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Post by theropod on Aug 26, 2024 17:06:57 GMT 5
Vividen and his crowd just have a passion for creative nicknames. This is the same fossil that Bendix-Almgreen already described and published in 1983 (indeed consisting of around 20 centra ranging from 10 to 23 cm, so if they are from one specimen the ratio would suggest the largest are probably pretty close to being the largest in the column, perhaps shy of it by a cm or so) and that has been discussed here numerous times before.
So there’s nothing new about it except whatever new information Jack might have uncovered about it, but the SVP abstracts don’t appear to be out yet (I could swear conference season is getting later every year), although I thought I had read rumours that the specimen had been lost (maybe these were misunderstandings?).
–– Bendix-Almgreen, S.E. 1983. Carcharodon megalodon from the Upper Miocene of Denmark, with comments on elasmobranch tooth enameloid: coronoïn. Bulletin of the Geological Society of Denmark 32 (1–2): 1–32.
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Post by Infinity Blade on Aug 26, 2024 18:17:59 GMT 5
I just want to know who did that really awesome piece. I want to say it looks like an RJ Palmer piece, but I’m not sure. |
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Post by elosha11 on Aug 27, 2024 0:17:26 GMT 5
Vividen and his crowd just have a passion for creative nicknames. This is the same fossil that Bendix-Almgreen already described and published in 1983 (indeed consisting of around 20 centra ranging from 10 to 23 cm, so if they are from one specimen the ratio would suggest the largest are probably pretty close to being the largest in the column, perhaps shy of it by a cm or so) and that has been discussed here numerous times before.
So there’s nothing new about it except whatever new information Jack might have uncovered about it, but the SVP abstracts don’t appear to be out yet (I could swear conference season is getting later every year), although I thought I had read rumours that the specimen had been lost (maybe these were misunderstandings?).
–– Bendix-Almgreen, S.E. 1983. Carcharodon megalodon from the Upper Miocene of Denmark, with comments on elasmobranch tooth enameloid: coronoïn. Bulletin of the Geological Society of Denmark 32 (1–2): 1–32.
There actually was a scientific publication that a few years ago tried to catalog and track down various Megalodon vertebral centra and regrettably found the 20 or so from the Denmark paper are indeed missing from the Museum in which they were supposed to stored. I think that article has been cited before on WoA, and I've definitely read it. But don't ask me to try to find it now.  I'd love to see if Honninger could supply any more info/pictures of what he found. Unfortunately, there used to be additional photos of the Meg fossils here from Honninger in the "Special Disclosures" thread, in addition to what I've posted there. But those other pics got lost on the servers from which they were posted on this forum. I'll try to reach out to Honninger again. |
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Post by Grey on Aug 28, 2024 22:50:54 GMT 5
Vividen and his crowd just have a passion for creative nicknames. This is the same fossil that Bendix-Almgreen already described and published in 1983 (indeed consisting of around 20 centra ranging from 10 to 23 cm, so if they are from one specimen the ratio would suggest the largest are probably pretty close to being the largest in the column, perhaps shy of it by a cm or so) and that has been discussed here numerous times before.
So there’s nothing new about it except whatever new information Jack might have uncovered about it, but the SVP abstracts don’t appear to be out yet (I could swear conference season is getting later every year), although I thought I had read rumours that the specimen had been lost (maybe these were misunderstandings?).
–– Bendix-Almgreen, S.E. 1983. Carcharodon megalodon from the Upper Miocene of Denmark, with comments on elasmobranch tooth enameloid: coronoïn. Bulletin of the Geological Society of Denmark 32 (1–2): 1–32.
There actually was a scientific publication that a few years ago tried to catalog and track down various Megalodon vertebral centra and regrettably found the 20 or so from the Denmark paper are indeed missing from the Museum in which they were supposed to stored. I think that article has been cited before on WoA, and I've definitely read it. But don't ask me to try to find it now. I'd love to see if Honninger could supply any more info/pictures of what he found. Unfortunately, there used to be additional photos of the Meg fossils here from Honninger in the "Special Disclosures" thread, in addition to what I've posted there. But those other pics got lost on the servers from which they were posted on this forum. I'll try to reach out to Honninger again. I'm aware of this, it's not done by Cooper but by the same team that proposed the new body shape earlier this year. I'm not even sure the incoming article focuses on the Danish vertebrae but I do know the new maximum length they will propose. People are confusing some research that was done privately by prehistorican with Vividen (but we have now news from him since months) from this forum and the actual research being done by those authors currently working on megalodon shape/size. Also, like for the big shastasaurids, people have a boring tendency to throw wild size figures here, especially in tonnage... The Peruvian specimens are apparently legit (reportedly confirmed by O. Lambert) and are being studied but the publication might come only years later. There are many things that will come from Peru in the next years like a new big whale... theropod yes the Danish material has been discarded but I guess the Bendix-Almgreen paper is enough to work with for the authors assimuming it focuses on the vertebral scaling. |
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Post by elosha11 on Aug 29, 2024 7:52:55 GMT 5
There actually was a scientific publication that a few years ago tried to catalog and track down various Megalodon vertebral centra and regrettably found the 20 or so from the Denmark paper are indeed missing from the Museum in which they were supposed to stored. I think that article has been cited before on WoA, and I've definitely read it. But don't ask me to try to find it now. I'd love to see if Honninger could supply any more info/pictures of what he found. Unfortunately, there used to be additional photos of the Meg fossils here from Honninger in the "Special Disclosures" thread, in addition to what I've posted there. But those other pics got lost on the servers from which they were posted on this forum. I'll try to reach out to Honninger again. I'm aware of this, it's not done by Cooper but by the same team that proposed the new body shape earlier this year. I'm not even sure the incoming article focuses on the Danish vertebrae but I do know the new maximum length they will propose. People are confusing some research that was done privately by prehistorican with Vividen (but we have now news from him since months) from this forum and the actual research being done by those authors currently working on megalodon shape/size. Also, like for the big shastasaurids, people have a boring tendency to throw wild size figures here, especially in tonnage... The Peruvian specimens are apparently legit (reportedly confirmed by O. Lambert) and are being studied but the publication might come only years later. There are many things that will come from Peru in the next years like a new big whale... theropod yes the Danish material has been discarded but I guess the Bendix-Almgreen paper is enough to work with for the authors assimuming it focuses on the vertebral scaling. Grey, thanks for the details. Are the Peruvian specimens you mentioned the Klaus Honninger Meg skeleton(s)? Did someone find them again, or convince Honninger to finally share more information? Do you know any more details? Remind me who O. Lambert is again. I know he's a researcher, but don't remember his background. What was the research from prehistorican and Vividen? I'm not familiar with that. |
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Post by Grey on Aug 29, 2024 16:13:25 GMT 5
I'm aware of this, it's not done by Cooper but by the same team that proposed the new body shape earlier this year. I'm not even sure the incoming article focuses on the Danish vertebrae but I do know the new maximum length they will propose. People are confusing some research that was done privately by prehistorican with Vividen (but we have now news from him since months) from this forum and the actual research being done by those authors currently working on megalodon shape/size. Also, like for the big shastasaurids, people have a boring tendency to throw wild size figures here, especially in tonnage... The Peruvian specimens are apparently legit (reportedly confirmed by O. Lambert) and are being studied but the publication might come only years later. There are many things that will come from Peru in the next years like a new big whale... theropod yes the Danish material has been discarded but I guess the Bendix-Almgreen paper is enough to work with for the authors assimuming it focuses on the vertebral scaling. Grey, thanks for the details. Are the Peruvian specimens you mentioned the Klaus Honninger Meg skeleton(s)? Did someone find them again, or convince Honninger to finally share more information? Do you know any more details? Remind me who O. Lambert is again. I know he's a researcher, but don't remember his background. What was the research from prehistorican and Vividen? I'm not familiar with that. Yes the Klaus related specimens, I don't have much details, just that Olivier Lambert (one of the describers of Livyatan) confirmed they are legit and will be described at some point. Prehistorican (with whom I discussed a lot) was working on scaling the Danish vertebrae to present it on the Vividen YT channel. |
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Post by elosha11 on Aug 30, 2024 4:51:42 GMT 5
GreyThanks. That's so encouraging to know the Peruvian Meg fossil(s) may have survived after all these years. I'm going to try to contact Klaus again for more details.
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otodus
Junior Member Rank 1
Posts: 20
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Post by otodus on Oct 18, 2024 22:59:47 GMT 5
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Post by elosha11 on Nov 3, 2024 0:18:17 GMT 5
@otudus Thanks for posting. For those who want to read the full abstract (can't copy it) go to Otudus' link above and scroll down to pp 494-495 of the SVP program. And indeed, the researchers estimate that if the 23 cm Denmark specimens were accurately measured in the 1983 scientific publication (and probably assuming the 23 cm centra was the largest in the skeleton), that specimen would scale to approximately 24 meters. This presentation was this past Thursday, on October 30. Grey@life theropodAnyone else have any more details or know when we might expect to see the full published article? |
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Post by elosha11 on Nov 4, 2024 0:19:27 GMT 5
Was able to find the official link to the SVP program, and copy the full abstract, still on pp. 494-95. vertpaleo.org/wp-content/uploads/2024/10/2024_SVP_Program_Final3.pdfHow large was the Neogene megatooth shark, Otodus megalodon (Lamniformes: Otodontidae)? Shimada, Kenshu1, Wood, Jake J.2, Sternes, Phillip C.3, Siversson, Mikael4 1Department of Environmental Science and Studies & Department of Biological Sciences, DePaul University, Chicago, Illinois, United States, 2Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida, United States, 3Department of Evolution, Ecology, and Organismal Biology, University of California at Riverside, Riverside, California, United States, 4Department of Earth & Planetary Sciences, Western SVP 2024 Program Guide 494 Australian Museum, Welshpool, Western Australia, Australia Otodus megalodon (Lamniformes: Otodontidae) is an iconic late Neogene shark. Because no complete skeleton of the species is known to date, its total length (TL) has traditionally been estimated based on comparisons with the teeth or vertebrae of the extant white shark, Carcharodon carcharias. Recently, previous TL estimates based on C. carcharias have been called into question by recognizing that the length of an incomplete vertebral column of O. megalodon from the Miocene of Belgium (IRSNB P 9893: Royal Belgian Institute of Natural Sciences, Brussels) measures about 11.1 m without the neurocranium or caudal f in, which is considerably greater than the previous TL estimate made for the individual based on C. carcharias. However, no further TL assessment of O. megalodon has been made since then. To determine the TL of O. megalodon based on IRSNB P 9893, we surveyed the proportional relationships of the neurocranial length and caudal fin length compared to the trunk length (= precaudal vertebral column length) across diverse extinct and extant neoselachian sharks comprising ten orders, 45 families, 119 genera, and 164 species. Whereas the median neurocranial length and caudal fin length are, respectively, 18.3% and 33.5% of the trunk length for all examined 164 species combined, they are 16.6% and 41.8%, respectively, in Lamniformes comprising four extinct genera and all 15 extant species in the dataset. If goblin sharks (mitsukurinids) and thresher sharks (alopiids) with a uniquely elongated neurocranium or caudal fin are excluded from the dataset of Lamniformes, those percentages are 16.6% and 32.6%, respectively. Because IRSNB P 9893 is considered to include a few caudal vertebrae and to have likely gently arched in life, we tentatively considered the vertebral column length consisting only of trunk vertebrae to be about 11 m. If the percentages attained from the ‘non-mitsukurinid/non-alopiid lamniforms’ are used to calculate the possible neurocranial length and caudal fin length for IRSNB P 9893, they would have been 1.8 m and 3.6 m, respectively, making the O. megalodon individual to have measured about 16.4 m TL. Whereas the largest vertebral centrum in IRSNB P 9893 measures 15.5 cm in diameter, the largest known putative vertebra of O. megalodon ever reported is photographic evidence from the Miocene of Denmark measuring about 23 cm in diameter. If the evidence is taken at face value, that O. megalodon individual would have measured around 24 m TL. |
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Post by elosha11 on Nov 11, 2024 19:18:35 GMT 5
theropodI noticed in your analysis of the Denmark fossils on deviant art using the Shimada methodology you got 23.6 meters, basically the same as the researchers estimate of about 24 meters. Nice analysis.
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Post by theropod on Nov 11, 2024 22:25:54 GMT 5
theropodI noticed in your analysis of the Denmark fossils on deviant art using the Shimada methodology you got 23.6 meters, basically the same as the researchers estimate of about 24 meters. Nice analysis. There is little analysis, but also very little surprise there. The two figures are so similar because they are based on the exact same, hyper-simplistic, and very straightforward method: isometric scaling from BRSNB P 9893. I originally scaled up from 15.9 m estimate made for the specimen (Cooper et al.), which was the only reasonable TL available at the time, since Sternes et al. (while they had made the claim that it was too low), did not provide any quantified alternative estimate in their original paper. In their recent abstract for SVP 2024, Shimada et al. finally provided such an estimate, and it ended up a lot closer to the original figure than what all the hyperbolic interpretations that are so widespread online (but probably fueled by the schematic illustration of the concept in Sternes et al., which originally depicted a much more dramatic length increase) would have led to believe (including, of course, the 28 m version I commented on). Their estimate for BRSNB P 9893 was 16.4 m, which, despite Sternes et al.’s vehement rejection of Cooper et al.’s research, is actually just a mere 3.1% difference (it is quite funny considering the drastic length increase many anticipated or already assumed based on the paper). Since those 3.1% are also just a length difference (the shark wouldn’t be wider or deeper-bodied than Cooper et al.’s version, on the contrary Sternes et al. imply that the opposite should be the case), in actuality they imply barely any change in size (and if there is one, it is unclear if it is upwards or downwards, seeing as the robusticity issue is yet to be quantified). From that revised figure, one gets 24.3 m for the Danish specimen as per Shimada et al.’s scaling in their abstract. |
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Post by elosha11 on Nov 12, 2024 19:11:30 GMT 5
theropodThanks. If the supposed close to full length skeleton from Peru with supposed 26 cm vertebrates can finally be verified and studied, it will go a very long way towards answering these questions as to Megalodon's body shape and length. Grey stated a few months ago that one of the Livyatan's leading researchers, Olivier Lambert, confirmed the existence of this skeleton. We shall see if anything comes out of it.
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Post by theropod on Nov 13, 2024 4:47:28 GMT 5
Considering I’ve been hearing varying claims about this skeleton (at one point I recall was told there were at least three, not sure what happened to the other two) for over a decade now, and how there has been essentially zero progress since then, I’m not exactly holding my breath.
If such a skeleton ever does end up being scientifically documented, it would obviously go a long way towards verifying that the extremely weird proportions of IRSNB P9893 are genuine, and hopefully also give us a solid idea of the proportions between the vertebral column and jaws. It would not, however, tell us much else about the body shape, unless there is some sort of body outline preservation (which I severely doubt is the case based on what photos I’ve seen shared of the finds or associated material). We have to keep in mind that "skeleton" in this case likely means "set of jaws with a more or less complete and articulated vertebral column attached", so it still wouldn’t answer questions related to the shape and extent of tissues that would have been around that vertebral column, but aren’t preserved. I.e. we still wouldn’t know how robust or slender the animal’s body was, we would still need to find ways to infer that from extant sharks.
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Post by elosha11 on Nov 18, 2024 23:16:10 GMT 5
^Good points. I share your skepticism. The only thing that gives me some encouragement is that Grey stated Olivier Lambert gave him some confirmation of the skeleton(s) authenticity and, presumably, accessibility. So, we'll see if anything ever comes out of it.
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