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Post by theropod on Oct 19, 2013 2:03:07 GMT 5
Gottfried is the best because it is the most rigorous. Which does not undermine others estimates. Period. Fragillimus, this is not Carcharodon anymore but Otodus or Carcharocles. Probably not Otodus, But yeah, it could be Carcharocles or Carcharodon. No one really knows for sure do they? Otodus is more likely than carcharodon, since megalodon is probably not a lamnid but an otodontid.
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Post by Grey on Oct 19, 2013 12:25:12 GMT 5
Gottfried is the best because it is the most rigorous. Which does not undermine others estimates. Period. Fragillimus, this is not Carcharodon anymore but Otodus or Carcharocles. Probably not Otodus, But yeah, it could be Carcharocles or Carcharodon. No one really knows for sure do they? No, according to Cappetta's 2012 update, Otodus is now valid and is used the latest publications about megalodon. museum.wa.gov.au/about/latest-news/palaeontological-detective-work-unravels-evolution-megatooth-sharksCarcharodon is now totally obsolete. Meg wasn't a white shark, not even a lamnid. We can discuss between Otodus, Carcharocles, even Megaselachus, but Carcharodon is out.
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Post by Grey on Oct 19, 2013 12:34:35 GMT 5
Again, why do you consider Casey & Pratt (1985) any less rigorous, when their method is actually the one with the bigger sample? Casey and Pratt did not perform prediction for megalodon. Why are you arguing this work as a data about megalodon weight ? The only prediction in a published paper, and later used by others (including Hubbell) is from Gottfried. Gottfried is not necessary right but there is no other stuff. That's your stuff. You are wise to have used Gottfried equation on Casey and Pratt sample (if really you did). I agree with the results, as much as I agree with the results from Gottfried, Compagnon and Bowman. Becuase of the reasons mentionned earlier : Gottfried pointing on a bulkier shark at parity, that the sample is larger is pointless as 175 individuals is already well enough as a reasonnable basis, and because you can get fluctuations from any comparable sample, the difference between Gottfried and your calculation being not that massive. That's why this even stupid we have to debate this. I only say you that you do not outclass Gottfried's data, no one has done. Which does not mean everyone is totally agreed with Gottfried, but that's the best data so far (see Kent's or even one of my earlier discussion from Ehret). So no need to perpetuate this.
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Post by theropod on Oct 19, 2013 16:18:54 GMT 5
Because it is the same thing Gottfried did, a weight/lenght curve based on great white sharks. Whether or not this was used for estimating the weight of megalodon is totally irrelevant to the accuracy of the method. The paper was about great whites, not megatooth sharks.
What "have used Gottfried equation on Casey and Pratt sample (if really you did)."?
I used the equation from Casey and Pratt, what is so difficult to understand about that? It is another regression analysis of the same kind, it is at least as good as Gottfried et al. (1996), there is up to date absolutely nothing indicating it is not. How am I supposed to "have used Gottfried's equation" on that sample?
Megaselachus is taxonomically invalid. It has been named many years after the erection of Carcharocles, so unless it's type specimen is not congeneric with megalodon, it has to be sunk into Carcharocles. The debate is pretty much between Otodus and Carcharocles, which depends on subjective considerations.
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Post by Grey on Oct 19, 2013 16:22:08 GMT 5
Truly I don't understand at all what you did exactly and I don't give a heck. Gottfried remains the best rigorous data about meg's weight, even though cautiously I prefer more basic and less steroided predictions.
Megaselachus is also precised in the latest papers, even though Otodus has to be prefered.
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Post by theropod on Oct 19, 2013 16:35:31 GMT 5
Mass(kg)=4.80376*10^-6*Tl(m)^3.0949 This is the formula given by the paper because of which you are engaging in a baseless and useless (as you yourself wrote) personal campaign against me since three pages.
Now would you please at least have a look at what you are talking about before you talk big, Mr "I don't give a heck"?
How can someone seriously let loose an endless rant on what I'm doing, just to then admit to not even have understood what that is, and think that's totally OK? As much as I'm trying to understand you, I just can't.
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Post by creature386 on Oct 19, 2013 17:54:12 GMT 5
Megaselachus is taxonomically invalid. It has been named many years after the erection of Carcharocles, so unless it's type specimen is not congeneric with megalodon, it has to be sunk into Carcharocles. The debate is entirely between Otodus and Carcharocles, which depends on subjective considerations. Megaselachus is not invalid. It isn't meant to be a synonym of Carcharocles. It only includes C. megalodon and C. chubutensis. The other Carcharocles species are referred to Otodus by the Megaselachus supporters. I don't prefer Megaselachus, because I don't believe the lack of lateral cusplets is sufficient to separate Megalodon from the other Carcharocles species, but I can accept that view (although only a minority of the workers think so).
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Post by theropod on Oct 19, 2013 17:55:40 GMT 5
Oh, thanks! So megaselachus is basically just a further separation within the Carcharocles lineage.
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Post by Infinity Blade on Nov 25, 2013 1:19:44 GMT 5
I'm just going to agree that whoever gets the first bite wins, assuming at parity. So probably 50/50 IMO. I'm sorry, but I can't think of anything else one has over the other that will allow it to prevail more often than not (unless I'm missing something here, but I don't feel inclined to read 45 pages of debate).
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Post by theropod on Nov 25, 2013 1:43:32 GMT 5
You don't miss much. It was about "which one is bigger/is either?"-which no agreement was reached about, and "whose bite is deadlier/can you say either is?"-with no agreement either.
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Post by Infinity Blade on May 19, 2014 6:48:00 GMT 5
I may be remembering wrong, but I think I recall Grey on the Carnivora variant of this thread saying that C. megalodon might have employed blunt trauma (or something similar) onto prey items, which could possibly counter the cetacean's ramming capabilities. Is this likely?
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Post by theropod on May 19, 2014 18:23:30 GMT 5
Of course it can use blunt trauma, but a ram as dangerous as that of the cetacean is unlikely for several reasons.
The shark's skull is not so pointed, and the internal support structures are cartilaginous and loosely connected, which will render it less effective at transmitting force--it will deform and cushion the impact. The heads of odontocetes (especially physeterids) are particularly well-suited for ramming, because they combine a lot of bulk with a relatively pointed but rigid and very robust snout, which will mean it will transmit the impact energy more efficiently and onto a smaller area (=better for causing injuries, as a smaller degree of strain is experienced by the ramming cetacean, which means the impact force and the resulting pressure are both greater). There’s a video of an orca ramming a false killer whale from below and flicking it high into the air in what looks like an effortless movement, so they are obviously very strong as well. Sperm whales have sunk ships, I recall there was even a paper on their ramming capabilities.
Ramming in sharks is simply a means of driving the teeth into prey when attacking from below, hence "ram-feeding". But naturally any powerful movement by a giant predator could kill or seriously injure a prey item only a tenth that size (such as a cetothere). As soon as it's about ramming a large opponent, the difference will be more apparent however.
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Post by Infinity Blade on May 19, 2014 23:49:20 GMT 5
So then how will C. megalodon counter the whale's ram?
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Post by Grey on May 20, 2014 6:20:35 GMT 5
A ram from the whale would surely be dangerous even if the whale is smaller.
But certainly, sharks have proved to be able to inflict effective rams. Cetaceans are not the only creatures able to sink boats.
I don't know any case of a whale ramming a similar-sized foe or larger sized.
Until someone disproves that O. megalodon exceeded 18 m and was a robustly built predator or that Livyatan's physiology is better known and that it is proved that it reached or exceeded 17.5 m, megalodon is still superior.
Hopefully more findings in respective species will clarify that.
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Post by theropod on May 20, 2014 15:49:05 GMT 5
I don't think anyone's opinion on how large these animals were respectively was the point...
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