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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,225 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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One point, if you shrink down spinosaurus to 14m it all breaks down to tail lenght. Such a spinosaurus (which based on the holotype already has a longer torso than Baryonyx, or maybe just a proportionally smaller skull) would have a huge, very long ribcage and a huge heavy structure on the back. It being as massive as a T. rex of comparable lenght is not far fetched, especially as being semiaquatic it is easily possible it was about 20% denser.
The reason why 21t is ridiculous is thus nnot that being comparable to T. rex at parity, such a short spinosaurus could be, but it being greater (due to allometry) than a greatly exagerated T. rex (round down sue to 12m and increase the highest estimate for another 700kg and you have what they used...They really WANTED to make the results as odd as possible, didn't they?)

The arms of Spinosaurus are unknown, but its relatives alltogether have very long, powerful ones, bearing strong claws. we can assume this for spinosaurus as well, the same way we would assume a new derived Tyrannosaur had short arms. How useful those arms are depends on the animals height, which is at the moment unknown. But as I said, I doubt just because of the low placement and limited range of movement most theropod arms weren't useful any more.
Firstly, strenght-flexibility is usually a payoff and to add to that nearly all theropod arms that I know are rathe rmassively constructed. they might not have been very flexible, but definitely strong, and there you have the probable reason for that limited range of movement.
Secondly, the majority of theropods just has to rear up a bit to bring similar-sized or larger opponents into range, nothing dramatic. Modern cats also have to change their posture for grappling.

I've just made a new sketch based on Baryonyx (overall lenght, Sl-Bl) Suchomimus (more robust bones to fit the more robust cranium) and the holotype (superimposed the known elements, normalised to dentary lenght, drawn the probably height of the spines, the dorsals are definitely longer than in either relative so I assume the torso would have been too)
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Drift
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theropod
Mar 28 2013, 07:55 PM
One point, if you shrink down spinosaurus to 14m it all breaks down to tail lenght. Such a spinosaurus (which based on the holotype already has a longer torso than Baryonyx, or maybe just a proportionally smaller skull) would have a huge, very long ribcage and a huge heavy structure on the back. It being as massive as a T. rex of comparable lenght is not far fetched, especially as being semiaquatic it is easily possible it was about 20% denser.
The reason why 21t is ridiculous is thus nnot that being comparable to T. rex at parity, such a short spinosaurus could be, but it being greater (due to allometry) than a greatly exagerated T. rex (round down sue to 12m and increase the highest estimate for another 700kg and you have what they used...They really WANTED to make the results as odd as possible, didn't they?)

The arms of Spinosaurus are unknown, but its relatives alltogether have very long, powerful ones, bearing strong claws. we can assume this for spinosaurus as well, the same way we would assume a new derived Tyrannosaur had short arms. How useful those arms are depends on the animals height, which is at the moment unknown. But as I said, I doubt just because of the low placement and limited range of movement most theropod arms weren't useful any more.
Firstly, strenght-flexibility is usually a payoff and to add to that nearly all theropod arms that I know are rathe rmassively constructed. they might not have been very flexible, but definitely strong, and there you have the probable reason for that limited range of movement.
Secondly, the majority of theropods just has to rear up a bit to bring similar-sized or larger opponents into range, nothing dramatic. Modern cats also have to change their posture for grappling.

I've just made a new sketch based on Baryonyx (overall lenght, Sl-Bl) Suchomimus (more robust bones to fit the more robust cranium) and the holotype (superimposed the known elements, normalised to dentary lenght, drawn the probably height of the spines, the dorsals are definitely longer than in either relative so I assume the torso would have been too)
Unless there are multiple other studies that have been conducted on the particular subject,IMO don't see how an assumption involving the use of for-limbs in an aggressive fashion against still living prey or a rival dino (opposed to the guesses made that they would use their primary means of taking down prey,the jaw and then either "holding" or inflicting superficial wounds) to be considered as 'not dramatic',or accepted as common behavioral patterns for the scaley animals unless there was vast amounts of concrete evidence to base it off.
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theropod
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Your sentence is too long, I already forget the beginning when I come to the end.
However if I have understood you right, you think we should not assume Spinosaurus used its most likely huge, large clawed forelimbs as a weapon.
My question: What for were they used then? what for do animals evolve huge claws and large, powerful arms? And what is that "scaley animal" supposed to be? And what do you consider as "not dramatic?"
I don't quite get what you mean.
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Black Ice
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My short term memory infected theropod lol
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theropod
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You are very posessive lol
Can others borrow your theropod?
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Tyrant
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The lethalness of theropod arms are overrated as I said before I favor spinosaurus(unless spinosaurus's size has been greatly exaggerated) but its arms are not going to be a factor in this fight.

Yes it has long claws, yes its arms are powerful for a theropod but there pretty redundant in a face to face fight with another theropod.

Due to the short length of spinosaurus's arms its not going to be using them effectively in this fight because it has to be ridiculously close to use them, to the point where its not able to use them even if the two animals snouts are touching!
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theropod
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The short lenght of maybe 2-3m?
And isn't a theropod neck flexible enough to move back?
This is no face to face fight, basically its "will rexy come past the jaws and claws and reach a part it can bite or will spino knock him over before that happens"
The arms could very well have been used for that, they are more than long enough.

I don't think they were killing weapons, but not being a killing weapon doesn't make something redundant. Cats don't use their claws as killing weapon either, and yet the vast majority of people here would favour a cat over an equally sized animal without claws.

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here's a closeup from Archosaur Musings

and here's a shot of the whole skeleton (damn, mounting ribs accurately is sooo difficult!)
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Does it seem as if rearing up a bit to bring its body in a horizontal line or even a bit higher and reaching out wouldn't suffice to bring a quite possibly 50% smaller T. rex into range?
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theropod
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here'seems like that's a T. rex arm:
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and T. rex was larger than Suchomimus, and suchomimus was only a fraction of Spinosaurus' size.

Keep in mind humans use their arms as weapons, pretty effectively even if they know how to do it properly. And they are the main tool for many actions that require strenght. The arm of that suchomimus is infinitely more massively constructed. What was it for, if not fighting? Doesn't look as if it was only decoration.
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ZealRaegus
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theropod
Mar 31 2013, 06:58 PM
here'seems like that's a T. rex arm:
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and T. rex was larger than Suchomimus, and suchomimus was only a fraction of Spinosaurus' size.

Keep in mind humans use their arms as weapons, pretty effectively even if they know how to do it properly. And they are the main tool for many actions that require strenght. The arm of that suchomimus is infinitely more massively constructed. What was it for, if not fighting? Doesn't look as if it was only decoration.
Dude. You need to keep in mind that Spinosaurids arms may be large, but that even Baryonyx and Suchomimus arms were nowhere as long as human's or as big cats. Again, please try to use common sense when trying to state something that is hypothetical. Sure, the arms could be used in a fight, I'm not denying that. But the cases for predatory dinosaurs is that they use their snouts more often than not, to use their jaws.
I'm disregarding the Raptors and Oviraptorids as well. They are a totally different subject due to their arm length and body design...
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theropod
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I never stated them to ahve been their primary means of attack, but they are a factor and they are not just harmless little useless things hanging of that animals pectoral girdle. And the robusticity of the bones in question should give you an idea of that.
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Jinfengopteryx
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Spinodontosaurus
Mar 28 2013, 07:54 PM
Only partly true.
I know of two megalosaurids off the top of my head that had long, robust arms by theropod standards (Eustreptosondylus and Torvosaurus). Two spinosaurids are known with forelimb material; Cristatusaurus and Baryonyx and both are long and robust.
So while we don't know exactly how long the arms were, the default standpoint has to be that they were long and robust.

There is, however, a ~75cm humerus known from the Albanian or Cenomanian of Morocco that is clearly a spinosaurid and about 1.5 times larger than the humerus of Baryonyx. It comes from the right time, the right place and is the right size for it to be a Spinosaurus' humerus, I would guess around the size of the holotype (MSNM V4047 was another 20% larger dimensionally). Whether it is a Spino' or not is another matter of course.
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EDIT: Image isn't displaying for me, here's the direct link: http://1.bp.blogspot.com/_6fVePgcYTJc/R81BSPwxUGI/AAAAAAAAARU/mcNhuow0yc4/s1600-h/Omero+Spinosaurus.JPG
I am very well aware of your first point, I also believe that Spinosaurus had long arms, but you shouldn't act like it is a fact, out-liners and exceptions always exist, however, unless if we have evidence against it, we should take it's relatives, sure.
I just wanted to be more careful. At the moment, many things about Spinosaurus are very debatable, say for example the size.
If you want to hear my opinion about Spinosaurus' size, I believe it was gigantic enough to win that battle, but I still listed the dubious size thing in my points.

I did not know about the second thing however (the gigantic arm).
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Tyrant
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Quote:
 
This is no face to face fight, basically its "will rexy come past the jaws and claws and reach a part it can bite or will spino knock him over before that happens"


With its arms? Arms that weigh less than tyrannosaurus's head? No the full weight of spinosaurus could knock over trex not its arm.

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I don't think they were killing weapons, but not being a killing weapon doesn't make something redundant. Cats don't use their claws as killing weapon either, and yet the vast majority of people here would favour a cat over an equally sized animal without claws.


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Keep in mind humans use their arms as weapons, pretty effectively even if they know how to do it properly. And they are the main tool for many actions that require strenght.


The arms of cats and humans are NOTHING like those of a theropod. First of they are WAY longer in proportion to their size. Secondly they are more flexible and have more versatile movement. And lastly they are placed in a convenient position.

I seriously don't see why you even made those comparisons you might as well have been comparing the arms of a spinosaurus to the wings of a vulture.

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The arm of that suchomimus is infinitely more massively constructed. What was it for, if not fighting? Doesn't look as if it was only decoration.


Hunting smaller prey like fishes? Ritual fighting? Ripping animal carcasses into swallowable chunks? All three? Not every weapon on an animals body was developed for serious fighting with similar sized animals.

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I never stated them to ahve been their primary means of attack, but they are a factor and they are not just harmless little useless things hanging of that animals pectoral girdle. And the robusticity of the bones in question should give you an idea of that.


What you don't seem to get is that these claws would minor lacerations on animal as large as trex and will do little to contribute in the fight.
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Monitor X
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Nobody knows the size of Spino arms. No one can predict how lethal it would be in a direct fight either. Nor even we know its true size.
Waiting for more stuff of him, no vote.

But looking again at their compared snout, T. rex puts Spino to total shame in terms of robustness. Just common sense. despite this fact, we surely need more from the african cretaceous grizzly.
Edited by Monitor X, Apr 4 2013, 02:53 AM.
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Spino is not as agile as t rex because of his sail and he neck seems long, t rex can bite the neck or body before spinosaurus can try to dodge it. Spino was also designed for eating fish and does not have as strong jaws as t rex
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SpinoInWonderland
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Nate
Apr 5 2013, 01:27 AM
Spino is not as agile as t rex because of his sail and he neck seems long, t rex can bite the neck or body before spinosaurus can try to dodge it. Spino was also designed for eating fish and does not have as strong jaws as t rex
Sail? What sail? And the jaws don't decide this battle, size and overall power does.
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