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Post by creature386 on Mar 4, 2014 1:50:13 GMT 5
Wow, I really need to read this paper more often, it has so much information I have overlooked (like the length/weight story). in this case you do not even need to read. Before reading what blaze wrote I did a few quick plausibility calculation and my estimate for stresses in a croc bite was not far off what blaze posted. I think learning to do fermi estimates on the fly will improve your abilities in judging such stuff: www.youtube.com/watch?v=0YzvupOX8IsMy problem was not the number itself, I simply didn't know the bite pressure of animals for comparison. As for your video, I understand what he did, but I guess I will have to practice how to use it in practical examples. What assumptions would I need to use it for bite force/bite pressure?
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Post by coherentsheaf on Mar 4, 2014 2:13:59 GMT 5
in this case you do not even need to read. Before reading what blaze wrote I did a few quick plausibility calculation and my estimate for stresses in a croc bite was not far off what blaze posted. I think learning to do fermi estimates on the fly will improve your abilities in judging such stuff: www.youtube.com/watch?v=0YzvupOX8IsMy problem was not the number itself, I simply didn't know the bite pressure of animals for comparison. As for your video, I understand what he did, but I guess I will have to practice how to use it in practical examples. What assumptions would I need to use it for bite force/bite pressure? Start off: How much area has a tooth at the tip? They look pointy, so maybe 1mm². How hard daoes a croc bite? Well crocs bite hard, so maybe 10^4N. How many teeth is the bite distributed on? Around 10. Multiplying this together we get an estimate for the pressure: 1 billion Newton per square meter, in line with the empirical figure.
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Post by Grey on Mar 4, 2014 5:35:20 GMT 5
As blaze remarked, pressure values become high quickly. To illustrate this, take a needle that is pressured by human body mass. Suppose its tip is somewhat narrow measuring 0.01 mm^2 and the man sitting on it weighs 100kg. Then the stress experience at the tip of the needle by the man is: 10 billions kg per square meter. So there you have it. A needle has "more force than Dukleosteus". Of course this calculation is total bollocks if you want to estimate biting potency. So is this: "The final result? Hundreds of millions of pascals! This is no joke. ~107-147 meganewtons/m2, or ~15,519-21,320.5 pounds/inch2, if you prefer. This is not a fanboyistic overestimation, this is a serious scientific figure. "The bladed dentition of Dunkleosteus provided for extremely high local bite stress (force/area) because the bite force was focused into a small area, the fang tip (147 million N m-2) or the blade edge (107 million N m-2)." To put that in perspective, the water pressure at the bottom of the deepest point in the Marianas Trench is estimated to be about ~108,592,427 newtons/m2 (~15,750 pounds/inch2). In the same ballpark as the FREAKING LOWER FIGURE of Dunkloesteus' bite pressure. This creature is a serious contender for the king of biters. Forget Tyrannosaurus, forget Megalodon, forget Pliosaurus, Dunkleosteus should be among the most cited when it comes to killer bites. It's bite pressure is seriously suspected to surpass the water pressure in the deepest area in the ocean. I bet it could cut through any biological matter ever on Earth. " I can assure you, the forces you wuld experience in the mouth of the tyrant king will be be higher than those by Dunkleosteus by an order of magnitude and s are the peak stresses, just like pliosaurs etcetera. Narrow needles, on the other hand, will beat the Tyrannosaur when it comes to peak stress. I hope users will not be as easily duped into believing such nonsensical statments i the future. To be fair, I once completely understood that, but having forgotten these statements about Dunk, had completly forgotten this, and believing the pressure at the tip was a physical phenomenon exclusive to Dunk. In any case, I'm surprised that Dunk does not have a so huge powerful bite force given its morphology.
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Post by Infinity Blade on Mar 4, 2014 6:03:06 GMT 5
Well that was a bit of an interesting and awesome smackdown regarding Dunkleosteus' bite.
As for the thread, I think this is a close fight.
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Post by Grey on Mar 4, 2014 15:23:46 GMT 5
I think that objectively, Carcharodon and Dunkleosteus are quite equivalant. But I fairly imagine Carcharodon, more advanced, near warm-blooded, skilled at killing large marine mammals, more explosive. Unless Dunk really reached close to 10 m. blaze who proposes quite rigorous reconstructions, suggests that it is unlikely though. His model of Dunk is not as massive as a white shark at similar length either.
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Post by Grey on Mar 4, 2014 16:52:34 GMT 5
THE MOST COMPLETE VERTEBRAL COLUMN OF DUNKLEOSTEUS TERRELLI: RESULTS OF THE CONTINUING LATE DEVONIAN CLEVELAND SHALE (FAMENNIAN) FISH RESEARCH AT THE CLEVELAND MUSEUM OF NATURAL HISTORY JACKSON, Gary1, CHAPMAN, David1, BOYLE, James T.2, ZELINSKI, Dale1, MARTIN, Terry G.1, KLUNDER, Joseph F.1, REICH, Kurt3, REICH, Mark4, ROBISON, Terry L.5, and RYAN, Michael J.1, (1) Dept. of Vertebrate Paleontology, Cleveland Museum of Natural History, 1 Wade Oval Dr, University Circle, Cleveland, OH 44106, gjackson@cmnh.org, (2) Evolution, Ecology and Behavior, State University of New York at Buffalo, 411 Cooke Hall, North Campus, Buffalo, NY 14260, (3) 24785 Gessner Rd, North Olmstead, OH 44070, (4) 5891 Rockport Lane, Fairview Park, OH 44126, (5) Natural Resources Division, Cleveland Metroparks, 4500 Valley Parkway, Fairview Park, OH 44126 The existence of the Cleveland Museum of Natural History (CMNH) is based, in large part, on the rich fossil resources of the Late Devonian (Famennian) Cleveland Shale in the Cleveland area. In the 1830's, a group of amateur natural historians put their large collection of fossils and natural artifacts on display for the public. This collection formed the basis for the foundation of the CMNH in 1920. The Vertebrate Paleontology (VP) Department was established in 1923 as the “Department of Geology and Paleontology”. Its first collector and preparator, Peter A. Bungart also helped amass significant fossil fish collections for the American Museum of Natural History and what is now the Natural History Museum (London), and was instrumental in establishing the study of Devonian fish in North America. The department's first curator, Dr. David H. Dunkle, established the new arthrodire Bungartius perissus in 1947 in Bungart's honor based on the only known two specimens, currently housed at the CMNH. Dunkleosteus was named in Dunkle's honor in 1956. Subsequent work by Dunkle’s successor, Dr. Michael E. Williams investigated arthrodire feeding strategies and predator/prey relationships. Fossil fish collection, preparation and research continues on material collected, in part, from the Cleveland Metroparks. Assisted by the efforts of VP departmental volunteers and local enthusiasts, recent discoveries have included a new specimen of Titanichthys that is being used to rediagnosis this problematic taxon, and the most complete segment of vertebral column known for the Famennian arthrodire Dunkleosteus terrelli. The latter specimen includes a partially articulated skull with at least 12 plates, including lower jaws, and a 14.6 cm long section of at least 20 vertebrae (each approximately 2.5 cm wide x 0.7cm long) that came from a subadult-sized Dunkleosteus that is estimated to have exceeded 3 m in length.
If a subadult D. terrelli exceeds 3 m, I somehow doubt that an adult reached close to 10 m long though.
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Post by DinosaurMichael on Mar 4, 2014 20:49:35 GMT 5
Mismatch.
Dunkleosteus is too big. Better match would be Otodus.
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Post by Grey on Mar 4, 2014 21:52:11 GMT 5
Mismatch. Dunkleosteus is too big. Better match would be Otodus. Not sure it's that big, it could be quite a bit smaller if you have read others comments.
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Post by coherentsheaf on Mar 4, 2014 21:58:58 GMT 5
Mismatch. Dunkleosteus is too big. Better match would be Otodus. Not sure it's that big, it could be quite a bit smaller if you have read others comments. Blaze found somewhere tat large specimen of Dunk were around 6m or larger. For what it is worh there are replica of plates ofa large Dunk for show in the vienna museum of natural history and it feels ver large but not absurdly huge.
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Post by creature386 on Mar 4, 2014 22:16:20 GMT 5
Where has he said the "or larger"? I remember I have posted a paper which said 6 m was already a "large specimen" with which blaze agreed. He even once said "no more than 6 m".
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Post by Grey on Mar 4, 2014 22:26:45 GMT 5
Not sure it's that big, it could be quite a bit smaller if you have read others comments. Blaze found somewhere tat large specimen of Dunk were around 6m or larger. For what it is worh there are replica of plates ofa large Dunk for show in the vienna museum of natural history and it feels ver large but not absurdly huge. It seems to me Blaze stated quite clearly that 6 m was an upper end for Dunk.
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Post by coherentsheaf on Mar 4, 2014 22:42:21 GMT 5
Where has he said the "or larger"? I remember I have posted a paper which said 6 m was already a "large specimen" with which blaze agreed. He even once said "no more than 6 m". Right. In any case anything much larger than that seems unfounded.
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Post by Grey on Mar 4, 2014 22:49:03 GMT 5
Where does come from the mention of 9-10 m, 3 600 kg often reported ? The other being 6 m, 1 000 kg.
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blaze
Paleo-artist
Posts: 766
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Post by blaze on Mar 4, 2014 23:51:20 GMT 5
Anderson and Westneat (2009) mention estimating the biteforce of a 10m long specimen in the abstract but the paper actually says that large specimen was 6m and 1 tonne. Indeed, I've said 6m is the upper end, Carr (2009) the paleoecology of Dunkleosteus terelli, says that known specimens range from 25cm to 6m, that paper is also the only one I've found that explains how they estimate the weight, using a regression equation from north atlantic sharks but that equation gives 1.5 tonnes for a 6m specimen so I don't know how the often quoted 6m and 1 tonne came to be nor I know how they estimate the length in the first place as the body is largely unknown, extrapolating from Coccosteus not even the largest skull I've found info about (72cm long, skull only, including pectoral plates probably approaches 1.3m) gets to 6m comfortably, the one in the size chart I made some time ago is around 5.7m and is already more elongated than commonly depicted.
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Post by Vodmeister on Mar 5, 2014 23:05:40 GMT 5
The Dunk is quite powerful build and that bite looks nasty. It's also a bit bigger than the GWS on average. Dunk wins 8/10 IMO.
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