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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,130 Views)
Wolf Eagle
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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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Spinosaurus aegyptiacus
Spinosaurus is a genus of theropod dinosaur which lived in what is now North Africa, from the lower Albian to lower Cenomanian stages of the Cretaceous period, about 112 to 97 million years ago. Spinosaurus may be the largest of all known carnivorous dinosaurs, even larger than Tyrannosaurus and Giganotosaurus. Estimates published in 2005 and 2007 suggest that it was 12.6 to 18 metres (41 to 59 ft) in length and 7 to 20.9 tonnes (7.7 to 23.0 short tons) in weight. The skull of Spinosaurus was long and narrow like that of a modern crocodilian. Spinosaurus is thought to have eaten fish; evidence suggests that it lived both on land and in water like a modern crocodilian. The distinctive spines of Spinosaurus, which were long extensions of the vertebrae, grew to at least 1.65 meters (5.4 ft) long and were likely to have had skin connecting them, forming a sail-like structure, although some authors have suggested that the spines were covered in fat and formed a hump. Multiple functions have been put forward for this structure, including thermoregulation and display. Dal Sasso et al. (2005) assumed that Spinosaurus and Suchomimus had the same body proportions in relation to their skull lengths, and thereby calculated that Spinosaurus was 16 to 18 meters (52 to 59 ft) in length and 7 to 9 tonnes (7.7 to 9.9 short tons) in weight. The Dal Sasso et al. estimates were criticized because the skull length estimate was uncertain, and (assuming that body mass increases as the cube of body length) scaling Suchomimus which was 11 meters (36 ft) long and 3.8 tonnes (4.2 short tons) in mass to the range of estimated lengths of Spinosaurus would produce an estimated body mass of 11.7 to 16.7 tonnes (12.9 to 18.4 short tons).

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Edited by Taipan, Apr 24 2015, 10:10 PM.
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Jinfengopteryx
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I now see that including a genus that is as obscure as Silgilmassasaurus in my theropod video was not the smartest thing to do.

@thesporerex
So much for their 95% confidence interval. It is also nice to see that there really seems to be a paper that estimated Sure at 4 t. 4 to 18 t, what an estimate range! lol
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blaze
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@thesporerex
It's just a minor correction of 163kg, what they found to be wrong was their growth model, they are not saying anything about their estimates.

And as I said the bigger Giganotosaurus (if it really is that much bigger) could match Sue in size, the error bars of their estimates overlap.
Edited by blaze, Oct 2 2014, 05:45 AM.
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theropod
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Regression equations based on propodial diameters are never going to be a replacement for volumetric estimates, especially if you have sufficient fossil evidence for the latter. You can see that in the figures.
They are much closer to volumetric figures now (simply because previous tries generally underestimated them by a factor of about two), after all they correct for the bias produced by using regressions designed for quadrupeds, but they are still different.
Also note that this can not account for the variation that exists between different bipeds (e.g. the case of Acrocanthosaurus), it will invariably produce a bias towards more cursorial animal with proportionately thicker propodials. I wonder what people would say if we used the circumference of the metatarsus as an indicator…

Where did you guys find the paper (Campione et al. 2014)?

And no, T. rex is not the biggest theropod.
It’s largest specimen is roughly on par with the largest specimen of Giganotosaurus based on the latest (and only comparative) volumetric figures, despite being known from 20 times as many individuals.

Ironically based on the table posted on the last page, MUCPv-95 assumed to be 6.5% bigger than the holotype would already outedge Sue’s estimate, and that despite this method being demonstrably biased towards the proportionately thick-femured taxa (i.e. Tyrannosaurus).
The Tyrannotitan specimen they used is the holotype, the paratype being some 11% bigger by femoral lenght would actually make it heavier than their estimate for Sue as well, their Mapusaurus is the 1.3m femur that’s in all likelyhood also a far call from the biggest specimens (which are indicated to exceed the Giganotosaurus holotype in size, and probably are on par with or bigger than MUCPv-95), and Carcharodontosaurus isn’t in the table at all (which is another taxon of comparable size, if you estimate it conservatively).

Note that I’m not saying this is relevant, (I don’t think it is) but it doesn’t support the point of T. rex being the biggest (that other specimen actually has a smaller femur circumference than sue as given, no idea how they got it to be heavier), since actually it indicates at least two taxa to be heavier, and probably a third.

Edited by theropod, Oct 2 2014, 06:04 AM.
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Jinfengopteryx
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blaze
Oct 2 2014, 05:43 AM
@thesporerex
It's just a minor correction of 163kg, what they found to be wrong was their growth model, they are not saying anything about their estimates.

And as I said the bigger Giganotosaurus (if it really is that much bigger) could match Sue in size, the error bars of their estimates overlap.
Looking at the image that thesporerex posted right above that quote, I believe he is very well aware of this, since this part of his post was about growth.
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thesporerex
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theropod
Oct 2 2014, 05:48 AM
Regression equations based on propodial diameters are never going to be a replacement for volumetric estimates, especially if you have sufficient fossil evidence for the latter. You can see that in the figures.
They are much closer to volumetric figures now (simply because previous tries generally underestimated them by a factor of about two), after all they correct for the bias produced by using regressions designed for quadrupeds, but they are still different.
Also note that this can not account for the variation that exists between different bipeds (e.g. the case of Acrocanthosaurus), it will invariably produce a bias towards more cursorial animal with proportionately thicker propodials. I wonder what people would say if we used the circumference of the metatarsus as an indicator…

Where did you guys find the paper (Campione et al. 2014)?

And no, T. rex is not the biggest theropod. It’s largest specimen is roughly on par with the largest specimen of Giganotosaurus, despite being known from 20 times as many individuals. The same applies to the other giant carcharodontosaurs and Spinosaurus.

I got the paper from a friend the day after it was published. I think he may have gotten it from a paleontologist. Though I am not sure. Also apparently Scotty is the oldest Tyrannosaurus rex currently found(like 32 years or above if I remember correctly) and apparently several comparisons have been made between Sue and Scotty but nothing official. He is definetly one of the big ones though but this is like his first official size estimate.
Edited by thesporerex, Oct 2 2014, 06:09 AM.
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blaze
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Scotty is old? nice! I think I confused it with Samson.
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MysteryMeat
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@thesporerex

If you look at Ibrahim's reconstruction, the mid-cervical centra are much longer than tall, but the sigilmassasaurus drawing in Cau's composite shows otherwise.
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theropod
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Where has Scotty's age been estimated? I don't remember seeing it in any of the studies dealing with that.
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bone crusher
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Sue might not be the largest in length but in terms of weight it's definitely the heaviest according to Scott Hartman.
http://www.skeletaldrawing.com/home/mass-estimates-north-vs-south-redux772013
In fact if we're talking about volumetric size than Sue is still the largest cubically as can be seen in the comparison. MUCPv-95 might not even be 6.5% larger than the Holotype if it actually turns out to be just a bigger jawed individual. So yeah as far as available specimens goes, Sue still takes the cake.
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theropod
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If MUCPv-95 just 6.5% larger than the holotype (versus 8% as published, Coria & Calvo 1998), Sue is only ~2% heavier by Hartman’s estimates. That’s an absolutely neglegible margin, and most likely not even measurable in life since it assumes the same density for both of them (as I already wrote, the highly pneumatised torso is comparatively small in Giganotosaurus; it has a little more weight in its limbs and tail and there the 2% go).

What’s far more important is that sue is the biggest in a huge sample of specimens by extinct theropod standards. The smaller specimen of Giganotosaurus is easily on par with an average T. rex, probably quite a bit larger. The giant pubis of Mapusaurus indicates an individual 10% longer than MUCPv-ch1 and thus ~8% heavier than Sue.
It still remains to be seen where Carcharodontosaurus and Tyrannotitan fall. If the former resembles Acrocanthosaurus in proportions it would be considerably bigger than any of the others for example.

So in conclusion Sue may be among the largest, but that does not make T. rex the largest species regardless.

BTW the theropod database (which seems to be offline again), and the Tyrant King both give the femur lenght of RSM 2523.8 aka Scotty at 1.29m, which is shorter than Sue. The specimen is not properly described yet (although news reports say 12m, but they always seem to do that…).



References:
Coria, Rodolpho A.; Calvo, Jorge O.: New Specimen of Giganotosaurus carolinii (Coria & Salgado, 1995), supports it as the largest Theropod ever found. Gaia, Vol. 15 (1998); pp. 117-122
Coria, Rodolpho A.; Currie, Philip J.: A new carcharodontosaurid (Dinosauria, Theropoda) from the Upper Cretaceous of Argentina. Geodiversitas, Vol. 28 (2006); 1; pp. 71-118
Larson, Neal L.; One Hundred Years of Tyrannosaurus rex: The Skeletons. In: Larson, Peter; Carpenter, Kenneth: Tyrannosaurus rex the Tyrant King. Bloomington (2008); pp. 1-56
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MysteryMeat
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Why would a carcharodontosaurine resemble basal carcharodontosaurids more than other carcharodontosaurines?

Extrapolating size from highly fragmentary remains are unreliable at best.
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blaze
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I'm pretty sure the theropod database is referencing The Tyrant King, anyway 2cm shorter than Sue's is nothing, Stan's and MOR 555's are only about 3cm shorter than Sue's, I think is clear that Tyrannosaurus femur didn't grow much in length if anything at all after 20 years of age.
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Ceratodromeus
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theropod
Oct 2 2014, 05:48 AM

And no, T. rex is not the biggest theropod.
It’s largest specimen is roughly on par with the largest specimen of Giganotosaurus based on the latest (and only comparative) volumetric figures, despite being known from 20 times as many individuals.

Ironically based on the table posted on the last page, MUCPv-95 assumed to be 6.5% bigger than the holotype would already outedge Sue’s estimate, and that despite this method being demonstrably biased towards the proportionately thick-femured taxa (i.e. Tyrannosaurus).
I think if we take if we take (MUCPv-95), which is just a small portion of the lower jaw, we have to take some relatively complete "giant" Tyrannosaurus individuals. I'm not talking about UCMP 135738, F. rex, or things of that sort. The UCMP toe could just as well be individual variation, or indication of injury/ disease. F. rex.... i don't really know.

Individuals like MOR 1126, Who Jack Horner said to be somewhere near 10% larger then "Sue", and are of somewhat decent remains...cannot be ignored. And i find it highly improbable that we've found thirty or so individuals of this species, that we've found the size limit for Tyrannosaurus rex in regards to "Sue". Nor have i seen any reason to assume these animals were smaller then FMNH PR 2081.

Seing how the size MuCPv-95 reputedly had over the holotype has shrunk from ~8% to ~6.5%, i don't see how we can really use this as a basis for establishing Giganotosaurus Carolinii as the larger species.

Wasn't Giga's holotype re-sized to 12.2 meters? MUCP-v95 would be ~12.8-13.1 meters in length based on that. Something like 7.5-8 tons as well, which is accepted as a size estimate for "Sue"

Regarding Mapusaurus, wasn't it decidedly more slender in build then Giganotosaurus?

We have more individuals of Mapusaurus then we do for Giganotosaurus, and from my understanding the largest individual found of M. roseae had a pubis ~10% longer then that of the Giganotosaurus holotype, thus only 3.5% larger then the questionable at best lower jaw fragment. That would put it at ~13.4-13.6 meters in length, and if Mapusaurus is indeed more slender in build as it's been suggested,This would point to it not being a heavier animal. And from what i've read it's noted as "a large, old individual". The largest found from the group, if i'm right. We cannot rule out the possibility that this is just a difference between species either, since both are in the same subfamily...so i take it with a grain of salt

I haven't been able to find a whole lot on Tyrannotitan, do you guys have somewhere a paper on it is available?

Edited by Ceratodromeus, Oct 3 2014, 10:34 AM.
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bone crusher
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Well reasoned Carnosaur18, T.rex is simply a proportionally bulkier animal at the same length or even under a slight length disadvantage, and often time these species DO reach similar length. So the chances of being the heavier animal is far more likely for T.Rex. I also see no logical reason for Mapu to be heavier if it's even lender than Giga, the largest individual might just be MUCPv-95's weight if not less.
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Teratophoneus
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Carnosaur18
Oct 3 2014, 10:23 AM
theropod
Oct 2 2014, 05:48 AM

And no, T. rex is not the biggest theropod.
It’s largest specimen is roughly on par with the largest specimen of Giganotosaurus based on the latest (and only comparative) volumetric figures, despite being known from 20 times as many individuals.

Ironically based on the table posted on the last page, MUCPv-95 assumed to be 6.5% bigger than the holotype would already outedge Sue’s estimate, and that despite this method being demonstrably biased towards the proportionately thick-femured taxa (i.e. Tyrannosaurus).
I think if we take if we take (MUCPv-95), which is just a small portion of the lower jaw, we have to take some relatively complete "giant" Tyrannosaurus individuals. I'm not talking about UCMP 135738, F. rex, or things of that sort. The UCMP toe could just as well be individual variation, or indication of injury/ disease. F. rex.... i don't really know.

Individuals like MOR 1126, Who Jack Horner said to be somewhere near 10% larger then "Sue", and are of somewhat decent remains...cannot be ignored. And i find it highly improbable that we've found thirty or so individuals of this species, that we've found the size limit for Tyrannosaurus rex in regards to "Sue". Nor have i seen any reason to assume these animals were smaller then FMNH PR 2081.

Seing how the size MuCPv-95 reputedly had over the holotype has shrunk from ~8% to ~6.5%, i don't see how we can really use this as a basis for establishing Giganotosaurus Carolinii as the larger species.

Wasn't Giga's holotype re-sized to 12.2 meters? MUCP-v95 would be ~12.8-13.1 meters in length based on that. Something like 7.5-8 tons as well, which is accepted as a size estimate for "Sue"

Regarding Mapusaurus, wasn't it decidedly more slender in build then Giganotosaurus?

We have more individuals of Mapusaurus then we do for Giganotosaurus, and from my understanding the largest individual found of M. roseae had a pubis ~10% longer then that of the Giganotosaurus holotype, thus only 3.5% larger then the questionable at best lower jaw fragment. That would put it at ~13.4-13.6 meters in length, and if Mapusaurus is indeed more slender in build as it's been suggested,This would point to it not being a heavier animal. And from what i've read it's noted as "a large, old individual". The largest found from the group, if i'm right. We cannot rule out the possibility that this is just a difference between species either, since both are in the same subfamily...so i take it with a grain of salt

I haven't been able to find a whole lot on Tyrannotitan, do you guys have somewhere a paper on it is available?

According to the latest estimate (Hartman's), Gig's holotype is 12.4 m long.

This message would make broly mad. :D
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