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Post by Grey on Dec 2, 2014 10:17:22 GMT 5
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Post by Godzillasaurus on Dec 2, 2014 20:52:06 GMT 5
The fulcrum is the point where the bite force would naturally be the strongest, simply because that is the area least-affected by distance from the origin of the force (jaw muscles). But just like you said, of course that is also the least-practical area to bite with in predator, unless of course that said animal is going to be crushing shellfish or turtles. The fulcrum of the jaw equals the craniomandibular joint. It's the least practical region to bite with because it does not bear teeth, and because the jaw muscles are in the way of putting something in there to bite it… I did not disagree with this...... |
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Post by theropod on Dec 2, 2014 21:19:39 GMT 5
I’m sure mosasaurus hoffmanni did have an enourmous bite force, in absolute terms. Whether it had one in relative terms remains to be seen, bite marks alone are no good evidence for bite force estimates (tough they can serve to further support inferences drawin from functional anatomy). Godzillasaurus: I read an "unless" in there…that means that you think there are circumstances were the fulcrum of the jaws was not the least practical (which is itself already wrong, because it’s impossible to bite something with a joint!). Namely that was "unless of course that said animal is going to be crushing shellfish or turtles". |
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Post by Grey on Dec 2, 2014 22:12:38 GMT 5
I've contacted famous fossil collector of marine Late Jurassic Fauna Steve Etches. He said me this mandible (in his possession) measures 2 m long.   He's not aware of something larger (under previate hands) from the Kimmeridge Clay. |
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Post by theropod on Dec 2, 2014 22:48:34 GMT 5
Looks impressive. But P. kevani at least is larger, it has a skull lenght of about 2m (originally reported as more), and pliosaur mandibles are slightly longer than their skulls.
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Post by Godzillasaurus on Dec 3, 2014 20:23:38 GMT 5
I’m sure mosasaurus hoffmanni did have an enourmous bite force, in absolute terms. Whether it had one in relative terms remains to be seen, bite marks alone are no good evidence for bite force estimates (tough they can serve to further support inferences drawin from functional anatomy). Godzillasaurus: I read an "unless" in there…that means that you think there are circumstances were the fulcrum of the jaws was not the least practical (which is itself already wrong, because it’s impossible to bite something with a joint!). Namely that was "unless of course that said animal is going to be crushing shellfish or turtles". Oh, right. What I meant to say was that biting with the posteriormost region of the jaws (just anterior to the joint) would be very much practical in crushing smaller animals as long as there were teeth in that region. Of course it cannot bite something with the joint itself; that is ludicrous as you said! Grey, those are excellent photographs of that pliosaur mandible! |
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Post by theropod on Dec 3, 2014 20:28:45 GMT 5
That was my point. Hence why the figures refer to the posterior end of the toothrow, not the fulcrum.
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Post by Godzillasaurus on Dec 3, 2014 20:43:29 GMT 5
Oh, I gotcha
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Post by Godzillasaurus on Dec 3, 2014 20:44:06 GMT 5
Grey, I must ask, is that an actual fossil finding or a reconstruction?
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Post by Grey on Dec 4, 2014 11:49:25 GMT 5
Godzillasaurus, that's a real mandible from a pliosaur of the Kimmeridge Clay.
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Post by Grey on Dec 8, 2014 8:40:24 GMT 5
ashipunov.info/jurassic/j/Manuals&Classica/1991_fossils%20of%20the%20oxford%20clay.pdfThe guide where Martill refers to teeth in excess of 40 cm at page 226 but no substantial data. It seems like Martill is still in the opinion that some Callovian and Kimmeridgian pliosaurs reached 18-20 m long based on fragmentary remains. I've tried to contact him but he's in a trip and will be back only and the end of the month. I wonder if the material he refersare the Perteborough vertebra and the BHM symphisis, and if so if he's aware of McHenry's estimates from these pieces. Or if he simply refers to other unpublished material unknown to us. I've found again the BBC page explaining the choice of Liopleurodon size. Nothing new but worth to link it. www.abc.net.au/dinosaurs/chronology/149/making.htm
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Post by coherentsheaf on Dec 8, 2014 15:03:56 GMT 5
Grey, if you contact him, try to ask where n Andrews the giant teeth are described. I gave it a look and found othing, but I may have missed something.
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Post by Grey on Dec 8, 2014 15:58:02 GMT 5
I ve sent him an email but he's in Morroco right now and wont be back before the end of the month. Hopefully he responds to my queries.
Oddly, I dont have any news from Richard Forrest anymore. That douchebag of Max Hawthorne said it was him who said him "20 m pliosaurs were likely". But all the emails I have from Forrest are very reserved about that. Maybe he has updated his opinion based on new located undescribed remains, who knows. I ll try again to reach him. I need to ask him too about his article of bite force for kevani.
I m also in contact with McHenry on FB but he did not respond yet.
Coherentsheaf, if these 40-45 cm pliosaurs are real, depending if they're from a Pliosaurus-like species or a Liopleurodon species, can they correspond in some manner to 20 m monsters ?
At least it would be interesting to note they would beat Livyatan as the largest teeth known.
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Post by theropod on Dec 8, 2014 17:21:38 GMT 5
At least as the longest, those of Livyatan are also remarkably tick (more so than the pliosaur teeth I’ve seen so far).
Another mention of teeth exceeding 40cm, this time in a scientific book, imo makes them a lot more credible than if solely based on a historic part of a website. McHenry wrote that the 33cm Pliosaurus tooth figured by Owen would correspond to an animal of ~10m using the maximally conservative assumption (that it is the largest in the dentition).
Considering that pliosaur teeth definitely vary several-fold in terms of size within one dentition, it’s not impossible that a tooth that size would be from such a behemoth. However, that’s a very speculative argument, as it’s more parsimonous that it’s one of the larger teeth (especially seeing as how that way it corresponds much closer to normal pliosaurs). That could even eb applied to smaller teeth.
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Post by coherentsheaf on Dec 8, 2014 19:17:46 GMT 5
40-45cm teeth would probably correspond to 13-15m (edit, miscalculated)pliosaurs if scaling from Kronosaurus is any indication. 20m seems to be pushing it.
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