Dakotaraptor
Junior Member
Used to be Metriacanthosaurus
Posts: 193 
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Post by Dakotaraptor on Jul 8, 2022 14:26:14 GMT 5
Yup, the remains may also have a big impact on future reconstructions of Giganotosaurus and other advanced carcharodontosaurids. Even the authors estimated the Giganotosaurus holotype's skull length of ~163 cm, based on Meraxes.
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Post by tyrannasorus on Sept 4, 2023 7:14:46 GMT 5
Thoughts on E.D copes size?
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Post by Infinity Blade on Sept 4, 2023 18:51:52 GMT 5
Thoughts on E.D copes size? I mean, the error bars are something to keep in mind here, but I honestly don't have a problem with some adult T. rex specimens reaching 10 or more metric tons, considering we have some specimens that probably approach such sizes anyway. To me, the question isn't "Could T. rex reach this size?" and more "Did this particular specimen reach this size?". The error bars alone are enough to make me feel a bit "Meh, it could still have been smaller, but huge in any case", more so than the Cope's fragmentary nature (the fact that they seem to have an intact femur isn't so bad). I'm honestly more curious about this Bertha specimen, which is apparently coming out with an actual paper. A worse crime IMO is the fact that they decided to name this awesome beast after Edward Drinker Cope; it deserves better lol. |
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Post by tyrannasorus on Sept 5, 2023 5:43:38 GMT 5
That’s pretty much how I feel since the size range in the video varies from 9.6 to almost 15 metric tons. But it wouldn’t be too much of a suprise if cope did weigh that much. I guess we’re just waiting on Bertha now. On a side note the possibility of the largest rex specimen being called Bertha is just  |
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Post by theropod on Sept 5, 2023 21:38:14 GMT 5
Yeah I noticed that specimen too in Paul et al.’s dataset. It is not all that fragmentary either. Besides the femur, there are also several skull parts (including a maxilla and dentary) as well as vertebrae and ribs. The femur is just the only part for which measurements have been reported (matter of fact, the femur wasn’t even listed in Larson’s original report on the specimen, which makes one wonder what else there might be in terms of additional material).
However it should not be completely ignored that the only other measurement that has been published (femur length) isn’t exceptionately large, and that none of the other remains have ever been noted to be of exceptional size either. T. rex specimens turning out to be larger than indicated by initial reports happens occasionally (see Scotty), but more commonly the opposite is true, and specimens are proclaimed to be the largest in the world only for actual measurements to show rather unambiguously that they are not (MOR 008, UCMP 137538, UCMP 118742).
Since this femur seems to be the most robust of any T. rex, but not exceptionally long, it would be worth checking if any of the other available remains can corroborate it being of exceptional size.
As for the size range from the video being that wide, I think that is mostly due to using different people’s mass estimates for more complete specimens, Dan Folkes’ most recent one seems to be about 2 tons higher than Hartman’s for the same individual (and this is nothing T.rex specific, his estimate for the Giganotosaurus holotype is also 2 t higher than Hartman’s), so that’s how you get to such a large mass range, nothing inherent about the specimen in question or it being too fragmentary.
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Post by Infinity Blade on Sept 5, 2023 23:48:11 GMT 5
Yeah I noticed that specimen too in Paul et al.’s dataset. It is not all that fragmentary either. Besides the femur, there are also several skull parts (including a maxilla and dentary) as well as vertebrae and ribs. The femur is just the only part for which measurements have been reported (matter of fact, the femur wasn’t even listed in Larson’s original report on the specimen, which makes one wonder what else there might be in terms of additional material). However it should not be completely ignored that the only other measurement that has been published (femur length) isn’t exceptionately large, and that none of the other remains have ever been noted to be of exceptional size either. T. rex specimens turning out to be larger than indicated by initial reports happens occasionally (see Scotty), but more commonly the opposite is true, and specimens are proclaimed to be the largest in the world only for actual measurements to show rather unambiguously that they are not (MOR 008, UCMP 137538, UCMP 118742). Since this femur seems to be the most robust of any T. rex, but not exceptionally long, it would be worth checking if any of the other available remains can corroborate it being of exceptional size. As for the size range from the video being that wide, I think that is mostly due to using different people’s mass estimates for more complete specimens, Dan Folkes’ most recent one seems to be about 2 tons higher than Hartman’s for the same individual (and this is nothing T.rex specific, his estimate for the Giganotosaurus holotype is also 2 t higher than Hartman’s), so that’s how you get to such a large mass range, nothing inherent about the specimen in question or it being too fragmentary. I wouldn't be surprised at all if E.D. Cope was indeed less massive than its femur circumference suggests. But from a biomechanical perspective, I do think having an exceptionally thick femur that also wasn't especially long would actually help with the animal's ability to bear massive weights. A shorter but thicker bone is a stouter, stronger bone, after all. Then again, if Cope were just less massive overall, it could be that having a relatively robust femur was a locomotory adaptation, increasing its limb bone strength and overall athleticism (which makes me wonder why other T. rex specimens, like Stan, seemingly have more gracile femora that would seem to limit their athleticism). This is all speculative, of course. |
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Post by theropod on Oct 1, 2024 3:02:28 GMT 5
If you search the paleo-scaling channel in Spinoinwonderland's server for "On the subject of obscure gigantic theropods, Camp (1935) described a femur shaft from the upper Shaxiamiao Formation 20 cm across in midshaft width." you should find the February 26 message that starts the discussion on the specimen's size. The discussion goes until February 29. I am not necessarily in favor of the 16 ton estimate (seeing as how Spinoinwonderland doesn't seem to be in favor of it), but 16 tons is within the range of possible estimates. Oh wow, that is interesting. Like spino, I also can’t seem to find a pdf of camp 1935 anywhere (if anyone can, that would be interesting). This was the cited source however, and luckily it includes the figure: www.fossilcrates.com/blogs/news/larger-than-tyrannosaurus-rex Based on the included figure and assuming the preserved portion is 200 mm wide, we can actually estimate the femur circumference at about 556 mm and the eccentricity at 155/106=1.46, at least the way it is reconstructed in the figure (which seems reasonable). Based on the phylogenetically corrected cQE with appropriate eccentricity correction (see MASSTIMATE package and Campione et al. 2014) that suggests a mid-point mass estimate of 6.9 t (error range 5.2-8.7 t). That’s huge, bigger than the Giganotosaurus holotype (for which the estimate using the same method is 6.2 t), and indeed a femur circumference similar to a really large T. rex specimen, although it is still a far cry from 16 tons.
This should probably be further examined by comparison with actual Yangchuanosaurus morphology, that being said I am fairly confident a single fragment of femur shaft like this one won’t be diagnostic on the genus level (but obviously a metriacanthosaur would be the most likely candidate given the provenance).
-- Camp, C.L., 1935. Dinosaur remains from the Province of Szechuan. Bulletin of the Department of Geology of the University of California 23: 467-471.
Campione, N.E. 2020. MASSTIMATE: body mass estimation equations for vertebrates. R package version 2.0-1. CRAN.R-project.org/package=MASSTIMATE. Campione, N.E., Evans, D.C., Brown, C.M. and Carrano, M.T. 2014. Body mass estimation in non-avian bipeds using a theoretical conversion to quadruped stylopodial proportions. Methods in Ecology and Evolution 5 (9): 913–923. |
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Post by dinosauria101 on Oct 1, 2024 6:13:17 GMT 5
If you search the paleo-scaling channel in Spinoinwonderland's server for "On the subject of obscure gigantic theropods, Camp (1935) described a femur shaft from the upper Shaxiamiao Formation 20 cm across in midshaft width." you should find the February 26 message that starts the discussion on the specimen's size. The discussion goes until February 29. I am not necessarily in favor of the 16 ton estimate (seeing as how Spinoinwonderland doesn't seem to be in favor of it), but 16 tons is within the range of possible estimates. Oh wow, that is interesting. Like spino, I also can’t seem to find a pdf of camp 1935 anywhere (if anyone can, that would be interesting). This was the cited source however, and luckily it includes the figure: www.fossilcrates.com/blogs/news/larger-than-tyrannosaurus-rexBased on the included figure and assuming the preserved portion is 200 mm wide, we can actually estimate the femur circumference at about 556 mm and the eccentricity at 155/106=1.46, at least the way it is reconstructed in the figure (which seems reasonable). Based on the phylogenetically corrected cQE with appropriate eccentricity correction (see MASSTIMATE package and Campione et al. 2014) that suggests a mid-point mass estimate of 6.9 t (error range 5.2-8.7 t). That’s huge, bigger than the Giganotosaurus holotype (for which the estimate using the same method is 6.2 t), and indeed a femur circumference similar to a really large T. rex specimen, although it is still a far cry from 16 tons.
This should probably be further examined by comparison with actual Yangchuanosaurus morphology, that being said I am fairly confident a single fragment of femur shaft like this one won’t be diagnostic on the genus level (but obviously a metriacanthosaur would be the most likely candidate given the provenance).
-- Camp, C.L., 1935. Dinosaur remains from the Province of Szechuan. Bulletin of the Department of Geology of the University of California 23: 467-471.
Campione, N.E. 2020. MASSTIMATE: body mass estimation equations for vertebrates. R package version 2.0-1. CRAN.R-project.org/package=MASSTIMATE. Campione, N.E., Evans, D.C., Brown, C.M. and Carrano, M.T. 2014. Body mass estimation in non-avian bipeds using a theoretical conversion to quadruped stylopodial proportions. Methods in Ecology and Evolution 5 (9): 913–923. I did some rereading of the conversation. Did not see it until now, but Palaeos looks to have found a PDF, hope this helps: file:///C:/Users/16475/Downloads/Camp_1935_-_dino_remains_from_Szechuan_China.pdf There definitely is a volumetric-favoring discrepancy between the femur circumference estimates you are using and the up to 16 ton volumetric estimates Spinoinwonderland was talking about, but even being deliberately minimalistic to play devil's advocate, the very lowest of the femur circumference estimates for this theropod would be right within the size range of an African bush elephant bull. Very impressive for a likely metriacanthosaur.  (This is probably off-topic, but I think this specimen would be a great protagonist in a Trilogy of Life-style documentary about Late Jurassic China alongside other undepicted/underdepicted Jurassic Chinese dinosaurs like the first ceratopsians and tyrannosauroids, Argentinosaurus sized mamenchisaurids, color-preserving dinobirds, and extra-spiky stegosaurs. Certainly would be a better time and place for a palaeodocumentary than Hell Creek.) |
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Post by theropod on Oct 1, 2024 6:47:52 GMT 5
I’m afraid you just sent the file path as a text, but thanks for trying  I went back to the discord thread and found it myself. Anyone who needs the file, I can email it. Well, he does acknowledge those aren’t very probable, but yes, as I said it should be looked into more, I am not saying that this femur circumference-based estimate is the best, it’s just another data point. It seems Spino already did estimates based on relative femur widths in other Metriacanthosaurs and carcharodontosaurids, although I think we need a better idea to how femur width scales with femur length in allosauroids. One caveat that I get the impression he was not considering is that the Tyrannotitan holotype and paratype have (mediolateral) femur midshaft widths of 260 and 295 mm respectively according to the supplement of Canale et al. (for anteroposterior widths of 149 and 160 mm respectively). If true, that would be far larger than this fragment (and larger than any other theropod). However I am not entirely sure what is going on there, as those measurements are totally inconsistent with the listed circumferences, and those reported elsewhere (they would give femur circumferences of 654 and 730 mm using the ramanujan approximation, the reported values are 514 and 541 mm). Perhaps there is some sort of typo in Canale et al… I fully agree. Jurassic China has been featured a few times, but usually with a strong focus on small maniraptorans like Epidexipteryx or Anchiornis. Sinraptor has actually made a number of guest appearances as the generic carnosaurian antagonist, but it was never given any real focus and never done particularly well (usually as some sort of boring carbon-copy of Allosaurus, sometimes quite literally – see life on our planet–, when really its morphology is quite distinct). Yangchuanosaurus, despite being a huge, impressive and unique-looking theropod, has never appeared at all, neither (as of my knowledge) has Mamenchisaurus, despite being an iconic and unique animal. It would be high time for these things to be given their time in the limelight. |
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Post by dinosauria101 on Oct 1, 2024 17:33:00 GMT 5
If you search the paleo-scaling channel in Spinoinwonderland's server for "On the subject of obscure gigantic theropods, Camp (1935) described a femur shaft from the upper Shaxiamiao Formation 20 cm across in midshaft width." you should find the February 26 message that starts the discussion on the specimen's size. The discussion goes until February 29. I am not necessarily in favor of the 16 ton estimate (seeing as how Spinoinwonderland doesn't seem to be in favor of it), but 16 tons is within the range of possible estimates. to be fair, that estimate was based on some wonky scaling that got a 163 cm femur estimate ( I don't remember exactly how it was obtained but it wasn't taken very seriously ) Edit: more plausible FL estimates are the original 140 cm and 133 cm from Mortimer. These get from 10-13 tonnes scaling from Yangchuanosaurus with FL of 95 cm. However, IIRC you can get him as low as 7-8 t if you take the alternate femur measurement of yang which is I think between 110-120 cm. On one hand, a larger femur like this does make yang look more like a typical theropod instead of having tiny legs like a Spinosaurus when you edit Dan's skeletal, but the 95 cm comes from the original description. and also just because it looks more plausible does not mean it is It wasn't based on a 163 cm estimate, rather a 152 cm estimate. Here's what Spinoinwonderland said. 152 cm was also based on Spinoinwonderland superimposing the femur shaft on a complete Yangchuanosaurus femur.  Even if the 16 ton estimate derived from the 152 cm length estimate wasn't taken very seriously, the fact that the 152 cm estimate itself was made with superimposing would if anything suggest to me that it is at least as if not more plausible than 133-140 cm (keep in mind it was a lower-bound from a range of up to 180 cm). And Spinoinwonderland seems to consider the 110-120 cm femur length to be dubious for these reasons. I would agree with him. Regardless of what the femur length is, though, Spinojnwonderland did point out a considerable issue with <10 ton estimates. I don't really want to pass judgement on a specific estimate (as theropod said this should be looked into more), but I figured it would be useful to make sure you are aware of the issues. |
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Post by razor45dino on Oct 1, 2024 22:40:17 GMT 5
to be fair, that estimate was based on some wonky scaling that got a 163 cm femur estimate ( I don't remember exactly how it was obtained but it wasn't taken very seriously ) Edit: more plausible FL estimates are the original 140 cm and 133 cm from Mortimer. These get from 10-13 tonnes scaling from Yangchuanosaurus with FL of 95 cm. However, IIRC you can get him as low as 7-8 t if you take the alternate femur measurement of yang which is I think between 110-120 cm. On one hand, a larger femur like this does make yang look more like a typical theropod instead of having tiny legs like a Spinosaurus when you edit Dan's skeletal, but the 95 cm comes from the original description. and also just because it looks more plausible does not mean it is It wasn't based on a 163 cm estimate, rather a 152 cm estimate. Here's what Spinoinwonderland said. 152 cm was also based on Spinoinwonderland superimposing the femur shaft on a complete Yangchuanosaurus femur. Even if the 16 ton estimate derived from the 152 cm length estimate wasn't taken very seriously, the fact that the 152 cm estimate itself was made with superimposing would if anything suggest to me that it is at least as if not more plausible than 133-140 cm (keep in mind it was a lower-bound from a range of up to 180 cm). And Spinoinwonderland seems to consider the 110-120 cm femur length to be dubious for these reasons. I would agree with him. Regardless of what the femur length is, though, Spinojnwonderland did point out a considerable issue with <10 ton estimates. I don't really want to pass judgement on a specific estimate (as theropod said this should be looked into more), but I figured it would be useful to make sure you are aware of the issues. "It wasn't based on a 163 cm estimate, rather a 152 cm estimate. Here's what Spinoinwonderland said." It was a while ago, so I may have misremembered some numbers, yes. "Even if the 16 ton estimate derived from the 152 cm length estimate wasn't taken very seriously, the fact that the 152 cm estimate itself was made with superimposing would if anything suggest to me that it is at least as if not more plausible than 133-140 cm (keep in mind it was a lower-bound from a range of up to 180 cm). So far, around ~150-180 cm, although the ~160-180 cm estimates based on "S." hepingensis and S. dongi are probably excessive" Sure, but at least from my experience, finding size using scale bars or drawings have notoriously led to inflated estimates at times ( including the infamous UCMP 137538, if I remember correctly ), and are a source of numerous giant sizes for various creatures that I'm also skeptical of ( 15 tonne deinosuchus, 22 t palaeoloxodon, for example ). "And Spinoinwonderland seems to consider the 110-120 cm femur length to be dubious for these reasons. I would agree with him." I agree that 120 cm does look very unlikely at first, but above 95 cm can seem more plausible once you look at reconstructions of yang, the two specimens. Going off of spino’s skeletal of yang, the smaller specimen would predict a ~101 cm femur for the bigger based off the lengths, which does lend credence to the original 95 cm measurement ( after all 101 isn't that far from 95 and individual variation is a thing ) however if you go by Dan’s skeletal who also uses the 95 cm measurement, you can see the difference in proportion between the two specimens, a 110 cm femur would make the larger yang look far less short limbed and more on the lines of a typical theropod. Scaling from the size of the smaller Yang by his reconstruction ( assuming its femur is 85 cm ) the larger Yang would actually be predicted to have a 116 cm femur if it had the same proportions! Now there is a caveat here and it is that the smaller specimen is apparently a subadult, but idk how metriacanthosaur ontogeny works. I also don’t know how there is such a discrepancy between Dan’s estimate and Spino’s estimate. Note that i’m not saying that 95 cm femur is less likely than a larger fl, just that there is some justification to believe the larger size. Edit: something may or may not work in favor of the larger FL measurement, is that using that and scaling to 140 cm actually gets it to be almost exactly 7 tonnes, perfectly lining up with the allometry estimate... www.deviantart.com/spinoinwonderland/art/Yangchuanosaurus-shangyouensis-skeletals-600792863www.artstation.com/artwork/8e43Pn |
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Post by dinosauria101 on Oct 1, 2024 23:01:06 GMT 5
It wasn't based on a 163 cm estimate, rather a 152 cm estimate. Here's what Spinoinwonderland said. 152 cm was also based on Spinoinwonderland superimposing the femur shaft on a complete Yangchuanosaurus femur. Even if the 16 ton estimate derived from the 152 cm length estimate wasn't taken very seriously, the fact that the 152 cm estimate itself was made with superimposing would if anything suggest to me that it is at least as if not more plausible than 133-140 cm (keep in mind it was a lower-bound from a range of up to 180 cm). And Spinoinwonderland seems to consider the 110-120 cm femur length to be dubious for these reasons. I would agree with him. Regardless of what the femur length is, though, Spinojnwonderland did point out a considerable issue with <10 ton estimates. I don't really want to pass judgement on a specific estimate (as theropod said this should be looked into more), but I figured it would be useful to make sure you are aware of the issues. Even leaving aside that this doesn't necessarily equate to scalebars/drawings being inherently prone to giving inflated estimates, the size estimate Spinoinwonderland was talking about is based on scaling to the written measurement of a 20 cm wide femoral shaft. Unless there is reason to question said written measurement, I don't see a reason to be specifically concerned with inflation. I am not the expert here but allometry would predict that theropod legs usually get shorter as they grow. This would lend credence to the 95 cm femur length above 101 cm plus for the adult, as it would come out to proportionally shorter than the subadult. Even if the femoral length was 140 cm*, I wouldn't say it does. The problem here is that volumetric estimates for these allosauroids often tend to be much higher than allometry because they are less cursorial than say tyrannosaurids (see volume vs allometry for Acrocanthosaurus and Giganotosaurus), suggesting that unless Yangchuanosaurus was notably cursorial for an allosauroid we would not expect the 2 types of estimates to be that closely correlated. *What I mean by this is that the Yangchuanosaurus-based estimate would be 152 cm as gone over above. That would come out to 9 tons instead of 7 tons, and considering what Spinoinwonderland said about <10 ton sizes - which you haven't specifically refuted - I'd still be inclined to go with >10 tons if I were to pass judgement on an estimate. And then after all this, the fact remains that (at least as far as I know) there is not even a direct source for a >95 cm measurement, shedding further doubt on it. If you happen to know of one, please share it. |
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Post by razor45dino on Oct 1, 2024 23:45:38 GMT 5
Even leaving aside that this doesn't necessarily equate to scalebars/drawings being inherently prone to giving inflated estimates, the size estimate Spinoinwonderland was talking about is based on scaling to the written measurement of a 20 cm wide femoral shaft. Unless there is reason to question said written measurement, I don't see a reason to be specifically concerned with inflation. I am not the expert here but allometry would predict that theropod legs usually get shorter as they grow. This would lend credence to the 95 cm femur length above 101 cm plus for the adult, as it would come out to proportionally shorter than the subadult. Even if the femoral length was 140 cm*, I wouldn't say it does. The problem here is that volumetric estimates for these allosauroids often tend to be much higher than allometry because they are less cursorial than say tyrannosaurids (see volume vs allometry for Acrocanthosaurus and Giganotosaurus), suggesting that unless Yangchuanosaurus was notably cursorial for an allosauroid we would not expect the 2 types of estimates to be that closely correlated. *What I mean by this is that the Yangchuanosaurus-based estimate would be 152 cm as gone over above. That would come out to 9 tons instead of 7 tons, and considering what Spinoinwonderland said about <10 ton sizes - which you haven't specifically refuted - I'd still be inclined to go with >10 tons. And then after all this, the fact remains that (at least as far as I know) there is not even a direct source for a >95 cm measurement, shedding further doubt on it. If you happen to know of one, please share it. "Even leaving aside that this doesn't necessarily equate to scalebars/drawings being inherently prone to giving inflated estimates, the size estimate Spinoinwonderland was talking about is based on scaling to the written measurement of a 20 cm wide femoral shaft. Unless there is reason to question said written measurement, I don't see a reason to be specifically concerned with inflation." What I was alluding to there wasn’t exactly that using scale bars and drawings to find size always leads to gigantic size estimates, rather that one should be cautious when using them as there have been multiple instances where the scale bars were off for particular drawings and scales. "I am not the expert here but allometry would predict that theropod legs usually get shorter as they grow. This would lend credence to the 95 cm femur length above 101 cm plus for the adult, as it would come out to proportionally shorter than the subadult." Neither am I, and I wouldn’t be shocked if it were the case, but going off Dan’s that’s a difference of over 22% linearly, and also may call into question that the femurs are supposedly gracile instead of actually being robust, because then the nearly 4 tonne creature could have problems with locomotion. Also consider that the femur could also only be say 108 cm or about 7% smaller linearly and still look like a regularly proportioned theropod. (Also, side note if they really have gotten smaller legs when increasing size that would suggest that our size estimates for the big one would be UNDERESTIMATES because his body would be even larger in comparison to his femur) " and considering what Spinoinwonderland said about <10 ton sizes - which you haven't specifically refuted - I'd still be inclined to go with >10 tons." I don’t know much about this topic of shaft width robustity, but if some of these scalings are getting <10 i guess that would inadvertently suggest they are? "Even if the femoral length was 140 cm*, I wouldn't say it does. The problem here is that volumetric estimates for these allosauroids often tend to be much higher than allometry because they are less cursorial than say tyrannosaurids (see volume vs allometry for Acrocanthosaurus and Giganotosaurus), suggesting that unless Yangchuanosaurus was notably cursorial for an allosauroid we would not expect the 2 types of estimates to be that closely correlated. *What I mean by this is that the Yangchuanosaurus-based estimate would be 152 cm as gone over above. That would come out to 9 tons instead of 7 tons, and considering what Spinoinwonderland said about <10 ton sizes - which you haven't specifically refuted - I'd still be inclined to go with >10 tons." yeah I agree with this, which is also why I said this may or may not work in it's favor, I just brung it up as it's a neat coincidence. "And then after all this, the fact remains that (at least as far as I know) there is not even a direct source for a >95 cm measurement, shedding further doubt on it. If you happen to know of one, please share it." AFAIK, the 110 cm measure comes from Molina-Perez and the 120 cm comes from Carrano ( 2006 ) By the way, if anyone is interested, someone I know from a discord server( name, dino_w )has made his own allometry calculator that seems to be more in line with volumetric estimates than others. docs.google.com/spreadsheets/d/104eb01OUY-To1S8-a15XMRRZFDnEmppOUe1DCRZVZao/edit?gid=0#gid=0 Also, the reason why allometry underestimates bipeds is apparently because it incorporates the femur allometry of birds into it. And the bone wall of bird femurs is very thin. If you used femur allometry based on human femurs, the difference would be much smaller Also, i'm asking because I don't know, is there a different method of calculating circumference of different theropod groups based on shaft width? because a 20 cm shaft width is larger than those of Sue's femora, but according to what theropod got, the femur circumference is lower. EDIT: I found out where the 163 cm measurement was from. It's actually scaled off Sinraptor measurements ( 98 cm FL, 12 cm shaft width ) and going off the photo of it it gets almost 2 meters for camps... On that note Sinraptor also suggest higher femur size for Yang, IIRC which is about 8 meters yet has higher FL than a 10.5 meter yang? naturalhistory.si.edu/sites/default/files/media/translated_publications/Gao_92a.pdf |
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Post by dinosauria101 on Oct 2, 2024 0:53:20 GMT 5
I actually lost interest in this topic about 5 minutes after I edited my comment, lol. Sorry to sound like a buzz kill but if anyone will continue the conversation with you, it's not going to be me.
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Post by theropod on Oct 2, 2024 3:35:10 GMT 5
Actually quite the opposite. That inflated estimate was based on comparing a measurement for greatest length of a phalanx to a measurement of articular length for the presumed equivalent phalanx in Sue. Analyzing the figure (there was never a drawing in that discussion) was what led to the conclusion that the inflated size estimate for that specimen was based on misunderstanding the measurement and wrongfully assuming them to be euivalent, something since confirmed by actual measurements.
Estimates based on figures and scalebars can indeed be problematic though, but the femur fragment in question actually has a relatively unambiguous measurement stated in the text of Camp et al., a midshaft width of 20 cm. So that part at least is fairly straightforward. Like with other obscure giant theropods (e.g. AMNH 5767), it would certainly be worth trying to look for the specimen and establishing that it can still be physically found and that the measurements and description are correct.
It would be somewhat circular to use one’s own scepticism of estimates derived from a method as evidence of its unreliability. I have not reviewed these estimates in detail (although I concur that the evidence suggests Deinosuchus is likely the biggest crocodyliform), but if there is something wrong with scale bars and figures that led to these estimates then that should be clearly demonstrable for those specific cases.
I agree though that an estimate based only on a scalebar can be quite problematic. Whenever possible it should be cross-validated against other figures and other scalebars (to see if they match up or contradict each other) or, better yet, measurements given in the text. That seems to be the case here, the measurement is from the text.
EDIT: oh sorry, I think I erroneously thought you were discussing the giant femur fragment with that statement.
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