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| Spinosaurus aegyptiacus v Tyrannosaurus rex | |
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| Tweet Topic Started: Jan 7 2012, 02:16 AM (459,288 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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| dinosaur | Jan 13 2013, 02:38 AM Post #1396 |
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Heterotrophic Organism
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YEEEEEEAAAAAAHHHHH! I WAS RIGHT AGAIN! That's exactly what I was trying to tell brolyeuphyfusion, but he wants things her way. |
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| MysteryMeat | Jan 13 2013, 03:13 AM Post #1397 |
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Herbivore
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What 95cm dentary? Stromer states a 75cm one. |
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| MysteryMeat | Jan 13 2013, 03:14 AM Post #1398 |
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Herbivore
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i didn't feel like cross-scaling the crest from the MNSN specimen. |
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| blaze | Jan 13 2013, 04:33 AM Post #1399 |
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Carnivore
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Nice reconstruction and... well, if the dentary is 75cm rather than the 95cm we've been assuming all along I guess you're right but then what is it doing there? btw: the Suchomimus femur in the skeletal is only off by 1cm, the tibia by 2cm, the humerus by 1cm and the radius by 1cm, the preserved premaxilla-maxilla seems to be the only one off by almost 10cm. I get that the reconstructed skull is more accurate but is not the reconstructed skull that I'm wary of, is the scalebar EDIT: GOD! the reconstruction of the fossil premaxilla-maxilla is not even to the same scale as the reconstruction below it! the complete skull reconstruction is only 83.8% of the fossil one! grrr I hate you Sereno... on the other hand that brings Sucho's skull back to being ~1.2m long. I'll put an image later but you can measure it for yourself, the fossil is 778px but the corresponding part in the skull reconstruction is 652px. Edited by blaze, Jan 13 2013, 06:32 AM.
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| theropod | Jan 13 2013, 04:59 AM Post #1400 |
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palaeontology, open source and survival enthusiast
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Stromer states 95cm actually:
Smith et al, 2006 Note the "possibly"? I'm going with the estimate there is no "possibly" in front of unless I see an argument why it should rather be 75cm than 95. Furthermore, I can easily read the "95cm lang" in the caption, But somehow what was appearantly regarded as "possibly" 75cm could just be messy handwriting (as common in scientists). The first one is obviously a 9, the second might just as well be a 9 rather than a 7. Do you think Stromer first gives a definite number and then writes a completely different one on the same piece of paper? Unlikely, that's a 95cm ![]() If the part was 75cm long, That would not change the size of MNSN V4047 in the slightest. It would just mean the holotype had in fact a smaller skull. This still doesn have anything to do with the respective size of other spinosaurus specimens with not overlapping material. ![]() See, if you make the dentary of the holotype 10cm shorter, the holotype will have a smaller skull. in the end, this actually would make MNSN even larger when compared to the holotypes already impressive size. That would only make a mixture of the dentary and the rostrum in one specimen, like the one Hartman did, even less likely.
duede, your posts don make sense. Where do you take all that stuff from? What "prey with limbs relatively narrower than those of T. rex"? and have I understood you correctly, you think spinosaurus was a quadruped? |
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| Kurtz | Jan 13 2013, 05:22 AM Post #1401 |
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Kleptoparasite
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"Its shape indicated to Stromer (1915) that its owner must have had a longer, narrower snout than normal big theropods. The teeth of Spinosaurus also differed from the gently recurved, laterally compressed, serrated teeth more typical for theropods, in that they were rounder in cross-section, had a straight central axis, and lacked serrations" "Instead, he concluded that Spinosaurus had a tall, narrow sail-like structure. This is an idea that was to remain popular afterwards" http://blogs.scientificamerican.com/tetrapod-zoology/2011/11/16/the-discovery-and-early-interpretation-of-spinosaurus/ Although traditionally depicted as a biped, it has been suggested since the mid-1970s that Spinosaurus was at least an occasional quadruped.[8][34] This has been bolstered by the discovery of Baryonyx, a relative with robust arms.[35] Because of the mass of the hypothesized fatty dorsal humps of Spinosaurus, Bailey (1997) was open to the possibility of a quadrupedal posture,[13] leading to new restorations of it as such.[35] The hypothesis that Spinosaurus had a typical quadrupedal gait has fallen out of favor, though spinosaurids may have crouched in a quadrupedal posture.[36] Theropods, including spinosaurids, could not pronate their hands (rotate the forearm so the palm faced the ground),[37] but a resting position on the side of the hand was possible, as shown by fossil prints from an Early Jurassic theropod.[38] i repeat for you bugs bunny:"Spino seems more flexible in overall body, more would have been able to use the front legs (mostly because of the stability on the ground |
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| lionsaurusrex | Jan 13 2013, 06:19 AM Post #1402 |
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Unicellular Organism
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T.rex wins most of the time due to reasons posted by other users.
Edited by lionsaurusrex, Jan 13 2013, 06:25 AM.
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| blaze | Jan 13 2013, 07:12 AM Post #1403 |
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Carnivore
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![]() I swear I didn't made any changes to the scale, I just cleaned up the lines in the fossil, they're the same size as they're in the paper ( I can provide the link, I though that when you reduced the size with the tags it linked the original but that's not the case) You can see that they're not to scale, the reconstruction is smaller, if we use the scalebar provided, Suchomimus skull is 101cm but, the preserved premaxilla-maxilla is 76cm according to the same scale bar, but the corresponding part on the reconstruction is only 64cm, if we assume the scalebar is right for the preserved fossil instead of the reconstructed skull that means the skull is actually 120.6cm. There's more, in the skeletal just below this, the preserved fossil is 85cm! and I've checked measuring the radius, femur, humerus and tibia that is off from the measurements given by only 1-2% (4.7% in the radius though), lets assume the whole skeletal is off by the percentage of the radius, that'll make the preserved part actually be 81cm, making the skull 128.5cm but what if it was only off by 1%? the preserved part would be 84cm and the skull 133.3cm... And all this discrepancy comes from drawings in successive order in the same paper, Sereno is bad with scalebars... Edited by blaze, Jan 13 2013, 07:21 AM.
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| MysteryMeat | Jan 13 2013, 08:53 AM Post #1404 |
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Herbivore
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I am simply going by what the published paper says: ![]() ![]() Highlighted sentence translates into: "Only the dentary and splenial are preserved in natural articulation on both mandibular rami in a length of over 75 cm, and there is also perhaps an isolated left angular." It is also consistent with the drawings published in the same paper. The tallest preserved neural spine, listed as 165cm in the paper, is clearly at least twice as long as the preserved mandible. |
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| MysteryMeat | Jan 13 2013, 09:04 AM Post #1405 |
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Herbivore
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The holotype does have a much smaller skull, not by 20%, but rather 30% IMO. If you assume the preserved holotype mandible is 95cm, then that would possible make the complete dentary over a meter long. That would make MNSN specimen only slightly larger than the holotype, not 20% larger, which would go against any estimate out there, except Hartman's drawing. You know I do not agree with your skull reconstruction. Do you see how grotesquely robust the mandible is compare to the skull? NO theropod has a head like that, not Baryonyx, not Suchomimus, not even Tyrannosaurus. The mandible is simply not that much deeper than the skull itself. If you make an articulated version of your spino skull, that poor creature can't even close it's mouth. There's also too many teeth on both the maxilla and mandible. My estimate is: Spinosaurus aegyptiacus holotype: skull length 1.2-1.3m, body length 12-13m, more likely 13m. "Spinosaurus" MSNM V4047: skull length 1.6-1.7m, body proportion unknown, probably 15-17m. Edited by MysteryMeat, Jan 13 2013, 09:07 AM.
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| theropod | Jan 13 2013, 09:35 AM Post #1406 |
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palaeontology, open source and survival enthusiast
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the point is the "über 75cm" How large the holotypes skull is remains unclear for now. My mandible might appear very deep, but compare its shape to dal sassos, does it superficially seem to fit the upper jaw? Animals can have very odd jaw shapes at times. if the part was smaller, the holotype was smaller, so why are we even arguing about it? and a 95cm dentary as seen in my scale results in an 16% longer MNSN, that's hardly just "slightly larger" |
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| blaze | Jan 13 2013, 01:12 PM Post #1407 |
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Carnivore
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@theropod In his own reconstruction the difference in size between dentary and rostrum is smaller than in yours, making that statement correct for his reconstruction. @Misterymeat Does it affect your reconstruction that its more likely for Suchomimus skull to be 1.2-1.3m rather than 1m? Edited by blaze, Jan 13 2013, 01:15 PM.
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| MysteryMeat | Jan 13 2013, 05:22 PM Post #1408 |
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Herbivore
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First of all, I think if it is 95cm long, then Stromer would have put 95cm in his paper, not "more than 75". That's not how you report scientific information. Secondly, the drawn diagrams shows a mandible about 75cm long, consistent with the reported figure. Let's take a look at del sasso's reconstruction: ![]() The lines show the preserved length of the rostrum, and scaled up mandible, the length are almost exact the same, which means the respective part of the mandible part in MSNM V4047 would be 99cm long. If holotype mandible is 95cm, then it means MSNM V4047 would only be 4% longer. The result doesn't change how big MSNM V4047's head is, but it will greatly affect the body length estimate. |
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| MysteryMeat | Jan 13 2013, 05:25 PM Post #1409 |
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Herbivore
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Nope it doesn't. I scaled up Irritator skull, not Suchomimus. I guess it makes sense if the skull is about 1.2m long. I think Spinosaurus holotype actually has a relatively shorter skull than Suchomimus, hmmm... Edited by MysteryMeat, Jan 13 2013, 05:29 PM.
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| Jinfengopteryx | Jan 13 2013, 07:29 PM Post #1410 |
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Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
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That can mean a lot, if it would be much more, he'd probably give another number. Also, he wrote "bis über 75 cm", so that's probably even just the maximum. |
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