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Post by Grey on Sept 5, 2013 19:29:03 GMT 5
Has someone thought or tried to deduce the approximative or exact perimeter of Livyatan jaws in order to get an idea of how voluminous would have been the chunks of food it took ?
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Post by Grey on Oct 13, 2013 0:31:49 GMT 5
No one has tried so far ?
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Post by theropod on Oct 13, 2013 2:22:53 GMT 5
Well, it's not exactly complicated, if I understood you right everyone here ought to be able to measure it quite easily.
The dentulous part of the rostrum measures approximately 1.4m in lenght and the rostrum is 1.3m wide at the level of the last alveolus. The part medial to the alveoli has an area of 39114px, 51980px for the whole rostrum which based on the scalebar equals 0.87 and 1.15 m² respectively.
The same part in the mandible is slightly longer but narrower, so that the upper jaw teeth are anterolateral to those in the dentary.
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Post by theropod on Oct 13, 2013 3:11:35 GMT 5
 The holotype of Livyatan melvillei and a large T. rex (BHI 3033, adapted from Hurum & Sabath [2003], at 1.4m) I think a very good example of how much of a role prespective plays in comparing animals (and how biased a view can thus result from omitting certain perspectives). In dorsal view, T. rex is absolutely dwarfed. It's still smaller, but looks far less pathetic in a lateral view. This is a result of differences in jaw shape; those of the cetacean are relatively shallow but wide, those of T. rex are too, for theropod standarts, but still relatively deep and narrow when compared to the whale's. NOTE: This particular T. rex specimen may have had a somewhat smaller skull when restored accurately (as in Hartman 2013 [skeletal]), I chose it because the portrayed silhouette and restoration reflects the skull size of a very large member of the species accurately. |
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Post by Grey on Oct 13, 2013 4:27:19 GMT 5
That's a good work. What I wonder is the exact perimeter and/or circumference in each upper and lower jaw. I know that's a bit tricky but I assume this can be an interesting data to known and add about Livyatan feeding apparatus.
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Post by theropod on Oct 13, 2013 5:17:31 GMT 5
Are you referring to jaw lenght or width by "perimeter"?
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Fragillimus335
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Sauropod fanatic, and dinosaur specialist
Posts: 573
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Post by Fragillimus335 on Oct 13, 2013 7:16:59 GMT 5
I'm guessing roughly 5.8 meters of tooth bearing bite surface, and a total perimeter of ~7.4 meters.
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Post by Grey on Oct 13, 2013 7:28:22 GMT 5
I'm guessing roughly 5.8 meters of tooth bearing bite surface, and a total perimeter of ~7.4 meters. Are you sure about that ? Only asking, if I'm educated in sciences, I'm an epic sucker in maths;.. |
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Post by theropod on Oct 13, 2013 15:23:17 GMT 5
The symphysis is a little over 1m long. Measured from the symphysis to the end of the ramus (as reconstructed in the description paper) the mandible measures 1.73m long. This region of the skull measured between mandibular articulation and law tip and within the margins of the tooth-bearing rostrum covers an area of 89465px/34225px=2.6m², for both jaws that's approximately 5.2m² (probably a little less) and the total lenght of the jaw margins would be ~6.9m. I already gave the data for just the dentulous part, which starts a good deal further anteriorly. The following is a gimp-file were you can easily make all the measurements you want to make using the measuring tool. 1mm=1px lmelvilleicranium.xcf (513.7 KB) |
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Fragillimus335
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Posts: 573
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Post by Fragillimus335 on Oct 13, 2013 21:58:39 GMT 5
I'm guessing roughly 5.8 meters of tooth bearing bite surface, and a total perimeter of ~7.4 meters. Are you sure about that ? Only asking, if I'm educated in sciences, I'm an epic sucker in maths;.. It was a roughish estimation, but Theropod's more detailed check is just a bit smaller. I was about .5 meters off on both measurements. |
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Post by theropod on Oct 13, 2013 22:05:14 GMT 5
Yeah, that was a pretty good guesstimate. At first when I saw those figures I just thought "wtf? BBC-pliosaur???" before I realised what exactly you meant by "bite perimeter".
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Fragillimus335
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Sauropod fanatic, and dinosaur specialist
Posts: 573
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Post by Fragillimus335 on Oct 13, 2013 22:12:02 GMT 5
Yeah, that was a pretty good guesstimate. At first when I saw those figures I just thought "wtf? BBC-pliosaur???" before I realised what exactly you meant by "bite perimeter". Yeah, a number like 7 meters really jumps out and seems huge! But a blue whale has a whopping ~18 meters of mouth perimeter!!! |
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Post by theropod on Oct 14, 2013 0:10:29 GMT 5
Because blue whales can have 6m+ skulls!
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Post by Grey on Oct 14, 2013 0:29:33 GMT 5
In anycase, the jaws of that predator are enormous, T. rex is totally ridiculous by comparison.
I'd really like to have a similar data for a rigorous megalodon jaws reconstruction.
The problem being that megalodons jaws are not all that good, nor all the same size.
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Post by theropod on Oct 14, 2013 1:51:19 GMT 5
You can probably approximate them relatively well by a roughly circular or oval shape, depending on the restoration (Jeremiah's is more circular for example).
T. rex looks indeed ridiculous by comparison, especially in dorsal view. It's notable how large animal jaws seem can heavily depend on the aspect you are seeing tough, T. rex for example will seem larger laterally because it's jaws are proportionally deeper (the contrary is the case when comparing it to most other theropods).
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