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Post by creature386 on Jul 14, 2013 16:54:48 GMT 5
But if it is something private, they would say so in the publication (did they do so?).
EDIT: Reply to theropod.
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Post by Grey on Jul 14, 2013 16:55:58 GMT 5
But if it is something private, they would say so in the publication (did they do so?). That's right and they didn't. Hubbell's material is always referred and credited in various publications for example.
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Post by theropod on Jul 14, 2013 16:59:33 GMT 5
^I'm not suggesting they reflect the largest size. It doesn't appear feasible that Bertucci's 19,4cm tooth was that size when Hubbel's 18,4cm one already appears a bit bigger. Sorry, didn't know about the history of Hubbel's tooth.
It could be in a museum collection. It simply isn't noted where that tooth is from. If it was owned by the researchers themselves, that should have been noted too.
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Post by Grey on Jul 14, 2013 17:05:04 GMT 5
^I'm not suggesting they reflect the largest size. It doesn't appear feasible that Bertucci's 19,4cm tooth was that size when Hubbel's 18,4cm one already appears a bit bigger. It could be in a museum collection. It simply isn't noted where that tooth is from. If it was owned by the researchers themselves, that should have been noted too. If it is was owned by them, i don't know if they would have precised it, but I do know that they would precise if the tooth was part of a private collection. But at the end this is not relevant of the thread. BTW I would avoid to use Bertucci tooth as 19.4 cm represents slant height. If the the scientific measurement is not slant height, then we don't have indication of its vertical size. Kent says in the Parotodus paper that the largest reliably (scientifically then) measured meg tooth is 18 cm high, precising the source is Robert Purdy through pers. communication. If so, what is that tooth then ? Perhaps one of Bertucci's findings ?
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Post by Grey on Jul 14, 2013 17:13:08 GMT 5
Theropod, if you have access to that page, could you post that part in the Meg size thread please, I don't have access to it in my country. Or at least send me it through PM...
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Post by creature386 on Jul 14, 2013 17:25:11 GMT 5
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Post by theropod on Jul 14, 2013 17:28:38 GMT 5
^I'm not suggesting they reflect the largest size. It doesn't appear feasible that Bertucci's 19,4cm tooth was that size when Hubbel's 18,4cm one already appears a bit bigger. It could be in a museum collection. It simply isn't noted where that tooth is from. If it was owned by the researchers themselves, that should have been noted too. If it is was owned by them, i don't know if they would have precised it, but I do know that they would precise if the tooth was part of a private collection. But at the end this is not relevant of the thread. BTW I would avoid to use Bertucci tooth as 19.4 cm represents slant height. If the the scientific measurement is not slant height, then we don't have indication of its vertical size. Kent says in the Parotodus paper that the largest reliably (scientifically then) measured meg tooth is 18 cm high, precising the source is Robert Purdy through pers. communication. If so, what is that tooth then ? Perhaps one of Bertucci's findings ? I only used the slant height as an indication of how much larger that tooth might be. Interesting enough, a 19.4cm-slant-lenght specimen when using the ratio seen in Hubbel's tooth ends up at exactly 18cm, so this could be the tooth in question, but we need confirmation of how large it really is in perpendicular height since the shape is not always exactly the same. Anyway it seems we can use the 18cm as maximum since it is significantly longer than Hubbel's tooth and could correspond to the biggest reported lenght-measurement. I'll send you some screenshots of Renz' book.I've E-mailed them to you.
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Post by Grey on Jul 14, 2013 17:39:53 GMT 5
Yes I wondered too about that. However, I doubt that Purdy has measured any specimen owned by Bertucci, but that's an interesting point. Thank you (you and creature).
If paleontologists use perpendicular height and not slant height measurements, it is interesting to note the gigantic teeth Brett Kent once observed in a private collection in Chile. He did not measure it, but I know that a rumor of a 20.3 cm tooth persists in the region and and talking of this with him, Brett acknowledged that this tooth certainly approached that size. It barely fit in a cigare box as he said. If Brett Kent was thinking about a perpendicular measurement, that specimen whatever its actual size may be huge. I should ask him if he owns a photo...
Regarding Mark Renz book, I think Renz made an error about the calculation since multiply 12 cm by 4.5 does not give 51 feet but 54 feet. To obtain 51 feet, the value should be 4.25, not 4.5. Since the 4.5 value is repeated twice, I think that this is the result which is flawed.
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Post by theropod on Jul 14, 2013 17:55:58 GMT 5
Perhaps that rumour is about slant lenght, since that is the measurement given in popular scientific sites and by fossil collectors. I've never seen a cigar box in my life, so I cannot comment on that.
I didn't even notice that calculation error, thanks for pointing it out.
So using Gottfried's regression for an 18cm (perpendicular) tooth, you get 17m, and 18m from that 6m shark.
You get a result of nearly 18m for a root width of 13cm. So I think the 17-18m range fits pretty well, but there are reports of bigger teeth in both regards, and, of course, Hönninger's skeletons.
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Post by theropod on Jul 14, 2013 18:03:07 GMT 5
Grey: I'd like to know where the info you posted about this specimen was from: It looks gigantic in terms of width, but the crack and odd proportions are problematic.
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Post by Grey on Jul 14, 2013 18:09:37 GMT 5
This is a broken chilean (again) tooth. I've contacted the owner who specified that it is not pathological but was cracked under the geological pressures. He said me the original width may have been around 6 inches. Steve Alter also reported me to have seen a lateral measuring 6x6 inches.It seems that this is the same specimen : www.megalodonsharkteeth.com/?generallayout=shop&cat=_Megalodon_Chile&layout=layout&start=10Regarding the 203 mm tooth that's right, but since Kent thinks not in slant but perpendiculary... I don't want to speculate, but certainly this is the largest teeth he observed (there were others very large). EDIT
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Post by creature386 on Jul 14, 2013 19:52:15 GMT 5
I believe Life could move some of the posts here in the Megalodon size thread.
Anyway a 20,3 cm tooth is impressive!
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Post by theropod on Jul 16, 2013 23:30:10 GMT 5
To quickly come back on Shimada, based on the scalebars and measurements in Pimiento et al. the green+blue lines are the measurement needed for the method: So it is the maximum lenght of the crown measured along the midline/long axis, going as far as the proximalmost protruding slant.
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Post by Grey on Oct 1, 2013 22:12:43 GMT 5
While there are multiple skulls for megalodon of all sizes right? There are no megalodon skulls reported anywhere in the world. You probably refer to the jaws reconstructions. Jaws reconstructions are of various quality and accuracy. The best are those mounted by professionnals collectors/paleontologists. Some good models are mounted with real teeth. But no jaw structure has been preserved so far. I mostly use quality and most plausibly reliable models. Megalodon is known by numerous teeth throughout the world, numerous worldwide, but still rare findings locally, because of the trophic traits of megalodon (apex predators, rare in some regions). A few vertebras are known. 20 centras with an isolated 16 cm high, 12 cm wide tooth were found in Denmark in 1983. Three complete set of teeth are known, two from US, one from Japan. These set of teeth are valuable in that they correspond to individuals dead at the given point (and not having lost a single tooth during its lifetime) and allowed to know the exact dentary formula and number of teeth in the species. One of this set if owned by Dr. Gordon Hubbell from Gainesville, Florida. This set of teeth is used as template for paleontologist Mike Siversson to estimate TL in megalodon with modern lamniforms set of teeth parameters, based on jaw perimeter rather than tooth height, which is the most reliable (or least worst) method to estimate the size of a fossil shark based on its teeth. All of this awaiting the peruvian skeleton to be, hopefully,properly described.
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Post by Grey on Oct 2, 2013 17:33:34 GMT 5
Dr. Stephen Godfrey indicated me the balaenopterid rib bitten by a presumed juvenile meg, discussed in his paper, belonged to a rorqual the size of a living fin whale.
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