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Giganotosaurus roseae
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Giganotosaurus roseae was a giant carcharodontosaurid theropod from the early Late Cretaceous (late Cenomanian to early Turonian stage) of what is now Argentina.
Just like some of its more famous relatives, G. roseae was one of the largest known theropods, with known specimens indicating an animal substantially heavier than Tyrannosaurus rex and very similar in size to the closely related Giganotosaurus carolinii. This species is commonly considered to be its own genus (Mapusaurus), but because this generic separation is based almost entirely on elements that the G. carolinii holotype does not preserve (making a proper judgement on almost all proposed differentiation between the 2 impossible), with the only differences noted in overlapping material being a less pneumatic quadrate and differently rugose nasals in G. roseae, Mapusaurus being a valid genus remains highly improbable unless a specimen of G. carolinii is discovered proving G. roseae to be generically distinct. Coria and Currie (2006) note the majority of possible adult specimens known are comparable in size to the G. carolinii holotype MUCPv-Ch1 (suggesting these G. roseae individuals were around 12.4 meters in length and 8320 kg), although not with the same exact proportions, having taller and wider neural spines, a more elongate fibula (101 centimetres compared to 98.5 centimetres) but more slender (81-89% the width as in MUCPv-Ch1) and with a differently proportioned skull that was deeper relative to its length. Considering this, a fragmentary maxilla is coherent with the size of the MUCPv-Ch1-sized individual (MCF-PVPH-108.169). A neural arch from an axis (MCF-PVPH-108.83) and a scapular blade fragment are also the same exact size as the same elements in MUCPv-Ch1. Moreover (contrary to popular belief), these aren't the largest remains from the bonebed - a pubic shaft (MCF-PVPH-108.145) 10% larger than that of MUCPv-Ch1 suggests a maximum size of 13.6-13.7 meters long and 11100 kg. Some tibiae (MCF-PVPH-108.68-73) also suggest very large sizes of roughly 12.7-13.2 meters long and 8950-9880 kg. The remains of G. roseae were discovered in a bone bed containing at least seven individuals of various growth stages. Since the bonebed's discovery and first report in 1997, researchers have speculated that this may represent gigantic theropods practicing pack-life (similar to modern carnivores like wolves and lions) and may provide clues about the behavior of this species. Paleontologist Rodolfo Coria, contrary to his published article, repeated in a press-conference the aforementioned earlier suggestions that this congregation of fossil bones may indicate that G. roseae hunted in groups and worked together to take down large prey, like the gigantic sauropod Argentinosaurus. If so, this would be the first substantive evidence of gregarious behavior by large theropods other than tyrannosaurids and Allosaurus, although whether they might have hunted in organized packs (as wolves do) or simply attacked in a mob, is unknown.
G. roseae skeletals by Franoys (top) and Gunnar Bivens (bottom).
Please keep in mind that the given length and weight are almost certainly far, far too low on both (see post #3), so these are here for their anatomical accuracy instead of for their given sizes. I wholeheartedly recommend scaling them to the outlined size estimates in this thread should you need to use them.  *This image is copyright of its original author  *This image is copyright of its original author Giganotosaurus roseae by NamDaoTetanurae.  *This image is copyright of its original author Giganotosaurus roseae mounted skeletons by Kabacchi.  *This image is copyright of its original author Giganotosaurus roseae skull by Neloadino.  *This image is copyright of its original author Giganotosaurus roseae skulls by theropod1.  *This image is copyright of its original author Giganotosaurus roseae from Planet Dinosaur. *This image is copyright of its original author
Just finished editing this into my size estimation post in 'Carnivorous dinosaurs other than the famous t-rex and spinosaurus'. I figure it would be useful to have directly in the animal's profile thread too.
Some of you have, without a doubt, noticed that my size estimates for G. roseae tend to be a lot larger than estimations that can be found elsewhere. Unsurprisingly, because of this, a number of people (both on and outside here) have strongly disagreed with them, suggesting they (at >13 meters and quite large weights) are 'older more out of date estimates', too large to be accurate, or something along those lines. Sources of disagreement that I have so far seen from those people are the following: the estimates being considerably larger than that of Franoys', the estimates being considerably larger than the published literature's maximum estimates that range from 10.2 to 12.7 meters as well as the weights proposed with those estimates, and the specimens in question estimated at >13 meters being fragmentary and not concrete, so the sizes they yield are untenable and should be rejected with what we have now. In that order, here is why my estimates here still stand in the face of all those. My estimates compared to Franoys' estimates: -Franoys assumes that MCF-PVPH-108.145 is simply a MUCPv-Ch1 sized individual with a robust pubis. They have even given an explanation for why they did so in the comments of here (date of April 7, 2018), which is often cited by these people who believe my estimate to be wrong due to its size. (Note that in their explanation are a few statements irrelevant to what I'm looking to demonstrate. They will be the ones that aren't addressed in quote boxes). Quote:Yes, MCF PVPH 108.145 (which is the catalog number used here) is a 7.2 cm long piece of the pubis shaft (important to mention that the whole pubis shaft of these animals would be over 1 meter long), which is 7.5*10 cm wide, a 10% wider (or about 0.75-1 cm wider) than the Giganotosaurus pubis on its narrowest portion; however; we can't posibly know if the portion of the Mapusaurus pubes belongs to the part of the shaft that would actually be narrowest; and the comparison between one and the other is just based on that paper (in which the exact dimensions of Giganotosaurus pubes aren't reported, only the 10% wider figure). This bone is part of the bones my Mapusaurus skeletal is scaled to; as in all likelyhood, there are more remains from this particular individual. The metatarsals suggest a minimum of 7 individuals, all substantially smaller than the Giganotosaurus type; then between the remaining bones several of them suggest an individual of similar size, unless you split each bone into a different specimen and then get at least 6 Giganotosaurus holotype sized individuals. Let's break it down, shall we? Quote:however; we can't posibly know if the portion of the Mapusaurus pubes belongs to the part of the shaft that would actually be narrowest; and the comparison between one and the other is just based on that paper (in which the exact dimensions of Giganotosaurus pubes aren't reported, only the 10% wider figure). Unless Franoys can give any evidence to the contrary, I am strongly inclined to trust the 10% wider figure over absolutely anything else. There is absolutely zero reason to believe this wasn't an apples to apples measurement concerning the same part of MUCPv-Ch1's pubis. Quote:This bone is part of the bones my Mapusaurus skeletal is scaled to; as in all likelyhood, there are more remains from this particular individual. The problem here is that there is literally nothing indicating that this is more likely to be the case than the pubic shaft belonging to its own animal 10% larger linearly than MUCPv-Ch1, and it therefore has zero base to be assumed over a standalone giant MCF-PVPH-108.145 (which does have a base to assume, that being its larger size than other elements). But as stated in the size estimate post, even if we assume out of nowhere that this is the case, the most likely individual (as per what SpinoInWonderland has told me) for it to belong to would be MCF-PVPH-108.73. This animal still appears to be substantially larger in both length and weight than Franoys' size estimate, so it's no argument against G. roseae reaching these >13 meter sizes and very large weights. Quote:There are a number of remains that match very well and when put together, they suggest an animal of almost the same exact dimensions to the Giganotosaurus holotype (the vertebral remains are the same exact size, suggesting the same size for the axial skeleton, or the same body length), just with slightly different proportions, for example a slightly longer but much narrower fibula proportionally, a shorter snout with a head about as deep but narrower and proportionally shorter, etc; which is something that is expected as inter-generic variation. Frankly, this is quite a poor argument. In a group of animals, there is usually going to be size variation that's notably different to the homogeny that Franoys is assuming (don't believe me? Look, for example, at wolf packs or deer herds, this level of size homogeny is nonexistent within them), and there's absolutely no evidence that this size variation within groups did not exist in G. roseae, while the varying measurements of the bones are suggestive that it did indeed exist, as would be expected. So Franoys' suggestion that the amount of MUCPv-Ch1-sized individuals supports MCF-PVPH-108.145 being one of them just doesn't work, owing to the lack of support for it from both other animals and the fossils themselves. There is no evidence of variation between Giganotosaurus species leading to an animal with a robust pubis instead of a giant that only preserves the pubis either. In fact, not only is there no evidence for any variation between the 2 Giganotosaurus species that is significant enough to skew my size estimates for the pubis downward, there's also no evidence that said variation (if it even existed at all) excludes MCF-PVPH-108.145 having a proportionally smaller pubis and thus being even larger than isometry from MUCPv-Ch1 suggests. I'm not suggesting this to have been the case, but there is really nothing suggesting it's any less likely than Franoys' proposal (after all, it cannot simply be assumed a priori that species variation skews dinosaur size downwards). Therefore, given that the varying measurements in the specimens suggests this size variation from MUCPv-Ch1 to have been present and give no evidence for variation between species that skews the estimates downward, all data strongly supports MCF-PVPH-108.145 being its own and very large individual, larger than both MUCPv-Ch1 and Franoys' estimate. Quote:Even if the pubes really was a 10% wider, or even a 10% bigger overall (the last case is what I used for my skeletal, so I asumed a generous scenario that I could revert soon) With all due respect, this statement couldn't be more incorrect. Franoys implies that a 10% larger pubis on a MUCPv-Ch1-sized animal is a generous scenario, but it's actually unrealistically minimalistic in light of the lack of evidence for MCF-PVPH-108.145 to belong to a robust-pubed animal. The scenario most likely to be correct from known data - which is so because no extra assumptions are made beyond what the fossils suggest - is that MCF-PVPH-108.145 is an animal 10% larger linearly and 1/3 more massive than MUCPv-Ch1, with a true generously assumed scenario being that MCF-PVPH-108.145 was an animal more than 10% larger but with a pubis that is smaller relative to the animal's size. Quote:It still makes sense to assign them to the same individual as the other remains considering Mapusaurus and Giganotosaurus are different genera and geological distortion. As stated before, there is absolutely no reason to do or assume any of this over MCF-PVPH-108.145 being its own, giant individual given known data. Unless Franoys would happen to have any, MCF-PVPH-108.145 completely lacks any evidence that its massive size is the result of geological distortion, variation between species, or being a robust-pubed, smaller specimen. Especially considering that (as also stated before) this geological distortion and variation - if it existed - could well make MCF-PVPH-108.145 represent an animal more than 10% larger than MUCPv-Ch1. Quote:(The authors of the paper also cite a size equal to Giganotosaurus, or 12.2 m long as written in the paper; as the maximum size for Mapusaurus) 12.2 meters as a maximum size for G. roseae is directly contradicted by the actual measurements in Coria & Currie (2006), as the size estimate post explains. While I do agree with them on a maximum size equal to that of G. carolinii (seeing as how both MUCPv-95 and MCF-PVPH-108.145 are 10% larger than MUCPv-Ch1 and thus indicate 13.7 meters as a plausible maximum for known specimens of both), there is absolutely no way that I know of to get 12.2 meters as an overall maximum with what's published in regards to measurements. In addition, as can be seen by its not being listed in their estimate, Franoys does not take into account MCF-PVPH-108.73. Why this is I do not know, but as was stated in the size estimate post, taking it into account results in an animal substantially greater in both length and weight than their estimate. My estimates compared to the published literature's estimates between 10.2 and 12.7 meter estimates accompanied with much lower weights: I will deal with 4 estimates here: that for the largest specimen estimated in Coria & Currie (2006), that from Greg Paul, that from Thomas Holtz, and that from Ruben Molina-Perez/Asier Larramendi, in that order. These are most often cited as evidence for my estimates being inaccurate and excessive. -Coria & Currie (2006) estimate a length of 10.2 meters and a weight of 3000 kg for some femora, although these aren't for the same individual. (Side note: even though several of the femora are stated to be adult, no reasoning or justification is given for this. I therefore would consider the age of these specimens, just as with all the bonebed's medium-large individuals, to be unknown unless reasoning is published). As they wrote on pages 103 and 116 respectively, these are the methods behind their weight and length estimates: Quote:The largest of these (MCF-PVPH-108.234) is 1300 mm long, with a shaft circumference of 455 cm. Using the formula developed by Anderson et al. (1985), a conservative weight estimate for this individual would have been 3000 kg. Quote:Estimated lengths (in mm) of animals represented in the Mapusaurus n. gen. bonebed. Calculations based on the relationship between femur length and body length for theropods in which both these values are known (equation is y = 1.0276x + 0.8437, where y is the logarithm of complete body length and x is the logarithm of femur length). Because of the diversity of theropod body forms, these calculations can only be considered as very rough estimates. The problem with the first estimate is that it's based on femur circumference. SpinoInWonderland has written a very good post on his blog about why femur circumference is a very poor choice to estimate size from, and one of his examples (the related Acrocanthosaurus) is actually a fairly useful proxy here - more on that later. Even publications that use femoral circumference (such as the paper on Scotty the T. rex that SpinoInWonderland rightfully condemned) note some animals it really fails on. Interestingly, Acrocanthosaurus is used as an example here as well. Quote:Greater femoral circumference with the capacity to withstand greater locomotor loads, rather than simply greater body mass, merits consideration as an explanation for the discrepancies between femoral lengths and girths in T. rex and G. carolinii. Relative locomotor activity may similarly explain the extreme discrepancies in weight estimations reported for the proportionately slim-femured carcharodontosaurid Acrocanthosaurus atokensis. Notably the 3.5 tonnes femur derived estimation for mass versus 5.5-7 tonnes based on volumetric estimation (Bates et al., 2009). And just as one would expect by what happened with Acrocanthosaurus, this method looks to have failed on G. roseae as well - a volumetric estimate based on MUCPv-Ch1 is considerably larger. MUCPv-Ch1 has a femoral length between 135 cm (page 6) and 136 cm (page 233), that I'll take the mean of, from which we get >7340 kg instead of 3000 kg for the 130 cm G. roseae femur based on my estimate for it (135.5/130(>8320)^3). In addition, this is pleasingly close to the 'correction factor' from femur circumference to volumetric estimates in Acrocanthosaurus - as noted in SpinoInWonderland's blogpost, the Anderson et al. (1985) equations gave 2400 kg to NCSM 14345 compared to the 6177 kg 'best estimate' in Bates et al. As for the 10.2 meter estimate from the length equation, unless any measurements are given for the femur from which it came, it's impossible to verify. But I recommend taking it with a very large grain of salt because measured specimens that have had the equation applied to them are much larger than the equation would suggest when going by the measurements. The length equation gives 8.8 meters for MCF-PVPH-108.202 (a specimen which I estimate at 12.4 meters with published measurements) and 9.8 meters for MCF-PVPH-108.68 (a specimen which I estimate at 12.7 meters with published measurements), so it's likely it's underestimating the femur as well. And the authors even note that the estimates are nothing more than very rough, which certainly doesn't lend credence to said often-cited 10.2 meter maximum. -Greg Paul estimates a maximum length of 11.5 meters, accompanied with a weight estimate of only 5000 kg. I don't know what specimen on which this was based, but it clearly isn't realistic for either of the specimens I estimated at >13 meters, seeing as how both of them are larger than the probably 12.4 meter and >8320 kg MUCPv-Ch1. -Thomas Holtz estimates a maximum length of 12.6 meters (although with no weight estimate). Granted, 12.6 meters does not seem at all unreasonable for some specimens - for one, it's very, very close to my 12.7 meter estimate for MCF-PVPH-108.68. However, there is absolutely zero reason I am aware of to prefer 12.6 meters over 13.7 meters (as well as 13.2 meters) for the larger specimens, seeing as how there is nothing about either those specimens indicating 12.6 meters is more likely than something in the 13-meter range. So with that lack of reason to prefer it over the aforementioned larger sizes, the 12.6 meter maximum estimate is quite unfounded. -Ruben Molina-Perez/Asier Larramendi estimate a maximum length of 12.7 meters and a weight of 7600 kg. Just as I wrote concerning the estimate from Holtz, this length estimate appears more or less on point for some specimens (ie: it matches exactly my estimate for MCF-PVPH-108.68). As a maximum length estimate, however, it doesn't really seem so. There's nothing I'm aware of concerning measurements of MCF-PVPH-108.73 and MCF-PVPH-108.145 that suggests an MUCPv-Ch1 based estimate would yield 12.7 meters instead of 13.2-13.7 meters, so given that the sizes of those specimens support nothing but the >13 meter sizes, it's by far the most likely that that's how big they were. The weight estimate is also suspect - 7600 kg as an absolute maximum is even somewhat lower than my estimate for the average of the possible adult specimens, and over 3500 kg smaller than my estimate for the maximum. What the estimate was derived from I do not know, but I strongly trust my own and much larger estimates given that I can actually reach them with the most current data. There's also one last point applying to all the literature's length and weight estimates that's been partially stated above but probably is best reiterated as an all-encompassing statement: Just because these estimates are in the literature, but my 13.2-13.7 meter, 9880-11100 kg estimates are not, is not a valid reason to prefer the former. At all. The published measurements for the bones themselves are exactly what all of my estimates for the largest G. roseae are based on, and those measurements offer zero support to the 10.2-12.7 meter, 3000-7600 kg maximum. Thus, it's very baseless and unparsimonious to take them as a maximum over my estimates just because they are in the literature. My estimates for >13 meter specimens being not concrete and based on fragments, so they should be discarded for the time being: -While it's true that the specimens are fragmentary and the estimates aren't set in stone, that is no reason to treat these specimens as if they simply did not exist. One person on Quora has said the following (admittedly it deals with the pubic shaft and not the tibia), which nicely represents the overall premise of this point when people who disagree with me voice their disagreement: Quote:The really big size estimates for this animal stem from a big pubic shaft. The big problem however basing this idea on a fragment of the pubic shaft is just not reliable at all. The section of pubic shaft that's 10% thicker but that's it, we don't even have the pubis length. You simply cannot extrapolate an (unusually) large size estimate for a multi-tonne animal, reliably from a fragment measuring merely centimeters. Once there is some concrete evidence that shows Mapusauruus or any big fully terrestrial theropod does actually reach over 13 meters long I will update my work accordingly. But so far there really is nothing concrete. Despite the resulting sizes having to be treated as nothing more than estimates due to the fragmentary nature of the specimens, if they indicate a really big size and there is nothing indicating against said size (as in this case), said size should be assumed even as a simple estimate. In a very similar case to what I noted on Franoys' remarks, it is unparsimonious to assume otherwise. The case to use MCF-PVPH-108.73 instead of discard it is even stronger, as it is a weight-bearing tibia and thus quite reliable to estimate size. Basically, it is fallacious to discard the sizes due to the bones being fragmentary because there is no evidence to the contrary of those sizes and Occam's razor is therefore contradicted by doing so. |
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