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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,355 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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then the antorbital fenestra is reconstructed too far posterior in that reconstruction. well, seems like the 1,95m are valid basing on this.
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theropod
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I´ve tried measuring Dal Sassos reconstruction fo the skull.


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Skull reconstruction wuth scalebar (20cm) and preserved part of the rostrum (premaxilla, nasal, maxilla), © Dal sasso et al, 2005, modofied by Theropod

As Fragillimus did, I scaled the rostrum to match the position of the naris. It ended up at ~1m and the whole skull is 1,75m basing on the scale bar, which was said to be 20cm in the paper. here the rostrum also fits the foramen antorbitale properly. Basing on this 1,75m is correct.
Now that I have a closer look at this particular skull reconstruction it´s angular has a really strange shape tough.

So there probably is some measuring problem. Which program did you use, Fragillimus?


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Black Ice
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A good way to tell the actually usable size.adv. For spino would be to remove the sail.
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theropod
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assuming it was a sail, if it was a crest it was actually "usable size.adv."
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Black Ice
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It was to tall and thin to be a crest.
A crest would be more like the one acrocanthosaurus has.
Plus it was a piscovore, extra muscle isn't needed to kill a fish.
Edited by Black Ice, Sep 8 2012, 06:19 AM.
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theropod
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A thing I wanted to ask for a long time: is there actually a name for that fossa between the premaxilla and maxilla? it doesn´t fit in the rostrum in Fragillimus image because it is stretched, but the naris does.
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Black Ice
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Your talking about the sheets of skin in between?
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theropod
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Black Ice
Sep 8 2012, 06:19 AM
It was to tall and thin to be a crest.
A crest would be more like the one acrocanthosaurus has.
Plus it was a piscovore, extra muscle isn't needed to kill a fish.
what about pulling a 2t struggling sawfish out of the water solely with your jaw and neck? It sounds pretty plausible that they served as a muscle attackment. plus the spines are actually not thin, where do you take that from? we have no postcranial remains except for the spines that where destroyed, and it seems like there is no dorsal or frontal view of them [1]. it actually seems that they are far from fragile, and their shape really resembles a bison pretty much (I know it has fat, not muscles, but they also have to bear weight, and according to you intestines are also a usable weight advantage, and a fatty hump would for shure be too heavy as to be an efficient fat storage it has to be much thicker than to be an effective muscle attachment...).

So why don´t you believe it was a muscular crest like it was likely present in Acrocanthosaurus? There is nothing indicating the spines to be too fragile, and concerning the height, spinosaurus was simply an extreme.

1. http://www.carnegiemnh.org/assets/science/vp/Smith%20et%20al.%202006%20Spinosaurus%20photos.pdf
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theropod
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Black Ice
Sep 8 2012, 06:22 AM
Your talking about the sheets of skin in between?
what sheets of skin? I´m talking about the curvy depression just at the point where maxilla and premaxilla meet.
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Black Ice
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1.its childs play kilking a 2ton fish when you weigh up to 16tons yourself.
2the spines were way to long to serve any kind of ectra muscle. It was more likely a temperature tool like the plates on stegosaurus.
Acrocanthosaurus had a low thick ridge which is more likely to house extra muscle then spinos sail.
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Fragillimus335
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It is likely a crest, not very thick, only like 3 feet thick at the base and narrowing as it goes up, like this...
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BTW my Spinosaurus skull is 1.95 meters long because I believe the rear portion of the skull is restored as too small in Dal Sasso's paper.
Edited by Fragillimus335, Sep 8 2012, 08:46 AM.
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Jinfengopteryx
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Black Ice
Sep 8 2012, 06:34 AM
1.its childs play kilking a 2ton fish when you weigh up to 16tons yourself.
2the spines were way to long to serve any kind of ectra muscle. It was more likely a temperature tool like the plates on stegosaurus.
Acrocanthosaurus had a low thick ridge which is more likely to house extra muscle then spinos sail.
Than what about extra muscels to support it's body?
And how does it weight 16t? That's pretty much the maximum. We've found Onchopristis Vetebra in the jaws of a 14m Spino, do you think this already weighs 16t?
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theropod
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Fragillimus335
Sep 8 2012, 08:44 AM
It is likely a crest, not very thick, only like 3 feet thick at the base and narrowing as it goes up, like this...
Posted Image


BTW my Spinosaurus skull is 1.95 meters long because I believe the rear portion of the skull is restored as too small in Dal Sasso's paper.
That´s exactly the reconstruction I had in mind

I agree about the rear portion, it really seems very short. what I wonder is how in this universe Therrien & Henderson managed to get it down to 1,5m...
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yigit05
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trex wins stronger bite,speed
spinosaurus paws, size avantage
50/50
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Verdugo
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Quote:
 
Than what about extra muscels to support it's body?
And how does it weight 16t? That's pretty much the maximum. We've found Onchopristis Vetebra in the jaws of a 14m Spino, do you think this already weighs 16t?

A 9 tons Spinosaurus can lift a 1,5 tons fish easily without the need of extra muscle
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