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Carcharodontosaurus saharicus v Tyrannosaurus rex
Topic Started: Jun 8 2012, 05:34 PM (129,978 Views)
Taipan
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Carcharodontosaurus saharicus
This huge meat eater was 45 feet long (5 feet longer than T-rex) and weighed 8 tons, making it one of the largest carnivores that ever walked the earth. This African carnosaur had a gigantic 5’4" long skull and enormous jaws with 8" long serrated teeth. It walked on two legs, had a massive tail, bulky body and short arms ending in three-fingered hands with sharp claws. Carcharodontosaurus is one of the longest and heaviest known carnivorous dinosaurs, with various scientists proposing length estimates ranging between 12 and 13 m (39-43.5 ft) and weight estimates between 6 and 15 metric tons. Its long, muscular legs, and fossilized trackways indicate that it could run about 20 miles per hour, though there is some controversy as to whether it actually did, a forward fall would have been deadly to Carcharodontosaurus, due to the inability of its small arms to brace the animal when it landed. Carcharodontosaurus was a carnivore, with enormous jaws and long, serrated teeth up to eight inches long.

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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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Tyrannosaurs Rex vs Carcharodontosaurus
Edited by Taipan, Apr 24 2015, 10:18 PM.
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Teratophoneus
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theropod
Jul 17 2013, 09:08 PM
^T. rex is only bigger than MUCPc-95 when assuming the same density, while studies point out to carnosaurs being denser (either way, also if we make them as much more pneumatic as stan appearantly got in Hutchinson as compared to Bates).

What best to scale SGM DIN 1 from is debatable, but "12,6-12,9m" is very conservative imo
Also it doesn't seem it has a shorter skull than the 6,5% MUCPv-95

And in the end, that's still comparing it [perhaps the only adult Carcharodontosaurus, or otherwise one of two specimens we can estimate and ~14m long] to the biggest known T. rex in more than 30 individuals.
~ 12.6-12.9 meters were estimates get based on Giganotosaurus. MUPCv-95 skull is very likely longer than SMG din-1 skull (1.64 centimeters vs 1.56 centimeters).
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theropod
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156cm doesn't base on a reconstruction based on Giganotosaurus. you have to restore the missing elements the same way in order to have an objective comparison, which includes giving Carcharodontosaurus a longer quadrate.

If you do that, the animal will be around 13-13,5m in lenght.
Edited by theropod, Jul 17 2013, 09:42 PM.
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Teratophoneus
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theropod
Jul 17 2013, 09:41 PM
156cm doesn't base on a reconstruction based on Giganotosaurus. you have to restore the missing elements the same way in order to have an objective comparison, which includes giving Carcharodontosaurus a longer quadrate.

If you do that, the animal will be around 13-13,5m in lenght.
With a 1.63 meters skull (your restoration) i get 13.12 meters based on MUPCv-ch1 for SMG din-1.
Edited by Teratophoneus, Jul 17 2013, 09:48 PM.
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theropod
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That falls within the range I gave. The rest depends on the skull/body ration in giganotosaurus, which is somewhat problematic.
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Teratophoneus
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theropod
Jul 17 2013, 10:18 PM
That falls within the range I gave. The rest depends on the skull/body ration in giganotosaurus, which is somewhat problematic.
But my opinion has not changed. Both were about the same size, Carcharodontosaurus had a larger skull and bite affected-meat, while Tyrannosaurus was more robust and bite from being crushed. For me, it's 50/50.
Edited by Teratophoneus, Jul 17 2013, 10:28 PM.
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theropod
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I didn't argue against that, just that your figures were imo too conservative.
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Spinodontosaurus
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theropod
Jul 17 2013, 09:08 PM
^T. rex is only bigger than MUCPc-95 when assuming the same density

Pretty sure Scott Hartman addressed points like this a couple of times in the comments section.
Besides he didn't just pick a density to use for the whole body, he assigned perfectly realistic densities to each body segment, so if Sue's density is off then MUCPv-Ch1 probably is too.


Quote:
 
Also it doesn't seem it has a shorter skull than the 6,5% MUCPv-95

I personally get 163cm when measuring MUCPv-95 at a low resolution; yet Hartman says it is 166cm. Larger than any realistic estimate of SGM-Din 1 that I have seen.

Of course we lack proper remains to try and determine averages or anything, so all we can do is compare specimens. I would say SGM-Din 1 loses to FMNH PR2081 but would probably win against CM 9380 on account of the latter's small skull.

The giant fragmentary rex's would win if you were to assume their estimated sizes are correct, but anything smaller than CM 9380 would probably lose.


BTW on MOR 008, Larson referred it and AMNH 5027 (among others)to "Tyrannosaurus X", suggesting these two specimens are pretty similar to each other. Whilst you may only get an estimate of 11.4 meters if you base MOR 008 on Sue or Stan (assuming a skull length of 134cm), if you use AMNH 5027 it would be more like 12.5 meters. Granted at this length it probably wouldn't be any heavier than Sue, but using CM 9380 as a base would achieve even higher estimates (as would using dentary lengths to do the scaling).

Note I am not now proposing we take this as fact and use MOR 008 in all matchups or anything, I just felt it was noteworthy to mention (and Broly, you might want to be careful how you throw around "Sue shouldn't be used to represent average T. rex", given your preferred specimens are the ones that suggest larger sizes for MOR 008).
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SpinoInWonderland
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Spinodontosaurus
Jul 17 2013, 11:30 PM
BTW on MOR 008, Larson referred it and AMNH 5027 (among others)to "Tyrannosaurus X", suggesting these two specimens are pretty similar to each other. Whilst you may only get an estimate of 11.4 meters if you base MOR 008 on Sue or Stan (assuming a skull length of 134cm), if you use AMNH 5027 it would be more like 12.5 meters. Granted at this length it probably wouldn't be any heavier than Sue, but using CM 9380 as a base would achieve even higher estimates (as would using dentary lengths to do the scaling).

Note I am not now proposing we take this as fact and use MOR 008 in all matchups or anything, I just felt it was noteworthy to mention (and Broly, you might want to be careful how you throw around "Sue shouldn't be used to represent average T. rex", given your preferred specimens are the ones that suggest larger sizes for MOR 008).
I see that you mentioned me, so I shall state my opinion.

I'm perfectly fine with ~12.5 meters for MOR 008 with an AMNH 5027-esque body.

At that length, it would likely have a mass between ~7-7.2 tonnes, closer to the lower bound(~7.13 tonnes by my calculations to be exact, AMNH 5027 is about ~6 tonnes imo, I seriously doubt it was the same mass as CM 9380 judging by shartman's comparison). In comparison, FMNH PR 2081 is around ~8 tonnes imo(I am one of those that view the density shartman used as a bit too high)

MOR 008 is what I view as a "high-end average" Tyrannosaurus(the "low-end average" being AMNH 5027, and average being CM 9380)
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7Alx
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Spinodontosaurus
Jul 17 2013, 11:30 PM
theropod
Jul 17 2013, 09:08 PM
^T. rex is only bigger than MUCPc-95 when assuming the same density

Pretty sure Scott Hartman addressed points like this a couple of times in the comments section.
Besides he didn't just pick a density to use for the whole body, he assigned perfectly realistic densities to each body segment, so if Sue's density is off then MUCPv-Ch1 probably is too.


Quote:
 
Also it doesn't seem it has a shorter skull than the 6,5% MUCPv-95

I personally get 163cm when measuring MUCPv-95 at a low resolution; yet Hartman says it is 166cm. Larger than any realistic estimate of SGM-Din 1 that I have seen.

Of course we lack proper remains to try and determine averages or anything, so all we can do is compare specimens. I would say SGM-Din 1 loses to FMNH PR2081 but would probably win against CM 9380 on account of the latter's small skull.

The giant fragmentary rex's would win if you were to assume their estimated sizes are correct, but anything smaller than CM 9380 would probably lose.


BTW on MOR 008, Larson referred it and AMNH 5027 (among others)to "Tyrannosaurus X", suggesting these two specimens are pretty similar to each other. Whilst you may only get an estimate of 11.4 meters if you base MOR 008 on Sue or Stan (assuming a skull length of 134cm), if you use AMNH 5027 it would be more like 12.5 meters. Granted at this length it probably wouldn't be any heavier than Sue, but using CM 9380 as a base would achieve even higher estimates (as would using dentary lengths to do the scaling).

Note I am not now proposing we take this as fact and use MOR 008 in all matchups or anything, I just felt it was noteworthy to mention (and Broly, you might want to be careful how you throw around "Sue shouldn't be used to represent average T. rex", given your preferred specimens are the ones that suggest larger sizes for MOR 008).
Not "is".

He probably meant 1.08x version rather than his best fit version, because 166 cm is closer to 108 % length of 154 cm.

154 cm x 1.08 = 166.32 cm

154 cm x 1.065 = 164.01 cm
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theropod
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^Exactly.

@spinodontosaurus: Then why does sue have such a low density compared to carnosaurs in skeleton-based studies? If you state it is too low, you can as well apply that to them.

If we take Acrocanthosaurus (0,91), Allosaurus (0.93) and Stan (0,9) for comparison you can see that. Now stan ended up at 0.87 in the Hutchinson study, which is a bit lower, but sue is still significantly lower in density than Stan, at 0,791.

If Acrocanthosaurus is slightly denser than Stan, which itself is 10% denser than sue, that is quite a difference, don't you think so?
Edited by theropod, Jul 18 2013, 02:01 AM.
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Shaochilong
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Spinodontosaurus
Jul 17 2013, 02:49 AM
Sue is seemingly larger than Giganotosaurus specimen MUCPv-95 (by all of 200kg, so virtually the same to be fair). MUCPv-95 seems to have had a longer skull than Carcharodontosaurus specimen SGM-Din 1. Seeing as that is all we have to go on in terms of scaling, claiming Carcharodontosaurus is larger than Tyrannosaurus is more than far-fetched.
Assuming the skulls are proportionately the same size is like assuming Uromastyx has the same proportionate skull size as Pogona. They are in the same positions relative to each other cladistically speaking as Giganotosaurus and Carcharodontosaurus and yet the proportions are drastically different...it is similarly far-fetched to assume that they have the same proportions because Carcharodontosaurus is closely related to Giganotosaurinae.
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Ustanak
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Scott Hartman has expressed several times in the comments part that the density question, if valid, has a limited impact of the final results. That T. rex was perhaps more pneumatized than carnosaurs does not make it a baloon, and it does not make carnosaurs anvils. That's again a broly-like argument in the purpose to downsize the cursed T. rex by any mean...

Damn, even if all the theropods specialists on Earth acknowledged Hartman works (which seems to be the case when looking at his facebook comments), there would still be dino-fascists like broly claiming otherwise.^^
Edited by Ustanak, Jul 18 2013, 07:51 AM.
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Spinodontosaurus
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Jul 18 2013, 06:38 AM
Spinodontosaurus
Jul 17 2013, 02:49 AM
Sue is seemingly larger than Giganotosaurus specimen MUCPv-95 (by all of 200kg, so virtually the same to be fair). MUCPv-95 seems to have had a longer skull than Carcharodontosaurus specimen SGM-Din 1. Seeing as that is all we have to go on in terms of scaling, claiming Carcharodontosaurus is larger than Tyrannosaurus is more than far-fetched.
Assuming the skulls are proportionately the same size is like assuming Uromastyx has the same proportionate skull size as Pogona. They are in the same positions relative to each other cladistically speaking as Giganotosaurus and Carcharodontosaurus and yet the proportions are drastically different...it is similarly far-fetched to assume that they have the same proportions because Carcharodontosaurus is closely related to Giganotosaurinae.

So you instead propose what? We use an animal that is even farther from Carcharodontosaurus because it yields a larger size? Carcharodontosaurus, Tyrannotitan, Mapusaurus and Giganotosaurus all group together in Carrano's analysis, and the latter 2 of those suggest almost identical sizes for Carcharodontosaurus (by my hand, 13.1 and 13.3 meters for Giga/Mapu respectively). Tyrannotitan doesn't have a suitable reconstruction to estimate size from. Where is the issue here?
Different proportions can work both ways. The "we don't know" argument isn't a justification for super-sizing anything.


And theropod, there is more variation in density between different reconstructions of the same specimen than 'equivalent' reconstructions between other specimens; how the models were reconstructed had more effect on density than the actual specimen used. Comparing these densities is rendered even more pointless when you consider that none of the skeletons used are even accurately mounted.
Edited by Spinodontosaurus, Jul 19 2013, 05:06 AM.
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Shaochilong
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I am not suggesting we use non-giganotosaurines to restore Carcharodontosaurus because it yields a larger size; I'm suggesting we be cautious about restoring Carcharodontosaurus based on giganotosaurines because it is not a member of that subfamily itself, but rather the closest taxon to the subfamily.
If I were trying to super-size Carcharodontosaurus I would be saying that it was a certainty that it had the same proportions as Acrocanthosaurus or another non-giganotosaurine. I am not completely taking out the possibility that Carcharodontosaurus had a comparable proportionate skull size to Gigaotosaurus or Mapusaurus. I am warning you to watch your step when assuming that it does, as proportions can vary widely even between closely related taxa; add that to the fact that Carcharodontosaurus is not known from very good material. And I never said that different proportions only works one way.
In summary, I'm not trying to super-size anything; I'm advising people to have care with these reconstructions...
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theropod
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Ustanak
Jul 18 2013, 07:50 AM
Scott Hartman has expressed several times in the comments part that the density question, if valid, has a limited impact of the final results. That T. rex was perhaps more pneumatized than carnosaurs does not make it a baloon, and it does not make carnosaurs anvils. That's again a broly-like argument in the purpose to downsize the cursed T. rex by any mean...

Damn, even if all the theropods specialists on Earth acknowledged Hartman works (which seems to be the case when looking at his facebook comments), there would still be dino-fascists like broly claiming otherwise.^^
Those figures are not made up the way of "T. rex is a coelurosaur so it is more pneumatic", they base on studies. Besides, most works have stated Giganotoaaurus to be heavier than T. rex, but that's irelevant.

I have discussed this with Hartman and I can accept his opinion (that being said he wasn't really disagreeing with my points, just sceptical). You should be able to accept mine or broly's for that matter.
Edited by theropod, Jul 20 2013, 04:26 AM.
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