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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,325 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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Grey
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Yes, but in this case this is even more speculated. I will discuss it with the man.
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genao87
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man that Spino is big looking. very big. and not so short. i cannot imagine an animal if it could weigh 17 tons to be so close to the ground the way Cau depicted it.

even with the short legs, i think we are exaggerating the possibililties of how short it can be. i believe it will still have some height advantage.


i believe the T. Rex is too big in comparison to the largest Spinos possible. but the height thing maybe around this

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Edited by genao87, Oct 28 2012, 01:42 AM.
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Grey
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genao87
Oct 28 2012, 01:38 AM
man that Spino is big looking. very big. and not so short. i cannot imagine an animal if it could weigh 17 tons to be so close to the ground the way Cau depicted it.

even with the short legs, i think we are exaggerating the possibililties of how short it can be. i believe it will still have some height advantage.
That's not Cau's that's Dal Sasso who's behind the short-legged model and behind the new study about Spinosaurus posterior limbs and vertebras. Andrea Cau is the theropod specialist who not acknowledge for now any theropod above 13 meters.

Regarding the Spinosaurus from the TV show, I didn't say it was small-looking, but its legs are already quite short, like all spinosaurids. I was saying earlier that my personnal feeling is that Spinosaurus could be somewhere between the life sized model and the BBC depiction.

However, if I had to select one, I would chose the Dal Sasso model. I don't see any problem of balance there and a such basic problematic would have been encountered earlier...

The only reasonnable thing to argue is that we'll verify that with the subsequent publication.
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Verdugo
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7Alx
 
I'm not against that Spinosaurus may be largest known theropod. But saying Spinosaurus is (=must be) far/much larger than for example Tyrannosaurus or Carcharodontosaurus is exaggeration too. BTW I am not T. rex defender here.

http://imageshack.us/a/img840/8913/spinosaurussuchomimusty.png

Tyrannosaurus, Spinosaurus and Suchomimus from Dal Sasso paper. Based on scale bar.

Normal Allosaurus is around size of Albertosaurus/Gorgosaurus, although shorter at height. Allosaurus amplexus is a bit debatable due fragmentary remains, but saying Epanterias=Allosaurus isn't wrong and many paleontologists still agree with it, unless the another studies will deny.

It seems like even Dal Sasso himself doesn't make Spinosaurus as big as some people imagination rolleyes

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BTW, some descriptions from Cau:

Andrea Cau
 
As is my practice, I will explain how I came to this estimate, so that any critical data may have to argue their objections.

I have reconstructed the series of vertebral basing sull'olotipo Spinosaurus (Stromer, 1915). In doing so, I made some changes to the identifications of these vertebrae. As mentioned in previous post, the caudal vertebrae attributed by Stromer (1915) are probably of ornithopod: therefore, were not included in the reconstruction.

If you exclude a cranial ridge, the remaining dorsal vertebrae have not explained merger between neural arch and the center: this, in addition to indicating the status of the subadult holotype (yes, if you did not know already, of the Spinosaurus Stromer, as great, is not a mature adult), raises doubts about some of the associations neural arch - center proposed by Stromer (1915). Henceforth, the numbers that will mention will refer to the numbering of the figures illustrated in Stromer (1915). In particular, the arc with the plug highest (n ° 6) probably did not articulate with the center n ° 6. The latter is markedly opistocelico, implying that it was a dorsal intermediate or front. However, the plug neural n ° 6 is too high compared to the other backbones front (those n ° 17,18,19) to be next to them. Furthermore, the plugs n ° 17,18,19 are inclined cranially, while the plug n ° 6 is inclined slightly caudally. Conclusion, the plug No. 6 can not be a dorsal anterior. The most plausible hypothesis to put it, is "aesthetically" that biomechanically, it is considered that the neural spines were inclined along the lines of discharge of muscle forces and gravity, which in a biped, converge on the limb back. Consequently, the inclination of the neural spines had to be in the cranial dorsal cranial and tend to vertical in the direction of the sacral vertebrae. Following this trend, we would expect to see a tilted caudal neural spines in a vertebra. Therefore, the plug n ° 6 is interpretable as a plug neural proximal caudal. It follows that the higher neural spines had to belong to the sacred (note: unlike the front dorsal and caudal, dorsal neural spines intermediate shown are fragmented and lack the apex).

This interpretation differs from that proposed by Clear et al. (1998), who argue that Suchomimus is indistinguishable from Spinosaurus (among other features), even for the point of maximum height of the neural spines at the level of the sacred, while Spinosaurus, according to them (and Stromer) should have a level area back. The new interpretation for Spinosaurus is, in my view, the most sensible from the point of view of phylogenetic biomechanically because it responds to the mechanical requirements of a biped and follows the trend typical of all theropods neural spines elongated.

The series of Stromer comprises two cervical. Although Rauhut (2003, see the first post of the giants of the Sahara), based on the marked difference in the height of the neural spines, places of doubt that these are the same cervical species they belong to the backbone, his objection is falsified by 'existence of taxa with low cervical spine together with elongate dorsal spines (Ouranosaurus some Lambeosaurinae, Hindricotherium, Bison). Therefore, as long as it will not be discovered an exemplary articulated Spinosaurus that dispelling this interpretation, there are no serious objections to the association of cervical with the ridges illustrated by Stromer (1915). One of the two cervical is clearly the axis (the second cervical), while the other seems un'intermedia, perhaps the sixth cervical.

Based on the reconstruction of the skull of Spinosaurus proposed by Dal Sasso et al. (2005), I articulated a skull having a size suitable for the size of the cervical vertebrae. The skull is not directed horizontally, but is tilted rostroventralmente: As I mentioned in a previous post, on the basis of the peculiar morphology of cranio-dental Spinosaurus, I think this is the posture "default" and foraging. This hypothesis can be falsified / verified by future specimens, analyzing the inner ear (in particular by determining the slope of the semicircular canals), similarly to what has been done with other dinosaurs (Sanders & Smith, 2006; Clear et al., 2007). Subsequently, I have superimposed this series skull-vertebrae to a silhouette of Suchomimus, modifying it for understanding inside the neural spines. Using the height of the neural spines highest (1.65 m) as a reference, I get that the holotype of Spinosaurus was about 12m long. However, as mentioned before, this specimen is a subadult. On the basis of differences in the maxillary teeth and dental, Dal Sasso et al. (2005) point out that the copy of Milan probably has a skull length of about 6/5 of the holotype, and could be an adult *. Using the size of the rostrum preserved in Milan to estimate the size of my reconstruction, an animal is 14.4 m long.
Therefore, with all the limitations in this type of procedure, and with the knowledge that any measurement based on fragmentary specimens is susceptible to change, this is my estimate of the size of an adult Spinosaurus.


* In any case, as I wrote in an old post about the size estimates extrapolated from the skull, this estimate should be taken with extreme caution.


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Jinfengopteryx
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Oh really? Than why has he written 16-18m? By the way, that Spinosaurus was 16m lang (count the squares). So it fits the lower figure.
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7Alx
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Maybe it depends on the tail or body length.
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theropod
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how massive it is depends on the reconstruction of course. imo that one seems far skinnier than you would expect, and it is 16m, not 17 or 18. besides that it is also in a pose with a low head and here more or less the same height as T. rex. No wonder it doesn´t seem large.
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7Alx
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Who said 18 m must be more accurate than 16 m? 18 m is the highest estimate, but it doesn't mean most accurate.
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theropod
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I didn´t say that it was, even though I think it is. But we are using sue (or even MOR 008 for the case it was really larger), record holder among not less than 31 T. rexes.....against the only adult spinosaurus currently known to science. There is no point in using cautious estimates just to give a cautious estimate here.
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7Alx
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MNHN SAM 124 is known as adult too, it's surely even smaller than MSNM V4047. So we have 2 adults. I know there are still less adult Spinosaurus than all known adult Tyrannosaurus specimens, but Spinosaurus size is still debatable, unless we will find relatively complete adult specimen.
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Fragillimus335
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Either way, Spinosaurus was way larger than your standard Tyrannosaurus. Conservative, and reasonable estimates for both would be 5 tons for rex and 10 tons for spino. The most likely estimates are 6-7 tons for rex and 14-18 tons for Spino. The most liberal would be 9.5 for rex and 20 for spino.
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Grey
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To my knowledge, the standard estimate for Spinosaurus by Dal Sasso was more 7-9 tons, at 16-17 meters.
10 tons is not the lower end in the scientific literature.
Like said above, nothing will be stated as a fact before more significant remains are uncovered.
I'm confident that the further works by Dal Sasso and Ibrahim will solve this, at least will progress.

Spinosaurus proportions are until now not as certain than those for even the fragmentary giants carcharodontosaurids.
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bone crusher
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Hey guys I'm new here, it's interesting to see t.rex vs spino is hotly debated here so I thought I'll share my perspective on this. First of all the new laser scan measurement is the most accurate method compared to the older equations. Another reason why T.rex's 9.5t new estimate is more reliable is simply because Sue's almost intact fossil find, which allows peeps to more accurately place the 3d meshes onto the digital skeleton accordingly. This method was used on an ostrich and the result came out very accurate so it's not unreasonable to apply the same to a T.rex. Of course there's always margin for errors but it's the closest to the real thing.
Now as far as Spino's weight is concerned, we can only hope to find a remain as complete as Sue's for an accurate measurement, so personally I'm not gonna take any weight estimates made for Spino at this stage, it could be anywhere from 7-18t but it's simply useless in this debate. On another hand we have a few more T.rexes bigger than Sue. The T.rex specimen UCMP137538 has a toe bone about 15% bigger than Sue's corresponding toe bone, which suggests an animal about 16.5t if you scale it up linearly. C.rex is also about 13t according to her bones that are 10% bigger than Sue's corresponding ones.
Here's a graph I made using all the largest specimens of each individual species for comparison, the number for Spinosaurus is a rough estimate only.
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Archer250
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^ your Mapusarus looks small for a 14.7m 13 ton animal.
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Verdugo
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theropod
Oct 28 2012, 05:45 AM
how massive it is depends on the reconstruction of course. imo that one seems far skinnier than you would expect, and it is 16m, not 17 or 18. besides that it is also in a pose with a low head and here more or less the same height as T. rex. No wonder it doesn´t seem large.
I think Cau estimate for 14,4m Spinosaurus looks Ok, the head isn't too large, the torso isn't too skinny, and his estimate is based on the tallest neural spine which seems quite accurate
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