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Post by Grey on Jun 15, 2013 2:19:17 GMT 5
I've yet to see this suggestion in my various discussions with meg specialists.
In some areas, we see mostly small and average teeth. But they can be indicative of nurseries.
In some regions, several record-sized specimens are regularly found. I imagine then the place at the time, roamed by gigantics sharks perhaps in the 18-19 m range...
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Post by Life on Jun 15, 2013 12:45:30 GMT 5
The information I read on the thread you contributed a considerable amount of suggests it attacked bony regions, even in large preys, but didn't bite through the bones, and comparable bite marks exist of Allosaurus. Eg. that flipper bone of a large whale in the video, it has deep gauges but is not bitten through. If you think I am overlooking something, post the relevant information, because all I see shows C. megalodon as a slicer, albeit a rather brutal one, not a bonecrusher, and did not crush or slice through large bones in large preys, merely damage them while taking out chunks of meat. Surely, a C. megalodon biting off a cetothere's head is not too different from a great white doing so with a human foot or an Allosaurus with a Dryosaurus. I can offer examples which may change your perception:- Example 1:A partially preserved bony segment of a whale was shown in the Deep Sea Killers episode of JFC program which featured a 9 inch long and 3 inch deep cut. Example 2:Look at this bony segment: en.wikipedia.org/wiki/File:Meg_bitten_cetacean_vertebra.jpg This image shows a whale vertebra bitten in half. Example 3:Within an hour, we’re off-roading in a landscape formed over millions of years by colliding tectonic plates. Our first stop: a large fossilized whale skeleton that includes eye sockets, a skull, and a partial spine and vertebrae. So what happened to the rest? “Erosion wouldn’t destroy half a whale,” Roberto says. “No, the lower part had to be taken by something strong, and that’s the megalodon. See the sharp break in the spine? Sometimes you’ll even find teeth marks on the bones.” All around us are earthy-looking heaps, more fossilized skeletons, but Roberto is barely interested in the whales — all he can think about are megalodons.Source: gailharrington.net/jurassicshark.aspx--- Large number of Megalodon bitten fossils have been found in the form of partially preserved bony segments. In most of these cases, much of the victim have been eaten. So yes, Megalodon's killing apparatus was formidable enough to bite through cetacean bones and tear them apart. Agreed with both of the last posts. The age of them is a good point in favour of the argument of different preys. What I wonder is whether we should not see some sort of adaption in Pliocene Carcharocles, since during miocene the available prey for both seems to have been similar, while the whale fauna was different during the pliocene. Are there any noted differences between Miocene and Pliocene Megalodons? Mr. Ward pointed out a sign of evolution in the younglings or neonates of Megalodon; he pointed out that neonates during Miocene epoch typically featured cusps in their dentition but neonates during the Pliocene epoch did not featured cusps in their dentition and were relatively larger in size. Other possible adaptations are not clear which is understandable.
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Post by Grey on Jun 15, 2013 13:03:16 GMT 5
Mike Siversson describes huge Pliocene balaenopterids vertebras sliced in half in one video.
The point that some bones are not entirely sliced does not demonstrate a limitation to sawing motion at all indeed.
And beheading or cutting in half a cetothere is not an unimpressive task even for a predator the size of meg.
Large cetotheres could weigh a good fraction of meg's weight, the largest during Miocene was already 13 m TL...
A better comparison would be like a giant carcharodontosaurid preying on a 2-tons ornithopod...
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Post by theropod on Jun 15, 2013 15:07:40 GMT 5
The largest cetothere bitten in half I heard of was not 13m tough, rather 7m, or were there bigger ones? While severely damaging the bones of a 2t ornithopod would not be a big problem for a carcharodontosaur imo, this analogy is not good.
I do not doubt those examples (and thanks for posting), I do not doubt Carcharocles megalodon was a proficient slicer of bony regions in its prey. That does not mean it has a drastically different way of killing large prey, and this is what was suggested. The gouges sufficiently show the bones in question were attacked, but not sliced through. In the case of that vertebra, we don't have a clue how large it is, neither in the case of the whale skeleton in the article. It would be good if someone could tell me what exact video by Siverson it is in which he points out such huge vertebrae being bitten in half. The fossil evidences suggest a slicer, one with robust teeth and an attack style not avoiding bones (which other slicers do not do either), but its kind of damaging bones is not comparable to a crusher like Livyatan.
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Post by Grey on Jun 15, 2013 15:16:03 GMT 5
The cetotherid in Bakersfield was conservatively estimated by Ciampaglio at 25 feet long. The cetotherids cut in half hinted by Cabrera and Hönninger in Ica are around 10 m. That represents ~10 tons animals or more cut in half or decapitated.
No evidences that I know of a 2 tons medium-sized ornithopod with deep gashes or decapitated by a carcharodontosaurid-like predator.
You suggest that meg would absolutely slice any bones it had to bite at any time. This is pointless. T. rex marks teeth neither always puncture through the whole bones of the preys. That's a sawing motion. Deep gashes of 3 inches deep or more should highlight you.
The video of Siversson is in the superpredatory sharks thread.
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Post by theropod on Jun 15, 2013 16:01:56 GMT 5
By a 50t+ shark. You always suddenly forget about its huge size when talking about how large the creatures it cut in half were ... There are Camarasaurus bones with gashes from Allosaurus bites, one supposedly chewed off on one end. Photographic documentation is not good I fear, nobody seems really interested in it, but I remember it has been confirmed in publications. Camarasaurus is conservatively 5-10 times the size of Allosaurus. A 2t ornithopod is conservatively a quarter the size of Carcharodontosaurus or Mapusaurus. I don't quite get the meaning of the next paragraph. Many of the bite marks simply seem to be collateral damage done while attacking soft tissue, they do not show the signs associated with a creature specialised in durophagous behaviour or specifically targetting the bones to break them. Usual signs include deep punctures and fractures, not scratch marks which are left by many slicers (eg. Allosaurus and various other late jurassic theropods, Rauhut& Hone, 2009). To what extend is the question here, but they are not that different by nature. Besides, an animal that kills by damagint bony structures would usually go for the spine of prey, not disable the flippers and take out chunks. My point is just that you seem to be suggesting C. megalodon was somehow an equally capable bone-damager and meat slicer as respective specialists in these fields. This is not true. Carcharocles clearly had the ability to slice through bones, not through all tough, and its primary goal was to take out chunks of soft tissues. There is no direct comparison between the jaws of C. megalodon and Livyatan.
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Post by creature386 on Jun 15, 2013 16:12:15 GMT 5
By a 50t+ shark. You always suddenly forget about its huge size when talking about how large the creatures it cut in half were ... We don't know anything about the size of the specimen who attacked the whale. For example the baleen whale with the healed bite marks was attacked by a juvenile.
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Post by theropod on Jun 15, 2013 16:14:58 GMT 5
creature386: The Shark that attacked the 7m Cetothere and bit its head off was suggested to be a relatively large Megalodon that would definitely have been huge compared to its prey item. I am not sure how reliable the show is, after all it is basically mythbusters, but Megalodon-expert-members told me it was great.
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Post by Grey on Jun 15, 2013 16:19:02 GMT 5
Gashes can also be made by claws, chewed bones are not necessarily deeply bitten. Which kind of bones also...
Any direct references of 1-2 tons dinosaurians preys presenting deep gashes or bones bitten in half by teeth from large allosaurs or carcharodontosaurids ?
A cetotherid representing 1/4 to 1/5 of the predator's mass actually bitten in half or decapitated is not something done by most predators. That's not even common at all as I know.
For the last paragraph : T. rex teeth marks are known on Trike bones without necessary entirely piercing it. That does not mean Rex cannot bite through the whole bone since we know it could.
In the same way, this is not because I'm going to saw with my chainsaw half of a tree that I cannot saw it whole.
A 3 inches deep gash does not show a limitation to the sawing process of megalodon teeth at all in the same way.
Check Siversson video.
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Post by Grey on Jun 15, 2013 16:23:13 GMT 5
creature386: The Shark that attacked the 7m Cetothere and bit its head off was suggested to be a relatively large Megalodon that would definitely have been huge compared to its prey item. I am not sure how reliable the show is, after all it is basically mythbusters, but Megalodon-expert-members told me it was great. Conservatively 25 feet according to Ciampaglio. 25 feet is 7.62 m. The size of a large orca. The show is valuable thanks to the work of Ciampaglio, the team who made the jaws under his supervision and the mythbusters who actually modeled a good proxy for the whale's size and density.
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Post by theropod on Jun 15, 2013 16:26:28 GMT 5
I suggest you to read Hone & Rauhut, 2009: Feeding behaviour and bone utilization by theropod dinosaurs Among some other inferences many would find surprising while they are not, there's this table:
Even carnosaurs did not avoid bone in the fashion often proposed, and sauropod bones show bite marks on occasion. These creatures did not kill by damaging bones, but had no problem biting bony regions. The same is true for Carcharocles, the only difference is how proficient the animals were at slicing bones.
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Post by Grey on Jun 15, 2013 16:28:23 GMT 5
""Many of the bite marks simply seem to be collateral damage done while attacking soft tissue, they do not show the signs associated with a creature specialised in durophagous behaviour or specifically targetting the bones to break them. Usual signs include deep punctures and fractures, not scratch marks which are left by many slicers (eg. Allosaurus and various other late jurassic theropods, Rauhut& Hone, 2009). To what extend is the question here, but they are not that different by nature. Besides, an animal that kills by damagint bony structures would usually go for the spine of prey, not disable the flippers and take out chunks. My point is just that you seem to be suggesting C. megalodon was somehow an equally capable bone-damager and meat slicer as respective specialists in these fields. This is not true. Carcharocles clearly had the ability to slice through bones, not through all tough, and its primary goal was to take out chunks of soft tissues. There is no direct comparison between the jaws of C. megalodon and Livyatan.""
You misinterpret again.
Check the sources, pics and the videos. Megalodon had no trouble to bite and saw through any kind of bones. No one is arguing of a bone-eating specialist at all. Please check sources before arguing.
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Post by Grey on Jun 15, 2013 16:30:02 GMT 5
Carcharocles bite deeply or through the whole bone.
These carnosaurs just imply surface bite marks. I let bite marks on my chicken bones...
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Post by theropod on Jun 15, 2013 16:46:50 GMT 5
^Evidence? Do not forget we are talking about sauropod bones. The plate of a stegosaurus was reportedly bitten through by an Allosaurus. And Stegosaurus is much larger compared to Allosaurus than a cetothere compared to Carcharocles. This doesn't make either of them a bone-specialist, and definitely implies a similar feeding and attack style with regard to the targetted regions. I think it would be wise if you would consider the possibility that it might not be me who misinterprets things. The marks on Triceratops pelvis are not crushing marks, and likely come from feeding, in which it logically must have used pulling motions to rip flesh effectively. An animal with such obvious adaptions for punturing, crushing and even shaking would kill by breaking vital structures, not by leaving gauges on the sacrum. These are not comparable at all. On the other hand, i doubt carcharocles would have fed on the flippers, there's not much flesh on them, yet they show such bite marks. This is an example of whale vertebrae bitten by C. megalodon: www.paleodirect.com/pgset2/mv21-024.htmLuckily, there's a hand in the picture so you can also get an impression of size (I'd say medium sized baleen whale), and what I see are deep gauges, but nothing crushed or sliced through. That's not the purpose of its jaws in a large prey item. People seem to misinterpret what I write. I think carcharocles megalodon had an absolutely deadly bite, and I do not see why everyone seems to believe it is necessary to crush bones for being truly dangerous. What I am arguing about is the purpose of its jaws, in relation to other predators, all that basically to point out what has to be considered when comparing them. The purpose of these jaws is clearly analogous to other animals primarily slicing through prey, this is demonstrated by both the tooth morphology and the patologies in sympatric whales. That does not mean it could not damage bones, as already demonstrated that is not after all that uncommon for slicers, neither is attacking bony regions. The obvious point however is that it did not kill large preys by breaking/slicing their bones, it just attacked bony regions. Therefore it is by no means an analogy for T. rex or Livyatan, which both likely killed by puncturing and crushing. The only video in the superpredatory sharks thread is the speech I already know, which only has a picture show in the background: theworldofanimals.proboards.com/thread/34/rise-super-predatory-sharksCarcharocles was a slicer, Livyatan was a crusher. Carcharocles was not a combination of both enabling it to be just as good at bone-damaging but a much better slicer. And that was what you seem to have suggested. I could continue this debate for a very long time if necessary, but I see no point in doing so, as this would only lead to us repeating ourselfes and at some point probably dispute. Is it that difficult to agree to disagree with me?
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Post by creature386 on Jun 15, 2013 16:53:10 GMT 5
He is maybe referring to the bite marks on the Sauropod bones (on one there were drag marks and on the other there was no detailed description). Most of the Tyrannosaurus bites here were described as "puncture bite marks" (puncture marks would be the "deep" bite marks Grey meant), but the ones of Allosaurus weren't: Also, the plate is not a very thick bone.
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