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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,253 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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mega t.rex the magnificent
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dinosaur
Feb 2 2013, 02:07 PM
Seriously, and i am not trying to annoy anyone. Tyrannosaurus wins like this:
Posted Image

Or this:
Posted Image

Or this:
http://theozzex.deviantart.com/art/T-Rex-kills-Spino-179510533

Or this:
Posted Image
sigh. That little punk again. realmad

Dinosaur, why are you still here?!
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Jinfengopteryx
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Godzillaman
Feb 2 2013, 09:04 AM
Spinosaurus probably shook large prey items in its jaws to help kill them, and fundamentally, dismember them.

Similar behavior is seen in modern crocodilians. When a crocodile attempts to kill and eat something too large to be swallowed whole, they normally shake their heads when that said item is clamped in their jaws. This violent maneuver can kill and easily rip apart large animals. Why do crocodilians do this? Well, they don't have carinae (cutting edges) on their teeth, unlike a large handful of various raisuchians and other prehistoric crocodilians.

I own the fossil of a spinosaurus tooth. The tip is non-present, and the tooth is rather short. However, when I examine it closely, I see what appears to be distinctive carinae. Similar features are seen on the teeth of crocodiles. However, this "carinae" is non other than a simple ridge. Nothing more, nothing less. It is not very sharp. This is a clue to how spinosaurus may have killed. Their teeth are very similar to those of modern crocodiles, and they appear to have adapted to a similar lifestyle.

My main point is that, although spinosaurus teeth lack the sharp cutting edges of carnosaurs, their similar morphology to those of modern crocodiles would surely make them a very dangerous animal in the Cretaceous Sahara.
This is an interessting point actually, than it would make sense why Spinosaurus didn't have a relatively strong bite, but a robust skull. I don't know if that's going to be easy with T-rex, but when once getting bitten, T-rex should have it hard to get free, so Spinosaurus could use that shaking strategy. Maybe a tooth get's stuck in T-rex when it comes free, that would weaken it for the rest of the fight.
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Jinfengopteryx
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dinosaur
Feb 2 2013, 02:07 PM
Seriously, and i am not trying to annoy anyone. Tyrannosaurus wins like this:
Posted Image

Or this:
Posted Image

Or this:
http://theozzex.deviantart.com/art/T-Rex-kills-Spino-179510533

Or this:
Posted Image
T-rex basically does the same in all these images, biting the neck.
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Maelstrom
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Godzillaman
Feb 2 2013, 09:04 AM
Spinosaurus probably shook large prey items in its jaws to help kill them, and fundamentally, dismember them.

Similar behavior is seen in modern crocodilians. When a crocodile attempts to kill and eat something too large to be swallowed whole, they normally shake their heads when that said item is clamped in their jaws. This violent maneuver can kill and easily rip apart large animals. Why do crocodilians do this? Well, they don't have carinae (cutting edges) on their teeth, unlike a large handful of various raisuchians and other prehistoric crocodilians.

I own the fossil of a spinosaurus tooth. The tip is non-present, and the tooth is rather short. However, when I examine it closely, I see what appears to be distinctive carinae. Similar features are seen on the teeth of crocodiles. However, this "carinae" is non other than a simple ridge. Nothing more, nothing less. It is not very sharp. This is a clue to how spinosaurus may have killed. Their teeth are very similar to those of modern crocodiles, and they appear to have adapted to a similar lifestyle.

My main point is that, although spinosaurus teeth lack the sharp cutting edges of carnosaurs, their similar morphology to those of modern crocodiles would surely make them a very dangerous animal in the Cretaceous Sahara.
Monsters Resurrected made that point, might have been one of the things they got right.

Jinfengopteryx
 
Spinosaurus didn't have a relatively strong bite, but a robust skull


Wouldn't a robust skull have some impact on the bite force. I posted something earlier on how Cau stated that the elongated rostrum made of solid bone increased the amount of force exerted by mandibular muscles. That together with the presence of the long nasal dorsal ridge to serve as a point of discharge to the forces and the long secondary palate, which would act as a mechanical expedient to resist torsion. Adaptations for a relatively powerful bite?
Edited by Maelstrom, Feb 2 2013, 06:30 PM.
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Fishfreak
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50/50 IMO, I'm neutral here, spinosaurus weight make up for its weaker bite and more slender built.
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Jinfengopteryx
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Maelstrom
Feb 2 2013, 06:12 PM
Jinfengopteryx
 
Spinosaurus didn't have a relatively strong bite, but a robust skull


Wouldn't a robust skull have some impact on the bite force. I posted something earlier on how Cau stated that the elongated rostrum made of solid bone increased the amount of force exerted by mandibular muscles. That together with the presence of the long nasal dorsal ridge to serve as a point of discharge to the forces and the long secondary palate, which would act as a mechanical expedient to resist torsion. Adaptations for a relatively powerful bite?
You should read this:
http://www.academia.edu/1812192/Structural_performance_of_tetanuran_theropod_skulls_with_emphasis_on_the_Megalosauridae_Spinosauridae_and_Carcharodontosauridae
Both the untransformed and the log–log data show unusual trends regarding how spinosaurids accommodatestresses within their skulls. Whilst Suchomimus demonstrates slightly lower skull stress than the trend predicts, Spinosaurus shows that stresses within the skull are much greater than that predicted by the allometric scaling relationship. Spinosaurus is the most proportionally longiros-trine theropod, and it may be the case that it wasrestricted to feeding upon smaller prey by possession of aproportionally weaker skull than similar-sized contemporaries such as Carcharodontosaurus.
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Maelstrom
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Jinfengopteryx
Feb 2 2013, 06:47 PM
You should read this:
http://www.academia.edu/1812192/Structural_performance_of_tetanuran_theropod_skulls_with_emphasis_on_the_Megalosauridae_Spinosauridae_and_Carcharodontosauridae
Both the untransformed and the log–log data show unusual trends regarding how spinosaurids accommodatestresses within their skulls. Whilst Suchomimus demonstrates slightly lower skull stress than the trend predicts, Spinosaurus shows that stresses within the skull are much greater than that predicted by the allometric scaling relationship. Spinosaurus is the most proportionally longiros-trine theropod, and it may be the case that it wasrestricted to feeding upon smaller prey by possession of aproportionally weaker skull than similar-sized contemporaries such as Carcharodontosaurus.
Thanks for the link, I couldn't find anything similar myself.

I did expect that allometric scaling would be unable to determine accurately the magnitudes of cranial stress. The tables did show stress to be proportionally higher on larger animals, Carcharodontosaurus too had proportionally higher cranial stress then it's counterparts. The other table showed that Spinosaurus's 'scaled load without teeth' was second only to Carcharodontosaurus, comparable to Acrocanthosaurus. However it was without teeth; and conical teeth, being able to withstand forces from multiple directions better, would have had a effect on Spinosaurus's performance. Still, I do agree that Carcharodontosaurus had a stronger bite than Spinosaurus. 'Proportionately' was a key word as Spinosaurus was larger so BF would rise but BFQ would decrease - so maybe it would still be a similar outcome.

The fundemental part at the end was this:

Quote:
 
It is important to remember that this study consists of 2D FE models created from skull reconstructions, which are restricted in their accurate representation of 3D morphology.


I'm not saying that this paper should not be trusted, but they said themselves that accurate conclusions could not be determined, especially considering that Spinosaurus's skull was proportionately more robust and thicker than Carcharodontosaurus.

What would you propose as methodical bite force estimates for them?
My opinion:
Spinosaurus ~ 2 tonnes
Carcharodontosaurus ~ 3 tonnes.
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Jinfengopteryx
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I agree with the bite forces you have stated. 3t would sound about right for Carcharodontosaurus, because I can't imagine it to really have a bite force 3 times weaker than the bite force of Tyrannosaurus, tough I think there was quite a high difference between their bite forces.
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Maelstrom
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Jinfengopteryx
Feb 2 2013, 07:29 PM
I can't imagine it to really have a bite force 3 times weaker than the bite force of Tyrannosaurus
Was that the proposal from Therrien in 2005 (being three times weaker) and is there a paper or other document? Judging by his other estimates in 2005 I would say that would be quite a unreliable proposition...
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Jinfengopteryx
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Yes, you can find it in Carpenter's book The Carnivorous Dinosaurs.
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Fishfreak
Feb 2 2013, 06:35 PM
50/50 IMO, I'm neutral here, spinosaurus weight make up for its weaker bite and more slender built.
You forgot about the claws.
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Godzillasaurus
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Jinfengopteryx
Feb 2 2013, 06:08 PM
Godzillaman
Feb 2 2013, 09:04 AM
Spinosaurus probably shook large prey items in its jaws to help kill them, and fundamentally, dismember them.

Similar behavior is seen in modern crocodilians. When a crocodile attempts to kill and eat something too large to be swallowed whole, they normally shake their heads when that said item is clamped in their jaws. This violent maneuver can kill and easily rip apart large animals. Why do crocodilians do this? Well, they don't have carinae (cutting edges) on their teeth, unlike a large handful of various raisuchians and other prehistoric crocodilians.

I own the fossil of a spinosaurus tooth. The tip is non-present, and the tooth is rather short. However, when I examine it closely, I see what appears to be distinctive carinae. Similar features are seen on the teeth of crocodiles. However, this "carinae" is non other than a simple ridge. Nothing more, nothing less. It is not very sharp. This is a clue to how spinosaurus may have killed. Their teeth are very similar to those of modern crocodiles, and they appear to have adapted to a similar lifestyle.

My main point is that, although spinosaurus teeth lack the sharp cutting edges of carnosaurs, their similar morphology to those of modern crocodiles would surely make them a very dangerous animal in the Cretaceous Sahara.
This is an interessting point actually, than it would make sense why Spinosaurus didn't have a relatively strong bite, but a robust skull. I don't know if that's going to be easy with T-rex, but when once getting bitten, T-rex should have it hard to get free, so Spinosaurus could use that shaking strategy. Maybe a tooth get's stuck in T-rex when it comes free, that would weaken it for the rest of the fight.
This isn't supposed to guarantee the spinosaurus a victory due to the heavy build and even stronger bite of tyrannosaurus, but, with a morphology similar to crocodiles, spinosaurus would have been a dangerous animal.
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Godzillasaurus
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Fishfreak
Feb 2 2013, 06:35 PM
50/50 IMO, I'm neutral here, spinosaurus weight make up for its weaker bite and more slender built.
The more slender skull is a true point, but the seemingly weak bite of spinosaurus is not. Refer to this thread: Spinosaurus Bite Force
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theropod
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The problem with that source is, as already pointed out, that it is only 2D, but also that it doesn't talk about bite force, but about stress resistance. It isn't suggesting a weak bite, but a rather weak skull, while the Jaw closing muscles and mechanical advantage etc. aren't studied.

I don't see the suggestion of a robust skull but weak bite here anywhere, I think we are talking about an animal with a relatively strong skull and bite, but not quite as strong as that of some other theropods, like Carcharodontosaurs or of course T. rex (and I'd say T. rex probably had a bite twice stronger than Carcharodontosaurus). Basing on Irritator it does have quite some space for adductor msuculature in its temporal region.

In spinosaurus, it is mainly the skull robusticity that is setting the constraints on the bite force, not the bite force that is weaker than would be expected from the skull strenght (like for example in allosaurus).
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theropod
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Godzillaman
Feb 2 2013, 11:47 PM
Fishfreak
Feb 2 2013, 06:35 PM
50/50 IMO, I'm neutral here, spinosaurus weight make up for its weaker bite and more slender built.
The more slender skull is a true point, but the seemingly weak bite of spinosaurus is not. Refer to this thread: Spinosaurus Bite Force
fishfreak was talking about more slender built in general, not jsut the skull, and it undeniably has a weaker bite than T. rex.

however I don't see the point of a slender built to be a disadvantage as long as you are significantly larger than your opponent, and while its jaws are not the perfect killing tools they are still fearsome and potentially deadly. Imo it would use them to clamp down on the throat like modern felines do on large preys if their bite force is not sufficient, the main work in fighting would be done by its sheer mass and the massive arms, but a bite could help a lot in wrestling and securing too.
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