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Post by prehistorican on Nov 21, 2017 22:28:48 GMT 5
So does anybody know the AVERAGE adult Megalodon size (length+weight)? I mean in my opinion Megalodon could have possibly reached or exceeded 20m and weighed up to 100 tons at maximum size (Not sure if that is correct or not). So I thought the average size would be around 13-16m 40-50 tons. If so then wouldn't that be on par with the average of a bull sperm whale's 30-50 tons?
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Post by Life on Nov 26, 2017 20:35:31 GMT 5
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Post by creature386 on Nov 27, 2017 15:30:48 GMT 5
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Post by Grey on Dec 22, 2017 11:20:57 GMT 5
Pimiento 2015 proposed some data but the method used appears to be unreliable at best.
There is a strong indication of temporal and regional body size variations, so this appears to be a complex question.
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Post by Infinity Blade on Mar 6, 2018 6:38:42 GMT 5
Pimiento 2015 proposed some data but the method used appears to be unreliable at best. There is a strong indication of temporal and regional body size variations, so this appears to be a complex question. You mean the one that came up with a supposed average size of 10.5 meters or something? Could you tell me more about the issues of the paper? Also, are there any, more recent papers with a more reliable methodology used to estimate the shark’s size? |
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Post by creature386 on Mar 6, 2018 15:04:44 GMT 5
Pimiento 2015 proposed some data but the method used appears to be unreliable at best. There is a strong indication of temporal and regional body size variations, so this appears to be a complex question. You mean the one that came up with a supposed average size of 10.5 meters or something? Yeah, it was that one. I don't know anything more recent. (I know that I haven't been the recipient of the question, but I still answered, as it is quite empty here, so I could be the only one) |
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Post by elosha11 on Mar 11, 2018 22:50:06 GMT 5
Ausar,
Whenever I have the chance, I'll look at Pimiento's paper again. I can't remember for sure, but it may be her research was determining the average size of adults, based on all sharks existing at any one point in time, including juveniles. I believe her research is discussed in detail on some threads in here, so if you do a search for her name, you might find more detailed answers to your question.
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Post by elosha11 on Mar 11, 2018 23:13:10 GMT 5
I see Sam1 and company are going on and on about Livyatan being a comparatively larger animal than Megalodon on carnivora. Certainly seems like a rehash from the same arguments he and others have raised before.
Hard to know if that's true or not, but I'd certainly take any purported estimate of average weights/sizes of the species with a large grain of salt. I'd cautiously state the evidence seems to suggest based on various tooth methodologies that Megalodon reached 18 meters and arguably up to 20 or more meters. The Livyatan holotype has the largest known teeth belonging to this species, and it suggests a length of 13.5 to 17.5 meters. The holotype was probably around the 15 meter mark. There have been other teeth similar to Livyatan holotype, but they have all been smaller, not larger. I will also note that as big/long as Livytan's jaws were, they were significantly more narrow and probably substantially less voluminous than Meg's. But the whale would have certain possible advantages, such as intelligence and or social pod behavior, regardless of whether it was smaller or larger.
It's possible that Livyatan was even bigger on average and at max size than Meg. The opposite is just as likely true. I'd say, very cautiously, that the evidence suggests the shark obtained longer maximum lengths. Comparative weight is almost impossible to know, regardless of any unpublished analysis.
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Post by Grey on Mar 12, 2018 15:47:26 GMT 5
Yup I see the guy bases his argument on comparing artistic depictions of the animals rather than looking at the data.
Sam1 has not improved himself over the years.
The data from Pimiento are most likely erroneous because the Shimada method is not appropriate to use on the Otodus lineage dentitions.
For now, there is no killer sperm whale bigger than the upper estimate from Lambert. 2010. There are good indications, both in the scientific records and in the private collections, of megalodon reaching larger sizes than this, irrespective of the method.
The presence of 40 cm teeth in Chile is irrelevant since the holotype upper teeth, uncomplete but wider than the lowers, may well have been that large.
The Livyatan holotype has a skull width about 2 m. Scaling from GWS specimens, megalodon chondocranium at 17 m may have been significantly wider than this.
Sam1 should come here confront his arguments.
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Post by Grey on Mar 12, 2018 16:46:02 GMT 5
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Post by elosha11 on Mar 13, 2018 19:29:47 GMT 5
Grey, with reference to the size of Livyatan's jaws, isn't the two meter width at the base of the skull, where the jaws are significantly wider? If you look along the length of the the entire mandible - where the animal's bite actually took place - it's much more narrow that 2 meters. I'd say from maybe 1 meter at the front of the mandible up to 1.5 meters at most And of course that's only for the upper mandible. The Livytan's lower mandible is much more narrow than that, less than one meter wide for the entire mandible. Megalodon's classic semicircular bite is as large for both the top and bottom of its jaws, and to me, it's fairly intuitive just by the eye test that Meg would have had a significantly larger bite volume than the whale. Here's a good look at the holotype's jaw size.  As far as 40 cm teeth, are these documented? I've heard this one from Chile is supposed to be 38 cms long along the curve.  |
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Post by creature386 on Mar 13, 2018 19:52:40 GMT 5
Sam1 should come here confront his arguments. I could of course mirror your posts on Carnivora, if you wish, just like I did with the GWS vs saltwater crocodile discussion. Or I just post the link from cambridge.org. |
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Post by Grey on Mar 14, 2018 15:49:41 GMT 5
Elosha, I was only alluding to the bizygomatic width of Livyatan skull, not the most posterior dentition width.
I don't have the the supp data at hand but I remember the max width of the dentition was about 120 cm (Boessennecker refered to a mouth width of 4 feet in his article describing the specimen), need to verify this.
The Calvert Marine Museum meg skeletal reconstruction has a width at its most posterior teeth of 107 cm (source : Stephen Godfrey, private com).
Scaled up at a TL of 18 m would result in a width of 170 cm.
This is probably not the max width as the reconstructed dentition here is somewhat horseshoe shaped.
But I was referring to the skull/head width.
The Livyatan holotype has a bizygomatic width of approx. 2 meters (Lambert 2008).
Based on the Lausanne taxidermised GWS (Maddalenna 2003), a 18 m meg could have a head width of approx. 3 meters.
But this is ultimately irrelevant as, being subject to the same constraints, ecologically and biomechanically, with a similar lifestyle and subject to very high Reynolds number, Livyatan and meg were probably sharing a similar overall bulk at the same length.
Also, contrary to what states Sam1, there is no data suggesting Livyatan was bulkier than Physeter. If anything, the skull of an adult bull Physeter is significantly more voluminous than Livyatan.
With a skull width of 2 m, Livyatan has the same skull width of a 15 m male Physeter. If the Livyatan holotype was actually more around 17-18 m as the upper estimate suggests, then it was in all likelihood not as thickheaded as a a 17-18 m Physeter.
In other words, Physeter, Livyatan and megalodon were most likely similar in mass at similar lengths and comparing artistic renditions is probably not scientifically solid to make a statement.
Creature386, yup you can share my comments.
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Post by Grey on Mar 14, 2018 15:53:01 GMT 5
The 40 cm teeth are just mentionned by Bianucci in his journal. But the holotype itdelf may well have had some upper teeth that long.
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Post by Infinity Blade on Mar 14, 2018 17:42:11 GMT 5
I should mention that since my last post Sam1 expressed his sentiment that O. megalodon was likely closer to 12-13 m on average, acknowledging that the Pimiento study included juveniles in their sample.
Nevertheless, I think he still believes the whale was typically larger. Not that I really care who was bigger than whom.
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