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| Giganotosaurus carolinii v Tyrannosaurus rex | |
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| Tweet Topic Started: Jan 31 2012, 05:48 PM (110,328 Views) | |
| Taipan | Jan 31 2012, 05:48 PM Post #1 |
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Giganotosaurus carolinii Giganotosaurus ("giant southern lizard"), was a carcharodontosaurid dinosaur that lived 93 to 89 million years ago during the Turonian stage of the Late Cretaceous period. It is one of the longest known terrestrial carnivores, bigger than Tyrannosaurus, but in length and weight, smaller than Spinosaurus. Although longer than T. rex, G. carolinii was lighter and had a much smaller braincase that was the size and shape of a banana. A well-developed olfactory region means it probably had a good sense of smell. Titanosaur fossils have been recovered near the remains of Giganotosaurus, leading to speculation that these carnivores may have preyed on the giant herbivores. Fossils of related carcharodontosaurid fossils grouped closely together may indicate pack hunting, a behavior that could possibly extend to Giganotosaurus itself. he holotype specimen's (MUCPv-Ch1) skeleton was about 70% complete and included parts of the skull, a lower jaw, pelvis, hindlimbs and most of the backbone. The premaxillae, jugals, quadratojugals, the back of the lower jaws and the forelimbs are missing. Various estimates find that it measured somewhere between 12.2 and 13 m (40 and 43 ft) in length, and between 6.5 and 13.3 tons in weight. A second, more fragmentary, specimen (MUCPv-95) has also been identified, found in 1987 by Jorge Calvo. It is only known from the front part of the left dentary which is 8% larger than the equivalent bone from the holotype. This largest Giganotosaurus specimen is estimated to represent an individual with a skull length of 195 cm (6.40 ft), compared to the holotype's estimated at 1.80 m (5.9 ft) skull, making it likely that Giganotosaurus had the largest skull of any known theropod. Giganotosaurus surpassed Tyrannosaurus in mass by at least half a ton (the upper size estimate for T. rex is 9.1 t). Additionally several single teeth, discovered from 1987 onwards, have been referred to the species. ![]() 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. 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. ![]() ______________________________________________________________________________
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| Jinfengopteryx | Oct 15 2015, 04:57 AM Post #406 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
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^It is more like 1N = 0.22 lb. 46 kN equals about 4,600 kg (less than a third of 14 metric tons) which is about 10,000 lb. You can simply copy and paste the links or put [url][/url ] (without spaces of course) around them. |
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| bone crusher | Oct 15 2015, 10:57 AM Post #407 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Heterotrophic Organism
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People need to realize the difference here. Even though a slicing bite could potentially kill the t rex in one bite through blood loss but the time it takes for that effect to happen is far longer than a single bone crushing bite which ends the fight almost instantaneously. So while technically both methods could kill in one bite, but in a fight which is based on the last one standing, t rex would surely be the victor here. Plus, weight advantage on is also on t rex's side at this point of time, we have more than a couple t rex specimens that's heavier than Giga holotype since the MUCPv 95's mass can't be sufficiently verified. 65/35 to t rex. | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| DarkGricer | Oct 15 2015, 11:43 AM Post #408 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Omnivore
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We've been over this. A slicing bite can easily cut through major veins, arteries, ect. Yes, TECHNICALLY an injury like that would lead to death by blood-loss, but a slit throat bleeds you out really, really fast. Perhaps the crushing bite would still kill faster, but the difference would be next to irrelevant. As for weight, if you insist on using the Giganotosaurus holotype, then you should also compare it to an AVERAGE specimen of T.rex. pretty much all the T.rex specimens that have a notable weight advantage over it are on the larger side of the spectrum. |
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| bone crusher | Oct 15 2015, 09:48 PM Post #409 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Heterotrophic Organism
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It's not whether I insist on using the Giga holotype or not when it's the only reliable specimen to gauge size with. I know it's somewhat unfair when there are more t rex specimens but the reality is we don't know if those "larger t rexes" are actually the larger than average or even below average ones. Same applies for giga, so again I have to stress that I'm not concluding this fight based on a species level but only what we've got. And it just so happens we have more reliable t rex specimens that are heavier than what we have of Giga. |
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| theropod | Oct 15 2015, 11:04 PM Post #410 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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palaeontology, open source and survival enthusiast
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We have a good idea that they are above average, because the vast majority of specimens are smaller, because we have got some idea of its age structure and know the likes of sue are exceptionately mature for a dinosaur, because we know enough adult T. rex specimens to tell whether something is particularly big for the species or not. In Giganotosaurus we have a holotype with a relatively well-constrained size. Fair enough, this could be a particularly large specimen, just as it could be a particularly small one, but in the absence of any evidence for either the middle ground (average sized) is already the least biased assumption if you must compare them. Also we have got a second specimen, which is larger than the holotype; which makes it all the less likely for it to be particularly large for its species, since then we’d have miraculously found two exceptionately big specimens in a sample of two. If Giganotosaurus bites any theropod’s neck it’s over for that theropod, irrespective of how long (most likely not long!) it takes that animal to die, it will have sustained severe damage to the musculature it needs to even keep holding its head up, it will very quickly go into shock (blood loss has more immediate effects than just the eventual death of the animal) all the more hastened by whatever neurological damage (vagus nerves) will result from such a bite, plus cut carotids equal immediate cessation of blood flow to the brain (actually that is more deadly than a broken spine, though the effects are the same). I.e. for all intends and purposes it is just as effective as a bone shattering T. rex bite. |
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| Spinodontosaurus | Oct 16 2015, 04:57 AM Post #411 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Herbivore
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If we sum up the femur lengths of all the specimens on the Theropod Database with the femur measurement listed (20 specimens), the mean femur length comes out at 127 cm, the same as the holotype specimen CM 9380, a specimen which is probably larger than the Giganotosaurus type specimen. This does exclude a few specimens that are not known from femurs, including some fairly large specimens like UCMP 118742 and MOR 008. Blaze estimated CM 9380 at 7,600 kg by GDI using Scott Hartman's skeletal and a modified version of his dorsal silhouette for Sue. I did the same and achieved an even higher estimate of 7,850 kg, although since my attempt at a GDI of Sue yielded an estimate of 8,750 kg I may be systematically overestimating them, so I prefer to cite Blaze's estimate seeing as he was at least able to replicate Scott Hartman's estimate of 8,400 kg for Sue. Of course, Hartman also estimate the two Giganotosaurus specimens at 6,800 kg and 8,200 kg, which averages out to 7,500 kg. If we assume that CM 9380 approximately represents an average Tyrannosaurus specimen then based on currently known specimens the average Tyrannosaurus and average Giganotosaurus are essentially identical in size. This also holds true if we use the largest known specimen of each instead of trying to find the average. I don't think either animal holds a size advantage here. |
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| Ausar | Oct 16 2015, 05:04 AM Post #412 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Xi-miqa-can! Xi-miqa-can! Xi-miqa-can!
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Agreed. Whether or not it's going to die shortly after the attack, it's not like a Tyrannosaurus is really going to fight back (let alone effectively) once it's sustained such a deadly bite. |
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| Spartan | Oct 16 2015, 06:41 AM Post #413 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Kleptoparasite
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I've just seen the comparison of Scott Hartman. Is it because of their bones that these theropods have such a low density? On the other side I've read that bird bones are rather dense.
Edited by Spartan, Oct 16 2015, 06:41 AM.
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| theropod | Oct 16 2015, 08:01 AM Post #414 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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palaeontology, open source and survival enthusiast
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Bird bones, dense? What would be the point of being hollow if not reducing density (and hence weight)? If you are referring to this→, the study measured the density of the bone tissue itself, not the density of the entire bones in question. That is indeed denser in birds, but that doesn’t mean their skeleton as a whole is. Think of a thin-walled steel (or lead, or gold, some dense material at any rate) tube that’s open on the ends and an aluminium rod of the same thickness and length. If you weigh them, measure the volume of the material itself, and divide mass by volume, the steel rod will have the higher density, because only the parts with the high density will be measured. That’s essentially what the study did. But if you close the ends of the tube and measure its displacement then, and divide mass by that, the overall density of the structure will end up much lower because the air-filled space is included in the volume, just as it is included in the volume of a living animal (such as a dinosaur). Admittedly it wasn’t very well explained in the abstract, without looking at the method for estimating volume one could have thought that it was referring to the entire bone, pneumatic spaces included, but that wasn’t the case, it was essentially a study on the density of their respective bone tissues, not the entire bone. Pneumatisation is widespread throughout saurischia, particularly in derived theropods and sauropods. By default (and with very few exceptions, like penguins and Spinosaurus) these animals should be assumed to have a density markedly lower than water. Actually the 913kg/m³ Hartman assumed still strikes me as rather high, considering he assumed a density of 0.9 for the neck-torso-tigh segment that is very heavily pneumatised (all but one vertebra in this part of the body is pneumatic in Sue). @spinodontosaurus: It seems I can’t replicate your result. I also got 20 (counting sue twice because both femora have slightly different lengths, although we actually should only count it once, and excluding all femora shorter than that of MOR 1125 did the trick for me) but I got a mean of 122cm. That’s broadly consistent (almost exactly the same) with the figure you get from Larson’s dataset, although the resulting animal would be slightly larger (11.4-11.5 vs 11.2m) based on the femur length of sue. > c(128,117,123,111, 129, 126,118, 118, 111, 120, 131, 119, 130, 131, 132, 114, 128,107,128,121)->femora > mean(femora) [1] 122.1 > length(femora) [1] 20 I recalled having attempted the same one other time years ago and also getting a considerably lower result than you did, but my sample then was smaller so I must have overlooked some specimens back then. Edited by theropod, Oct 16 2015, 09:00 AM.
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| Drift | Oct 16 2015, 10:33 AM Post #415 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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High Spined Lizard
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@DarkGricer A shark attack on what? Presumably not one of those photos of a blubbery seal with a notch taken out of his midriff,defenseless preys acquisition has no correlation here when the window of opportunity on an actually formidable opponent wouldn't be an ambush imo. | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| DarkGricer | Oct 16 2015, 11:44 AM Post #416 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Omnivore
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@Drift: Because I totally looked at a shark attacking a seal and said that's exactly what would happen if Giganotosaurus bit a T.rex. Yes, a shark does typically prey on things that are more defenseless then a T.rex. That's what any predator does. The purpose of the comparison was to demonstrate not that Giganotosaurus would remove a tenth of the T.rex's body mass with a single bite, but rather that slicing bites can deal just as much damage as a crushing bite. I mean, a T.rex isn't going to kill a Giganotosaurus on contact either. And if that example still displeases you, well then, can we still agree that slashing someone's throat with a dagger is gonna be just about as fatal as hitting someone's throat with a morningstar, because the concept is similar enough. |
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| Spinodontosaurus | Oct 16 2015, 12:55 PM Post #417 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Herbivore
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@Theropod Ok so this was pretty careless of me but I've found where the discrepancy is coming from. I had 20 femur lengths totalled up, but only divided by 19. Oops. Because the result looked reasonable I didn't catch the mistake, and that result has been sitting in a spreadsheet for months now. That doesn't fix the problem though, because I'm now obtaining a lower estimate than you are, and I count 20 actual specimens without using both of Sue's femur lengths (I'll list the ones I counted at the bottom). Using just the measurements from the Theropod Database, I get a mean of 120.65 cm. If I replace the femur lengths of Stan and the type specimen with those reported by Scott Hartman instead, that mean falls to 120.45 cm. The median femur length is 120.5 cm (there isn't a true middle value, so I had to average out the femur lengths of Black Beauty and LL 12823). Using either CM 9380 or Sue as a guide, this leads to an 'average' Tyrannosaurus being essentially Stan-sized; 11.3 meters and 6,500 kg. Using Stan itself as a guide leads to a much smaller estimate of only 10.6 meters and 5,700 kg (based on Blaze's GDI estimate of 6,850 kg for Stan. I was actually able to replicate this one, with my estimate being 6,900 kg). I'm not sure which is the 'normal' proportioned specimen and which is the outlier. It's complicated further by MOR 980, which has a fairly short femur at just 123 cm, but Scott Hartman restored it at roughly 12 meters long back in 2004, longer than all bar Sue. MOR 1125 also has a very short femur at just 107 cm, but it's cranial material is comparable in size to that of Black Beauty and the Type specimen. There are 6 other specimens on the Theropod Database that have cranial measurements but no femur measurements. These are: AMNH 5027, BHI 4182, LACM 23844, MOR 008, UCMP 118742 and CM 1400. Based on their measurements, all of them are probably Stan-sized at the very least, so our femur-only estimates are probably too low. But by how much? Well, we could assign them some arbitrary femur lengths and see what it does to the median. If we assume that these 6 specimens are all Stan-sized or larger, then we can say they all have femur lengths of 128 cm or more too (for the sake of this anyway). This raises the median femur length to 126.5 cm, which would bring size estimates back up to ~7,500 kg, comparable to Giganotosaurus again. The new median is in between the femur length of specimens MOR 1128 and CM 9380, so as long as we assume the 6 skull-only specimens I listed above have femurs equal to or greater than CM 9380's, then the median will remain 126.5 cm. Specimen list; femur lengths for 'Sue', 'Stan' and the Type based on Scott Hartman's measurements, the rest are taken from the Theropod Database.
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| theropod | Oct 16 2015, 06:40 PM Post #418 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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palaeontology, open source and survival enthusiast
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I see. I didn't include Usnm 6183, and as you see I rounded to the nearest cm, so those results seem consistent. But I find it hard to believe that all specimens without a femur are supposed to be on the big side. Edited by theropod, Oct 16 2015, 06:40 PM.
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| Spinodontosaurus | Oct 17 2015, 01:32 AM Post #419 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Herbivore
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It would be a weird coincidence, but 4 of those 6 specimens have skull bones unquestionably larger than Stan's. One of the ones that does not is CM 1400, who has a maxilla equal in length to Stan, and the other is MOR 008. But MOR 008's skull is quite complete and in my opinion it is clear that it was at least as long as Stan's skull, almost certainly longer, it simply had a proportionally shorter snout (not unlike AMNH 5027 in that regard). Maybe they weren't all on the large size, although I'm struggling to think of a way they couldn't be based solely on the measurements available, but I think it's clear that none of them are on the small side, so my point that our femur only estimates are probably on the low side does remain. |
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| Fist of the North Shrimp | Oct 17 2015, 03:05 AM Post #420 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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vá á orminum
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I do not think that the lenght measurements of long bones are good for estimating individual size/weight. | ||||||||||||||||||||||||||||||||||||||||||||||||||
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