whipped out by a meteor. Wait, this deserves another discussion. Forget what I just said.
Hi
t-rex90
MemberCompsognathusAug-22-2013 12:01 PMI could never see birds actually being dinosaurs, that's why I'm still a little hesitant on fully believing that even though there's plenty of fossil evidence to suggest that. I really don't want to give up eating chicken and turkey lol. Although according to some scientists only some species of dinosaurs evolved into birds (like the ostrich and emu) so there's still a chance maybe that not all of them are evolved dinosaurs.
Rex Fan 684
MemberCompsognathusAug-22-2013 12:42 PMBirds are birds. If one or two are dinosaurs, they all are. That's just how things work honestly. You can't say an anaconda is a snake, but a python isn't.
Birds being dinosaurs makes total sense to me. Just look at the feet. Or the way they move.
[img]http://3.bp.blogspot.com/-rqLACtV0iLc/URuEYBUPvhI/AAAAAAAACW0/REbRIqkwgUQ/s1600/Emu-03.jpg[/img]
[img]http://images3.wikia.nocookie.net/__cb20090828152142/dinosaurs/images/1/1d/Gallimimus.jpg[/img]
Add a tail and arms to the emu, and you could not tell the difference.
"Men like me don't start the wars. We just die in them. We've always died in them, and we always will. We don't expect any praise for it, no parades. No one knows our names."
―Alpha-98
t-rex90
MemberCompsognathusAug-22-2013 1:00 PMTrue, I'd really be interested in knowing which birds are evolved of certain dinosaurs (Please don't let a chicken be a T-Rex, I'd rather a hawk or an eagle lol)
Rex Fan 684
MemberCompsognathusAug-22-2013 1:09 PMThe non-avian dinosaurs closest to the avian-dinosaurs(birds) are the maniraptors. Dinosaurs like Troodon and Oviraptor are in this group and the dromaesaurs are closely related to the maniraptors. Tyrannosaurs belong to the coelurosaurs, like maniraptors and dromaesaurs, but were not as close to avian-dinosaurs as maniraptors and dromaesaurs. No specific dinosaur would evolve into a specific bird.
"Men like me don't start the wars. We just die in them. We've always died in them, and we always will. We don't expect any praise for it, no parades. No one knows our names."
―Alpha-98
Rex Fan 684
MemberCompsognathusAug-22-2013 1:49 PMCloser than Allosaurus, Triceratops, etc. But not directly, no.
"Men like me don't start the wars. We just die in them. We've always died in them, and we always will. We don't expect any praise for it, no parades. No one knows our names."
―Alpha-98
Deltadromeus
MemberCompsognathusAug-22-2013 1:51 PMI accually see a lot of dromeaosaur in hacks and egales. Just look at microraptor. Its practically a bird. Also, there are some Dromeaosaurs that scientist don't know whether they are birds or dinosaurs, and those are the ones with wings and can fly.
Hi
t-rex90
MemberCompsognathusAug-22-2013 4:13 PM*sigh* thanks Rex Fan, I'm relieved to know that haha.
Deltadromeus, it's hawks and eagles, not hacks and egales (though I'll assume those were typos) lol. I do agree actually that eagles and hawks do look more raptor like now that I look at the the claws too especially. Well, there were many types of Dromeaosaurs as well.
Deltadromeus
MemberCompsognathusAug-22-2013 4:15 PMI can't spell egales and my iPad has autocorrect so it must have said hacks instead of hawks.
Hi
t-rex90
MemberCompsognathusAug-22-2013 4:27 PMunderstandable, I've heard of people who have the same problem with that too heheh.
Acrocantho
MemberCompsognathusFeb-20-2014 2:37 AMSo...I like your way of thinking, however it seems there is some lack of knowledge regarding taxonomy and evolutionary biology. Attention: longer text is coming ;).
The "experts":
I do not know which "experts" you are talking about, but since the discovery of Archaeopteryx it was clear that dinosaurs were very related to birds.
Reptile, bird or dinosaur?
Here we have to take a look at modern taxonomy. Today species and genera are classified as "clades", which are always part of bigger clade, which is the clade of their ancestors. Let's take a look on the taxonomy of the dog:
The dog (Canis lupus) is a member of the clade Canis (its genus), which is a member of Canidae, which belongs to Carnivora...
And now a greater look at the pigeon, a bird.
Pigeons (Columbidae) --> Psittacimorphae --> Neornithes --> Aves (birds) --> Coelurosauria --> Theropoda --> Saurischia --> Dinosauria --> Archosauria --> Diapsida --> Reptilia
So birds are in a cladistic view in fact dinosaurs and reptiles. But we have to distinguish between "classic" reptiles and the clade reptilia. The allocation of vertrebrates in the five main groups fishes, amphibians, reptiles, birds and mammals is antiquated, the classic reptiles (turtles, snakes, lizards, crocodyles) are in fact paraphyletic, which means they don't have the same ancestor. Crocodyles for example are more related to dinosaurs and birds than to lizards and snakes.
The clade reptilia (synonym Sauropsida) covers a big bunch of clades e.g. the "classic reptiles" and their ancestors, ichthyosaurs, pterosaurs, dinosaurs and therefore also birds.
So, you are right. Dinosaurs aren't very similar to classic reptiles, because they weren't one. Indeed the classic reptiles aren't a homogenous group themselves. But they are all part of the bigger clade reptilia, which exists since the Carboniferous.
Similarities between mammals and some reptilia:
It's right there some similarities between different mammals and reptiles (I now use reptile as a synonym for reptilia). But this doesn't mean they are very related, in fact they are only similar on the first look, take a second (anatomical and genetics) you can easily see the differences. After modern scientific opinion (and proven through fossils and genetics) the cladistic classification of mammals is the following:
Mammals --> Therapsida --> Synapsida
Synapsids themselves are the sister taxon of Reptilia, which means they had the same ancestor. Both clades evolved during Carboniferous-Permian. So how can we explain these optical similarities? It's a phenomenon, which is called convergent evolution: different species evolve similar attributes in a similar environment. A good example are wings. Birds, bats, pterosaurs and insects evolved wings. All wings have a similar shape (aerodynamic reasons) but have completely different origins. Birds use feathers (originaly scales), bats and pterosaurs a membrane skin, insects chitin. So you can explain the mutuality between ichthyosaur-dolphin, elephant-sauropd etc. more an similar ecological niche than a factual relationship.
So these should be the main points. As references nearly every modern specialized book for biology.
(No offence ;) )
Given enough time hydrogen begins to wonder where it came from and where it is going.
Robotron
MemberCompsognathusJul-28-2014 9:40 AMI have always wondered if the fossils of dinosaurs can actually be proven as reptiles, with the possibility that they could be something else. Perhaps, if a complete dinosaur carcass in reasonable condition has been found and preserved, we could see what it really was like.
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