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Post by Runic on May 30, 2013 2:30:11 GMT 5
I don't either grey.
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Post by Grey on May 30, 2013 2:31:23 GMT 5
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Post by theropod on May 30, 2013 2:59:42 GMT 5
Judging from killing apparatus I infer Livyatan had a much smaller maximum prey size than Megalodon. Of course i'm basing this on jaws alone so I may be wrong. That's what I infer too. I've posted scientifical viewpoint on that manner. Christian De Muizon about Livyatan :
Let us be clear, it could not have tackled a 35 meters blue whale. But there was at that time a large number of small baleen whales specimens measuring between 5 and 7 meters and which were all chosen preys for such a sea monster. theworldofanimals.proboards.com/thread/6/livyatan-melvilleiLeonardo Compagno about megalodon : Compagno (1990b:57) hypothesized that Carcharodon megalodon "may have been capable of preying on large baleen whales without the cooperative pack-hunting tactics that the smaller killer whale apparently needs to use to subdue difficult prey....Various reconstructions of the jaws of C. megalodon...suggest that this shark had a predatory apparatus capable of inflicting mortal injuries on even a fin whale or blue whale."
The Neogene Sharks, Rays, and Bony Fishes from Lee Creek Mine, Aurora, North Carolina Robert W. Purdy, Vincent P. Schneider, Shelton P. Applegate, Jack H. McLellan, Robert L. Meyer, and Bob H. Slaughter This fits what we see in other animals, tough I am not fully convinced a large Livyatan wouldn't have posed a threat to a large baleen whale. Wide-gaped jaws, capable of extracting chunks of meat of big animals, and killing by immobilising prey and letting it bleed to death, are associated with gigantophagy in other animals too. These same jaws are not necessarily the more deadly ones in a fight between similar-sized animals tough, I recall that you agree with that from comparable scenarios in theropods were you even favoured the crushing-type. The lamniform being larger is not proven, it bases on conservative figures for Livyatan. A more balanced point of view would be the assumption that both were similar in size. I myself would say a lenght close to 18m is maybe more likely for the Livyatan holotype, based on estimates derived from Zygophyseter and comparison with other raptorial cetaceans. It didn't necessarily have a strict, physeteroid body plan very much like Physeter in head-body proportions. However that's my opinion. 18m is definitely not the average size of C. megalodon btw, we are talking about an at least fairly large individual here. De Muizon also states it to be about the size of Physeter in the video Grey posted. There isn't a lot of new data I can provide for now, but I heard something about a new paper on Livyatan which might help us. And again, that jaw-comparison is certainly better than the lateral pencil sketch with odd gapes, however not conclusive either. Livyatan is behind the guy used for scale, Megalodon is in front of him. Livyatan's longer jaws produce a bias here, since it's posterior cranium is about 2-3m further away from the camera than the jaws of the otodontid. |
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Post by Grey on May 30, 2013 3:30:08 GMT 5
That's what I infer too. I've posted scientifical viewpoint on that manner. Christian De Muizon about Livyatan :
Let us be clear, it could not have tackled a 35 meters blue whale. But there was at that time a large number of small baleen whales specimens measuring between 5 and 7 meters and which were all chosen preys for such a sea monster. theworldofanimals.proboards.com/thread/6/livyatan-melvilleiLeonardo Compagno about megalodon : Compagno (1990b:57) hypothesized that Carcharodon megalodon "may have been capable of preying on large baleen whales without the cooperative pack-hunting tactics that the smaller killer whale apparently needs to use to subdue difficult prey....Various reconstructions of the jaws of C. megalodon...suggest that this shark had a predatory apparatus capable of inflicting mortal injuries on even a fin whale or blue whale."
The Neogene Sharks, Rays, and Bony Fishes from Lee Creek Mine, Aurora, North Carolina Robert W. Purdy, Vincent P. Schneider, Shelton P. Applegate, Jack H. McLellan, Robert L. Meyer, and Bob H. Slaughter This fits what we see in other animals, tough I am not fully convinced a large Livyatan wouldn't have posed a threat to a large baleen whale. Wide-gaped jaws, capable of extracting chunks of meat of big animals, and killing by immobilising prey and letting it bleed to death, are associated with gigantophagy in other animals too. These same jaws are not necessarily the more deadly ones in a fight between similar-sized animals tough, I recall that you agree with that from comparable scenarios in theropods were you even favoured the crushing-type. The lamniform being larger is not proven, it bases on conservative figures for Livyatan. A more balanced point of view would be the assumption that both were similar in size. I myself would say a lenght close to 18m is maybe more likely for the Livyatan holotype, based on estimates derived from Zygophyseter and comparison with other raptorial cetaceans. It didn't necessarily have a strict, physeteroid body plane very much like Physeter in head-body proportions. However that's my opinion. 18m is definitely not the average size of C. megalodon btw, we are talking about an at least fairly large individual here. de Muizon also states it to be about the size of Physeter in the video Grey posted. There isn't a lot of new data I can provide at now, but I heard something about a new paper on Livyatan which might help us. And again, that jaw-comparison is certainly better than the lateral pencil sketch with odd gapes, however not conclusive either. Livyatan is behind the guy used for scale, Megalodon is in front of him. Livyatan's longer jaws produce a bias here, since it's cranium is about 2-3m further away from the camera than the jaws of the otodontid. Theropods match up are not good analogues. Megalodon is not a carcharodontosaurid, nor its killing apparatus, nor in its morphology and size compared to Livyatan than carcharodontosaurs with T. rex. There's no proxy here. That's not a question of the lamniform or the whale being larger proven or not, that's a question of which size both had ? At best for Livyatan, it only equals some of the large, accepted estimates for megalodon, if we follow the litterature. Megalodon being slightly larger is somewhat supported by several authors that I've quoted several times. I don't understand why you insist with Livyatan being closer to 18 m, whereas nothing supports this more than the lower bound. Lambert only confessed that more than 15 m is what he thinks the most likely, but nobody here argues the upper is the better, both are valuable. De Muizon and others argue it is the size of Physeter. Yes, since Physeter ranges from 15 to 18 m. In litterature, it is listed at 18,3 m. Livyatan upper estimate is at 17,5 m. In private mail I had posted, De Muizon state both animals being of the same size, at 15 m. Also, I don't know why you keep insisting at making Livyatan different than a sperm whale body shape. Are the others macropredatory forms built like orcas ? No. And they are closer than orca in size. Why Livyatan would be ? 18 m is not an average size for megalodon, that's obvious. But why the holotype of Livyatan would be necessarily a small or average individual and no matter it was nearer than 13,5 m or 17,5 m ? That's speculations. We have one individual, we do with what we have. Regarding megalodon reconstructions I don't use the proposed upper sizes. And no matter the actual body length, I look at the actual predatory apparatus. The last photos I've posted with both jaws are not scaled each other at the same size. Their purpose is to show their size compared to a man, and the dimensions of their jaws in width as well as lentgh. In Livyatan, you clearly see that the guy (Big Al) is almost sit on the tip of the mandible. You can appreciate both the length of the jaws and its width. The volume is clearly dwarfed by megalodon's jaws. The guy with the megalodon is just in front of the jaws, perhaps just one feet beyond (check the video), and here too you can appreciate both the width and the lateral length of the jaws. Frankly, I've posted differents photos from different angles and each time the result is the same. Megalodon jaws appear just much larger overall. Once again, these jaws represent large megalodon but not by liberal standard, I try to be as fair as possible. |
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Post by theropod on May 30, 2013 3:41:21 GMT 5
I think you inferred C. megalodon winning this based on supposed superior bite? Size is very debateable, so is the bite, however the latter is what we at least have fossils to infer it from.
If you rather support the biting mode of the shark, that is understandable, but I just note you do not do that always, which means you must be aware of the obvious differences.
The Livyatan holotype beigng the only individual is likely just of average size. no reason to compare it to the largest specimens of C. megalodon.
There is nothing wrong with assuming proportions more like those of Zygophyseter, I merely think these proportions are more likely because of its ecological niche. No Orca-like proportions needed, tough those would potentially result in sizes exceeding 20m, just those published in its official description or even inferred from one specimen of Physeter.
I was talking about the last comparison.
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Post by Grey on May 30, 2013 3:56:38 GMT 5
I think you inferred C. megalodon winning this based on supposed superior bite? Size is very debateable, so is the bite, however the latter is what we at least have fossils to infer it from. If you rather support the biting mode of the shark, that is understandable, but I just note you do not do that always, which means you must be aware of the obvious differences. The Livyatan holotype beigng the only individual is likely just of average size. no reason to compare it to the largest specimens of C. megalodon. There is nothing wrong with assuming proportions more like those of Zygophyseter, I merely think these proportions are more likely because of its ecological niche. No Orca-like proportions needed, tough those would potentially result in sizes exceeding 20m, just those published in its official description or even inferred from one specimen of Physeter. I was talking about the last comparison. My assumption of megalodon winning is based on a combination of bite force potency, slicing, exsanguination potency and size volume of the bite. I focuse on the killing apparatus size of both, not even their actual body size. The size of the bite in megalodon is not really debatted, the reconstructions I've posted have been made by paleontologists or supervised by paleontologists, not by amateurs. And they do not represent the highest body sizes in litterature. I avoid to use the largest reconstructed jaws normally. Why the holotype of Livyatan is likely an average individual ? That's probable yes but it could be too a slightly larger or slightly smaller individual than the average. Nothing indicates this is necessarily an average animal. All what we know is that it was an adult of that species, probably died at an advanced age, as nothing suggest a disease or a predation on it. Even so, if it's an average-sized animal, we still don't know its precise size, that's why I consider 15 m or so as safe guess. And I don't even compare it with the largest reconstructions of megalodon. Also we can speculate at length on the plausible or implausible size of a species that we don't even know the precise size because known only by an isolated skull...bad science if you ask me. Fair enough if you compare it with Zygophyseter more than orca, since it is used as a size proxy in the publication... But you forget that 17,5 m is based on the most liberal estimate for Zygophyseter itself, the lower giving a size of 16,2 m. And just like for megalodon estimates, the margin of error is vast as Livyatan is far beyond the data range, based itself on an incomplete proxy ( Zygophyseter). And again, I did not see anything stating Zygophyseter being that bulky. Here's a reconstruction of Livyatan with the sperm whale. Given the proportions and size between the two skulls, I believe they are intended each other scaled up. If this is true, Livyatan does not appear to be literally as big as the sperm whale, but more compact.  In the last comparison I posted, just take a look at the teeth rows of both on each pics. Do I need to say more ? The tooth row in the inferior mandibe of Livyatan is just short compared to megalodon. It is not even the length of an adult man. Look at the inferior teeth row in the meg jaws. It is even far wider than long is the tooth row in Livyatan, even its superior teeth row. Look at the width of the most posterior teeth in Livyatan's mandible. It is barely wider than Big Al's body. Look at the width of the most posterior teeth in the mandible of the meg. Do I need say more ? You can even compare the width of the entry of the gullet of Livyatan and compare with megalodon's width at the same point. That's quite clear there's no comparison there. At the very worst, it simply seems to show that the sizes of the preys items in megalodon were beyond the size of Livyatan's preys. That's what indicate the words of the authorities I quoted (De Muizon and Compagno). What else is needed really ? Yes of course, there are still uncertainties in megalodon's jaws structure, perhaps future findings will disprove it or not. But that reconstruction is considered as scientifically reliable. Just like for Livyatan, we do with the best we have at the moment... |
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Post by Runic on May 30, 2013 4:04:52 GMT 5
It's likely an average individual because it is nearly impossible to find extremely large specimen of an extinct animal. Mainly because bones stop growing at a certain age (except for the skull I think)
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Post by Grey on May 30, 2013 4:15:28 GMT 5
It's likely an average individual because it is nearly impossible to find extremely large specimen of an extinct animal. Mainly because bones stop growing at a certain age (except for the skull I think) It is not impossible to found a large (who talks of extremely large ?) individual in fossils. Larger specimens are likely to be well preserved (because of larger more robust bones), and smaller are likely to be preserved because of the larger number of these individuals. But there's no reason to think it is obligatory an average one. Matt Wedel about this question : For the dinosaurs, is imposible to find record specimens fossils, the largets fossils we found are normally the average size of the real animal.
"Actually, we donÂ’t know this. ItÂ’s not impossible to find record specimens, merely unlikely. And we donÂ’t know if the fossils we find are average-sized, or slightly smaller (which should be more numerous) or slightly larger (which might be easier to preserve). Probably they are close to the average, but we have no cause to feel certain." |
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Post by Runic on May 30, 2013 4:22:45 GMT 5
^ That's exactly my point. The Livyatan we have is more than likely an average individual (not the biggest or close to it based on the rarity of finding above average extinct specimens). We simply need more samples.
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Post by Grey on May 30, 2013 4:25:26 GMT 5
^ That's exactly my point. The Livyatan we have is more than likely an average individual (based on the rarity of finding above average extinct specimens). Not above average. We simply need more skeletons. Your sentence contradicts what's you're saying to be agreed with.  Wedel :
Probably they are close to the average, but we have no cause to feel certain. |
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Post by Runic on May 30, 2013 4:26:11 GMT 5
^ That's exactly my point. The Livyatan we have is more than likely an average individual (based on the rarity of finding above average extinct specimens). Not above average. We simply need more skeletons. Your sentence contradicts what's you're saying to be agreed with. Wedel :
Probably they are close to the average, but we have no cause to feel certain.
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Post by Runic on May 30, 2013 4:27:30 GMT 5
I edited my reply before you quoted Grey. God I can't get this quoting right -_-
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Post by Grey on May 30, 2013 4:30:51 GMT 5
^ That's exactly my point. The Livyatan we have is more than likely an average individual (not the biggest or close to it based on the rarity of finding above average extinct specimens). We simply need more samples. That still contradicts my quote from Wedel !
And we donÂ’t know if the fossils we find are average-sized, or slightly smaller (which should be more numerous) or slightly larger (which might be easier to preserve). |
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Post by Runic on May 30, 2013 4:32:23 GMT 5
No it doesn't, he actually sorta agrees with me. Where does he state "Or some of the largest of their species" at? I do see this though,
"ItÂ’s not impossible to find record specimens, merely unlikely"
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Post by Grey on May 30, 2013 4:41:26 GMT 5
For the dinosaurs, is imposible to find record specimens fossils, the largets fossils we found are normally the average size of the real animal.
Actually, we donÂ’t know this. ItÂ’s not impossible to find record specimens, merely unlikely.
You stated it was almost impossible.
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