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Post by dinosauria101 on Sept 3, 2019 21:43:28 GMT 5
@dinosauria: What, he just wrote 15 tons in the very same post you are referring to! I'm not sure what you mean by that |
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Post by theropod on Sept 3, 2019 21:54:39 GMT 5
Well, you answered to this: If Aramberri or Sachicasaurus were around 15 tonnes in body mass, they would have had a posterior bite force as high as what Wroe calculated for a 48 tonnes Otodus.With this: That's very interesting! I'd think a 20-25 ton pliosaur would be needed to match Megalodon's bite if that holds trueThat I don’t think the first statement is quite accurate notwithstanding (I just showed the figures for Sachicasaurus again, as for Aramberri, if it isn’t proportionately bigger-skulled than McHenry assumed for Pliosaurus macromerus, its dry-skull bite force also wouldn’t be much more than 9t):
A: "This 15t animal has the same bite force as this other animal of 48t." B: "Very interesting! I think it would have to be 20-25t to have the same bite force as this other 48t animal then!" See what I mean? Now don’t get me wrong, I think 20-25t is actually way more realistic for a pliosaur with a comparable bite force. That would still be an almost twice higher bite force at comparable body mass, like the difference between T. rex and Giganotosaurus. But known pliosaurs weren’t that big. |
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Post by Grey on Sept 3, 2019 21:56:18 GMT 5
Theropod, what about using also Sachicasaurus skull width ?
I was expecting meg comparable forces since you expect Aramberri to have had a bite force in this neighborough of 10 kN. The vertebra measurements of Aramberri appear to be very much comparable to the corresponding measurements in Sachicasaurus.
Given its enormous skull and dentition, I was expecting something similar for it.
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Post by dinosauria101 on Sept 3, 2019 21:57:29 GMT 5
Well, you answered to this: If Aramberri or Sachicasaurus were around 15 tonnes in body mass, they would have had a posterior bite force as high as what Wroe calculated for a 48 tonnes Otodus.With this: That's very interesting! I'd think a 20-25 ton pliosaur would be needed to match Megalodon's bite if that holds trueThat I don’t think the first statement is quite accurate notwithstanding (I just showed the figures for Sachicasaurus again, as for Aramberri, if it isn’t proportionately bigger-skulled than McHenry assumed for Pliosaurus macromerus, its dry-skull bite force also wouldn’t be much more than 9t):
A: "This 15t animal has the same bite force as this other animal of 48t." B: "Very interesting! I think it would have to be 20-25t to have the same bite force as this other 48t animal then!" See what I mean? Wasn't Megalodon around 60-75 tons? I was under that assumption when I posted that |
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Post by theropod on Sept 3, 2019 22:01:04 GMT 5
Theropod, what about using also Sachicasaurus skull width ? I was expecting meg comparable forces since you expect Aramberri to have had a bite force in this neighborough of 10 kN. The vertebra measurements of Aramberri appear to be very much comparable to the corresponding measurements in Sachicasaurus. Given its enormous skull and dentition, I was expecting something similar for it. Yes, but that was based on in-vivo scaling (even though it was the adapted equation from the Purrussaurus paper, which gives less astronomic results, it could still be higher than dry-skull estimates for the same specimens). Scaling based on comparable methods would give it a somewhat lower figure, see post above. I haven’t tried skull width, that is an interesting proposal. P. kevani is around 80cm wide at the jaw joint according to Foffa et al. Based on the figure, I got around 1.3m for Sachicasaurus (see earlier post regarding skull width). That could indeed support 10t+ bite forces. But I’m not so convinced I buy it. Going to look into this more. A skull comparison of the two would be interesting… |
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Post by theropod on Sept 3, 2019 22:03:19 GMT 5
Wasn't Megalodon around 60-75 tons? I was under that assumption when I posted that Some megalodon were probably that size. 48t is still a perfectly reasonable estimate for a good-sized adult megalodon. Depending on the method, this has even been published as a maximum size estimate (by Gottfried et al. 1996, the study to originally propose the figure), even though recent revisions of size estimate methods make that improbable. |
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Post by creature386 on Sept 3, 2019 22:03:39 GMT 5
Wasn't Megalodon around 60-75 tons? I was under that assumption when I posted that There is no universal consensus how much Megalodon weighed, much less what its average weight was (or how that could even be defined). See, you can't always assume others think the way you do, that's why being specific can avoid misunderstandings. |
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Post by dinosauria101 on Sept 3, 2019 22:05:59 GMT 5
Yeah that makes more sense.
Next time I'll include the weights for an animal I had in mind
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Post by Grey on Sept 3, 2019 22:06:02 GMT 5
I find interesting that as of 2019 we find the remains of 15-20 m or more marine fauna from the Neogene (Livyatan sp.; ancestral balaenopterids; O. megalodon, even relying only on the rare centra) as well as from the Triassic (shastasaurids) and the Jurassic (pachycormids), yet we don't have any good remains of any pliosaur surely over 12 m, and only a very tentative upper estimate is known for an obscure symphysis fragment.
Not to say there were no larger pliosaurs, there were certainly, but if we can easily envision 17 m as a reasonable size for most of those taxa, pliosaurs are pretty far from it as of now.
The mosasaurs presumably went extinct before they could evolve even larger.
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Post by Grey on Sept 3, 2019 22:12:41 GMT 5
Wasn't Megalodon around 60-75 tons? I was under that assumption when I posted that That is certainly possible but this depends the actual length and girth of the body. Some suggests meg was a bit less bulky than Gottfried 1996 suggestions. But it appears pretty sure this species at least could reach sometimes 18 m. If you use Gottfried equations, you get the figures you suggested. If you use a more mako-like build, you still get 50 tonnes. So a 48 tonnes meg is a totally reasonable conservative estimate, and again, the weight of sharks can vary a lot depending the season... |
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Post by theropod on Sept 3, 2019 22:12:43 GMT 5
Yes, there is a rather significant size gap there between pliosaurs and the "super-giants". But as I wrote, we don’t know whether it is due to intrinsic or extrinsic factors. Would pliosaurs have been unable to grow larger than that, or was there just no reason for them to do so? Both are possibilities.
At least there is evidence pliosaurs were very capable apex predators, in spite of their relatively modest size and, alledgedly, weak skulls. Biting in half large ichthyosaurs and attacking giant pachycormids is everything you could expect a Jurassic/Lower Cretaceous apex predator to do, whether it is 10 tons of 50 tons.
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Post by Grey on Sept 3, 2019 22:17:23 GMT 5
Maybe a combination of both>>> based on what we have today, a 15 m pliosaur appears to be a good scientific possibility, not reality. A 18 m pliosaur is pure fiction.
Also, is it me or the recent Aristonectes specimen estimated at 15 tons appear to be the heaviest plesiosaur (including pliosaurs) formally described and named ?
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Post by Grey on Sept 3, 2019 22:20:35 GMT 5
their relatively modest size and, alledgedly, weak skulls. Biting in half large ichthyosaurs and attacking giant pachycormids is everything you could expect a Jurassic/Lower Cretaceous apex predator to do, whether it is 10 tons of 50 tons. I was also thinking about the indications that they extremely generalists and not exclusively macrophagous, yet able to tackle even on giant, fast pachycormids. McHenry determined that Kronosaurus prey size ranged from 3kg to 3000 kg I think. This very wide range added to formidable caoabilities could explain this. |
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Post by theropod on Sept 3, 2019 22:55:14 GMT 5
Well, no large marine predator is "exclusively macrophagous". Orcas or great whites eat lots of juvenile seals, penguins and fish. By all means, Foffa et al. are certainly right to consider a prey item half the predator’s body length to already be quite large, even if I disagree that this is the largest a pliosaur could take.
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Post by theropod on Sept 3, 2019 23:03:53 GMT 5
 Judging by scaling to actual measurement and measuring the same in both, actual greatest skull width seems more like 130 vs 90cm. You can really appreciate in this how Sachicasaurus’ skull may only be 25cm longer than that of P. kevani, but it is way larger overall. Attachments:
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