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| Spinosaurus aegyptiacus v Tyrannosaurus rex | |
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| Tweet Topic Started: Jan 7 2012, 02:16 AM (459,134 Views) | |
| Wolf Eagle | Jan 7 2012, 02:16 AM Post #1 |
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M E G A P H Y S E T E R
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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. ![]() 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).
Edited by Taipan, Apr 24 2015, 10:10 PM.
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| blaze | Sep 8 2014, 05:25 AM Post #3706 |
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Carnivore
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I think that trying to make it much bigger than T. rex based on the current fossil evidence is doing it a disservice, by either making it out to have a narrow, long-snouted head that is ridiculously small compared with the rest of the body or by making it out to be arguably the most unathletic giant theropod there is, combining its "diminutive" vertebrae with weights over 10 tonnes. Some people are so enthusiastic with increasing its "stats" that are forgetting the biomechanical implications of doing so. |
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| theropod | Sep 8 2014, 05:40 AM Post #3707 |
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palaeontology, open source and survival enthusiast
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Is there any way you can make Spinosaurus have anything but a narrow, long-snouted skull? With a snout almost a metre long and about 20cm wide that seems undisputable. There are many points to consider besides athleticism (although I think nobody doubts Spinosaurus is a less athletic animal than T. rex, especially given that it’s bigger). There’s fatigue (spending half your time in water=less of it), there are different modes of loading due to differences in the internal and external built of the vertebrae, there are different savety factors due to differences in what the animal needed to do on a regular basis. Has anyone ever tried to quantify what effect having pro- or opisthocoelous vertebrae as opposed to amphiplatyan or amphicoelous ones has for example? How much bigger do the latter have to be in order to resist dislocation to the same degree? That could very well be the main factor here, along with bending strenght of the vertebra itself (complicated by that of the spinous process of course), not resistance to axial compression (which bone is both very strong in and which external dimensions don’t matter much for). |
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| blaze | Sep 8 2014, 07:09 AM Post #3708 |
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Carnivore
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"narrow, long-snouted head that is ridiculously small compared with the rest of the body" That goes together, I'm not disputing that you can't reconstruct the head as anything but narrow and long snouted but what I meant is how big that head ended up proportional to the body, the larger "reconstructions" gave a head that was long and narrow on top of being relatively "tiny". That's another one regarding my athleticism comment, if based on current evidence is larger it'll be less athletic even if its vertebrae was similar in size to that of T. rex but is not, is much smaller making it comparatively even more sluggish. Are we sure Spinosaurus spend its time inside the water? isn't its feeding model compared to that of a stork rather than a crocodile? I don't think such analysis has been done (that of vertebral shape). Edited by blaze, Sep 8 2014, 07:19 AM.
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| theropod | Sep 8 2014, 07:14 AM Post #3709 |
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palaeontology, open source and survival enthusiast
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How tiny it is compared to the rest of the body doesn’t change its absolute size, or that of the fish it likely hunted. Also, nothing changes the lenght of those vertebrae. It is possible it had a proportionately larger head than Baryonyx or Suchomimus. It’s also possible it didn’t, allometric enlargement of the jaws may not be present in an animal that specialized in smaller prey. |
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| blaze | Sep 8 2014, 07:17 AM Post #3710 |
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Carnivore
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That's what I mean, no matter if you make it 9, 10, 11 tonnes or more it'll still have the same long narrow jaws that aren't much more wider than 20cm at the tip and throughout their length. And nothing changes how shallow and narrow those vertebrae are too. Edited by blaze, Sep 8 2014, 07:18 AM.
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| theropod | Sep 8 2014, 07:26 AM Post #3711 |
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palaeontology, open source and survival enthusiast
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Yes, my point was that no matter how heavy you might "make" it, the lenght of its body and therefore the proportions between its head and body are somewhat constrained by the lenght of its vertebrae. The relevance the diameter of these vertebrae has has yet to be clarified. I think I’ve already argued elsewhere that we can realistically get a Spinosaurus holotype 70-84% the body mass of Sue (i.e., basically T. rex-sized) using Hartman’s reconstruction of its proportions and Cau’s estimate for the width of the body, and I still retain that I think MNSM V4047 is about 37% larger overall-as comical as some people might find my and Dal Sasso et al.’s restoration of the lower jaw, I incorporated all the material as best I could, and I think so did they, and independently the results were fairly similar. Now I admit that my mass estimate needs a redux due to issues with the silhouette I traced, but I find the head-body proportions on Hartman’s Spinosaurus fairly believable (though maybe that’s simply because it is the skeletal we all grew to think of as the default), don’t you? The only thing I disagree with is the relative scaling of the dentary and rostrum that apparently yielded only little over 11% difference for him. Edited by theropod, Sep 8 2014, 07:28 AM.
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| blaze | Sep 8 2014, 08:17 AM Post #3712 |
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Carnivore
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I also found his (Cau's) reconstruction to look weird but not so much after the scaling I did with Baryonyx skull elements, the dentary ends up looking similar. That paper can't come soon enough. |
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| theropod | Sep 8 2014, 09:25 PM Post #3713 |
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palaeontology, open source and survival enthusiast
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Yeah, that seems to be a far too common condition in palaeobiology. "Just wait ’till that paper comes out, it should be due any day now! Months later… I just read an announcement that that taxon is going to be published soon!" |
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| Spartan | Sep 8 2014, 10:49 PM Post #3714 |
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Kleptoparasite
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37% larger than Sue or than the holotype? |
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| theropod | Sep 8 2014, 11:56 PM Post #3715 |
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palaeontology, open source and survival enthusiast
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That of the holotype. |
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| theropod | Sep 8 2014, 11:58 PM Post #3716 |
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palaeontology, open source and survival enthusiast
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Sorry, I meant 36. I always mess that up because I used to use different figures before I finished my updated reconstruction. |
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| Verdugo | Sep 9 2014, 12:30 AM Post #3717 |
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Large Carnivores Enthusiast
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No you still misunderstood me ! I'm not here to talk/discuss about f****** Ichthyosaur, Plesiosaur or Gallimimus. Here's the link original in Italian, use Google translator or whatever translator that help you understand. I think what Cau pointed out here are pretty clear that i'm not expected to have any discussion about this. http://theropoda.blogspot.com/2013/12/risposta-ai-lettori-vertebre-di-t-rex.html Pneumatization has nothing to do here, you know pneumatization has no relation to bone strength , don't you ?? I know you're not satisfied so here are the BONUS: ![]() Posterior dorsal vertebrae of various theropodi views in lateral right (left) and posterior (right). From top left: Spinosaurus , Tyrannosaurus , Ichthyovenator , Allosaurus , Baryonyx and Carnotaurus .
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If those are not enough to convince you then i would consider you being ignorant and stop debating here (because you've given me nothing exciting). All you have to defend for your point (Spino being more massive than T-rex) are Paul's statement in a very generic way, lifestyle differences and pneumatization arguments (lifestyle differences and pneumatization arguments have been demonstrated to be invalid by Cau). Seriously, back yourself up with proofs (including publication papers, books, research/quotes from scientists), your pure opinions won't convince anybody Edited by Verdugo, Sep 9 2014, 12:34 AM.
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| Spartan | Sep 9 2014, 02:32 AM Post #3718 |
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Kleptoparasite
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That would make it not significantly heavier than Sue. In this case I would favour the T-Rex. |
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| theropod | Sep 9 2014, 06:17 AM Post #3719 |
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palaeontology, open source and survival enthusiast
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Err what? It definitely would! |
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| The Reptile | Sep 9 2014, 06:20 AM Post #3720 |
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Herbivore
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It was undoubtedly capable of striking its jaws down and inward on fish, but that is where it needs to be capable of quickness. Locomotory quickness is just not as necessary for it as it is for other theropods because it would most likely not be chasing down fast-moving prey. And still, spinosaurus would be striking down with its jaws anyway; it is not going to be killing things by chasing them down. Whether or not its preferred prey type is powerful or not, it was designed for quick head-striking and restraining. Edited by The Reptile, Sep 11 2014, 07:34 AM.
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