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Post by Grey on Oct 22, 2013 21:14:34 GMT 5
Your posts have nothing to learn me. What Hoktz states is what I usually suggested, period. Believe what you want, and try to be more modest instead of thinking you are necessary the teacher around.
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Post by theropod on Oct 22, 2013 21:16:19 GMT 5
And it starts again... I just made an edit, you might wanna read that.
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Post by Grey on Oct 22, 2013 21:27:51 GMT 5
What Holtz says is that 50 individuals (with a number lacking datas about size and maturity) is not enough to get a reasonnable idea of the size patterns within a population. 2 specimens or 50 is almost as meaningless (especially lacking data about life stage in Giga). You should read the last paper about Cardabiodon where they justly talk about that question to get a good idea of size status in a species. They note that over 100 (reasonnably complete or reliably estimated) individuals is the ideal.
In other words, almost all discussions about average sizes in extinct animals are endless discussions and endless speculations.
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Post by theropod on Oct 22, 2013 22:46:26 GMT 5
What we have is never "ideal", and yet this does not mean average sizes are not being deduced or at least tried to be deduced. That is no reason to spit on something as a so called "speculation", oblivious of the fact that everything else is even more speculative.
As I already tried to explain to you, data on exact state of maturity are not necessary, but we have a good verifyable sample of adult specimens (and I guess you certainly do not want to challenge that status). Since we don't have anything more precise in most cases, it is best to compare adults to adults, not segregate between normal adults and those that have reached maximum size, the latter obviously a rare occurrence, rather than the norm, in all of theropoda.
I cannot comprehend how a 25-fold difference is in any way "meaningless".
In the end, in extinct species we (humanity, not you or me) always have a much better idea of the average size than of the maximum size. Maximum sizes are always somewhat arbitrary and affected by sample bias, even in extant animals (eg. bears, crocodiles).
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Post by Grey on Oct 23, 2013 3:23:53 GMT 5
Yes, I spit on speculations like that, because this is playing to the Russian roulette. 1 or 50 is nothing on a population, all is a matter of personnal interpretation. My interpretation is at least correlated by Holtz and Hartman (with whome I've discussed at length about these kinds of matters).
Now believe what you want, but don't try to establish your opinion as a definitive fact to me, especially when you know that I have little interest for your posts since a while, in fact since you have started to discuss primarily about these matters in any thread.
Frankly man, these speculations about "that one is average", "that one not", "that one more likely was bigger even without more specimens" are absolutely boring and meaningless, at least to me. I totally prefer your posts about anatomy, measurements and mechanical biology which are at least, despite potential errors, based on actual stuff, material and interesting works, like the posts about Livyatan's bite perimeter. This, at least, is concrete or solid. It is also potentially verifiable in evidences.
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Fragillimus335
Member
Sauropod fanatic, and dinosaur specialist
Posts: 573
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Post by Fragillimus335 on Oct 23, 2013 6:12:14 GMT 5
Our proposition IS definitive fact. The extent to which Tyrannosaurus specimen represent larger maximum sizes is unknown, but statistically it is present in our sample. If you can't grasp that it's no longer of my concern.
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Post by Grey on Oct 23, 2013 6:16:08 GMT 5
Statistically, it is not present in our extant sample. More than 100 individuals are the ideal. No offense but I favor Tom Holtz expertise in that field over theropod and Fragillimus335...
We know that there were certainly larger T. rex and very certainly larger Giga. But claiming by how much respectively and which one had the larger individuals, is anything but real science. That's boring speculations. Even with data about Giga life status, this would remain that difficult.
At now, we simply know they are very very similar in overall size/mass. That is real science. I like numbers in bones, not numbers in blabla.
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stomatopod
Junior Member
Gluttonous Auchenipterid
Posts: 182
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Post by stomatopod on Oct 23, 2013 12:55:10 GMT 5
Theropod, I think it is a bit strange to estimate the age of a specimen by using likeahood. The common procedure for a bone would be to use histlogy and not stochastics using populations of different animals. To say that the specimen is more likely to be not on the ontogenetic stage of Sue while not having checked the hard evidence is simply wrong.
To Fragillimus, As I have demonstrated, the chance of finding a larger Giganotosaurus is only a tiny bit better, to the point that it is statistically unimportant, as both samples are too small to say anything. And using 50 specimens of T. rex is even very lenient to you, as most of those specimens are to incomplete or to badly descibed to say anything about their size. Then there are all those juveniles. I hope you get the idea.
There is a reason why Hartman says that the samples are to small. Of those 50 specimens maybe 15 are relevant, and for most of them we do not have accurate size estimates.
If one does not agree with this, I would like to know the average size of T, rex then based on those 50 specimens, together with the data it is derived from.
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Oct 23, 2013 13:23:50 GMT 5
I'm surprised that nobody posted the new titan abelisaurid and the new Deinocheirus material, instead they talk and argue all again about that certain same coelurosaur
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Post by theropod on Oct 23, 2013 17:39:27 GMT 5
We have a decent sample of femurs, that's something to start with (and yes, even if that's just like 15 or so, it's better than just taking some random individual instead). The average femur lenght for T. rex adults based on these data is not aboveroughly 1.2m, that's (of course) well below sue-sized. Notably, data from two independant sources yield very similar average femur lenghts and almost the exact same value as a percentage of the values given for sue (about 9% smaller in linear dimension), which makes them somewhat reliable because it provides some self-correction for errors in the datasets. And don't tell me they might all have had proportionally shorter femora, smaller T. rex specimens (prime example: Stan) and theropods in general, have proportionally longer, not shorter appendicular elements. Thus a comparison with sue is certainly not liberally underestimating in this regard. In the absence of histological data, one CAN only use probability. Since I'm quite certain nobody here has histological data and growth tables for Giganotosaurus, the only thing one can assume is the most probable thing. The most probable thing for a random adult is that it's not in sue's state of maturity, because we know sue is a relatively old and thus rare type of individual. What's supposed to be wrong about that? To be exact, the probability of a T. rex as large as, or larger than, sue is below 5%, while that for a Giganotosaurus or Spinosaurus at least the size of the respective holotypes is 100%, ergo, the latter is a much more "normal" occurrence. Why should sue be any more representative for its species than B-rex? Because sue is large and B- rex as well as several others aren't? @broly: The problem with those new findings, as amazing as they are, is that there is no concrete information of any kind. Deinocheirus didn't even receive a rough estimate. We have to wait a little longer, until we get to see a description or at least the secondary sources reporting about it--then I'm sure there will be plenty of new interesting stuff. Grey: Neither I nor Fragillimus have done the "boring speculations" you are accusing us of. As I already pointed out, Holtz' adresses a different point in the article, that of ontogeny, and this is a point applicable to carnosaurs as well as Tyrannosaurs, and for all we know to other non-avian theropods as well.
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Post by Grey on Oct 23, 2013 18:31:01 GMT 5
That's speculation, your interpretation, an interpretation never used in rigorous paper works or any other reliable documentation. What Holtz says is the exact same point I talk about, the issues about ontogeny : we don't know the ontogeny of the one or two Giga individuals, but you keep your interpretation that they are necessarily medium-sized or average sized individuals. That's no science. I repeat : We know that there were certainly larger T. rex and very certainly larger Giga. Everything else is non-scientific, non-rational interpretation. And yes, that's boring, that's annoying, because there's no stuff behind this.
In fact, if these useless discussions/speculations keep to be perpetuated on the board by guys like you who are potentially very educated in more rational, more serious discussions but have all the time this tendency to make their own science, suggestions or propositions as facts, which are definitely not, I'm starting to think I will be less and less present here.
I'm really tired to all the time read the same crap like this when you have the ability to perform very good, authentic research. By example, when you've hinted the scientific medial measurement of meg teeth. I was very critic at the beginning but after verification (and discussion with one of my experts contacts), I've quick realized that you were right and admitted it without problem. On the other hand, this is months there you're trying to establish facts of your interpretations of size and life status in isolated fossils species, and that you cannot convince me or others rational, mature minds, for the reason that you cannot do it with any material, any scientific work, any serious support. And I keep thinking that is because of your propencity, which is understandable when someone loves paleontology, to all the time promoting bigger than life things.
Paleontology is a beautiful science, with extraordinary real facts, and it does not need to be filled with speculations inevitably bringing to overexagerations soon considered by the random reader as facts. Popular medias are already enough good at this. And you could certainly perform far better works than this.
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Post by theropod on Oct 23, 2013 18:48:41 GMT 5
And what is science? Insisting they must be part of the quite rare 28-year old category, insisting they must be large specimens?
I'm not doing any "work", "making up facts" like you seem to imagine. I am merely stating obvious statistical facts about what is probable and what is not. I should not need to "perpetuate" that. The material is present, on the fossil record, and it should sink into your mind, sooner (?preferred option) or later.
On the issue about Megalodon tooth measurements; you know very well how you reacted to my observations (and I should not have to repeat the exact wording here) on this and similar issues (eg. "jaw gape angle of mounted megalodon jaws"). You first tried to turn it on me, and now try to make it a testimony of your own maturity. You'd be well advised to not bring it up, I'd be willing to forget about it given you learned your lesson (yes, I wrote that).
Palaeontology is a science that consists of 99% hypothesis (= educated speculation=the most probable speculation). Dinosaurs having feathers is speculation, but it is the most probable one there is. T. rex having eyeballs is speculation, but it is so probable it approaches certainty. It ain't possible to classify these into what you consider "speculation" and what you consider "fact".
The same way, you may call the individuals of monotypic species being average a "speculation", but it still is the most likely one, and thus justified. Them being extremes, be it the kind of extreme you see in a sample of 30 or the kind of extreme in your so called "ideal" sample, is also speculation by the very same logic, but it is far less likely.
I appreciate you made some concrete points.
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Post by Grey on Oct 23, 2013 19:36:35 GMT 5
Ok I totally abandon any attempt to discuss with you. You're obsessed.
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Post by creature386 on Oct 23, 2013 19:38:45 GMT 5
I'm surprised that nobody posted the new titan abelisaurid and the new Deinocheirus material, instead they talk and argue all again about that certain same coelurosaur Why didn't you post it then? (I didn't do so, because I am too stupid to find what I search for, in that huge abstract list, for example I can't find the one about the feathered ornithopod. Maybe you had the same problem. By the way, could anyone give me the names of the scientists describing the ornithopod?) Anyway, here the one on Deinocherius:Lee, Y., Barsbold, R., Currie, P., Kobayashi, Y., Lee, H. NEW SPECIMENS OF DEINOCHEIRUS MIRIFICUS FROM THE LATE CRETACEOUS OF MONGOLIA p. 161 here: vertpaleo.org/PDFS/0d/0d20d609-f7e6-4bb3-a0c4-765fcffde49b.pdfI can't find the one on the giant abelisaurid.
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Post by theropod on Oct 23, 2013 20:48:21 GMT 5
Yeah, that document is really long and a pain to navigate, because loading a search takes ages.
The feathered ornithopod is on page 136:
The giant abelisaurid: "A GIANT ABELISAURID THEROPOD FROM THE LATEST CRETACEOUS OF NORTHERN TURKANA, KENYA SERTICH, Joseph, Denver Museum of Nature & Science, Denver, CO, United States, 80205; O'CONNOR, Patrick, Ohio University, Athens, OH, United States; SEIFFERT, Erik, Stony Brook University, Stony Brook, NY, United States; MANTHI, Fredrick Kyalo, National Museums of Kenya, Nairobi, Kenya The African fossil record of Cretaceous non-marine vertebrates has expanded significantly over the past two decades. However, these discoveries have been limited to Lower and middle Cretaceous horizons with a conspicuous absence of fossils from the latest Cretaceous, an interval of prolonged African isolation. Recently recovered vertebrate fossils from the Lapurr Mountains of northwestern Turkana, Kenya, comprise the first definitive non-marine fauna from this critical terminal Cretaceous interval. This diverse fauna from the Lapurr sandstone (“Turkana Grits”) has been dated to the Maastrichtian and includes crocodyliforms, pterosaurs, and dinosaurs. Though fragmentary, the dinosaur record includes at least two iguanodontian ornithopods, three macronarian sauropods, and two large theropods. Here we report on one of these theropods, a new abelisaurid that significantly expands the upper limits of body size in ceratosaurians and represents the youngest diagnostic dinosaur material yet reported from the Afro-Arabian continent. The new taxon is known from multiple isolated specimens including portions of the skull, axial column, and appendicular skeleton. Referral of unassociated remains to a single taxon is based on morphological consistency and on the recovery of specimens from a narrow stratigraphic and geographic area. A comprehensive phylogenetic analysis substantiates referral of the new Kenyan taxon to Abelisauridae based, among other features, on the presence of a tall, rugose premaxilla, an anteroventrally inclined posterior border of the postorbital, and a prominent dorsal projection of the parietals and supraoccipital. An associated partial skull is strongly coossified, with a thickened but weakly sculptured skull roof. Unlike many other abelisaurids, no prominent cranial ornamentation is evident. As in other ceratosaurians, the astragalocalcaneum is completely coossified and displays a prominent transverse sulcus on the anteroventral surface. Like other abelisaurids, the ascending process is low and subrectangular, separated from the anterior surface of the astragalus by a distinct fossa. Comparison of preserved elements with those of other, more complete abelisaurids indicates that the new taxon likely exceeded 11-12 meters in length. Furthermore, the presence of a large- bodied abelisaurid in the Kenyan fauna parallels many other Late Cretaceous Gondwanan faunas, reflecting global early Late Cretaceous turnover from allosauroid and spinosaurid dominated ecosystems." page 211
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