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Post by Grey on Mar 14, 2018 21:11:58 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. Going by Pimiento data (which is erroneous for the reasons explained in the link), the average size of the adult megs is in the 14-15 m range, not 12-13. Note, even assuming Pimiento data being correct, the largest specimen in her matrix at 17.9 m is an error. Actually this specimen is, using Shimada equation, 19.6 m... Note also that the size figures in Pimiento are only mean figures among various possible positions. Which implicitly assumes that the specimen could a bit smaller or a bit larger and still be in a reasonable range. Sam1 is simply not rigorous in his research. Also, the Livyatan was a full grown specimen, possibly of advanced age, which died of natural causes. The average adult meg size from Pimiento data doesn't come from full grown specimens but simply adult specimens which were still living when they lost the tooth that appears in the data. Adult, full sized megs specimens which died at some point are represented by the specimens of associated dentitions. Those are the specimens that have to be directly compared to the Livyatan holotype. You can copy this response for him. |
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Post by Grey on Mar 15, 2018 12:49:18 GMT 5
From Sam1 Sam1 needs to read properly my responses and stop ad hominem attacks. I rather expect him to have the decency to read my response properly. Being factual about research isn't being cultist. Using random artistic depictions and guess to make a point isn't being factual. 1) A number of isolated teeth from Peru and Chile in private collections are definitely from Livyatan. Various pictures are available on google images and various fossil collectors FB pages. These teeth are massive but not larger than those in the holotype. Isolated killer sperm whales teeth related to Livyatan have been found/described these latest years. These teeth are big but quite smaller than those of Livyatan. This simply demonstrates that Livyatan is the only really gigantic KSW genus. 2) Pimiento sample acknowledges the 18 m TL for meg. However this particular specimen itself is wrongly estimated, the actual mean size from the possible positions is 19.6 m. (Yes Sam1, it's been 3 years since I look at Pimiento matrix and thesis and I do some research with some of her co-workers). So at least one specimen, the largest in the matrix, is subject to an error. And this one is almost 2 m longer than the original erroneous estimate. 3) The actual average adult meg size in Pimiento matrix is a bit above 14 m (and a bit more if using the corrected TL of 19.6 m for the largest specimen). Remember Pimiento considers, based on Gottfried 1996, specimens as adult once they reach 10 m. However, it should be noticed that Gottfried 1996; Table I considered the largest immature female to be 13.9 m while the largest immature male is 9.1 m. The smallest mature male being 10.5 m. So, theoretically using Gottfried 1996, any meg between 9 and 14 m can be either immature or mature. So if Sam1 considers 12-13 m to be an average size for megalodon (based on what ?), the actual data says a 12-13 m meg is potentially an immature specimen. According to this Table, definitive adult megs are above 13.9 m TL. So the average adult size would be obviously above 13.9 m, and comparing the adult Livyatan holotype, estimated and 14-17.5 m, with a most likely immature 12-13 m meg is simply not logical. Livyatan holotype is a full grown specimen that died of old age, a 12-13 m megalodon is, according to the data, not full grown since potentially immature/subadult. 4) Ultimately, all of this is irrelevant since Pimiento estimates, based on Shimada equation, are certainly wrong : www.cambridge.org/core/journals/the-paleontological-society-papers/article/3d-fossils-for-k12-education-a-case-example-using-the-giant-extinct-shark-carcharocles-megalodon/DCA3D6625962AC54633C32E9CBD0E0C6#fndtn-informationConclusion :
•there is no scientific way to say the Livyatan holotype is an average-sized specimen, although current fossil evidence tentatively suggests it was rather on the large side. (Also, the 15 m figure Sam1 uses for the holotype is itself based on nothing; while I do rely on the 16.2-17.5 m estimates from Lambert 2010).
•the largest meg in Pimiento matrix is actually 19.6 m TL, not 17.9 m TL.
•Based on Gottfried data, which is the basis for ontogenetic stages in Pimiento matrix, the average size of adult megalodons was above 13.9 m.
•anyway, the Shimada method based on crown height to estimate TL used by Pimiento is probably prone to wrong estimates. So anything from the matrix has to be taken with, at best, a huge grain of salt.
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Post by Grey on Mar 15, 2018 15:38:08 GMT 5
Now Sam1 could check this 2016 work. www.researchgate.net/publication/308891065_SIMPLIFYING_THE_METHODS_-_BODY_LENGTH_ESTIMATES_FOR_CARCHAROCLES_MEGALODON_USING_ASSOCIATED_TOOTH_SETS_AND_JAW_WIDTH_RELATED_DATA_FROM_GREAT_WHITE_SHARKS_AND_MAKOSThese are estimates based on associated dentitions, not isolated teeth. Which means those are megalodon individuals which died and let their dentition, unlike Pimiento matrix which is relying on teeth shed at a certain point by individuals of various ages which were still living and growing (as sharks never stop their growth). Furthermore, the estimates here are using the width of the whole dentition which a much larger body parameter than using the isolated crown height of a single tooth. This is thus a much more stable method and comparable to the method used by Lambert 2010. for Livyatan which used skull width. The results based on various adult white sharks specimens suggest a size range for the adult dentition from Yorktown of 17-20 m. Yet, the individual teeth in this dentition are not quite as large/wide than some of the largest isolated teeth on record. The reason for this larger estimate is that for a megalodon UA tooth that is about 2.9 times larger than a GWS tooth, the dentition itself was 3.5 times larger than the GWS dentition. Because the megalodon dentition decreased in size more slowly than the GWS. Yet, whole dentition parameters are much more likely to be reliable than using a single tooth parameter. It is basically much more reasonable to assume megalodon body length was more directly correlated by the size of its dentition than by the size of a single tooth. The same way Livyatan TL estimates were based on the width of the skull rather than by the size of a much smaller element. The table also shows how much Pimiento matrix is unreliable; for the Yorktown specimen itself, depending on the tooth position, the range of possible TL is from 12 m to 45 m. While by comparison, the upper dentition method suggests a range of 17-20 m using adult GWS as basis. It is pretty much understandable why using Shimada method on the Otodus dentition is hardly trustable. |
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Post by Grey on Mar 15, 2018 16:24:30 GMT 5
BTW, Pimiento herself considers megalodon to be "the largest marine apex predator that ever lived" (2016). If one wants to rely on hyperbolic statements.
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Post by Grey on Mar 16, 2018 9:43:06 GMT 5
Hash slinging slasher wrote :
Hi,
The Beaumaris 18 m estimate is simply reflective of the upper estimate for Livyatan according to Erich Fitzgerald in a discussion on Twitter. Actually based on the size of the tooth he was rather thinking about a 15 m estimate.
Anyway he's actually describing it and new material and teeth have even been found in Beaumaris since then, I've seen pictures. So an interesting paper will come soon.
The 40 tonnes figure also appears to be a guess estimate based on the modern sperm whale.
And creature, you could avoid yourself to describe me as a cultist. I study the fossil species, I don't worship it.
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Post by creature386 on Mar 16, 2018 19:58:29 GMT 5
And creature, you could avoid yourself to describe me as a cultist. I study the fossil species, I don't worship it. I should have used quotation marks since I meant to say that in a sarcastic way. |
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Post by Grey on Mar 16, 2018 21:51:31 GMT 5
Sam1 wrote :
Klaus Hönninger appears to be a fraud, many local paleontologists and collectors have been disappointed by him.
This does not make me a liar, I was one of those who were scammed. And this has no relevance to the discussion here.
There is still a suspected skeleton in the area. A chubutensis preserved jaw is currently under description by some of the team who described Livyatan.
I need to see where there is any lie in my posts. All what I state is sourced or easily checked for anyone willing to do some research.
The discussion with Fitzgerald about the Beaumaris KSW was on Twitter in april 2016 and anyone can contact the man. As for the new material under description, I simply have some useful contacts, no big deal.
So I'm still waiting for a true response to my previous, scientifically sourced, statements.
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Post by Grey on Mar 17, 2018 4:11:21 GMT 5
Because the fraudulence became apparent only one or two years ago and I'm not in contact with Sam1 since five years ago.
As I said already, Hönninger misled many people, not just some guy on the internet.
FORGET all of this.
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Post by Grey on Mar 18, 2018 6:51:21 GMT 5
All what I state is factual arguments.
15.5 m is not the average size of Livyatan. No other specimens are known and all the recorded isolated teeth from the same locality are usually smaller.
Neither is 14 m for meg. Pimiento determined the mean size for living individuals, not the average size of a megalodon when it died, like the Livyatan holotype.
Assuming Livyatan holotype to be average size is like assuming the Denmark meg to be an average size.
14 m + would anyway be the result of a wrong method.
As I've alreasy explained and linked and expect you to read before you respond me.
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Post by Grey on Mar 18, 2018 18:15:46 GMT 5
1. Saying the Livyatan holotype is average sized is like saying the Danish meg specimen (vertebra associated with a tooth, hence an adult individual which died at this point) is an average size specimen. Because the Danish specimen is the first meg specimen that has been found in a the state where the shark achieved its life, unlike isolated teeth.
Using the tooth size parameters of the Danish specimen and all the current methods to estimate TL (Gottfried et al.1996; Shimada 2002; Jeremiah 2002; Leder et al. 2016), the minimum TL estimate for this specimen would range between 14.5 and 18.5 m TL. But there is no reason to consider it an average size specimen, just like the Livyatan holotype.
The Carnegie T. rex was the first specimen ever found, yet it remains to this day in the upper size range of all the specimens ever discovered.
2. Pimiento data is about mean size, not average size.
3. The methodology used by Pimiento is erroneous anyway.
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Post by Grey on Mar 18, 2018 23:32:47 GMT 5
The isolated teeth found around the Peru/Chile border prior to the discovery of the skull and now held in private collections are definitely from Livyatan. Givanni Bianucci directly assigned them to the genus in his journal. These teeth are only comparable to those found in the skull but not larger. The wiki page simply omitted them. There are various pictures available on the internet. I'm not referring to the isolated teeth from other parts of the world. Pimiento simply didn't remark the issues but one of his students and co-worker, Victor Perez, did remark this method is inaccurate on megalodon and reported it in the links I've previously mentionned. For the same dentition from Yorktown, Shimada method suggests an absurdly large size range of 12-45 m. Hence, we're working on the new method (Leder et al. 2016, I'm one of the coauthors) to more accurately predict meg size, based on the whole dentition metrics. The direct incidence is to invalidate Pimiento's matrix. According to this site, -> www.elasmo-research.org/education/white_shark/teeth.htm"In 1998, Canadian paleontologist John Clay Bruner presented estimated tooth replacement rates in the White Shark by examining the jaws of 31 specimens, ranging in total length from 4.7 to 15.1 feet (1.4 to 4.6 metres). Bruner's analysis concluded that the average replacement rate of the second anterior teeth differed between upper and lower jaws and between younger and older sharks. He found that in young White Sharks, the average tooth replacement in the upper jaw is about 106 days, while in the lower jaw it was 114 days. Similarly, Bruner found that in older Great Whites, the average rate was 226 days in the upper jaw and 242 days in the lower. The tooth replacement rate of younger White Sharks is probably faster than in older ones because metabolic rate generally decreases with age, thus the tooth-generating membrane forms teeth and grows more slowly in older individuals." Younger shark seems to have almost twice faster tooth replacement rate which can possibly cause bias toward to smaller teeth in fossil record. This invalidates even more any attempt to establish an average size from Pimiento matrix, already using a flawed method. You forget the most important point : the 36 cm teeth in the holotype are the largest that are preserved and are lower teeth. The upper teeth aren't conserved outside of the alveoli but their diameter is way larger than the largest lower teeth. In short, when complete, the holotype had upper teeth certainly larger than 36 cm and probably close to 40 cm. Bianucci agrees on this (personnal communication). So, there is so far zero material suggesting individuals larger than the holotype. Which makes dubious at best any statement that this individual had to be, for some reason, an average sized individual. In the meantime, the Yorktown meg dentition suggests a body size range of 17-20 m, despite its largest teeth being far from the largest recorded from the species. I'd appreciate you check the previous links and stop the personnal attacks. Thanks. |
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Post by Grey on Mar 18, 2018 23:50:59 GMT 5
The actual question is simple.
The Livyatan holotype was an adult which presumably died of old age.
Is it more logical to compare its estimated body size with the average TL estimated from isolated megalodon teeth from any life stage, using a flawed method ?
Or to rather compare it with the remains adult megalodon specimens which actually died at a certain point such as the Danish specimen represented by centra and a 12 cm wide toorh and the Yorktown associated dentition, a dentitition 3.6 times larger than the C. hubbelli dentition described by Ehret 2009. as coming from an approx. 5 m long shark...
The answar is obvious.
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Post by Grey on Mar 18, 2018 23:57:22 GMT 5
The most recent paleontological data does not suggest the Livyatan holotype to be an average size animal. No one of the describers ever stated that either in the original publication or in the more recent publications about it.
The most recent paleontological data from Perez 2016. and Leder 2016. do suggest Pimiento estimates to be inaccurate and not adequate on the Otodus/Carcharocles genus.
I was hoping the sources previously linked woyld be checked but apparently no one wants to take the risk to update his mind. Too bad.
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Post by Grey on Mar 19, 2018 1:21:54 GMT 5
Again, the 36 cm teeth in the holotype are lower teeth. No upper teeth are preserved in state except for their root diameter which suggests a larger size.
You have seen the isolated teeth described by Bianucci ? I doubt it, no photo is available of them. So there is no way you can apply a position for those teeth you don't have seen.
I've questionned Bianucci about those teeth and if they indicate something larger than the holotype. He negatively responded, as the holotype itself may have had upper teeth around 40 cm when complete.
However, the other teeth in private collections I have seen all have the wear pattern. Yet their actual position can't be determined.
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Post by Grey on Mar 20, 2018 3:00:50 GMT 5
Yup but it depends of the actual growth rate of the species. Even recently we found out GWS live way longer than we thought and that theoretically, a very aged female could clearly reach 8 m. Also, juvenile fossil teeth tend to be more accessible than mature teeth because younger/ smaller megs lived in shallow regions more accessible and preserved today. There is also, hinted in Pimiento 2015, the potential size differences between the populations. Added to the very issues relative to the crown height related method to predict size, you understand how it can be deceptive to try to establish an average size for the species. Then there is the possibility of a moderate average size but colossal maximum sizes... The problem is using which method ? It appears Shimada method is unreliable on this fossil genus because of the proportion of the dentitition (much slower decreasing size toward the posterior teeth). We don't even know the maximum size of the species. Not only larger and larger teeth are discovered but also extremely large very lateral, lower or posterior teeth that suggest TL way in excess of those usually published (various are seen on this board, and actually I've seen so much of them that I tend to not post all of them). I personnally rely (based on the original advises of Mike Siversson and Brett Kent) on the dentition width based method from Leder et al. 2016 because it gives the most stable results and are based on the largest body metric (whole associated dentitions) we have from this species. From this, the Yorktown set gives a 17-20 m TL (the dentition is 3.6 times larger than the Carcharodon hubbelli dentition). Yet, this set is not the largest known (a Chilean one is reportedly even larger and will be studied in this project) and many isolated teeth are way larger than the Yorktown dentition.. So the question of megalodon maximum size is far to be solved, let alone the average size. The alternative is to calculate the TL based on the teeth in Pimiento matrix while adjusting their position in the sets in Leder 2016. then calculate the resulting TL. I've already started this but I prefer to wait for the final study from Leder et al. before completing it. I think you didn't read Leder 2016. I link it again. www.researchgate.net/publication/308891065_SIMPLIFYING_THE_METHODS_-_BODY_LENGTH_ESTIMATES_FOR_CARCHAROCLES_MEGALODON_USING_ASSOCIATED_TOOTH_SETS_AND_JAW_WIDTH_RELATED_DATA_FROM_GREAT_WHITE_SHARKS_AND_MAKOS You just need to read properly the description in the supplementary data (Lambert 2010) or "Macroraptorial sperm whales (Cetacea, Odontoceti, Physeteroidea) from the Miocene of Peru" Lambert 2016. The classic lateral reconstruction of the skull clearly shows itself that the upper teeth are missing except for some of their roots in the alveolis. Page 55-56 : Upper teeth: For the upper dentition, only parts of
the roots are preserved in situ: six (1–2; 4–7) could
be measured in the left maxilla and five (1; 4–7) in
the right maxilla (Table 10). Sections perpendicular
to the long axis of the teeth are roughly circular, but
because mesial teeth are anteroventrally directed,
preserved sections are not perpendicular to the long
axis of the tooth, being therefore oval. Transverse
diameters of roots at the surface of the alveoli range
from 93 to 122 mm, with the most robust teeth at
that level being teeth 4–6. These measurements
provide only minimum diameters, as the root can be
even more robust outside the alveolus, due to the
continuous addition of cementum layers on the outer
surface of the roots in physeteroids (Hohn, 2002).
The dentine–cementum boundary is easily detected
based on aspect and colour on the transverse section
of the root at the surface of the alveolus; the
maximum radial thickness of the cementum ranges
from 21 to 28 mm in right maxillary teeth 1 and 4–6.
Lower teeth: For the lower dentition, only the basal
part of the root of one left tooth (left tooth 3) is
preserved in situ. Nine additional teeth, with
varying degrees of preservation, were found
detached around the two mandibles (Figs 33, 36;
Table 11). Their position in the lower jaws is
inferred based on the outline and measurements of are also more distinctly curved, for both the root and
the crown. Intermediate teeth are the largest, and
their long axis is closer to a straight line. Distalmost
teeth also have a smaller root diameter, but they are
less curved than mesialmost teeth. Considering the
curve of the root and crown, and the position of
occlusal facets where present, most of the preserved
lower teeth seem to originate from the righ
the presumed corresponding empty alveoli, as well
as the curvature of their root and crown. Mesialmost
teeth have a lesser maximum diameter of the root
than teeth more intermediate on the tooth row; they mandible. None of the teeth is complete, but some
(for example the right teeth 1, 5 and 7) only lack a
few fragments at the base of the root or at the apex
of the crown. All the well-preserved teeth have a
maximum height > 310 mm. The highest measured
tooth is left tooth 2–3, with a maximum height of at
least 362 mm. The shortest is right tooth 1, at
approximately just over 315 mm. However, the
height of the distalmost teeth (8–11) is unknown;
considering the size of the corresponding alveoli,
teeth 10–11 were probably the shortest, as is
observed in Acrophyseter deinodon above.
The wikipage was simply wrote by guys unable to read precisely their sources. bianucci@dst.unipi.it The email is not hard to find. If you want screenshots, you should come here. Back then I was always showing the original screenshots of my conversations with various authors. Stop the suspicions about the conspiracy theories . This is not a Youtube discussion. I've spent countless hours reading and calculating all the material available with many contacts all around the world and I now work as an amateur researcher with some professionals (Leder 2016.). That's not one camp against the other, that's the research of the data, nothing else. |
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