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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,194 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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Megalosauroid
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spinosaurus rex
Nov 21 2013, 07:37 AM
i agree with spinodontosaurus. spinosaurus was definitely longer then 14 meters and i heard all about the big headed, short tail theory as a result of it becoming older. i just don't see it happening. spinosaurus was fully capable of reaching 16 meters at the least. i say somewhere around 17 to 17.5 meters are max. a spinosaurus with a big head and shot tail would be the outlier of its entire species.
That is unclear, but from what Hartman has restored it does not seem likely that Spinosaurus was a long tailed, short skulled animal, the only Spinosaur that seems to come with this proportions is Baryonyx, but again the specimen is a Subadult, morphologically different to an adult due to ontogeny.

Suchomimus whose skeleton is well described is a rather short tailed and long skulled animal if you asked Hartman.
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blaze
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Sereno had "~11m" in his paper but the skeletal in figure 3 is actually that long from tip to tip, almost as long as Hartman's, the difference in overall length between that skeletal and Hartman's appear to be the length (not size) of the skull and/or neck.

I never said anything in favor estimates over 16m, what bring that up?

We have vertebrae of Spinosaurus to estimate the size of its body, skull estimates for Suchomimus vary from 1.2 to 1.4, using the skull length for scaling is not that good in this case since is not well constrained.
Edited by blaze, Nov 21 2013, 02:03 PM.
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Vobby
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Megalosauroid
Nov 20 2013, 10:08 AM


An where did they exactly say the estimated 1.75 m for the MSMN V4047 specimen is wrong?
I was referring to Adrea Cau, which has seen and studied the rostrum and recostructed the whole skull as shorter than 1,5 m. But I'm now quite convinced that Spinodontosaurus is right, skull measurements aren't a good way to judge Spinosaurus lenght. So I ask... @blaze, have you ever measured the same way Spinosaurus's torso? It's the only thing we have to directly compare it with other giant theropods dimensions, I guess.
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Jinfengopteryx
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Megalosauroid
Nov 21 2013, 01:16 PM
I guess we need a closer relative to Spinosaurus to do the estimate.
Like Irritator? This is pointless, as the estimates for Irritator have to be based on Suchomimus and Baryonyx too.
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Megalosauroid
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Vobby
Nov 21 2013, 08:49 PM
Megalosauroid
Nov 20 2013, 10:08 AM


An where did they exactly say the estimated 1.75 m for the MSMN V4047 specimen is wrong?
I was referring to Adrea Cau, which has seen and studied the rostrum and recostructed the whole skull as shorter than 1,5 m. But I'm now quite convinced that Spinodontosaurus is right, skull measurements aren't a good way to judge Spinosaurus lenght. So I ask... @blaze, have you ever measured the same way Spinosaurus's torso? It's the only thing we have to directly compare it with other giant theropods dimensions, I guess.
A Spinosaurus with a 5 ft long skull is not gonna measure more than 12-13 meters, if truly giant fish lived in that environment then Spinosaurus should have had a relatively long skull for its body size.
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Megalosauroid
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Jinfengopteryx
Nov 22 2013, 12:04 AM
Megalosauroid
Nov 21 2013, 01:16 PM
I guess we need a closer relative to Spinosaurus to do the estimate.
Like Irritator? This is pointless, as the estimates for Irritator have to be based on Suchomimus and Baryonyx too.
Not Irritator, It i just a skull, we need a closer relative with a fairly complete skeleton.
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Megalosauroid
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blaze
Nov 21 2013, 02:02 PM
Sereno had "~11m" in his paper but the skeletal in figure 3 is actually that long from tip to tip, almost as long as Hartman's, the difference in overall length between that skeletal and Hartman's appear to be the length (not size) of the skull and/or neck.

I never said anything in favor estimates over 16m, what bring that up?

We have vertebrae of Spinosaurus to estimate the size of its body, skull estimates for Suchomimus vary from 1.2 to 1.4, using the skull length for scaling is not that good in this case since is not well constrained.
OK

We only have vertebrae to estimate the holotype but not the paratype and there is not enough evidence to claim that the paratype was an older individual than the IPHG specimen, or just an adult individual of smaller size than the paratype.
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Jinfengopteryx
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Megalosauroid
Nov 22 2013, 05:55 AM
Jinfengopteryx
Nov 22 2013, 12:04 AM
Megalosauroid
Nov 21 2013, 01:16 PM
I guess we need a closer relative to Spinosaurus to do the estimate.
Like Irritator? This is pointless, as the estimates for Irritator have to be based on Suchomimus and Baryonyx too.
Not Irritator, It i just a skull, we need a closer relative with a fairly complete skeleton.
There is no other option. It and Spinosaurus are the only known spinosaurines.
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Spinodontosaurus
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Nov 22 2013, 05:54 AM
A Spinosaurus with a 5 ft long skull is not gonna measure more than 12-13 meters, if truly giant fish lived in that environment then Spinosaurus should have had a relatively long skull for its body size.

And yet Scott Hartman's restoration of the type specimen has a 148cm skull (almost 5 feet) and manages to hit 14 meters to boot.

I mean, look at the preserved portions. The missing vertebrae from the torso can only be within a certain size range, because that is dictated by the ones that are already known, and those gaps have been filled in with both Baryonyx AND Suchomimus - it isn't just an up-scaled version of either, as indicated by the notably longer torso.
The only real way to shrink the type specimen down to 12 or 13 meters would be to shorten the neck, tail and rear portion of the skull, none of which will have a huge impact on the overall weight and thus size.

Because of this arguing over whether the type specimen was 13 or 15 meters is pointless - it could be either, anything in between or something completely different, because there is enough un-known in highly variable body regions.


EDIT:
Quote:
 
There is no other option. It and Spinosaurus are the only known spinosaurines.

There is Oxalaia too, but given that it is a mere premaxilla fragment it is useless in this context.
Edited by Spinodontosaurus, Nov 22 2013, 06:44 AM.
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Megalosauroid
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Spinodontosaurus
Nov 22 2013, 06:42 AM
Megalosauroid
Nov 22 2013, 05:54 AM
A Spinosaurus with a 5 ft long skull is not gonna measure more than 12-13 meters, if truly giant fish lived in that environment then Spinosaurus should have had a relatively long skull for its body size.

And yet Scott Hartman's restoration of the type specimen has a 148cm skull (almost 5 feet) and manages to hit 14 meters to boot.

I mean, look at the preserved portions. The missing vertebrae from the torso can only be within a certain size range, because that is dictated by the ones that are already known, and those gaps have been filled in with both Baryonyx AND Suchomimus - it isn't just an up-scaled version of either, as indicated by the notably longer torso.
The only real way to shrink the type specimen down to 12 or 13 meters would be to shorten the neck, tail and rear portion of the skull, none of which will have a huge impact on the overall weight and thus size.

Because of this arguing over whether the type specimen was 13 or 15 meters is pointless - it could be either, anything in between or something completely different, because there is enough un-known in highly variable body regions.


EDIT:
Quote:
 
There is no other option. It and Spinosaurus are the only known spinosaurines.

There is Oxalaia too, but given that it is a mere premaxilla fragment it is useless in this context.
It is actually 1.467 m in pmx-Occ length and 1.54 m in Pmx-Qj length, the mandible length is even longer at 1.567 m and the body length about 14 m, so based on that an animal with a 1.48 m long skull (In Pmx-Qj length) would measure 13.1 m and not 14.

Remember that very few cranial material has everv been found for IPHG VIII 1912, and even if Hartman makes the best restorations available, we should not take his skeletal too seriously, as far as the only material yet found consists in a few vertebrae, a lower dentary, fragmentary ribs and spines but nothing else.


His Spinosaurus has some proportions equal to that of Baryonyx, he basically restored his Spinosaurus with the same proportions as Baryonyx in terms of skull/body length and vertebrae/body length, while the tail was restored more like that of Suchomimus, but if you are going to reconstruct the vertebral column of an animal you are not going to use two animals with completely different vertebrae structure to make a single vertebral column, if you restore the tail like that of Suchomimus, you base your size estimate and the rest of the vertebrae for the Spinosaurus on Suchomimus, restoring the body size of Spinosaurus based on Baryonyx would make the tail and the body size estimates to be based entirely on Baryonyx.
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blaze
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@Vobby
I just did. Hartman's skeletals of

Spinosaurus (holotype)
14.0m total length
6.99m snout-sacrum length
torso lenght 2.55m

Suchomimus
11.65m total length
5.77m snout-sacrum length
torso length 2.14m

Baryonyx
10m total length
4.64m snout-sacrum length
torso length 1.64m
MSMN V4047
As always, I could be wrong on the exact measurements by some centimeters.

@megalosauroid
The measurements above disagree with Hartman's just having based everything on Baryonyx, we don't exactly know what he did but it certainly wasn't as simple as you make it out to be, anyway, why is length so important to you?

btw, I think you measured the skull wrong, Hartman says his versión of MSMN V4047 has a skull 163-164cm from premaxilla to quadratojugal, thus, given how he estimates MSMN V4047 to be 11.4% larger than the holotype, the skull of the holotype in the same measure has to be between 146-147cm, that's why I got too in my measurements above.
Edited by blaze, Nov 22 2013, 09:17 AM.
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Megalosauroid
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blaze
Nov 22 2013, 08:56 AM
@Vobby
I just did. Hartman's skeletals of

Spinosaurus (holotype)
14.0m total length
6.99m snout-sacrum length
torso lenght 2.55m

Suchomimus
11.65m total length
5.77m snout-sacrum length
torso length 2.14m

Baryonyx
10m total length
4.64m snout-sacrum length
torso length 1.64m
MSMN V4047
As always, I could be wrong on the exact measurements by some centimeters.

@megalosauroid
The measurements above disagree with Hartman's just having based everything on Baryonyx, we don't exactly know what he did but it certainly wasn't as simple as you make it out to be, anyway, why is length so important to you?

btw, I think you measured the skull wrong, Hartman says his versión of MSMN V4047 has a skull 163-164cm from premaxilla to quadratojugal, thus, given how he estimates MSMN V4047 to be 11.4% larger than the holotype, the skull of the holotype in the same measure has to be between 146-147cm, that's why I got too in my measurements above.
It is not that Hartman based absolutely everything of Spinosaurus from Baryonyx but that he restored Spinosaurus from two animals with quite different vertebral and skull morphologies to restore the proportions of an animal whose few only bones were destroyed in WW2 and the rest are from fragmentary private specimens and a snout.

From what your measurements say, the proportions restored from Baryonyx and Suchomimus scaled to the size of Spinosaurus are:

Suchomimus tenerensis 14 m

6.93 m snout-sacrum length
Torso length 2.57 m

Baryonyx 14 m
6.5 m snout-sacrum length
2.24 m

It seems that Hartman is basing much of his estimates for the torso and tail of Spinosaurus on Suchomimus, I actually did a scaling from the 15 th vertebrae of Baryonyx compared to the 15 th vertebrae of Spinosaurus (IPHG 1912) and it yielded 14 m, but usng the same from Suchomimus the estimate yields 13.2 m, so if Hartman is using Suchomimus to restore the Torso and the tail, why not the body length?

I actually think Spinosaurus has been exaggerated in body size for years and that the real size is smaller than what many claim.

Tyrannosaurus has been dismissed in size many times, from 15 m to 14 then 12.9 then 12.8 and now 12.3 m which is the current estimate.
Giganotosaurus holotype has been dismissed from 14 to 13 to 12.2-12.5 m to just 12.4 m which now has a reduced skull from 1.8 to 1.6 to 1.54 m

One question, do you speak spanish? because you corrector has the Word version in spanish, with an accent, if you do, where are you from?



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blaze
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Maybe he did but used more than one vertebra, who knows, also, I don't know why but Hartman's Baryonyx does have a long tail at 54% of total length compared to his Suchomimus and Spinosaurus that have a tail 50% of total length, that might have affected your comparison.

T. rex old reconstructions were that long mostly because of extra long tails or plain exaggeration, the Field Museum always claimed that Sue was 12.8m long but they never measured it, which became obvious when the axial length was measured from laser scans in 2011.

Giganotosaurus actual original estimate for the holotype was 12.5m and it has pretty much stayed there since then, only the press were giving it 13-14m, the same goes for the skull, it was originally estimated at 1.53m and most authors seem to have rounded it up to "about 1.6m", the hyperelongated doesn't-look-like-any-of-its-relatives 1.8m skull is pretty much a hunch of Novas and up to this day he still claims Giganotosaurus had a 1.8-1.95m long skull.

Another example is Allosaurus, back in the 1970s, it was up to 12m long, and 4.5m tall, but it was 4.5m tall in godzilla pose as the 12m long claim is based on a composite reconstruction that by the own admission of the author had a leg a length just shy of 2m.

mmm I think we've talked before, are you Megalosaurid in deviantart?
Edited by blaze, Nov 22 2013, 11:41 AM.
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Spinodontosaurus
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It is actually 1.467 m in pmx-Occ length and 1.54 m in Pmx-Qj length, the mandible length is even longer at 1.567 m and the body length about 14 m, so based on that an animal with a 1.48 m long skull (In Pmx-Qj length) would measure 13.1 m and not 14.

The skeletal on DeviantArt is 93px from Pmx-Qj, with a 63px scale bar, thus 147.6cm. This is from an individual he himself states to be 14 meters long. In any case this is meaningless, because as has already been stated, total skull length is not the deciding factor.

And because spinosaurines and baryonychines have totally different rear portions of the skull, you can't really compare them. Baryonychines have rather typical backwards swept quadratojugals, so the Pmx-Qj measurements is essentially the same as Pmx-Squamosal. In spinosaurines this isn't the case.

Hartman's Spinosaurus is not a up-scaled version of either Baryonyx or Suchomimus; why do you continue to treat it as such? It is the same as any skeletal of fragmentary species, the gaps between known elements are filled in based on material from related species. That the general proportions end up being somewhat close to the species used as a reference shouldn't be a surprise, nor should it be a surprise that they aren't identical.
Especially with Suchomimus; both it and Spinosaurus are African and lived very close together chronologically, yet they are not the same species nor are they each others' closest relatives, so unsurprisingly their proportions are different.


BTW Blaze, I can't replicate your Spinosaurus torso length. I'm not sure exactly what you have measured as the torso (I usually measure it as the pectoral girdle to the last sacral), but I can replicate Suchomimus' by simply measuring all the dorsals, or by measuring from the pectoral girdle to the illium. When doing this with Spinosaurus, the results are much higher than your 255cm.
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blaze
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I measured only from d1 to d12, it seemed to me Hartman either restored it with 13 dorsals, which is more than the 12 in his Suchomimus and Baryonyx or he gave it 5 sacrals instead of the 4 in his Suchomimus and Baryonyx

Edit
I measured 12 vertebrae, but I just realized that I didn't count the atlas when counting the number of the vertebrae of the neck so I'm not sure what exactly I measured haha, either d2-d13 or d3-d14.
Edited by blaze, Nov 23 2013, 11:17 AM.
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