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| Spinosaurus aegyptiacus v Tyrannosaurus rex | |
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| Tweet Topic Started: Jan 7 2012, 02:16 AM (459,212 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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| Big G | Jun 12 2013, 01:07 AM Post #2536 |
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Herbivore
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I had read that it had been discovered that the nostrils of MSNM V4047 were closer to the tip of the snout than thought before. So, we have a 56 foot Theropod against a 41 foot Theropod. Spinosaurus wins. |
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| SpinoInWonderland | Jun 12 2013, 01:37 AM Post #2537 |
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The madness has come back...
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Where did you read such thing? Better NOT be Cau's ultraconservative estimate... |
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| theropod | Jun 12 2013, 01:39 AM Post #2538 |
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palaeontology, open source and survival enthusiast
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Irritator is only an isolated part of the cranium, we cannot use it to scale up since there are no postcranial remains that could allow any conclusion about the proportions. 1,5m for Spinosaurus is also highly unlikely. |
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| SpinoInWonderland | Jun 12 2013, 01:43 AM Post #2539 |
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The madness has come back...
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Agreed. The rear portion of a ~1.5-meter long MSNM V4047 skull would be too compressed. People should just stop this "let's shrink Spinosaurus" thing, it's mostly just weak arguments, oversized heads and such. |
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| Jinfengopteryx | Jun 12 2013, 02:11 AM Post #2540 |
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Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
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That sounds interesting, do you have a source? |
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| SpinoInWonderland | Jun 12 2013, 02:37 AM Post #2541 |
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The madness has come back...
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There is no source about it, he basically made it up. |
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| Jinfengopteryx | Jun 12 2013, 03:30 AM Post #2542 |
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Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
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You don't know that. He maybe read something you and I haven't heard of yet. We don't know everything about Spinosaurus. Also, I may remind you that there is new Spinosaurus material (what unfortunately will be described next year and not this summer as we thought D:), maybe there is already info about it somewhere in the web (for example on a scientists' blog). |
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| SpinoInWonderland | Jun 12 2013, 03:38 AM Post #2543 |
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The madness has come back...
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We have the snout of Spinosaurus(MSNM V4047) and it's clear that the nostrils are not where he thinks it is. |
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| Big G | Jun 12 2013, 04:48 AM Post #2544 |
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Herbivore
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I did not invent anything. I had read that the nostrils of Spinosaurus were closer to the tip of the snout than believed. And also that the Spinosaurus MSNM V4047 was a old, and since it was in the process of shrinking from old age, had a shorter snout estimates of 1.75 meters, more like 1.5 meters. |
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| theropod | Jun 12 2013, 05:19 AM Post #2545 |
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palaeontology, open source and survival enthusiast
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A shorter snout would make the whole skull larger, not smaller. But I don't think any age-related conclusion have been drawn on MNSM V4047. When it is about Spinosaurus, it is very important to assess which sites you can trust, as lots are written by fanboys and haters. |
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| Big G | Jun 12 2013, 05:24 AM Post #2546 |
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Herbivore
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This was written by Andrea Cau. Cau think that the skull was smaller than estimated due to the fact that it was old specimen. |
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| theropod | Jun 12 2013, 05:26 AM Post #2547 |
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palaeontology, open source and survival enthusiast
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How does he know, that's the question. 1,5m is completely outlandish in any case. If you don't believe me, just have a try fitting a 1m rostrum into a 1,5m Spinosaur skull, or reducing everything but the snout so that the total lenght is 1,5m. The result will not be feasible, i guarrantee you. |
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| Jinfengopteryx | Jun 12 2013, 05:31 AM Post #2548 |
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Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
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Could you give us a link? |
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| Big G | Jun 12 2013, 05:48 AM Post #2549 |
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Herbivore
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From Theropoda Blogspot: "I never stated that Spinosaurus was proportioned as a tyrannosaurid. I wrote (in another post, not here) that all the extrapolations producing adult Spinosaurus as longer than 14-15 meters are poorly supported. It's currently unknown whether skull size in Spinosaurids decreased with age: being them long-snouted animals, it could result the opposite, with adults with proportionally longer skulls than juveniles and subadults: look at long-beaked fish-eating birds ontogeny: chicks show relatively shorter skulls than adults. In another post I showed that the fact that MSNM V4074 interalveolar space at the maxilla is 20% longer than the interalveolar space in the Spinosaurus aegyptiacus holotype maxillary fragment does not mean that the body of the former was 20% longer than the latter, since a 20% difference in maxillary dimension is present among Tyrannosaurus specimens with just a 5% difference in femur size (and femur is a better proxy for body size than maxilla). Also, even assuming that Spinosaurus holotype dorsals are 150% those of Baryonyx holotype does not mean anything about their relative size differences as adults, since the ontogenetic stage of both specimens is unclear. And even when you just extrapolate Spinosaurus holotype size from Baryonyx holotype size (about 9 meters) in such a naive way, you have a 9 * 1.5 = 13.5 meters long animal. The total skull length of Spinosaurus is unknown. MSNM V4074 is 1 meter long snout, and probably includes around 2/3 of the original skull length, not less (only oviraptorosaurs have snout about half the skull, all other nonavian theropods have longer snouts, and spinosaurids were probably among the longest-snouted theropods, thus the snout was most of the total skull length). Thus, the total skull was probably around 1.5 meters long, not 1.75. The 17 (or more) meters long animal is a just a monster myth for kids." In the comments: http://theropoda.blogspot.it/2012/08/la-coda-destra-della-taglia-theropode.html#comment-form |
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| Jinfengopteryx | Jun 12 2013, 06:11 AM Post #2550 |
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Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
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Thank you.
Edited by Jinfengopteryx, Jun 13 2013, 02:58 AM.
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