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Saurophaganax maximus v Tyrannosaurus rex
Topic Started: Dec 15 2012, 10:02 PM (59,189 Views)
DinosaurMichael
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Saurophaganax maximus
Saurophaganax ("lizard-eating master") is a genus of allosaurid dinosaur from the Morrison Formation of Late Jurassic Oklahoma (latest Kimmeridgian age, about 151 million years ago). Some paleontologists consider it to be a species of Allosaurus (A. maximus). Saurophaganax represents a very large (13 metres (43 ft) long). Saurophaganax was one of the largest carnivores of Late Jurassic North America. Ray even gave an estimate of the body length of fifteen metres and Chure of fourteen, though later estimations have been lower. The fossils known of Saurophaganax (both the possible New Mexican material and the Oklahoma material) are known from the latest part of the Morrison formation, suggesting that they were either always uncommon or appeared rather late in the fossil record. Saurophaganax was large for an allosaurid, and bigger than both its contemporaries Torvosaurus tanneri and Allosaurus fragilis. Being much rarer than its contemporaries, making up one percent or less of the Morrison theropod fauna, not much about its behavior is known. Stovall in Oklahoma also unearthed a considerable number of Apatosaurus specimens, a possible prey for a large theropod.

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Tyrannosaurus rex
Tyrannosaurus is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex (rex meaning "king" in Latin), commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the Maastrichtian age of the upper Cretaceous Period, 67 to 65.5 million years ago.[1] It was among the last non-avian dinosaurs to exist before the Cretaceous–Paleogene extinction event. Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to the large and powerful hindlimbs, Tyrannosaurus forelimbs were small, though unusually powerful for their size, and bore two clawed digits. Although other theropods rivaled or exceeded Tyrannosaurus rex in size, it was the largest known tyrannosaurid and one of the largest known land predators. By far the largest carnivore in its environment, Tyrannosaurus rex may have been an apex predator, preying upon hadrosaurs and ceratopsians, although some experts have suggested it was primarily a scavenger. The debate over Tyrannosaurus as apex predator or scavenger is among the longest running in paleontology. Tyrannosaurus rex was one of the largest land carnivores of all time; the largest complete specimen, FMNH PR2081 ("Sue"), measured 12.8 metres (42 ft) long, and was 4.0 metres (13.1 ft) tall at the hips. Mass estimates have varied widely over the years, from more than 7.2 metric tons (7.9 short tons), to less than 4.5 metric tons (5.0 short tons), with most modern estimates ranging between 5.4 and 6.8 metric tons (6.0 and 7.5 short tons). Packard et al. (2009) tested dinosaur mass estimation procedures on elephants and concluded that dinosaur estimations are flawed and produce over-estimations; thus, the weight of Tyrannosaurus could be much less than usually estimated. Other estimations have concluded that the largest known Tyrannosaurus specimens had a weight exceeding 9 tonnes.

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Edited by DinosaurMichael, Dec 15 2012, 10:02 PM.
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SpinoInWonderland
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Tyrant
Jun 2 2013, 02:53 AM
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Megalodon became extinct just ~2 million years ago, the whale size was very likely similar to today's back then, and no modern shark has yet enough time to evolve to succeed Megalodon.


My point was that you claim that Jurassic theropods are probably larger than Cretaceous ones because the former lived amongst larger fauna. With this logic modern day sharks would be larger than megalodon as modern day whales are far larger than those during megalodons time, yet none nearly even approach its size.

Until we actually have any reliable fossil evidence of a large Jurassic Park theropod bigger than Tyrannosaurus, spinosaurus and the like no one can really claim that Jurassic Park theropods were larger than those living in the Cretaceous.
How much basis do you have for modern whales being far larger than those during Megalodon's time?

Have you considered that the Megalodon threat was likely the cause of whales evolving massive sizes, and they had no evolutionary reason to shrink even though Megalodon already became extinct?
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Jinfengopteryx
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brolyeuphyfusion
Jun 2 2013, 02:01 AM
It makes more evolutionary sense that Jurassic theropods are larger, look man, there is a huge abundance of huge prey in the Jurassic, unlike in the Cretaceous, where smaller ornithopods are more common.
I now want my African polar bears!
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SpinoInWonderland
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Jinfengopteryx
Jun 2 2013, 02:56 AM
brolyeuphyfusion
Jun 2 2013, 02:01 AM
It makes more evolutionary sense that Jurassic theropods are larger, look man, there is a huge abundance of huge prey in the Jurassic, unlike in the Cretaceous, where smaller ornithopods are more common.
I now want my African polar bears!
There's none, but there was the Arctotherium, which lived with large megafauna in prehistoric South America...
Edited by SpinoInWonderland, Jun 2 2013, 03:01 AM.
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Jinfengopteryx
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The megafauna was about as big as the one today in Africa, so there would have to be a 1 t African bear.
Also, you said larger prey HAS to mean larger predators. But if there is an exception today, there could have been one in the past. Taking an example for your claim, does not debunk an exception.
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Spinodontosaurus
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brolyeuphyfusion
Jun 2 2013, 02:29 AM
Apparently you, as you do everything to downsize Saurophaganax.

No I don't. I simply use the most realistic and accurate figures, and don't base it on an incorrect scale bar and a poor base model.

I would also like to point out that I believe Allosaurus fragillis to be larger than the oft. quoted 9.7 meters, and also believe Carcharodontosaurus to be smaller than many of the other users on this forum think.


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Why not just have them at mass parity so this long and sensless size argument wouldn't have happened?

Because the evidence at hand suggests that it wouldn't be at mass parity.

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There is nothing ignorant there. If you actually looked through the known paleoecology of the Jurassic, there are strong reasons for Jurassic theropods to be larger.

Name as many reasons as you wish, the theropods themselves don't follow your trend. There is at most two known giant Jurassic theropods; Epanterias and Saurophaganax.

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They were exceptions.

Right...
So I guess tyrannosauridae and spinosauridae are also inconvenient exceptions?
In the same vein, allosauridae and megalosauridae must also be exceptions, as they don't follow your trend either.

Name any 'giant' Jurassic theropod, and I can name two Cretaceous ones larger than it.


Note: I don't consider the fragmentary giant Tyrannosaurus' to be reliable. I was simply making a point that they are no worse than basing ones entire argument on an incorrect scale bar.
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SpinoInWonderland
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Spinodontosaurus
Jun 2 2013, 03:09 AM
Name any 'giant' Jurassic theropod, and I can name two Cretaceous ones larger than it.
19IGR and 16IGR using Torvosaurus' based estimates.
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theropod
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Tyrant
Jun 2 2013, 02:53 AM
Quote:
 
Megalodon became extinct just ~2 million years ago, the whale size was very likely similar to today's back then, and no modern shark has yet enough time to evolve to succeed Megalodon.


My point was that you claim that Jurassic theropods are probably larger than Cretaceous ones because the former lived amongst larger fauna. With this logic modern day sharks would be larger than megalodon as modern day whales are far larger than those during megalodons time, yet none nearly even approach its size.

Until we actually have any reliable fossil evidence of a large Jurassic Park theropod bigger than Tyrannosaurus, spinosaurus and the like no one can really claim that Jurassic Park theropods were larger than those living in the Cretaceous.
lol jurassic park?

good one tyrant!

I think wpinosaurus should be excluded here, since it is not a terestrial macropredator like the others. Generally, it is very well possibleJurassic theropods were just as large or larger than cretaceaous ones, do you agree with that? However there is no hard evidence at now, just some footprints that make me pretty sure they existed.

I think with modern day sharks and whales it is a different thing. in evolutionary terms, C. megalodon went extinct only a pretty short time ago. No huge predator had time to evolve. Also, the whales during its time were probably just as large, and likely more numerous than today. also its extinction was probably caused by the ice age, since whales now live in waters too cold for a giant lamniform.
I think it is the same here; Jurassic sauropods weren't just quite possibly even larger than cretaceous ones but obviously extremely numerous compared to the cretaceous.
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Tyrant
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Quote:
 
jurassic park?

good one tyrant!


You know what I meant. Tyrant has been watching too many movies!

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. Generally, it is very well possibleJurassic theropods were just as large or larger than cretaceaous ones, do you agree with that?


Yes its possible, no you can't say its likely until evidence suggests that.

Quote:
 
I think with modern day sharks and whales it is a different thing. in evolutionary terms, C. megalodon went extinct only a pretty short time ago. No huge predator had time to evolve. Also, the whales during its time were probably just as large, and likely more numerous than today. also its extinction was probably caused by the ice age, since whales now live in waters too cold for a giant lamniform.


Yeah and that's kind of the point I was getting at, evolution is more complicated than big herbivores=big predators. For example why would the growth of creatacous predators shrink or stagnate? Sure the herbivores of their time were smaller but that doesn't mean it would be advantageous for the predators to get smaller as well. After all at parity ceratopsians and ankylosaurs are far more dangerous prey than sauropods and stegosaurs, and it would be in a predators interests to develop a size advantage on those animals.
Edited by Tyrant, Jun 2 2013, 03:29 AM.
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Spinodontosaurus
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brolyeuphyfusion
Jun 2 2013, 03:13 AM
Spinodontosaurus
Jun 2 2013, 03:09 AM
Name any 'giant' Jurassic theropod, and I can name two Cretaceous ones larger than it.
19IGR and 16IGR using Torvosaurus' based estimates.

You completely missed the point.
Nevertheless:
I don't even know how big they are supposed to be when accurately estimated. And if you are so against UCMP 137538 because of foot variation, your usage of ichnotaxon is confusing.
I know of some European tracks comparable in size to Tyrannosaurus (Stan) ones, so am assuming that sort of size range. In which case, both Spinosaurus species and all giant carcharodontosaurids with the exception of Acrocanthosaurus are larger (the latter, along with things such as Suchomimus and Tarbosaurus are still comparable to Stan).
But like I said, you completely missed the point.
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SpinoInWonderland
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Spinodontosaurus
Jun 2 2013, 03:47 AM
brolyeuphyfusion
Jun 2 2013, 03:13 AM
Spinodontosaurus
Jun 2 2013, 03:09 AM
Name any 'giant' Jurassic theropod, and I can name two Cretaceous ones larger than it.
19IGR and 16IGR using Torvosaurus' based estimates.

You completely missed the point.
Nevertheless:
I don't even know how big they are supposed to be when accurately estimated. And if you are so against UCMP 137538 because of foot variation, your usage of ichnotaxon is confusing.
I know of some European tracks comparable in size to Tyrannosaurus (Stan) ones, so am assuming that sort of size range. In which case, both Spinosaurus species and all giant carcharodontosaurids with the exception of Acrocanthosaurus are larger (the latter, along with things such as Suchomimus and Tarbosaurus are still comparable to Stan).
But like I said, you completely missed the point.
Footprints are actually more useful for size estimation than isolated toe bones, because a footprint at least gives the idea of the shape of a complete fleshed-out foot...

And the footprints I am talking about are ~90 cm long...
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Godzillasaurus
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theropod
Jun 1 2013, 11:35 PM
"Using direct force"?

Can you explain how exactly that is the deciding factor? You would favour it just because it has a stronger bite force?

The force production in allosaurid bites may have been tremendous too, just not the adductor force. otherwise, Allosaurus' cranium wouldn't be so strong. We are not just talking about two similar animals, but one with a weaker bite. We are talkign about animals that kill differently.

One has teeth built to slice, together with powerful head-depressor musculature and attachments making it function efficiently. Arguably a strike-and-pull-bite would have done huge damage. You cannot measure how effective a bite is solely by looking at the force generation between mandible and cranium.
All the evidence points out to the Allosaurid having a bite every bit as formidable at parity.
I realize that allosaurids had teeth that were very well designed for slicing; I already knew that. I already knew that the hatchet bite could prove useful. But tyrannosaurus was still more robust nonetheless. At similar lengths, tyrannosaurus wins
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theropod
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^At similar lenght, perfectly true. I was talking about similar overall body mass. At similar lenght, an allosaurid wouldn't be as heavy as a Tyrannosaurus. Of course at lenght parity the tyrannosaur would be heavier and hence also overally more powerful. But at weight parity I don't see a reason to favour its bite, do you?

@Spinodontosaurus: The Morrocan tracks are definitely the size (and I don't mean lenght) of a large T. rex specimen, rather larger. There are also some 70cm+ ones in Europe (Germany, Switzerland, Spain and Portugal), but not quite as big, and some of those include clawmarks.

Broly got his Allosaurus to be 12,8m in standing lenght with foot that's 12% too small. Not sure how accurate his scaling is, but it is obvious the tracks belong to something huge, comfortably above 13m in standing lenght and possibly 15m in axial lenght. Absolutely on par with huge cretaceous carnosaurs or tyrannosaurs, even tough probably not as large as Spinosaurus.
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thesporerex
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t-rex wins 80% of the time. With its larger size, superior strength, bite force, bulk and stamina.
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Makaveli7
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I think Tyrannosaurus could win against a 13 meter Saurophaganax. Close, but Rex is pound for pound the stronger animal. If Saurophaganax could avoid the T. rex's jaws with its speed and agility it wins but there's a 50-55% chance Tyrannosaurus could pull out the win IMO. Sauro wouldn't go down easy at all though and could win a good portion of the time.
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Godzillasaurus
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Aug 7 2013, 10:40 AM
I think Tyrannosaurus could win against a 13 meter Saurophaganax. Close, but Rex is pound for pound the stronger animal. If Saurophaganax could avoid the T. rex's jaws with its speed and agility it wins but there's a 50-55% chance Tyrannosaurus could pull out the win IMO. Sauro wouldn't go down easy at all though and could win a good portion of the time.
But one thing about saurophaganax is that its highest size estimates could, very well, be a little too high.
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