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Post by Grey on Jul 13, 2013 2:13:56 GMT 5
No, the maximum height in meg tooth corresponds to the slant height. The axis is the long of the tooth itself.
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Post by theropod on Jul 13, 2013 2:15:08 GMT 5
How is slant height an axis?
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(Edit: I have considered your sources, which are not primary sources but interpretations themselves, and don't know better than we do (worse actually considering we both have an additional source). We both know what Kent writes.
You were not able to tell me how slant height is measured along "the midline" (Kent) or "long axis" (Gottfried et al.). I am not some sort of self-centered moron because you did not convince me by citing that site.
You are centering on the "maximum height" and ignoring the rest ("along the long axis/midline"), just because you cannot see slent height being cited for the tooth in question (surprise, it has not been mentioned at all, anywhere, and anyway, slant height doesn't have to be as much bigger as in some specimens, depending on how wide the tooth is). You have not given evidence and as long as you want to tell me slant height is measured along the midline that won't convince me.
Give me something that has credential and explains this matter, it doesn't matter to me personally whether those are perpendicular height or slant lengght, but I will only accept for what there is actual evidence, and the actual evidendence you can read (ignoring some random sites in the internet), or that is presented in upcoming publications does not agree with that measurement being slant lenght.
I have the impression it matters to you personally, extremely much even. You should calm down and stop advocating something you read on some site as a fact, and instead spend more time actually considering my posts before you make claims about them.)
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Post by Grey on Jul 13, 2013 2:31:02 GMT 5
Can someone explain us what Gottfried measurement corresponds to ? I'm thinking it's the slant, though not certain but I won't convince theropod who's certain of what he argues.
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Post by theropod on Jul 13, 2013 2:45:18 GMT 5
Yes, please explain it to me! I am not, as you all the time assume, certain of my opinion (which at the moment is that Gottfrieds et al.'s measurement is not slant height and will change as soon as there is evidence for the contrary). Luckily this is not a matter of opinion but something that can be verified. I therefore mailed to Compagno and Gottfried, hoping one of them will respond. Their answer can be regarded as factual, since they are the ones that measured the teeth. Up to then, it is unlikely to me that "midline of the tooth" or "long axis" refers to slant lenght, without stating this as a fact like Grey tried to imply. Also, be careful with taking what the page you gave me in your PM claims, it's not a rigorous source (unless you believe maximum lenght of C. megalodon was 13-16,5m. btw it states an average figure I know you wouldn't like). |
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Post by Grey on Jul 13, 2013 20:16:44 GMT 5
Mail from Brett Kent about why meg was most likely the largest top predator in existence, educated opinion about L. melvillei size and Gottfried's tooth measurement (sounds like Theropod is right after all, though I'd like more statement as Brett himself does not seem that certain either).  |
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Post by theropod on Jul 13, 2013 20:31:53 GMT 5
Not really a surprise, is it? He wrote that in his paper. If at all, there is the possibility of him himself having misunderstood that part, but it seems more likely "fossilguy.com" did, considering what is written in Gottfried et al..
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Post by Grey on Jul 13, 2013 20:50:17 GMT 5
What sounds weird is that 7 inches teeth in slant height are very symbolic and stated as very rare by fossils collectors and that I'm skeptical that the one owned by Gottfried et al. was that long. I've seen the tooth in one video with Gottfried, and it doesn't simply look at as a 7 incher, compared to others 7 inchers I had observed. Also, it sounds much more compact.
I would tend to think you're right, but I have still uncertainity. Awaiting more clues come...
Whatever, tooth height is variable and likely less revelant than tooth width when predicting the size of lamniforms (but useful when specified to the great white).
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Post by theropod on Jul 13, 2013 22:37:08 GMT 5
I got no response yet (one cannot expect that after so short a time), in any case this is one of the subjects that have a single, factual solution and can be cleared up.
But you see, I don't just reject things out of stolidity, I do research and consider sources, but I do not agree with them without being convinced, I will argue what seems logical, not what seems to be the general opinion, and this is nothing I will change, because it is a good trait. And in this case, frankly, your sources were not convincing, and you can see why this was the case yourself. Thanks for editing your posts, I hope the next time you think I was denying something you will remember this.
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Post by theropod on Jul 13, 2013 22:43:40 GMT 5
It doesn't surprise me the tooth Gottfried and colleagues used probably was a very large specimen. After all, it was supposed to represent maximum sizes. It doesn't have to be the biggest in the world, but a truly big specimen nevertheless. It doesn't make sense to me that they would have used a specimen less than 17cm in slant lenght, that just sounds to small to be used as a viable basis for maximum estimates.
What video are you referring to?
It is often difficult to gauge lenghts in videos, due to movement, distance and angle. It could have looked smaller than it was.
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Post by Grey on Jul 13, 2013 22:55:19 GMT 5
Yes, but even then, I know how to recognize a 7 incher in a hand, and it really not looked as such. The video is the last part of Paleoworld : Sea Monsters, part3 on YT, that was around the publication of Gottfried.
The tooth was reported to be large for sure, and it is large, but what disturbs me is that nowhere has reported that a complete 7 incher was in the possession of Gottfried et al. 7 inchers in perfect condition are extremely rare. That being said, due, to its very compact shape, the tooth could not be 7 inches in slant but slightly less belove the symbolic mark (for fossils hunters). However it seems really wide.
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Post by theropod on Jul 13, 2013 23:27:46 GMT 5
Compact shape (higher width/height ratio) should actually increase slant lenght relative to perpendicular height. That being said absence of evidence is not evidence of absence.
I'm gonna check out that vid.
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Post by Grey on Jul 13, 2013 23:36:27 GMT 5
This is the same tooth that it is pictured in the actual paper.
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Post by theropod on Jul 13, 2013 23:46:00 GMT 5
Watched the paleoworld episode.
Firstly:
The tooth in the vid is stated to be 6 inches long, undoubtedly a rounded figure, but this figure equals 15,24cm, which is not even close to the measurement of the upper anterior used in the study. It could be a different measurement, but it is still 4mm shorter than the perpendicular height that is yielded by applying the ratio of Hubbel's tooth to the UA in question, and as you already mentioned it looks very robust. Lenght measured up to the medial fossa in the root on the other hand would probably be even lower for a specimen with that slant height.
Secondly:
The shown specimen resembles the lateral tooth figured in Gottfried et al., 1996, and since he figured that tooth in the publication, he possibly showed it in the documentary for the same reason.
Thirdly:
The study doesn't seem to mention the tooth in question was in their posession, they just mentioned verified tooth heights for megalodon went up to that size. This may also be the reason for not figuring that tooth but the lateral one, the latter being available and accessible.
EDIT: took me too long to respond, so "Secondly" is redundant
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Post by Grey on Jul 13, 2013 23:56:30 GMT 5
This is not a lateral one (laterals have a slightly curved, shorter slant), and since the tooth was available for the paper (not in private collection), I don't see why it was not available for the doc. The tooth figured in the paper seems to be the one used for the study. This was the same used by Shimada in 2003. The comments of the narrator were talking about global size in meg teeth, not the size of that particular specimen. But I'm fairly convinced that this tooth is the one seen and used in the study. The overall size simply corresponds (only I don't see it as a toping 7 incher).
But whatever, I'm awaiting comments from others fellow members on that.
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Post by theropod on Jul 14, 2013 0:08:53 GMT 5
In figure one of Gottfried et al. It sais "(A) Upper lateral tooth"
This isn't the 168cm UA used in the estimates
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