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| Spinosaurus aegyptiacus v Tyrannosaurus rex | |
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| Tweet Topic Started: Jan 7 2012, 02:16 AM (459,135 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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| Drift | Sep 5 2014, 01:29 PM Post #3691 |
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High Spined Lizard
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I don't remember asking for a psychoanalysis on my alleged posting habits,which makes it clear some members argumentative nature gets the best of them and imo that's what is truly "tiresome".You didn't contribute anything to the topic with that response,It just serves as an unimaginative attempt at the assassination of my character,to be honest... |
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| Verdugo | Sep 5 2014, 11:27 PM Post #3692 |
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Large Carnivores Enthusiast
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Those new materials are probably still under study before the publication. I don't know, at first when i looked at the restoration you posted, it's like a slap to the face you know. I thought the pic was from poor, unreliable source. But after digging the Internet for a while, it's actually not far from impossible imo. Spinosaurus is quite extreme for me, being very enlongated and slender even when compared to other Spinosauridae like Baryonyx for instance, the spiny things do exist in other Spinosauridae but nowhere near as pronounced as Spinosaurus. It makes me feel that Spinosaurus is the evolutionary extreme of Spinosauridae, the most specialized of them all. ![]() Theropod with ridiculously short legs is not fer from truth anyway Those are just my pure opinion about the short legs restoration. At least for now, we have no publication papers nor sources to discuss about the legs of the animal. For me, the short-legged Spinosaurus is not that hard to accept, if its legs are actually that short of course
You know that i'm not a bridge expert and i didn't actually discuss about bridge right ? What i really meant is you cannot put massive weight on sth that is not built to support that kind of weight. The same thing would happen to Spino, which we would discuss below
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Their vertebrates ARE NOT evolutionary adaptation for being semi-aquatic or cursorial
I'm sure Blaze are talikng about allometric scaling for by comparing Spinosaurus vertebrate to Baryonyx vertebrate in the thread involving that "18m Spino". But it's not what we are discussing so forget it
6,1 tonnes for T-rex is still outdated anyway, the most accurate weight estimation for Sue until now is 9,5 tonnes by Hutchinson
What Paul said is true, however he spoke that in a very generic way while Cau directly put two specific Theropod (T-rex and Spino) together for better research and examination Seriously, all you have is Paul quote in a very generic way, don't you have anything better to back yourself up ? Edited by Verdugo, Sep 5 2014, 11:59 PM.
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| Jinfengopteryx | Sep 5 2014, 11:54 PM Post #3693 |
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Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
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Since summer 2014 was predicted as time of appearance for the new publication, does anybody actually have a more precise date now? I am sure the legs will get assessed there. @Drift Honestly, what Spinodontosaurus said is far from a psychoanalysis. Only his first sentence looked a bit like this. His message was simply that he is tired of you always criticizing MR even though everyone here knows that it is crap. |
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| blaze | Sep 6 2014, 12:31 AM Post #3694 |
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Carnivore
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I found some interesting posts yesterday in the dml in the thread on the news of Dreadnoughtus.
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| theropod | Sep 6 2014, 01:08 AM Post #3695 |
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palaeontology, open source and survival enthusiast
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I’ve got no problem with short legs (even though those in the mount seem too extreme if one looks at other short-legged animals) like the ones you see on Hartman’s Majungasaurus or Torvosaurus, they would actually make sense. The problem is that the preliminary pictures that were released (which basically means the poor photograph of the mount and the back-half life restoration that seemed to be part of a poster) don’t just show very short legs, but also very gracile and cursorial ones, exactly what one would NOT expect the legs of a giant, short-legged animal to look like, but exactly what one would expect from the legs of a smaller one. That is not to say the adult animal’s legs could not still be rather short mind you, just way more robust and with a way longer femur (and larger hip), as would be expected from a large creature. Ichthyosaurs and Plesiosaurs have nothing to do with it. Ichthyosaurs have more, but shorter vertebrae than theropods, and they fulfill a different purpose. These are animals about as far from theropods as a diapsid can be. They are also about as far from either Spinosaurus or T. rex as anything can be in terms of ecology. And besides, it’s the diameter that’s the point here, not the shape. Actually I’d be far more inclined to accept Cau’s suggestion if Spinosaurus’ vertebrae were the same shape as those of T. rex, but they are not, not even close. Ichthyosaurs seem to have proportionately smaller vertebrae than T. rex. The largest known ichthyosaur centra have a diameter of 22cm, based on Temnodontosaurus burgundiae that would suggest a 15-16m animal, which implies a weight several times that of any known theropod, even though their centra would appear similar to those of Sue or smaller. The same applies to other animals. Based on regressions (Gottfried et al. 1996, Caillet et al. 1985) for great white sharks, the largest vertebral centrum being 30cm in diameter (as is the case in sue’s posteriormost dorsal) would suggest a ~17.5m animal. So if you consider those examples relevant in some way, you’d definitely have to consider that too–they do not help your point at all. Tyrannosaurs are very cursorial animals. Not sure how the fact that much smaller animals have more elongated vertebrae disproves that, it’s well documented in the literature (Paul 2008, Holtz 2004, Holtz lecture notes). I guess that Spinosaurus was less cursorial doesn’t require a lot of arguing. Stromer himself explicitely stated the dorsal vertebrae of Spinosaurus are not hollow, it’s a fact. Also, I’ve already read all that, you are telling me nothing new. 6.1t for Sue may not be accurate, no (although it is not the lowest volumetric estimate there is and certainly no worse than the 9.5t one). But it’s still Paul’s most recent estimate, as opposed to the ones you and Cau cited, which have been completely overhauled. I’m well aware of that. The point is that the method you use to determine whether something is built to support that kind of weight or not is very simplistic, just like your analogy. Both use a single factor, vertebral diameter or building material, and then generalize from that without actually testing the hypothesis. Edited by theropod, Sep 14 2014, 02:21 AM.
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| Fist of the North Shrimp | Sep 6 2014, 01:20 AM Post #3696 |
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vá á orminum
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The Spinosaurus from NatGeo seems to be the same as the one from Dinosauri in Carne e Ossa(Hope thats the right spelling. Obviously Cau seems to know most about the upcoming research. But of course he wont tell anything, he isnt James Kirkland. |
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| Verdugo | Sep 6 2014, 02:09 AM Post #3697 |
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Large Carnivores Enthusiast
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Dude, WTF are you even talking about ??? You completely misunderstood me and Cau. Next time, read somebody posts carefully before deciding to make such such irrelevant replies I used Google translator to translate Italian to English. Yes, i know it's not the best translator in the world, some parts may be a little bit hard to understand or not even make sense at all. But there's nothing i can do, i know no Italian |
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| theropod | Sep 6 2014, 02:28 AM Post #3698 |
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palaeontology, open source and survival enthusiast
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You say I completely misunderstood the information in question, and that my reply was irrelevant, so could you point out how? I know as little Italian as you do, and I think it isn’t a prerequisite for scientific discussions (albeit certainly helpful)–given that google translator is sufficient for understanding the meaning of Cau’s posts that is what’s actually irrelevant. If you think it is not, then you shouldn”t be discussing his hypotheses at all. What am I even talking about? The passage you quoted contains several things. • Why the comparison of vertebral proportions with Ichthyosaurs and Plesiosaurs is irrelevant–it’s the vertebral diameter compared to the body size that was the point, not the lenght/width ratio. Ichthyosaur vertebrae are so short because an ichthyosaur has so many of them. Also, these animals live in a near-weightless environment all the time, their vertebral function is different from either theropod. • Why the fact that the vertebrae of Elaphrosaurus and Gallimimus are more elongated than Tyrannosaurus’ does not mean Tyrannosaurus wasn’t cursorial itself. That it is is really beyond obvious and has been published on quite intensively. • Why Baryonyx is of absolutely no importance regarding the axial pneumaticity of Spinosaurus–because there are published data on Spinosaurus itself, notably that its dorsal centra are solid bone. What exactly was so irrelevant about that? |
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| Fist of the North Shrimp | Sep 6 2014, 02:44 AM Post #3699 |
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vá á orminum
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I think Caus main point is that Spinosaurus vertebrae do not indicate an aquatic animal, and this is what Verdugo wants to argue, too. |
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| theropod | Sep 6 2014, 03:11 AM Post #3700 |
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palaeontology, open source and survival enthusiast
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I know that, spinosaurids are not considered semi-aquatic due to osteological correlates (neither do I think any direct osteological correlates for amphibious habits have been identified for non-avian theropods. Not surprising since they are a very diverse group and as far as we know there are only very few semi-aquatic members. Hippos also aren’t really adapted for life in water, they don’t even swim, but yet they spend the entire day in water). I consider them semi-aquatic due to oxygen isotope analysis (Amiot et al 2010) showing greater similarity to turtles and crocodilians as opposed to terrestrial theropods. http://sourcedb.cas.cn/sourcedb_igg_cas/cn/zjrck/200907/W020120622356922971023.pdf |
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| The Reptile | Sep 6 2014, 06:49 AM Post #3701 |
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Herbivore
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So now people are talking about spinosaurus' vertebrae being evidence of a primarily aquatic lifestyle? Really??? |
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| Verdugo | Sep 6 2014, 05:21 PM Post #3702 |
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Large Carnivores Enthusiast
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Yes, yes that what i really meant. Thank you MantisShrimp @Theropod: No you still misunderstood Cau and me. Why is it even so hard for you to understand ? Yes, we acknowledge that Spino is semi-aquatic and T-rex is cursorial (for its size), those are not what we are discussing about What Cau really meant is some critics argue that using vertebrate to indicate their size is incorrect because one animal is semi-aquatic while the other is cursorial. The differences in their vertebrate are probably just evolutionary adaptations for their different life style . And Cau replied to those critics by using Ichthyosaurs and Plesiosaurs as an example for aquatic animals, Gallimimus and Elaphrosaurus as an example for cursorial animals. If Spinosaurus vertebrates were evolutionary adaptations for its aquatic life style, then it's supposed to be short and robust like Ichthyosaurs and Plesiosaurs, instead of being long and slender. Therefore, Spinosaurus vertebrates are NOT evolutionary adaptations for its life style . The same conclusion for T-rex
No we aren't. @Theropod just misunderstood Edited by Verdugo, Sep 6 2014, 05:24 PM.
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| theropod | Sep 6 2014, 09:00 PM Post #3703 |
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palaeontology, open source and survival enthusiast
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Well, it seems I did 't misunderstand it. As I already wrote, ichthyosaurs and plesiosars are simply not a relevant analogy. These are, again, animals with vastly different relationships and lifestyle. And yet, as I wrote earlier, at least ichthyosaurs do seem to have had proportionately smaller vertebrae. Their vertebral proportions (which are simply a result of having a different number of vertebrae along with a very different body shape, not with aquatic habits) were not the point, their size was. It would have to be demonstrated that semi-aquatic habits have no influence on relative vertebral diameter. And if fully aquatic animals like Ichthyosaurs (or sharks, or whales…) were really a relevant analogy, then that already seems to be falsified, as these do appear to have proportionately smaller centra than Tyrannosaurus. Given you accept that T. rex was cursorial and Spinosaurus was semi-aquatic, there can really be no doubt that this represents a relevant difference, among others completely opposed to the notion that if you know their relative vertebral diameters, you know their relative body masses. Edited by theropod, Sep 8 2014, 07:17 AM.
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| Jinfengopteryx | Sep 8 2014, 02:06 AM Post #3704 |
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Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
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Sorry if this sounds a bit stupid, but I had a discussion with one of the few decent posters on topix who assumed that Spinosaurus could, as a fish-catcher, have an edge in reflexes. What do you think? I believe this is highly speculative because Spinosaurus' fishes were probably not that fast and a technique that consisted of restraining and killing larger ones would be more likely than killing swift ones with a quick bite. P.S. Three words that mean fast in one sentence, nice! |
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| theropod | Sep 8 2014, 03:37 AM Post #3705 |
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palaeontology, open source and survival enthusiast
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Not necessarily reflexes/reactions (I also don’t think its lifetstyle is a very good indicator, animals that are very fast at performing a certain motion can be quite clumsy in other regards), but likely striking speed. One would conclude that pretty much by default though, considering it’s skull is certainly much less massive. |
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