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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,259 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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SpinoInWonderland
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Black Ice
Jan 30 2013, 12:56 PM
brolyeuphyfusion
Jan 30 2013, 12:54 PM
Black Ice
Jan 30 2013, 11:51 AM
Grey
Jan 30 2013, 11:42 AM
I don't have an opinion about the spines and I've not seen something substantial about a muscular ridge on its back, time to time suggested but never established. Most of the professionnal reconstructions still depict a robust sail.

And bigger, perhaps, but how bigger then, and with which proportions ?

The modern datas regarding Spinosaurus are all contradictory, that's the main problem.

Whereas there is a linear updated progression in Tyrannosaurus and the giants carcharodontosaurids.
Spinosaurus spines were quite thin
Posted Image
As for the size, I don't know, most if not all the pages of this debate are really just posters debating on which relative of spinosaurus to use for a reconstruction or the similar. Little actual debating.
You do realize that the very same image shows how broad Spinosaurus' spines are do you?

You can't just ignore the side view...the spines being thin at front view only suggest a thinner structure than a bison hump, it doesn't debunk a muscular ridge, which is thinner than a hump but thicker than a sail...
Muscles don't attach paralleled from spines. At least... Not the ones that produce physical force. The sides can be as broad as they want, but if they front is thin, too much muscle would bend the bone.
They may not attach parellel to spines in living animals, but for Spinosaurus, it may have had...to give extra strength to the legs and torso, it needs it, due to the laws of physics on such a massive biped...and to make fast strikes at swimming fish at the water...

And the muscles aren't gonna be that much. It woule be a relatively slender structure, triangular in cross-section, which would have a mass of like 1 tonne at best...

And you do realize that one of the spines you see in the image you posted is bent...
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Fist of the North Shrimp
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Maelstrom
Jan 30 2013, 05:41 AM
Jinfengopteryx
Jan 30 2013, 05:26 AM
I've scaled the Suchomimus to 16m, because that's what you get when scaling up Suchomimus' skull length to Spinosaurus' skull length. About Baryonyx, it was actually estimated at 1,7t (by Paul 1988), there I too used skull length (0,91m).
Scaling Irritator gives a 17.5 m estimate for Spinosaurus, wouldn't that be better than scaling Suchomimus? The reason I didn't scale weights for Irritator because I couldn't find a reliable weight estimate, the one source I did find indicated a mass of 19-25 tonnes if scaling with Irritator - obviously that's too much.

References

http://en.wikipedia.org/wiki/Irritator
https://sites.google.com/site/paleofilescom/irritator

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I don't think it is generally too conservative, but with all those animals it depends on te reconstruction as most are pretty fragmentary, for example, a weight estimate based on a graphical metod for carcharodontosaurus can only be reliable IF te reconstruction it bases on is reliable, which is even pess certain than an accurate lengt estimate. The spinosaurus weight estimte doesn't make sense assuming proportions similar to those in Suchomimus, that's the problem, ad we should assume it's relatives proportions unless something suggest otherwise. This means, the most likely explanation for the disparity here is that the image used was not taking this int account.


That could be a likely explanation; do you know what reconstruction they used?
Scaling the "Angaturama" specimen of Irritaor gives pretty different results, because the skull is about 70- 80 centimeters for a 6 meter Animal.
The actual Femur is about 60 centimeters.
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Black Ice
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Quote:
 

the bone.
They may not attach parellel to spines in living animals, but for Spinosaurus, it may have had...to give extra strength to the legs and torso, it needs it, due to the laws of physics on such a massive biped...and to make fast strikes at swimming fish at the water...


No, they don't attach like that period for force production. Muscles positioned parallel to the spine are mainly used to keep the spine in place and prevent injuries to the disk.

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And the muscles aren't gonna be that much. It woule be a relatively slender structure, triangular in cross-section, which would have a mass of like 1 tonne at best...



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The Spinosaurus spiny sail along its back is perhaps the most recognized feature of this large Cretaceous carnivore. The Spinosaurus’ sail is a particularly unusual addition to the dinosaur family; however, it was not unlike the sail of Dimetrodon, an 11 foot long Synapsid living 280 to 265 million years ago. Unlike creatures such as the Stegosaurus whose plates raised out of the skin the sail of the Spinosaurus was anchored by extensions of the vertebrae along the back of the dinosaur completely anchoring them to the skeleton. These extensions of the back vertebrae could grow as long as 5.5 feet and the sail like structure that connected the vertebrae are thought to have been thin and skin like. Towards the trips of the sail it was thought to be similar to the webbing between amphibious toes. There is some argument as to the actual composition of the sail itself. While it is understood that the spines within the sail were anchored to the vertebrae it is unknown as to what the sail was made from.

While some paleontologists believe that the sail of Spinosaurus was more like that of Dimetrodon, there are also those like Jack Boman Bailey who believed that due to the thickness of the spines within the sail, the sail itself may have been much more than a thin skin like membrane. Bailey suggests that perhaps the sail of the Spinosaurus was a particularly fatty structure skin to those of common day buffalo. The actual composition of the Spinosaurus sail is unknown at this time due to the complete lack of specimens to provide trace tissue samples


This added with the previous quote, it seems unlikely. Though I'm up for a light ridge if you can explain how that would help spinosaurus control a animal as robust and powerful as T-rex. ( To set things clear before the accusation fest begins, I favor spinosaurus here purely from size)

Quote:
 
And you do realize that one of the spines you see in the image you posted is bent...

The whole bone would bend around the center, not the tip.
Edited by Black Ice, Jan 30 2013, 01:26 PM.
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SpinoInWonderland
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Quote:
 
The Spinosaurus spiny sail along its back is perhaps the most recognized feature of this large Cretaceous carnivore. The Spinosaurus’ sail is a particularly unusual addition to the dinosaur family; however, it was not unlike the sail of Dimetrodon, an 11 foot long Synapsid living 280 to 265 million years ago.
Epic quote fail.

Spinosaurus:
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Dimetrodon:
Posted Image

Spinosaurus' spines are not thin rods like Dimetrodon's, that's so obvious that I shoudn't even have to point it out...
Edited by SpinoInWonderland, Jan 30 2013, 01:31 PM.
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SpinoInWonderland
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Anyway, even if Spinosaurus' spine was made of jelly, it woudn't really change the outcome by much...
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Black Ice
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Quote:
 
EPIC QUOTE FAIL

rolleyes

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Unlike creatures such as the Stegosaurus whose plates raised out of the skin the sail of the Spinosaurus was anchored by extensions of the vertebrae along the back of the dinosaur completely anchoring them to the skeleton. These extensions of the back vertebrae could grow as long as 5.5 feet and the sail like structure that connected the vertebrae are thought to have been thin and skin like.


EPIC MISCOMPREHENSION on your part. Both Dimetrodon AND spinosaurus spines were anchored to the skeleton.

Edited by Black Ice, Jan 30 2013, 01:39 PM.
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SpinoInWonderland
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Black Ice
Jan 30 2013, 01:35 PM
Quote:
 
EPIC QUOTE FAIL

rolleyes

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These extensions of the back vertebrae could grow as long as 5.5 feet and the sail like structure that connected the vertebrae are thought to have been thin and skin like.


Why would an animal develop broad spines for a skin-like structure? It would have developed Dimetrodon-esque spines if it had a skin sail, but it didn't....

Spinosaurus just wasn't a sailback...
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SpinoInWonderland
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Black Ice
Jan 30 2013, 01:35 PM
Both Dimetrodon AND spinosaurus spines were anchored to the skeleton.

But their shape was very different...
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Black Ice
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Quote:
 
Why would an animal develop broad spines for a skin-like structure? It would have developed Dimetrodon-esque spines if it had a skin sail, but it didn't....

That wasn't the point of the quote when they were doing the dimetro spino comp.
Quote:
 
the sail of the Spinosaurus was anchored by extensions of the vertebrae along the back of the dinosaur completely anchoring them to the skeleton.

I don't believe in a sail myself but that part is interesting. Added there's always thermoregulation, mate attracting etc.


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Black Ice
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brolyeuphyfusion
Jan 30 2013, 01:42 PM
Black Ice
Jan 30 2013, 01:35 PM
Both Dimetrodon AND spinosaurus spines were anchored to the skeleton.

But their shape was very different...
Only if your looking at them from the same perspective.......
Though as of right now, no definite answer of what the sail can be made sense there hasn't been any tissue sampling done yet. So it's all just personal preference as of now.
Edited by Black Ice, Jan 30 2013, 01:48 PM.
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SpinoInWonderland
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Black Ice
Jan 30 2013, 01:43 PM
Quote:
 
Why would an animal develop broad spines for a skin-like structure? It would have developed Dimetrodon-esque spines if it had a skin sail, but it didn't....

That wasn't the point of the quote when they were doing the dimetro spino comp.
Oh, okay, I was so agitated by the Spinosaurus haters on youtube that I opposed any similarites between Dimetrodon and Spinosaurus, even though they have nothing to do with what the spine looked like...

Black Ice
 
Quote:
 
the sail of the Spinosaurus was anchored by extensions of the vertebrae along the back of the dinosaur completely anchoring them to the skeleton.

I don't believe in a sail myself but that part is interesting. Added there's always thermoregulation, mate attracting etc.
An endotherm has no need for a large thermoregulation structure...Mate attraction, display, and intimidation can be done with any kind of structure the spines would have formed...
Edited by SpinoInWonderland, Jan 30 2013, 01:49 PM.
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SpinoInWonderland
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Black Ice
Jan 30 2013, 01:44 PM
brolyeuphyfusion
Jan 30 2013, 01:42 PM
Black Ice
Jan 30 2013, 01:35 PM
Both Dimetrodon AND spinosaurus spines were anchored to the skeleton.

But their shape was very different...
Only if your looking at them from the same perspective.......
Though as of right now, no definite answer of what the sail can be made sense there hasn't been any tissue sampling done yet. So it's all just personal preference as of now.
Okay, I can do with that, but even if Spinosaurus' spine was made out of playing dough, the outcome woudn't really change by much...
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Black Ice
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Okay, I can do with that, but even if Spinosaurus' spine was made out of playing dough, the outcome woudn't really change by much...

I already said spinosaurus would win this...... Now had you been theropod this would have taken forever to reach the same conclusion.....
Edited by Black Ice, Jan 30 2013, 01:53 PM.
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SpinoInWonderland
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Black Ice
Jan 30 2013, 01:52 PM
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Okay, I can do with that, but even if Spinosaurus' spine was made out of playing dough, the outcome woudn't really change by much...

I already said spinosaurus would win this...... Now had you been theropod this would have taken forever to reach the same conclusion.....
I know you already said Spinosaurus would win, I just said that to tell others...and you made it seem as if theropod was a really stubborn guy lol
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Black Ice
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brolyeuphyfusion
Jan 30 2013, 01:56 PM
Black Ice
Jan 30 2013, 01:52 PM
Quote:
 
Okay, I can do with that, but even if Spinosaurus' spine was made out of playing dough, the outcome woudn't really change by much...

I already said spinosaurus would win this...... Now had you been theropod this would have taken forever to reach the same conclusion.....
I know you already said Spinosaurus would win, I just said that to tell others...and you made it seem as if theropod was a really stubborn guy lol
I'm sure you've seen how he acts when I questioned a muscular ridge lol
Compare his reaction to your more subtle one and you'd see my point.
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