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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,165 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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theropod
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Posted Image
Edited by theropod, Feb 10 2014, 07:43 PM.
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Tyrannoceratospinosaurus Rex
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^ T.Rex looks more massive even in side view IMO. But this is the holotype....
Edited by Tyrannoceratospinosaurus Rex, Feb 10 2014, 05:00 AM.
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TheMechaBaryonyx789
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Tyrannoceratospinosaurus Rex
Feb 10 2014, 04:53 AM
^ T.Rex looks more massive even in side view IMO. But this is the holotype....
Not really, their mid-torsos appear to be around the same size/depth, and Spinosaurus' sail would add more weight.
Edited by TheMechaBaryonyx789, Feb 10 2014, 07:00 AM.
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theropod
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Depends on what point you look at. Spinosaurus IS bigger in side view, even at the most conservative measurement. Of course being more elongate will always make it look slender, even if it is more massive. And yes, that’s the holotype.
If we include MSNM v4047 (which of course was the point in even making this thread) we have a specimen ~36% larger in linear terms, ergo 2.5 times the weight.

Under the assumption that Cau’s rib scaling is representative (ie. that sue has a 70% wider torso than the S. aegyptiacus holotype), that would mean the following:
holotypeMSNM V4047 (136% larger)FMNH PR 2081volume ratio Spinosaurus/T. rex
minimum341606318228919holotype: 0.695
MSNM:1.748
liberal410537593228919holotype: 0.835
MSNM: 2.101

Regarding the absolute weight figures, you can do the math yourselves, depending on what densities and amount of soft-tissue etc. you prefer. Just multiply the ratio by whatever estimate you prefer for sue (but make sure it really is for sue, and neither for B-rex nor for "junior(!!!!!!)"!).

PS: it’d still be 19 or 43% at 20% for MSNM, but I find it strange that figure is so often used, considering it is not consistent with dal Sasso et al.’s own reconstruction unless you put in a 95cm dentary (which itself is probably just derived from sloppy handwriting).
Edited by theropod, Feb 10 2014, 07:18 AM.
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7Alx
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If the holotype is 14 m and above 8 tonnes (assuming it's heavier than FMNH like you think), based your estimate, MSNM v4047 would be exaggerated sounding 19 m and 20+ tonnes . I do not want to wish you something bad, but... I hope you will not force me to thinking exactly the same as you think.
I agree with Headden, the dentary may not fit perfectly not matter how much bigger you make dentary than in original size. I agree with Cau (don't jump on me) about this
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The “20% hypothesis” is in my opinion not necessary: it produces an extremely deep posterior end of the dentary, an interpretation that I feel as unrealistic compared to the dept of the maxilla at the level of the antorbital region.

Let alone 36 % version, which would look like really funny with very deep mandible even compared to Irritator-ish skull reconstruction.
Edited by 7Alx, Feb 10 2014, 07:04 PM.
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theropod
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I don’t think that, look at the numbers above.
imo the holotype was 70-80% the weight of sue (not 50 though). It could be anything from 12.6-14m in lenght, depending on the lenght you restore for the tail (resulting in a 17-19m animal for MSNM V4047, yes, but with almost the same weight).
What one has to keep in mind is that it would be a narrow yet very long-bodied animal.

As regards 36%, I do not see how the mandible is oversized at that size. It is almost the same size you get from Dal Sasso’s restoration, and this is what the mandibles will look like relative to the skull:
https://lh5.googleusercontent.com/-SQL3fw6krJo/UvYc8A1wlsI/AAAAAAAACX0/IqmLKKtQgXo/w1045-h698-no/spinosaurus_scaling.png
Not so absurdely oversized if you ask me. This is simply the size they have to have, based on Suchomimus’ proportions.

I certainly do not want to force my opinion on others. Of course I want to convince others of my opinion, I want them to consider it.

To me, this:
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looks more feasible than this:
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Regarding all the spinosaurid material at hand suggesting spinosaurid dentaries were longer than their rostra, not shorter, and regarding the good arguments against an overbite.
Edited by theropod, Feb 10 2014, 07:59 PM.
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coherentsheaf
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theropod
Feb 10 2014, 04:19 AM
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Tail of spinosaurus looks much thicker. Could be a source of error.
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theropod
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Why? If it’s tail is deeper, it is deeper, and will be more massive unless it is considerably narrower (which it is of course, but I accounted for that). What will be affected by variation in tail lenght is not the bulky part (that holds most of the important musculature), but the thin tip that has barely any mass.

Owing to the built of Spinosaurs, their tails would have been fairly deep.
Posted Image

Note this depth I’m assuming is to approximate the mass the ridge would add, for different amounts of bulk. That’s why I took a slightly to considerably deeper body outline. The smaller one accounts for a fairly slender structure, the bigger one is for a roughly triangular crest.

or do you mean this?
Posted Image
its neglegible, just around 400px, a difference of slightly above 1% (and only affecting the conservative measurement)

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7Alx
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If 75 cm is full length of BSP's incomplete dentary then scaled up to 136 %, it would fit well to 175 cm Dal Sasso's reconstruction. I checked. Although i wonder... is 75 cm based on good dimension?

Posted Image

Edit: sorry for small image. I made 1 pix = 1 cm

Reconstructions by Dal Sasso et. al (2005) and Stromer (1915)
Edited by 7Alx, Feb 10 2014, 09:20 PM.
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theropod
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This scaling of 75cm is consistent with Stromers measurements, 62cm for the oral margin (measured along the curve), a depth of 13.5cm and width of 5cm at the convexity in the front, a depth of about 19cm in the back and a lenght of the ventral margin of 72cm, and with his estimations of complete dentary lenght a little over 80cm and mandible lenght over 120cm.
Edited by theropod, Feb 10 2014, 09:54 PM.
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Hatzegopteryx
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TheMechaBaryonyx789
Feb 6 2014, 05:26 AM
Hatzegopteryx
Feb 6 2014, 04:29 AM
A 15 metre Spinosaurus is no less than 9 tons, scaling from the (gracile) immature Baryonyx specimen.
Can you teach me how to scale isometrically?
Sure, let's say we want to know how much FMNH PR 2081 would weigh if it was 15 metres instead of 12.3. So here's how we do it:

8.4*(15/12.3)³ = 15.2

So FMNH PR 2081 is ~15.2 tons at 15 metres. 8.4 is the animal's weight, 15 is the length you want to know the weight for, and 12.3 is the length that the animal is at 8.4 tons.

Now, to scale down. How much does FMNH PR 2081 weigh at 2 metres?

8.4*(2/12.3)³ = 0.036

That means that a 2 metre long version of FMNH PR 2081 would be ~36kg.

Ps.: When calculating this, type this on the Google search bar rather than using a calculator:

(your calculation) to the third

I have tried scaling isometrically on other calculators but they all go wrong results, while the Google calculator always got me the correct answer. I know, it's quite awkward, but it is the only reliable method I have found... (Also, you must type "to the third" instead of "³" since Google will see ³ as 3 and so it won't work)
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Hatzegopteryx
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TheMechaBaryonyx789
Feb 10 2014, 06:58 AM
Tyrannoceratospinosaurus Rex
Feb 10 2014, 04:53 AM
^ T.Rex looks more massive even in side view IMO. But this is the holotype....
Not really, their mid-torsos appear to be around the same size/depth, and Spinosaurus' sail would add more weight.
Muscle ridge not sail

Also the Spinosaurus silhouette IS larger, despite the fact our brain kinda tricks us (FMNH PR 2081's silhouette looked larger for me too).
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Hatzegopteryx
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Tyrannoceratospinosaurus Rex
Feb 7 2014, 05:19 AM
theropod
Feb 7 2014, 04:07 AM
So T. rex is "the biggest and strongest theropod" now? And Spinosaurus again a weak fish eater? I thought we were long over this...
No one said that Tyrannosaurus is ''the biggest and strongest theropod''. That's crazy talk lol And no one said Spinosaurus is weak. It just seems that Tyrannosaurus was bulkier than Spinosaurus.
Bulk becomes irrelevant if Spinosaurus turns out to be larger
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Tyrannoceratospinosaurus Rex
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TheMechaBaryonyx789
Feb 10 2014, 06:58 AM
Tyrannoceratospinosaurus Rex
Feb 10 2014, 04:53 AM
^ T.Rex looks more massive even in side view IMO. But this is the holotype....
Not really, their mid-torsos appear to be around the same size/depth, and Spinosaurus' sail would add more weight.
Maybe you're right. But just asking, is there any way to know how much Spino's sail (or whatever it was) may have weighted? I'd really like to know this
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theropod
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@hatzegopteryx: sure you aren’t forgetting some parantheses or something like that?

It has always worked fine with every calculator for me:
#lenghtB divided by lenghtA (÷)

#Then take the cube of that number (³)

#Then multiply by the known weight for lenghtB (×)

It works both ways, for scaling up and for scaling down.
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