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Post by dinosauria101 on Nov 7, 2019 20:46:04 GMT 5
Here is the ~90° angle. Tricky to place the lower jaw and not to make it look dislocated. But overall I wouldn't dismiss this being a possibility also. Livyatan relied on bite force, no? I believe gaping that wide would be very detrimental if that was the case |
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Post by sam1 on Nov 7, 2019 20:52:51 GMT 5
Here is the ~90° angle. Tricky to place the lower jaw and not to make it look dislocated. But overall I wouldn't dismiss this being a possibility also. Livyatan relied on bite force, no? I believe gaping that wide would be very detrimental if that was the case That was discussed already. Basically there's no clear indications of the gape ratio/bite force correlation. |
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Post by sam1 on Nov 7, 2019 20:55:06 GMT 5
..and one visual comparison attempt. Not perfect but I think it does a good job at putting some things into perspective.  |
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Post by Grey on Nov 9, 2019 16:55:49 GMT 5
sam1Objectively, this comparison gives the best perception of the size of these jaws, both depicts here the width, length and volume.
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Post by sam1 on Nov 9, 2019 19:39:58 GMT 5
sam1 Objectively, this comparison gives the best perception of the size of these jaws, both depicts here the width, length and volume. Objectively, your scaling is way off . Here is a proper take..the heads and arms of the two humans are scaled to roughly the same square unit size.  |
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Post by Grey on Nov 10, 2019 0:44:10 GMT 5
I doubt it is accurate, the young guy seems really massive compared to this. The simple take is to see how typical humans look like in comparison, there is no need to modify the human size to scale to exact same size since these guys certainly don't have the same size.
I hope we are not going to debate about this.
Using the strict lateral view of Livyatan and a human possibly likely inaccurately similar-sized to the other is not going to give a solid view.
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Post by sam1 on Nov 10, 2019 2:21:32 GMT 5
I doubt it is accurate, the young guy seems really massive compared to this. The simple take is to see how typical humans look like in comparison, there is no need to modify the human size to scale to exact same size since these guys certainly don't have the same size. I hope we are not going to debate about this. Using the strict lateral view of Livyatan and a human possibly likely inaccurately similar-sized to the other is not going to give a solid view. ..wait a minute.. You're actually dismissing what is OBVIOUSLY MUCH MORE ACCURATE take of what YOU YOURSELF presented as "objectively giving the best perspective " ?!? I never said my version is perfect, I just tried to make it as objective as possible, correcting the material at hand. Again, it's you who presented this as "the objectively best perspective" while not giving any scale of reference. Notice how much larger the head on the megalodon guy is?! And the only things we can work with here to try some reasonable scaling, are the heads and arms. So now that I used some actual tools in attempt to give as unbiased depiction as possible ( as opposed to your erroneous version) you're deciding to dismiss it. Unbelievable.. |
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Post by Life on Nov 10, 2019 11:11:29 GMT 5
sam1These type of comparisons can be misleading because of following considerations:- 1. Humans are not equal in size. 2. Position of a human relative to a jaw structure in each photo. 3. Accurate comparison is only possible when the two jaw structures are depicted side-by-side in real which might not be happening anytime soon. 4. Accuracy of jaw reconstructions in the case of Megalodon, and the size factor as well. Excellent example in this post: theworldofanimals.proboards.com/post/48736I also pointed out that Megalodon's jaw structure would have biomechanical elasticity factor to stretch to great extent while opening: theworldofanimals.proboards.com/post/48489This is not mathematics - simply scale humans to equal size irrespective of angles and such and viola. Livyatan certainly have a massive jaw structure but it is rather elongated, and not designed to clamp down on something as massive as itself. Teeth in the lower jaw of Livyatan are not pointing upwards but sideways as in to prevent escape of an animal trapped within, this is compatible with efforts to prey upon small-to-medium-sized mysticetes as inferred in Lambart et al (2010). When larger mysticetes arrive in the geological timeline and become more frequent, Livyatan's distribution patterns seem to shrink and the species eventually disappear around 5 mya mark. Of-course, Livyatan could continue to target small-to-medium-sized mysticetes throughout and additional factors might have been involved in driving Livyatan-types to extinction.
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Post by sam1 on Nov 10, 2019 14:22:43 GMT 5
sam1 These type of comparisons can be misleading because of following considerations:- 1. Humans are not equal in size. 2. Position of a human relative to a jaw structure in each photo. 3. Accurate comparison is only possible when the two jaw structures are depicted side-by-side in real which might not be happening anytime soon. 4. Accuracy of jaw reconstructions in the case of Megalodon, and the size factor as well. Excellent example in this post: theworldofanimals.proboards.com/post/48736I also pointed out that Megalodon's jaw structure would have biomechanical elasticity factor to stretch to great extent while opening: theworldofanimals.proboards.com/post/48489This is not mathematics - simply scale humans to equal size irrespective of angles and such and viola. Livyatan certainly have a massive jaw structure but it is rather elongated, and not designed to clamp down on something as massive as itself. Teeth in the lower jaw of Livyatan are not pointing upwards but sideways as in to prevent escape of an animal trapped within, this is compatible with efforts to prey upon small-to-medium-sized mysticetes as inferred in Lambart et al (2010). When larger mysticetes arrive in the geological timeline and become more frequent, Livyatan's distribution patterns seem to shrink and the species eventually disappear around 5 mya mark. Of-course, Livyatan could continue to target small-to-medium-sized mysticetes throughout and additional factors might have been involved in driving Livyatan-types to extinction. Erm..then why did you liked Grey's depiction, which was actually much more misleading? |
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Post by Life on Nov 10, 2019 14:57:18 GMT 5
sam1 These type of comparisons can be misleading because of following considerations:- 1. Humans are not equal in size. 2. Position of a human relative to a jaw structure in each photo. 3. Accurate comparison is only possible when the two jaw structures are depicted side-by-side in real which might not be happening anytime soon. 4. Accuracy of jaw reconstructions in the case of Megalodon, and the size factor as well. Excellent example in this post: theworldofanimals.proboards.com/post/48736I also pointed out that Megalodon's jaw structure would have biomechanical elasticity factor to stretch to great extent while opening: theworldofanimals.proboards.com/post/48489This is not mathematics - simply scale humans to equal size irrespective of angles and such and viola. Livyatan certainly have a massive jaw structure but it is rather elongated, and not designed to clamp down on something as massive as itself. Teeth in the lower jaw of Livyatan are not pointing upwards but sideways as in to prevent escape of an animal trapped within, this is compatible with efforts to prey upon small-to-medium-sized mysticetes as inferred in Lambart et al (2010). When larger mysticetes arrive in the geological timeline and become more frequent, Livyatan's distribution patterns seem to shrink and the species eventually disappear around 5 mya mark. Of-course, Livyatan could continue to target small-to-medium-sized mysticetes throughout and additional factors might have been involved in driving Livyatan-types to extinction. Erm..then why did you liked Grey's depiction, which was actually much more misleading? I liked the way he put the two pictures together and he did try to factor-in [1] and [2] in his comparison - he did give these two considerations a thought. But of-course, his comparison is not perfect. In your case, you made the two people equal and this perspective forced you to position the skull of Livyatan ahead of that of Megalodon while at it. This is not accurate comparison by any measure. The aforementioned considerations are for all, not just you. These should be kept in mind before comparisons are made. Nevertheless, continue to express your thoughts. |
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Post by theropod on Nov 10, 2019 15:45:09 GMT 5
Err what, ahead of that of megalodon? How so? That skull is behind the person, just like the meg jaws are (mostly), if anything more so. Way better than countless comparisons on this thread, where one set of jaws actually is way closer to the camera (and it’s usually the meg jaws). Are you guys telling me that all this time, you weren’t even scaling the humans based on exact measurements, but more based on feeling and appearance and on how much you guessed one of the people was likely bigger than the other? No wonder the comparisons are so inaccurate compared to what you get when actually scaling the jaws to real measurements. This is very misleading, especially since when I see a size comparison, I tend to assume it is accurate to what it is supposed to show, and properly scaled, so I don’t check the scaling on every single one. Obviously, the only really good way to make a comparison is to ignore all of those factors Life listed. Take jaws that you know the dimensions of, easy for Livyatan, slightly trickier for megalodon (but Grey has provided two pictures, one for lateral view, and one for anterior view) and scale them to the appropriate size (summed width of the dentition is the baseline for both jaw size and total body size in this scenario, so tooth row length is relatively well constrained). And yes, this is mathematics, an accurate size comparison must be free of anything that isn’t, otherwise it’s worthless guesswork. But if we insist on scaling based on humans in the frame, humans whose relative sizes we don’t know, are you seriously suggesting that there is no need to actually scale them to the same size? These comparisons demonstrates what that leads to… Roughly accurate (as much as can be using this scaling method), humans in picture scaled to the same size (we do not know which human should be bigger, so we should not make assumptions who is, unless you are saying we know those guys personally): Two photos inserted without any scaling whatsoever, with the human next to the meg jaws quite clearly bigger than the guy next to the Livyatan jaws: As much as I don’t find this way of making comparisons very valuable due to the problems with scaling people and the perspective that’s never really accounted for, I had at least assumed the scaling was based on actual…scaling, rather than complete guesswork. Seems I was wrong not to check, otherwise I’d have noticed the second isn’t even a comparison, it’s two images randomly put next to each other. If we treat the latter as a comparison, the guy next to the megalodon is scaled roughly 30% larger than the one next to the Livyatan when judging from the length of the arms (both shoulder to elbow and elbow to hand). That means if the guy next to the megalodon is a typical 1.8 m male, the guy next to the Livyatan is a 1.4 m dwarf, or if the guy next to Livyatan is 1.8 m, the one next to megalodon is a 2.3 m giant. Yes, I really do hope that there is no need to further discuss this, there just cannot be any justification for something like that.
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Post by Life on Nov 10, 2019 20:14:57 GMT 5
Err what, ahead of that of megalodon? How so? That skull is behind the person, just like the meg jaws are (mostly), if anything more so. Way better than countless comparisons on this thread, where one set of jaws actually is way closer to the camera (and it’s usually the meg jaws). Are you guys telling me that all this time, you weren’t even scaling the humans based on exact measurements, but more based on feeling and appearance and on how much you guessed one of the people was likely bigger than the other? No wonder the comparisons are so inaccurate compared to what you get when actually scaling the jaws to real measurements. This is very misleading, especially since when I see a size comparison, I tend to assume it is accurate to what it is supposed to show, and properly scaled, so I don’t check the scaling on every single one. Obviously, the only really good way to make a comparison is to ignore all of those factors Life listed. Take jaws that you know the dimensions of, easy for Livyatan, slightly trickier for megalodon (but Grey has provided two pictures, one for lateral view, and one for anterior view) and scale them to the appropriate size (summed width of the dentition is the baseline for both jaw size and total body size in this scenario, so tooth row length is relatively well constrained). And yes, this is mathematics, an accurate size comparison must be free of anything that isn’t, otherwise it’s worthless guesswork. But if we insist on scaling based on humans in the frame, humans whose relative sizes we don’t know, are you seriously suggesting that there is no need to actually scale them to the same size? These comparisons demonstrates what that leads to… Roughly accurate (as much as can be using this scaling method), humans in picture scaled to the same size (we do not know which human should be bigger, so we should not make assumptions who is, unless you are saying we know those guys personally): Two photos inserted without any scaling whatsoever, with the human next to the meg jaws quite clearly bigger than the guy next to the Livyatan jaws: As much as I don’t find this way of making comparisons very valuable due to the problems with scaling people and the perspective that’s never really accounted for, I had at least assumed the scaling was based on actual…scaling, rather than complete guesswork. Seems I was wrong not to check, otherwise I’d have noticed the second isn’t even a comparison, it’s two images randomly put next to each other. If we treat the latter as a comparison, the guy next to the megalodon is scaled roughly 30% larger than the one next to the Livyatan when judging from the length of the arms (both shoulder to elbow and elbow to hand). That means if the guy next to the megalodon is a typical 1.8 m male, the guy next to the Livyatan is a 1.4 m dwarf, or if the guy next to Livyatan is 1.8 m, the one next to megalodon is a 2.3 m giant. Yes, I really do hope that there is no need to further discuss this, there just cannot be any justification for something like that.
Both comparisons are problematic. In the photo featuring Megalodon, the guy is standing in front of its jaw structure. In the photo featuring Livyatan, the guy is standing midway on the right side of its jaw structure. And both photos show respective jaw structures from a side-view angle. Additionally, on what grounds are WE assuming that the two guys have equal stature? Comparison from member sam1 position the jaw structure of Livyatan ahead of that of Megalodon by several feet since Livyatan's jaw structure is elongated, assume the two guys to be of equal stature, and this perspective make Livyatan's jaw structure look larger than it actually is since Livyatan's skull is very wide at the backend where eyes would be present (this part is not a true representation of the actual jaw structure of the animal in question). Here is a better view of Livyatan's jaw structure:  - if one wish to look at how broad was the maw factor. Now what should be the size of the Megalodon that must be compared to Livyatan? There are jaw reconstructions of Megalodon in which Livyatan's skull will fit right in (example below). You understand the problems now? These type of comparisons are highly subjective to be honest.  |
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Post by theropod on Nov 10, 2019 22:37:36 GMT 5
Both are in anterolateral view. In both cases, the person in the shot is the same distance from the camera as at least part of the dentition. The guy next to the meg jaws is standing anterior to the jaws at about the level of the anterior teeth, the guy next to the Livyatan jaws is sitting left laterally to it, at about the same distance as the mid-maxillary and mid-dentary teeth. Scaling them based on that seems perfectly reasonable (ignoring the problems with using people for scale), even if the anteriormost teeth of Livyatan were closer to the camera than the closest teeth of meg (which doesn’t seem to be the case anyway), because the distance would at least be the same for where the people are positioned, and they are both positioned in roughly the same distance with regard too the tooth rows. Scaling both based on the size of the person puts at least most of the jaws in both pictures at pretty much the same distance from the camera. This is as good as it gets using the highly imprecise and unreliable method of scaling based on human scalebars (whose sizes we don’t know, and who are seen in different postures and at different angles). But if you think we cannot do this, which I would totally agree with, then the proper course of action would be to not make a comparison using this method at all, not to just randomly scale the person up to a size that is just a total guess. I have already posted multiple size comparisons of their jaw apparata that based on actual measurements of the things being scaled, and that are hence free of all these problems. e.g.  Livyatan’s skull has a restored length of 294 cm, and megalodon jaw reconstructions have certain width, height and jaw perimeter too, so if we scale them to those measurements, there can be no doubt that they are the right size depicted next to each other. But somehow we keep going back to using blurry photographs with only people for scale, for reasons that I fail to comprehend. I wasn’t the one to propose doing that, but if we must do it, the scaling in Sam1’s comparison is the best so far. On what grounds would we assume they do not? The size of the average megalodon would make sense. The above comparison by Sam1 depicts the size of a large female. |
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Post by Life on Nov 11, 2019 16:29:44 GMT 5
Both are in anterolateral view. In both cases, the person in the shot is the same distance from the camera as at least part of the dentition. The guy next to the meg jaws is standing anterior to the jaws at about the level of the anterior teeth, the guy next to the Livyatan jaws is sitting left laterally to it, at about the same distance as the mid-maxillary and mid-dentary teeth. Scaling them based on that seems perfectly reasonable (ignoring the problems with using people for scale), even if the anteriormost teeth of Livyatan were closer to the camera than the closest teeth of meg (which doesn’t seem to be the case anyway), because the distance would at least be the same for where the people are positioned, and they are both positioned in roughly the same distance with regard too the tooth rows. Scaling both based on the size of the person puts at least most of the jaws in both pictures at pretty much the same distance from the camera. This is as good as it gets using the highly imprecise and unreliable method of scaling based on human scalebars (whose sizes we don’t know, and who are seen in different postures and at different angles). But if you think we cannot do this, which I would totally agree with, then the proper course of action would be to not make a comparison using this method at all, not to just randomly scale the person up to a size that is just a total guess. I have already posted multiple size comparisons of their jaw apparata that based on actual measurements of the things being scaled, and that are hence free of all these problems. e.g. Livyatan’s skull has a restored length of 294 cm, and megalodon jaw reconstructions have certain width, height and jaw perimeter too, so if we scale them to those measurements, there can be no doubt that they are the right size depicted next to each other. But somehow we keep going back to using blurry photographs with only people for scale, for reasons that I fail to comprehend. I wasn’t the one to propose doing that, but if we must do it, the scaling in Sam1’s comparison is the best so far. On what grounds would we assume they do not? The size of the average megalodon would make sense. The above comparison by Sam1 depicts the size of a large female. Your comparisons are very well done, never questioned them. I find that Museum Megalodon sculpture questionable though (based on Mako shark) and jaw structure is not realistic either - sharp turns midway which is unrealistic based on actual dental imprints of Megalodon on the bones of whales. Not sure why people even bothered to construct a sculpture like that. Jaw reconstructions cited by me are very well done. Gottfried et al (1996) have also done a decent job. |
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Post by sam1 on Nov 13, 2019 23:36:26 GMT 5
Livyatan holotype vs megalodon based on the 320cm dUJP jaw reconstruction. I made meg with close to 90° gape, and livyatan with around 75°.  |
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