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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,151 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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ArachnidKid
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Jinfengopteryx
Mar 19 2014, 12:35 AM
I don't want you to look through all the pages, but according to your logic ("300 pages full of baseless speculation"), something like that should be found on every page which is obviously not the case (I have participated in this debate and I can tell you that although there was a lot stupidity, 90% of the comments were far smarter than that).
I actually mentioned there was almost 300 pages of facts vs speculation seeing as how there are some responses that aren't totally nonsensical, most however suffer from favoritism another example is on the very first page.member populator essentially has the same viewpoint as apex "this one wins because it looks like it would win", which was the point i wanted to make.Not many decisions on this matter were made using logic if that was the premise in which their standpoint stood atop ( the alleged size aspect )
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BoomerSooner
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T-Rex wins IMO. Spino's jaws seem inadequate for killing large animals.
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TheMechaBaryonyx789
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Inadequate for killing large animals? That's where you're wrong. Spinosaurus hunted 8 metre long rhino-sized sawfish such as Onchopristis in its ecosystem.
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Tyrannoceratospinosaurus Rex
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mecha I think he meant large terestrial animals
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theropod
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How does that make a difference?
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TheMechaBaryonyx789
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Tyrannoceratospinosaurus Rex
Mar 21 2014, 01:48 AM
mecha I think he meant large terestrial animals
Spinosaurus still hunted large terrestrial animals as well.
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BoomerSooner
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I'm sure it could hunt large animals if it wanted to. I'm just saying it's jaws are inadequate for such large prey. The modern gharrial can probably hunt bigger animals, but it's jaws are more adept to catching slippery fish. Rex's Jaws look way more robust.

You probably know more than me, I'm just going off what the passage says and a basic observation. I'm not too familiar with this creature.
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spinosaurus rex
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thats actually a terrible analogy. a fresh water crocodile is a better analogy. spinosaurus jaws were composed mainly out of solid bone and had a far deeper skull in proportion to about any crocodilian species. its teeth are also used quite diffrently. in both terms of proportions and relitive size, spinosaurus had much larger teeth then eny known crocodilian species. they actually rival tyrannosaurus in size.( being around 10 inches or possibly larger). their used for impaling and griping prey, and its skull high resistence to vertical forces aids in its hunting stratogy. and these arn't slippery fish. some of the celacanth species can outweigh a rhino and covered in thick scales that would require not only an adaquet biteforce, but a special detition designed perfectly for impalling
Edited by spinosaurus rex, Mar 23 2014, 02:22 AM.
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theropod
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©BBC

This is the clip of the Ct-scan from PD. It seems to be the whole snout. What you can see very well is that it’s much more solid than other theropod snouts. At its posteriormost extent, it has a pneumatisation proportion of just ~19.4% (and much less still throughout most of its lenght).

Compare that to the ~50.9% in the mid-rostrum of T. rex as shown here→.
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theropod
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spinosaurus rex
Mar 23 2014, 02:17 AM
thats actually a terrible analogy. a fresh water crocodile is a better analogy. spinosaurus jaws were composed mainly out of solid bone and had a far deeper skull in proportion to about any crocodilian species. its teeth are also used quite diffrently. in both terms of proportions and relitive size, spinosaurus had much larger teeth then eny known crocodilian species. they actually rival tyrannosaurus in size.( being around 10 inches or possibly larger). their used for impaling and griping prey, and its skull high resistence to vertical forces aids in its hunting stratogy. and these arn't slippery fish. some of the celacanth species can outweigh a rhino and covered in thick scales that would require not only an adaquet biteforce, but a special detition designed perfectly for impalling
Re teeth: the largest tooth described by Stromer is >23cm long, with a crown 34mm long mesiodistally, and "? 24mm" wide transversely.
By comparison, very large T. rex teeth reach 30cm in lenght.

The rest depends on how much larger we assume MSNM v4047 was, and on whether they were the same taxon or not. But spinosaurus’ teeth are without doubt among the largest of any terrestrial animal.

But note that the biggest tooth in MSNM has a mesiodistal lenght of over 5cm, so if it had even remotely similar proportions it was humungous (and would imply positive allometry in tooth size even using my assumptions on the specimen’s relative size).
Edited by theropod, Mar 23 2014, 02:35 AM.
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spinosaurus rex
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thats very close to 10 inches. the teeth size very in sized along the jaw lining( i am 100% sure you already know this) so although being a bit of a guess, it is plausable for them to reach 10 inches. also the evidence on msnm being its own taxon interests me a bit. not only does it suggest that msnm being another taxon, it also shows how much the robustity difference there was with the skulls between the two spinosaurus specimens. what do you think about the idea?
in my honest opinion( though not 100% sure) could msnm just manages to have the much more robust skull due to it being the larger and older of the two? younger birds and reptiles aften gain propertionally larger heads as they get older. and i belive the many ceratosaurus specimens from c. nasicornis to c. dentisulactus show that theropods were no exception.
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theropod
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I’m undecided about the idea of those two being separate taxa, but that is a subjective decision. Animals of a taxon always show variations, how much it takes in order to be separated is hard to quantify.

There is no such thing as a robusticity difference between the two, they share no overlapping material (except perhaps a few upper teeth).
Many are of the opinion that them being the same taxon results in an overly massive mandible for the rostrum (tough I do not think so), i.e. that the holotype was too robust to be the same taxon.

I think a very massive mandible fits the presumed feeding technique of this animal (having very deep dentaries to resist the bending force from a heavy fish that’s gripped and lifted), and it is nothing unheard of (take for example Tylosaurus). In addition, mere depth and width are misleading, since the upper jaw is so compact. It makes sense for the mandible to be more rigid (greater depth and width) in this case.
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TheMechaBaryonyx789
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BoomerSooner
Mar 23 2014, 01:18 AM
I'm sure it could hunt large animals if it wanted to. I'm just saying it's jaws are inadequate for such large prey. The modern gharrial can probably hunt bigger animals, but it's jaws are more adept to catching slippery fish. Rex's Jaws look way more robust.

You probably know more than me, I'm just going off what the passage says and a basic observation. I'm not too familiar with this creature.
The gharial is a terrible comparison for Spinosaurus, the large Spinosaurid had far more superior dental weaponry than the gharial. Spinosaurus had some very impressive teeth, and also it would have a very strong bite force (not proportionally) due to it being so large. Definitely adequate for hunting multi tonne terrestrial prey on occasions:
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BoomerSooner
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Then someone needs to change the description because it's misleading.
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theropod
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you mean the OP? it actually doesn’t mention gharials, just crocodilians in general.
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