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| Spinosaurus aegyptiacus v Tyrannosaurus rex | |
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| Tweet Topic Started: Jan 7 2012, 02:16 AM (459,298 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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| SpinoInWonderland | Dec 29 2012, 03:37 PM Post #1246 |
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The madness has come back...
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Using the same growth curve would result in animals far too heavy to be effective bipedal predators |
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| theropod | Dec 29 2012, 11:19 PM Post #1247 |
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palaeontology, open source and survival enthusiast
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who sais all T. rexes that age where still actively growing, the sample size is far too low! Do all animals of a species grow the same way? No, some reach adult size earlier than others, that´s the case here UCMP 137538 is an undetermined Pedal phalanx as you can see, it is too different from sue to even determine its positioon, not to mention the animals size MOR 1126 is C-rex, isn´t it? Wasn´t it entirely based on Horners guess? MOR 008 is a skull reportedly 1,5m long. Sue is 1,53m. not larger than sue, and actually IMPOSSIBLE to be larger when basing it on the reported maxilla and dentary size and the photo that you can see online. About spinosaurus, you should view the whole matter when compared to skull size, it might have simply had proportionally torso, that doesn´t mean it also had a proportionally alrger head when comapred to total lenght. And All I think is silly is to regard the 16-18m figure as debunked. |
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| MysteryMeat | Dec 30 2012, 03:09 AM Post #1248 |
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Herbivore
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It would still weigh less than Spinosaurus, so why is it impossible? Spinosaurus is bipedal and predatorial. |
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| theropod | Dec 30 2012, 03:17 AM Post #1249 |
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palaeontology, open source and survival enthusiast
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There is simply nothing suggesting an individual that had attained an adult size would still continue to grow, that´s a baseless speculation that was used by fanboys to extrapolate astronomic figures. A normal male human doesn´t grow larger than 1,8-1,9m, but it might be that large at an age of 15-or at an age of 18. if it had a larger percentage of its growth earlier it will grow less later, eg if I was 15 and 1,8m it is unlikely that I will continue to grow with the rate of someone that attains this size when he´s 18. The growth rates that we have for T. rex are at best unreliable by now, even the comparatively large sample size we have here is far too small to ahve reliable data on growth rates, and there is simply no reason to suspect this animal didn jsut grow earlier. Also, we totally lack comparative data from other theropods. |
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| MysteryMeat | Dec 30 2012, 03:59 AM Post #1250 |
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Herbivore
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There are differences between individuals yes. I suspect robust forms would take longer time to grow. Some could reach adulthood sooner, or later. Could you list characters that differ UCMP 137538 that's not due to variation amongst individuals? If it's examined in Tyrannosaurus cannibalism paper than I assume it's a T. rex. What about its size? It's too big too be real? There's no exactly measures on MOR 1126, but I don't think Horner is full of shit either. Sue's skull is not 1.53 meters. It's 1.4 meters from tip of the snout to the end of quadratojugal, it is stated in Brochu's paper. Even if you measure it to end of the quadrate, I don't see it being 13cm longer. Most rex skulls are measured by the same standard, it's very possible that MOR 008 is slightly larger than Sue. Plus, if it's T. X, then it's got a proportionally small head. I can only find photos of the restored skull. It has a smaller dentary for sure. The right side of the skull looks like largely fossil cast, and it looks pretty good proportionally. Rex head proportions vary a lot. Holotype has a shorter maxilla, but a longer dentary than AMNH 5027. While Sue has a huge maxilla compare to Stan, its entire skull is not that much bigger. I don't understand your comment on Spino. The majority of the length of the animal is the axial skeleton. It's more accurate to calculate length base on vertebra anyways. Skull length estimates are not very accurate as head proportions differ a lot even within the same species. |
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| Fragillimus335 | Dec 30 2012, 04:17 AM Post #1251 |
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Omnivore
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Ummm...if that is correct. It implies MSMN V4047 was quite heavy, like 20 tons+. Considering V4047 was ~20% larger than the holotype. Wow, I just measured the snout to ilium length for Baryonyx and multiplied it by 1.93, and got a length of 9.2 meters for the holotype. If MSMN V4047 is indeed 20% larger, that means a Spinosaurus with a tailless length of 11 meters....that's huge. Edited by Fragillimus335, Dec 30 2012, 04:31 AM.
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| theropod | Dec 30 2012, 07:29 AM Post #1252 |
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palaeontology, open source and survival enthusiast
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I suspect animals that where 12m at 16 years old wouldn´t continue to grow like ones that attained this size much later in their lifes.
Depends, if you suggest it was an IV-3--yes, but the paper describing it said it was an IV-2, which it doesn´t resemble at all. It is simply not properly assigned if you ask me, it is highly likely imo that it was a deformed toebone from a higher position like IV-1 or so, maybe in Big al fashion, who knows?
If that´s the case, what about the 2,4m spinsoaurus skull he reported? And, oh hey, I think T. rex might be a scavenger. No, I´ve learned not to trust unconfirmed claims Horner made.
Sues skull is 1,53m from the premaxilla to the occipital condyle (Holtz chapter on tyrannosaurs in THE DINOSAURIA, 2004), and that´s likely the way MOR 008 was measured. i already mentioned, going by the reported measuremends for dentary and maxilla and the reported photo is cannot be larger than Sue, have a try comparing and measuring their respective proportions in an image manipulator please. And it is everything buit sure whether T. X, which is at best inofficial, has a proportionally smaller skull. Stan for example has a larger one than sue. Of course proportions vary, but if you don´t know them don´t hypothetise them but go by the reported ones.
OK, I might have expressed it badly. what I mean is, that you don´t know the relation to the whole axial skeleton to the skull, it might have simply had a proportionally longer torso. |
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| MysteryMeat | Dec 30 2012, 05:06 PM Post #1253 |
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Herbivore
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I am basing my numbers on Brochu's paper, Osteology of Tyrannosaurus rex: insights from a nearly complete skeleton and high-resolution computed tomographic analysis of the skull See the measurements below: Premaxilla to the occipital condyle=tip of premaxilla to frontoparietal suture+frontoparietal suture to occipital condyle Which is, 105.8cm+30.0cm=135.8cm, not 153cm I highly doubt that Brochu would mismeasure the skull by 20cm. |
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| MysteryMeat | Dec 30 2012, 05:23 PM Post #1254 |
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Herbivore
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The paper's assignments are questionable I agree. Judging by the image, it's a lot bigger than either IV-2 or IV-3. I believe it is a mis-assigned, and mis-diagramed IV-3, in which case it's a 13cm IV-3 as the paper states, it's a lot bigger than that of Sue's I don't see any resemblance to big Al's toe. There's no nasty texture on the bone that resemble big an Al's toe. The paper also makes no mention of signs of injury of disease, and it did not contribute any character described to pathology. However, if you agree with the paper's assignments, then the MOR 1126 toe digit II-2, as it is assigned, is so much bigger than that of Sue's. That bone looks much more like a II-1 though. I am not aware of Jack Horner reporting 2.4 meter Spino skull. I don't think he's ever studied any Spinosaur. His opinion on Tyrannosaurus behavior is another issue. I still don't know what you mean. We got Spino skull material to reconstruct it, and we could reconstruct the axial skeleton based on the holotype as well. So a skull to axial skeleton ratio estimate of Spinosaurus can be obtained. Which specimen has a longer torso? |
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| Verdugo | Dec 30 2012, 05:36 PM Post #1255 |
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Large Carnivores Enthusiast
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Skull length from the tip of the snout to the quadratojugal, i agree the length from the premaxilla to the occipital condyle may be a bit longer, but ~ 15cm longer is too much ![]() http://s6.postimage.org/yccgepmsh/Sue_measurement.png And yes, T x has proportionally shorter skull than T rex, it would mean that MOR 008 is at LEAST as big as Sue. |
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| SpinoInWonderland | Dec 30 2012, 05:43 PM Post #1256 |
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The madness has come back...
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Spinosaurus has a mostly piscivorous lifestyle that doesn't require it to run down prey unlike Tyrannosaurus |
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| SpinoInWonderland | Dec 30 2012, 05:51 PM Post #1257 |
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The madness has come back...
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Outlandish. That would make the subadult holotype have a mass of ~17.16 tonnes, scaling from an 8.5-meter, 2-tonne Baryonyx...MSNM 4047 would be the size of a large sauropod in that case... |
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| theropod | Dec 30 2012, 09:50 PM Post #1258 |
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palaeontology, open source and survival enthusiast
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Look, obvious we cannot properly assign that toe, isn´t it? The info on Jack Horners spino skullw as poster on this board for several times. I´ll try it again: The info you posted merely refers to the axial skeletons proportions, not to the proportion of the axial skeleton to the skull. It might just have had a proportionally longer torso and in exchange a shorter tail, that doesn´t mean it had a proportionally larger head. @verdugo: Holtz made that up then? The point is, regardless whether that measurements is correct that there is more than one way the skull could have been measured, if 1,53m for sue is incorrect, why not 1,5m for MOR 008? And it is not proven that the measurement is really incorrect. Who guarantees you that if Holtz is incorrect with his figure for the skull of sue, the press release about MOR 008 is correct and measured the same way as 1,4m sue? Is there a source stating T. X had a proportionally smaller skull? What I have seen suggests otherwise. |
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| theropod | Dec 31 2012, 01:31 AM Post #1259 |
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palaeontology, open source and survival enthusiast
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I scaled my T. rex skull to the measurement Brochu reported and it ended up at a maximum lenght of 146cm:![]() ![]() It is obvious T. rex has the more impressive skull, it´s even more notable from a dorsal or ventral view which I didn´t include here. Still I wouldn´t say spinos skull is whimpy (well, the rostrum might be, but the dentary definitely isn´t). In any case it is still large and powerful in absolute terms, even tough when it is only about the bite T. rex has a clear advantage. Edited by theropod, Dec 31 2012, 01:32 AM.
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| MysteryMeat | Dec 31 2012, 05:02 AM Post #1260 |
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Herbivore
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No it's actually shorter. Just look at the measurements in the image you linked: Premaxilla to the occipital condyle=tip of premaxilla to frontoparietal suture(measurement 6)+frontoparietal suture to occipital condyle(measurement 7) Which is, 105.8cm+30.0cm=135.8cm, not 153cm |
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