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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,178 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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Vobby
Jan 26 2014, 05:23 AM
Yes, Hone stated that there are chances of other known theropods of being bigger than T. rex, but is opinion is clearly that T. rex is the biggest. Anyway, it is not only Hone who makes guesstimates, but Dal Sasso and Maganuco too, since the paragraph in which they try and discuss the size of the animal is called " Skull Size and Hypothetical Body Size". The authors then proceed saying: "As some postcranial elements (i.e., the limb bones and the caudal vertebrae)
are hitherto unknown in Spinosaurus, it is difficult to reconstruct accurately its body proportions, so the real size of MSNM V4047 can be only tentatively hypothesised" and "With an appropriate degree of caution, the size of the whole animal (Fig. 5C) can be calculated by reconstructing the skeleton on the basis of both the remains of the holotype of Spinosaurus (Stromer, 1915) and Suchomimus (Sereno et al., 1998). The estimated length for MSNM V4047 is about 16–18 m". While we know from Hartman, Paul, Cau that 16 - 18 metres is very very unlikely. The two authors main purpose wasn't to estimate the size, they just guesstimate it, and do it wrongly, as we all here seem to agree with.
Body size estimates in prehistoric animals are hypothetical in the majority of cases. That is not the same as a guess.

Dal Sasso et al. based their reasoning on other spinosaurids, and their reasoning is in agreement with Hartman or Paul (which both state Spinosaurus was around 16m long). I think blaze sufficiently explained the differences between those estimates.

A few things about each estimate of course don’t make perfect sense (eg. Dal Sasso et al have a really anorexic Spinosaurus in their weight estimates and their skeletal, while Hartman’s MNHM v 4047 seems oddly small compared to the holotype), but they are as good as they get at the moment.
Note that just because one claims an estimate to be very rigorous and reliable, that does not automatically make it better than one that has been conceded to be tentative. The latter is at least fully aware of the problems. My problem is, that I don’t see Cau’s reasoning being better than the other’s, but he claims it to be.

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But since we discussed this kind of matters to exaustion (I also have the impression that we are starting hating each other, I wouldn't like it) I'm more interested in how do you figure Spinosaurus using its arms. You said to Dinopithecus that you don't think that theropods as big as these would have been capable of high dorsiflexion. This is of course even more true for Spinosaurus, was enlarged neural spines would touch each other quite soo it it tries to flex is vertebral column.

Indeed, the large spinous processes make the spine somewhat rigid in dorsoventral direction (not surprising considering that is their very purpose). My point is that whatever attacked it and was then apprehended by its jaws would more or less automatically end up below its body, within the reach of its arms (after all the size of mid-sized elephant forelimbs).

That is, unless upcoming evidence really suggests Spinosaurus was tremendously short legged. But the flimsy fragments of information that seeped through are not enough to make me believe the femur of Spinosaurus was no larger than that of Suchomimus (let alone that the whole animal wasn’t).
large image


Also, it seems nobody really studied the movement range in the forelimbs of megalosauroids. It is possible that they were larger than in Carnosaurs and tyrannosaurids, them being an entirely different and differently specialized clade. That’s mere speculation of course.

What this means in the end is that its jaws would not have to do the task of controlling its opponents on their own. They would be just part of the apparatus excerting the forces necessary here.

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So yeah, the arms were most likely big, but the head and the neck would be reached by Tyrannosaurus before it would be catched by its arms (but they would probably just got bited away, IMO), since only in Maniraptora we find arms long enough to reach higher distances than the jaws. Note that sinc Spinosaurus neck wasn't S-shaped at all, its long snout would be even more distant from the arms.
How do you know it wasn’t s-shaped at all?
Edited by theropod, Jan 26 2014, 09:27 PM.
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Spinodontosaurus
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theropod
Jan 25 2014, 08:51 PM
Also, pretty big humeri, almost as large as would be expected for MNSM V4047, have actually been found:
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credit goes to fragillimus335, dunno whether any of you remember him.
Did fragillimus actually claim he put that together...? He didn't - I did, but I need to re-do it because it's about 3 years old, was made in Microsoft Paint (lol) and it's scaling is all over the place.
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theropod
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He didn’t, he just posted it (you know where). My bad, I thought he had made the comparison.

Do you have the paper that describes the humerus? Since that’s perhaps the most massive theropod forelimb bone known (though Therizinosaurus and Deinocheirus have longer ones), it would be interesting to read.
Edited by theropod, Jan 26 2014, 09:38 PM.
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Spinodontosaurus
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I learned of it from a post by Andrea Cau from 2008 (regarding Spinosaurus' size ironically, of course he has since changed his stance), where he briefly mentions the humerus at the foot of the post;
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Click here for larger version.

Ref: Russell, 1996. Isolated dinosaur bones from the Middle Cretaceous of the Tafilalt, Morocco. Bulletin du Muse'um national d'Histoire naturelle (4e se'r.) 18:349-402.

I don't have access to the paper, no.
Edited by Spinodontosaurus, Jan 26 2014, 09:57 PM.
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theropod
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Thanks, that’s interesting.

Here, I’ve made this:
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Note that this Allosaurus is probably somewhere in between MOR 693 and DINO 2560 (rather closer to the latter though), ie. below 8.5m. T. rex is sue, and S. aegyptiacus is an extrapolation for MNHM V4047 based on the assumption that it is 80% larger linearly than Baryonyx.
EDIT: NOTE that this comparison is OUTDATED and does not showcase accurate proportions for the giant north-african humeral shaft, which has a proportionately narrower distal end and greater torsion than Baryonyx.
Edited by theropod, Oct 19 2014, 03:29 AM.
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TheMechaBaryonyx789
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theropod
Jan 26 2014, 10:42 PM
Thanks, that’s interesting.

Here, I’ve made this:
Posted Image
Note that this Allosaurus is probably somewhere in between MOR 693 and DINO 2560 (rather closer to the latter though), ie. below 8.5m. T. rex is sue, and S. aegyptiacus is an extrapolation for MNHM V4047 based on the assumption that it is 80% larger linearly than Baryonyx.
Interesting comparison. It appears that Tyrannosaurus' and Allosaurus' humerus are very similar in size but considerably different in overall shape. Spinosaurus' humerus is far larger also.
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theropod
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They are similar in size because the Allosaurus is less than 70% the lenght, and probably just a quarter the body mass. Yes, Tyrannosaurid humeri have some peculiarities, they are relatively straight and club-like (they were once described as "shapeless", which is a problematic term since their shape is quite distinct, but I can see what it is supposed to refer to, the humerus’ doesn’t have such marked curves, expansions and protuberances). And of course the distal end is not as wide since the radius and ulna are far smaller and less massive at the same humerus size.
What I find surprising is that they are actually similarly robust at the same lenght (though this is obviously a particularly robust T. rex and normal Allosaurus).


Yeah, Spinosaurs probably have the most massive and largest humeri of all known carnivorous theropods. The sheer width of those things is quite impressive.
Edited by theropod, Feb 10 2014, 04:39 AM.
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Hatzegopteryx
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Canadianwildlife
Jan 26 2014, 02:31 PM
Hatzegopteryx
Jan 26 2014, 12:41 PM
Vobby
Jan 26 2014, 11:27 AM
Hatzegopteryx
Jan 26 2014, 11:05 AM
Biteforce, their mean weapons, won't work effectively against each other.
Why? They are predators of comparable sizes, there is really nothing that stops both of them to bite each other. I've yet to see a precise estimate of the gape of both these animals, but even if it was like 60-70° then it is like that of a lot of modern predators, like Hyenas, Wolves and pantherines, which are perfectly able of biting hard trough animals several times bigger than themselves. The head, the neck, the limbs, the tail and I'm sure the flanks too are pefectly fine targets for them to bite.

The amount of damage the two would inflict each other is not even comparable of course.
(I meant *main not mean)

Spinosaurus had the gape advantage but its weaker bite is not killing its foe if the foe itself couldn't kill an Edmontosaurus by biting its head with more force. o I don't think biteforce will matter much here.
Bite force most certainly matters here! It can be the difference of killing your opponent. A super strong bite force means more damage in the bite, and having a much stronger bite force means that when you bite the other opponent, you can damage him a lot more, which will weaken him, and give you a better chance of winning the fight. So, for example, when the rex bites down, lets say for example he breaks a few bones, and breaks the spinos back bone, which is unlikely, but its just an example. But when the spinosaurous bites down, all the damage it does is give a few deep cuts or wounds, and maybe break a bone. Whoever has more damage to their body has more of a chance of losing. It was a bad example, I know, but you get what I'm trying to say. Even if one has more physical advantages, if they are more injured and weakened than their opponent, then that gives the other opponent a great advantage. I think it may come down to whoever seriously injurs the other first, then the less injured one can take advantage of the more injured one. Kind of like a, whoever gets in that first nasty bite thing. Who can damage the other opponent first.
How does it matter? It doesn't at all; A T. rex bite wasn't enough to kill an Edmontosaurus, and it was a bite to the head. Why would that bite be strong enough to kill an animal much larger than the other one that survived a bite from it?

Spinosaurus, on the other hand, has a weaker bite, so if the stronger bite doesn't kill the spinosaurid, the weaker bite is not killing the tyrannosaurid either, due to many pathologies that healed on BHI 3033 (a specimen that i actually UNDER average size)

You are talking about them like if they were drunk men, but they aren't. They will defend themselves from an attack instead of taking every single blow from each other.

Stop speculating about how they would fight.

You are underestimating the 13 ton spinosaurid as well, those teeth are pretty large (although not proportionally, but still) and the animal actually has a skull that suggests a strong bite on its own, which I believe that in addition to its dentition would be about as effective as the tyrannosaurid's bite in this fight. Both animals have advantages and disadvantages here regarding their biteforces which compensate eachother, so their bites are about as much as effective in this specific fight I believe.

Stop speculating about their fighting techniques, we don't know how those two would deal with eachother. Their bites are not kiling eachother and the tyrannosaurid's bone-crushing biteforce plus its small gape won't work against a large animal that also fights back.
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Hatzegopteryx
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TheMechaBaryonyx789
Jan 26 2014, 06:17 PM
Hatzegopteryx
Jan 26 2014, 11:05 AM
Tyrannoceratospinosaurus Rex
Jan 26 2014, 04:44 AM
It seems i'm the only one backing T-Rex here.... And i'm not changing my mind. T-Rex takes this...i'll be back with more reasons soon...
Why? Biteforce, their mean weapons, won't work effectively against each other.

@TheMechaBaryonyx789: We don't know if Spinosaurus would actually even ram, that is purely baseless speculation, correct me if there are any sources. I haven't seen any. The lighter tyrannosaurid (don't say it is a ninja for being lighter than a 13 ton animal that is ridiculous) probably had less rotational inertia, but not sure how much less. Still, I do believe it could outflank the spinosaurid, but I'm not taking that into consideration, not to mention how it doesn't help it by much. Still, I don't think the spinosaurid would ram into the tyrannosaurid, since we have no evidence of it ramming in conflicts.

I still back Spinosaurus.
Modern day animals ram into each other in fights, why couldn't Spinosaurus and Tyrannosaurus? Since Tyrannosaurus is the lighter one, it will be knocked over during a ram. Also I never called Tyrannosaurus a ninja, I actually said there would be hardly any agility difference between them at all.

I also back Spinosaurus in this fight.
It's still baseless speculation about two animals that cannot be tested in behaviour terms which makes it a hypothesis and we cannot consider it since we want accurate results and speculation takes us nowhere. So just stop the mindless speculation.

I never said you did, you don't need to bring it up. I just had said that so people wouldn't think I was saying this tyrannosaurid was a ninja because of its lighter build
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Jinfengopteryx
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As I said before, we don't know if the bite to the Edontosaurus head was well placed. I could also say great white sharks can't kill a false killer whale because seals often survive their bites.
Edited by Jinfengopteryx, Jan 26 2014, 11:49 PM.
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Tyrannoceratospinosaurus Rex
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Jinfengopteryx
Jan 26 2014, 11:47 PM
As I said before, we don't know if the bite to the Edontosaurus head was well placed. I could also say great white sharks can't kill a false killer whale because seals often survive their bites.
^ Exactly! Just one rare case can't be used as an indicator of what would've happened in a general situation
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Vobby
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theropod
Jan 26 2014, 07:52 PM
How do you know it wasn’t s-shaped at all?
The absence of a sygmoidal curvature in Spinosaurus neck is pretty much accepted I guess, but you gave me the occasion to link this:

http://theropoda.blogspot.it/2014/01/forma-funzione-ed-ecologia-di.html

Andrea Cau last, very nice post, seems really to see Spinosaurus moving and hunting at the sea-shore, and it also has something that could be said here:

"Overall, Spinosaurus appears theropode a relatively elongated but gracilis for its body size , both at the level of jaws that skeleton spine. Combining the elongated proportions of the vertebrae (which suggests a relatively slender body) with the extreme elongation of neural spines, it is clear that Spinosaurus had the body surface to volume ratio highest among large theropodi."

"The mandibles, narrow and elongated, are weak at the junction between the dental and bone postdentali, a detail pointed out by Stromer (1915) and evident by observing the reduced thickness of the region of the dental posterodorsale (and also present in Baryonyx), which suggests a relative independence and mutual mobility of the symphysis dental and compared to the rest of the jaw, then a capacity of mechanical strength along the dorsoventral axis less than in other large theropodi.


Posted Image
Holotype of Spinosaurus tooth in lateral and dorsal views. As in all spinosauridi, the jaw is stretched but very narrow in thickness. Note, in particular, the reduced thickness of the region of the rear margin of the oral dental (red arrows), just at the point of articulation with the other jaw bones; remarked a detail from the same Stromer.

Meanwhile, the secondary palate, very large and elongated, typical of spinosauridi, mechanically strengthens the rostrum with respect to torsional forces, the same as the jaw discharge effectively at the level of loose joint between bones and dental post-dental. These factors, combined, indicate a weak bite dorsoventralmente, but relatively rapid, dynamic and elastic side (a result confirmed quantitatively by Sakamoto 2010)."

"The conformation of the jaws, and the shape of the teeth (conical, not inflected and devoid of serrations), therefore, agree in hypothesizing a diet purely ittiofagica for Spinosaurus and a limited (if not absent) capacity macrophage (ie, the absence of adaptations to actively consume prey of comparable size to that of the predator): mandibles had the primary function of "impale" medium-sized prey, which were grabbed and swallowed whole (the relative weakness of the joint intramandibolare allowed a partial expansion of the mouth in the case prey to swallow whole, and a preliminary study on the shape of the articulation joint in some square spinosauridi from Cenomanian of Morocco confirms a potential capacity expansion of the oral cavity, similar to that of certain birds ichthyophagous, Hendrickx and Buffetaut 2008), which are in fact, the main component of paleofaune in which are found the remains of Spinosaurus."


" Spinosaurus is one of the most interesting and fascinating theropod. Its morphology is unique and very unusual, and can be explained only by integrating functional and anatomical information with the environment. The tapered shape of the jaw is reminiscent of other Archosaurs ichthyophagous, such as crocodiles, but also many water birds.
The skeleton elongated and slender (when compared to the other giants theropodi), associated to the tapered shape of the jaws, combined with the paleoenvironmental context, confirm the apt image Maganuco that Simon has given this theropode: a giant heron with teeth."
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Hatzegopteryx
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Jinfengopteryx
Jan 26 2014, 11:47 PM
As I said before, we don't know if the bite to the Edontosaurus head was well placed. I could also say great white sharks can't kill a false killer whale because seals often survive their bites.
But then that is more speculation we can't say it wasn't well placed since we have no evidence for that.
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Jinfengopteryx
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But we have data on Tyrannosaurus bite force and it's bite damage, so we can predict what a well placed bite could do to Edmontosaurus' skull.
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Vobby
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We also know that one Tyrannosaurus managed to break one triceratops horn, not to talk of the horrible injuries inflicted on the face of Stan. There is really no point in denying T. rex's bite force, it is one of the most studied and accepted things in paleonthology.


Edit: I may have missed the reference of the Edmontosaurus surviving a bite from Tyrannosaurus on its head, would someone post it again (I can't find it in the previous posts...).
Edited by Vobby, Jan 27 2014, 12:32 AM.
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