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Post by Krissy on Sept 27, 2011 20:47:07 GMT
So, what do you think? Do you believe the 1946 specimen and 'Jane' warrant their own genus, that of Nanotyrannus, or do you think they are juvenile specimens of Tyrannosaurus? Myself, I seem to change my opinion on this issue every time I read into it. So I'm interested in hearing as many expert/amateur opinions as I can.
So...anyone?
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Post by sid on Sept 27, 2011 21:16:27 GMT
At first i was: Of course it's a young Rex  But then i was: No way! It's a different species!  So, yeah, these times i'm more inclined to think it's probably another species, especially considering that baby Tarbo recently discovered and the recent analysis of the Nano-T holotype made by Witmer... Oh well, Tarbo had Alioramus and Rexy had Nano-T ;D |
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Post by Horridus on Sept 27, 2011 22:39:25 GMT
My knowledge is rather limited. And we really need to wait for that paper to be completed. But for now, I'm saying that they're T. rex juveniles. Seems to make more sense.
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bfler
Junior Member
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Post by bfler on Sept 28, 2011 8:47:22 GMT
A young T-Rex.. In the limited area of Northern America there wasn't enough room for a lot of species of mid sized/large carnivores.
In my opinion many other dinosaurs with different names, like all the ceratopsians, belong to the same species (Juveniles, male and female, deformations through genetic defect or disease). I think if sombody would find some remains of humans after extinction there would also many different kinds of homo sapiens.
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Post by gwangi on Sept 28, 2011 11:09:20 GMT
A young T-Rex.. In the limited area of Northern America there wasn't enough room for a lot of species of mid sized/large carnivores. Why is that? There are plenty of predators sharing space today. In some North American ecosystems you have bear, wolves, mountain lions, coyote, foxes, bobcats, weasels and the list goes on. I think at best we have a limited sampling of a much more diverse dinosaur ecosystem and there must have been multiple predator species. Few places today have only one or two predators. But there are many different kinds of Homo sapien. |
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Post by arioch on Sept 28, 2011 12:15:06 GMT
Considering what we know of tyrannosaurids ontogeny, yes, its more likely a juvenile T. Rex.
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bfler
Junior Member
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Post by bfler on Sept 29, 2011 10:47:47 GMT
A young T-Rex.. In the limited area of Northern America there wasn't enough room for a lot of species of mid sized/large carnivores. Why is that? There are plenty of predators sharing space today. In some North American ecosystems you have bear, wolves, mountain lions, coyote, foxes, bobcats, weasels and the list goes on. I think at best we have a limited sampling of a much more diverse dinosaur ecosystem and there must have been multiple predator species. Few places today have only one or two predators. But there are many different kinds of Homo sapien. But Trex and Nannotyranus are a little bit larger than a fox or coyote and so they would have needed a lot more territory and prey. I don't think that the limited area of the western American continent was large enough for that. And with homos sapiens I mean the current human species. For example let someone find the remains of a Lilliputian. This could lead to the same problems as in the case of T-Rex and Nannotyrannus. Or a while ago I watched a documentary about a family in eastern Europe with a genetic defect which forced them to walk quadruped. Imagine what someone could think if he finds human skeletons with such deformations. |
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Post by eriorguez on Sept 29, 2011 23:09:09 GMT
Juvenile Tyrannosaurine, in a time and area where Tyrannosaurus is the only known adult Tyrannosaurine, and of whose juveniles may be assigned to Nanotyrannus.
Occam's Razor. Keep in mind that adult Nanotyrannus would be a large Tyrannosaurid.
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Post by sid on Sept 30, 2011 9:17:58 GMT
In the Serengeti reserve (which covers a way smaller area than the Late Cretaceous North America) multiple predators live their lives: lions, cheetas, hyenas, crocs, birds of prey, wild dogs (if i'm not mistaken), leopards... Heck, i'd bet back in the Maastrichtian there were at least a dozen or more predators roaming the land along with T.rex! Most of them probably were small to medium sized but i don't see anything impossible in a scenario where, along with the King, another "albertosaurus-sized" tyrannosaur (aka, adult Nano-T) could have lived there as well.
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Post by eriorguez on Sept 30, 2011 11:11:19 GMT
Except it'd have to compete with young Tyrannosaurus. Tyrannosaurs were really good at hogging ecological niches. Not to mention, an Albertosaur-sized predator would have a REALLY hard time getting food at Hell Creek, with the herbivores (ALL of them) being some 5 times larger than it. Daspleto and Gorgo could handle each other, but were quite different, and, all in all, Das won the race.
Also, lions are newcomers to the pack-hunting business, and quite worse at it that hyenas and wild dogs; in fact, they have to share the spot of apex predator, despite being several times larger than a hyena. Leopards are oportunists and target different prey items than lions most of the time.
When you go to Hell Creek, you find a proportion of just Tyrannosaurus equal to the total large carnivore proportion to be expected. It was the sole large carnivore there, no Allosaurus-Torvosaurus-Ceratosaurus equivalent there. The second largest things are juvenile Tyrannosaurines that most likely are Tyrannosaurus, then we have Quetzalcoatlus, who obviously wasn't killing Triceratops, then beaver-sized Deinonychosaurs.
Mammals still make bad comparations to dinosaurs: Dinosaurs ALWAYS start out small, then go through different ecological niches as they grow; while things like a baby elephant are always large animals. There is no room for an Albertosaur-sized animal when you have direct competition that will become stronger than yourself in no time, while you are at your peak.
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Post by sid on Sept 30, 2011 12:45:47 GMT
Except it'd have to compete with young Tyrannosaurus. Tyrannosaurs were really good at hogging ecological niches. Not to mention, an Albertosaur-sized predator would have a REALLY hard time getting food at Hell Creek, with the herbivores (ALL of them) being some 5 times larger than it. Daspleto and Gorgo could handle each other, but were quite different, and, all in all, Das won the race. Also, lions are newcomers to the pack-hunting business, and quite worse at it that hyenas and wild dogs; in fact, they have to share the spot of apex predator, despite being several times larger than a hyena. Leopards are oportunists and target different prey items than lions most of the time. When you go to Hell Creek, you find a proportion of just Tyrannosaurus equal to the total large carnivore proportion to be expected. It was the sole large carnivore there, no Allosaurus-Torvosaurus-Ceratosaurus equivalent there. The second largest things are juvenile Tyrannosaurines that most likely are Tyrannosaurus, then we have Quetzalcoatlus, who obviously wasn't killing Triceratops, then beaver-sized Deinonychosaurs. Mammals still make bad comparations to dinosaurs: Dinosaurs ALWAYS start out small, then go through different ecological niches as they grow; while things like a baby elephant are always large animals. There is no room for an Albertosaur-sized animal when you have direct competition that will become stronger than yourself in no time, while you are at your peak. We don't know if ALL dinosaurs went throught different ecological niches as they grew up; we have too few samples of those ancient ecosystems to reconstruct 'em properly, let alone dinosaur behaviour... And yes, i'm also talkin' about Hell Creek; even if it's one of the most rich fossil-bearing formations in the world, at least regarding Maastrichtian dinos, what we have there is probably just a shadow of the peak of the iceberg that was its biosphere. I hope you don't believe that the fossils found so far are equal to the exact number of species that lived there... |
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Post by gwangi on Sept 30, 2011 22:31:15 GMT
I thought a long time about how I was going to respond but Sid already said it all. We really don't know the behavior of these animals, the exact niches they occupied or when they occupied them and we don't even know the total number of species living in a given region. The way you're talking I could swear you were there yourself.
There could have been multiple Tyrannosaur species who did very different things. If I were to present you with the skeletons of lions, tigers and leopards you would be hard pressed to tell the difference...especially if they had been extinct for 65 million years. They all look amazingly similar under the skin and live side-by-side but live vastly different lives. You say mammals make bad comparisons but that is all we got, and mammals do occupy the same niches dinosaurs did. There are no major animal groups alive today that live quite like the non-avian dinosaurs did so we need to look at something in order to get an idea of how things were. The game stays the same, only the players change.
Despite my argument I do believe Nanotyrannus was likely a juvenile Tyrannosaurus but I don't rule out the notion of it being it's own species.
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Post by Griffin on Oct 1, 2011 0:09:46 GMT
"The game stays the same, only the players change."
Hey that's my line!
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Post by gwangi on Oct 1, 2011 0:32:37 GMT
"The game stays the same, only the players change." Hey that's my line! Is it? |
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Post by Griffin on Oct 1, 2011 4:48:31 GMT
Well I said it a on another thread. I dunno if its been said before that.
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Post by gwangi on Oct 1, 2011 12:40:49 GMT
Well I said it a on another thread. I dunno if its been said before that. I think I picked it up from a documentary or something. I know I've heard it before. |
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Post by arioch on Oct 1, 2011 13:20:18 GMT
Yes, with agile, fast growing juveniles capable of taking down prey practically since they hatch and the vastly offensive armed adults, there´s actually very little room for another big predator apart from T.rex in that environment. Albertosaurines were hard competitors for a while, but eventually wiped out by Rex grandaddy. And azdarchids seem very well adapted to focus on small game .
The sad truth is that dinosaur diversity decreased drastically at the end of the Campanian, not only Tyrannosaurs became scarce, also hadrosaurs and ceratopsians, represented by roughly 1 or 2 species in Maastrichtian North America. So we can figure that Hell Creek late Maastrichtian fauna wasn´t significantly much more varied than what we already know.
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Post by sid on Oct 1, 2011 16:44:04 GMT
"Sad truth"? More like "educated guess" |
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Post by arioch on Oct 1, 2011 17:33:37 GMT
Almost everything in paleontology is based on guessings, but some are more likely than others, some evolve in theories and others remain just speculative, and in this case the theory is supported by the fossil record (and there´s a wide consensus about it). That is the "truth" until proven otherwise with new evidence. You might not like it, but that´s how it works... |
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Post by gwangi on Oct 1, 2011 17:38:34 GMT
Well you did say "Sad Truth" as though it was indeed the truth rather than an educated guess. The sad truth is that at best we have educated guesses.
I have heard the argument about dwindling dinosaur populations at the end of the Cretaceous but I'm not sure how convinced I am. I've also heard scientists claim that dinosaur life was as abundant as ever in the late Cretaceous. I need to read up on it more honestly.
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