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Post by theropod on Jul 6, 2013 13:34:43 GMT 5
I'm just as skeptical of Spinonyx as I am of Spinitator. He makes it to simple while scaling, the rostrum is merely scaled to the depth at some point of the skull. It also seems to be scaled a little too large.
He shifted the antorbital fenestra far further back and his maxilla is overlapping the jugal as if there had to be no space for the articulation. That rostrum is not just elongated, it seems far too massive for the skull it is mounted on. It is not that easy.
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Post by Grey on Jul 6, 2013 21:04:08 GMT 5
Shartman expressed that Cau makes good points about the uncertainity of the data, but he's not going to change his reconstruction just yet.
The point of Cau is simply to be very cautious with this material and do not have much faith into a "mythical monster" created a decade ago.
Now it's a matter of educated opinion to prefer one or the other, I recommend to not dismiss one or the other.
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Fragillimus335
Member
Sauropod fanatic, and dinosaur specialist
Posts: 573
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Post by Fragillimus335 on Jul 6, 2013 23:36:29 GMT 5
Cau's skull is downright bad! It is a blind rush to shrink Spinosaurus at all costs. Judging by Hartman's recons I think a likely size for MSNM is 16.2-17 meters long. I still think he oversized the skull by a tad.
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Post by Grey on Jul 7, 2013 0:12:13 GMT 5
Cau does not want to shrink Spinosaurus at all cost but simply show that the sizes spoken on the internet are anything but certain.
Of course the skull with Baryonyx snout is not realistic in its depth structure but it is plausible in terms of length. The one with the Irritator muzzle is visually better (as Irritator is more related to Spinosaurus and known actually by a complete skull) but it still shows that Spinosaurus skull was perhaps not that long.
You cannot judge him like that. Of course, he should publish and test further his works but his main purpose is to show the ast uncertainity in this particular taxon.
Personnally, I'm half convinced by Cau and Hartman's reconstruction at the same time.
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Post by creature386 on Jul 7, 2013 0:20:16 GMT 5
Cau does not want to shrink Spinosaurus at all cost but simply show that the sizes spoken on the internet are anything but certain. I believe most of the people here realize that 16-18 m can't be the only possible size range, they simply view it as more likely than the lower estimates. |
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Post by Grey on Jul 7, 2013 0:24:49 GMT 5
Cau does not want to shrink Spinosaurus at all cost but simply show that the sizes spoken on the internet are anything but certain. I believe most of the people here realize that 16-18 m can't be the only possible size range, they simply view it as more likely than the lower estimates. According to Hartman himself, 16 m or 17-18 m depends of the tail length, not of the body size itself. So I'm more disposed to envision 16 m (which does not change anything at the potential badassness of Spinosaurus). Some people here despises Andrea Cau when he suggests something that does not please them. At least, it could be discussed respectfully. |
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blaze
Paleo-artist 
Posts: 766
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Post by blaze on Jul 7, 2013 0:56:10 GMT 5
I also agree with 15-16m (heck I was even content with 14m, the size of the holotype, as its maximum size) but the thing I don't like about these latest posts by Cau is that they're very simplistic, he is basically assuming that the rostrum is totally complete, ignoring the missing articulations with the jugal and lacrimal and basically copy pasting it on top of other reconstructions based on the height of the preserved rostrum a the posterior end alone, a value that is obviously going to increase as you complete the missing pieces (as they are, it gets taller posteriorly).
I'm not really sure that he is doing them just to highlight the uncertainty of the estimates, why then put "END OF DISCUSSION" in big, red, bold letters at the end of his last post? maybe is an artifact of the automatic translation but these posts read like "see? the skull was only 130-140cm, I'm right and you're wrong"
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Post by Grey on Jul 7, 2013 1:09:33 GMT 5
I've discussed with him privately, I can say he does not want to establish anything as true (even if it is clear he does not believe in 17 m giants) but only to show that nothing can be established. He's more fighting against sensationnalism than imposing his own truth.
Have you posted on his post your queries ?
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blaze
Paleo-artist
Posts: 766
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Post by blaze on Jul 7, 2013 1:13:43 GMT 5
No, I always thought that he will dismiss me, but if you say that's what he's trying to do with his posts then I'm totally find with his remarks.
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Post by theropod on Jul 7, 2013 1:14:00 GMT 5
That's what I meant too. No problem with Cau himself, and certainly not trying to dismiss him, but he is the one who always seems to dismiss everything but his own work (which includes calling a Spinosaurus the size of Hartman's reconstruction a childrens myth, not just enthusiastic AVA guesses!) and take things like those rather simplistic demonstrations (12,5m spinosaurus or 1,4m Spinosaurus skull) as the best estimates there are, while they are clearly pretty simplistic.
If the depth structure doesn't fit, the lenght arguably won't fit either (especially when it bases on scaling to depth!, For asessing the lenght, it would be wiser to also scale to it, if not making a proper reconstruction of the skull). The problem is that one cannot just scale it to the skull depth at some hapazard antorbital point and then claim it to be the "end of discussion". It's hardly the people who are sceptical of Cau's estimates that are making the extreme claims.
Nobody here is talking about the 16-18m range as a fact, but Cau seems to regard it as a children's myth, while the majority of figures actually points out to it.
Btw Irritator is only known from a posterior cranium, missing the whole rostrum, not a complete skull.
And I think some people have a somewhat transfigured view of what Cau is suggesting. If he just wanted to show how uncertain estimates are, why are his always by far the lowest figures, and are such by lots of simplistic or liberal assumptions?
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Post by Grey on Jul 7, 2013 1:19:23 GMT 5
I quote him from our discussion.
Unfortunately, the sample among the known specimens is so scarce that we cannot determine in a more precise way how body/skull sizes changed among spinosaurids and among large theropods in general.
This is why I prefer to follow a conservative approach until more data is available. The hypothesis of a 14 meters long spinosaur as largest size is more scientific than a 18 meters long, being the former more easy to falsify than a never seen super-giant theropod.
In conclusion, in my posts I would like the reader to understand that almost all estimations based on scarce specimens are very poorly supported, and thus it's better to be conservative instead of arguing for a super giant animal based on very rough extrapolations. Size is important since it got indications on biology, but size estimations in fossils may be more robust than the methods cited by most online: I think, when only few bones are known, it would be better to say nothing instead of creating a myth.
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Post by Grey on Jul 7, 2013 1:24:07 GMT 5
I have to say, I have no preference, but I have a reason why I'd appreciate that Spinosaurus would be shrunk at this scale : that would just "simplify" the task to know which theropod was the biggest and baddest, and a comeback to the more classical massive-headed carcharodontosaurs and tyrannosaurs for the discussion.
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Post by theropod on Jul 7, 2013 1:35:00 GMT 5
^It would make the task more difficult actually, since the size differences would be smaller and the title of the largest theropod less unequivocal.
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Post by creature386 on Jul 7, 2013 1:37:21 GMT 5
I believe most of the people here realize that 16-18 m can't be the only possible size range, they simply view it as more likely than the lower estimates. According to Hartman himself, 16 m or 17-18 m depends of the tail length, not of the body size itself. That's true, but this debate is not about how badass Spinosaurus is. I believe most people here have enough objectivity to realize that. |
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Post by theropod on Jul 7, 2013 1:38:28 GMT 5
What has "badassness" to do with this? it is totally irrelevant to the subject.
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