|
|
Post by Grey on Sept 6, 2013 22:08:34 GMT 5
Yes, that's a comparison between individuals, not species.
Rest my case with my last post, we cannot know for sure if there are higher chances in one or the other, and I don't know any sentence pointing toward this. If we had datas regarding the growth curve and life history of the Southern Giant, we could perhaps provide some better comparison with Rex.
|
|
|
|
Post by theropod on Sept 6, 2013 22:26:36 GMT 5
This is the sentence: www.skeletaldrawing.com/home/mass-estimates-north-vs-south-redux772013Clearly expressing this exact issue. A comparison of specimens cannot be transformed into a comparison of species, the same way a comparison between a cape leopard and giant eurasian lynx means nothing to their species' comparative sizes. We know very well in which there are higher chances, I just demonstrated them. What we don't know for sure is of course whether and how much one was actually larger, but the probability clearly points out to this. We don't know for sure how this will influence their respective size ranges and speculating on potential maximum sizes to compare them won't lead us in the right direction for sure. Hence a good comparison (or more fitting, the best) we can make, even tough it has to be taken with a grain of salt, is smallest vs smallest (G. carolinii>>T. rex) largest vs largest(T. rex ?~? G. carolinii*), which compares their size ranges and is the most (and only) objective one at the given data, and which paints a clear image of which size range is higher. We happen to be in the favourable situation of knowing many reasonably complete T. rex specimens that can be reconstructed and estimated with reasonable certainity if done well, and, also importantly, we know their ages and can segregate the immature ones easily. We should use this to our advantage instead of to the advantage of one of the two animals in a hypothatical fight. Even if the animal with the (15 times) bigger size range was bigger at maximum (or the same size), this wouldn't deduce it was bigger as a species (or the same size) unless it was also bigger at minimum (or mean, if it's available). I'm not talking of facts (and neither are the palaeontologists), but likelyhoods here. If a scientific assumption is made, which bases on other assumptions (eg. "T. rex compared to Giganotosaurus is that big"), these should always be the most likely (and objective) possible. *I already commented on this elsewhere |
|
|
|
Post by Grey on Sept 6, 2013 22:34:28 GMT 5
There's no likelihood when based on the whole population that existed in these animals, 2 or 30 is basically equal. But if you have a source of paleontologist discussing higher likelihood to found Giga, provide it.
|
|
|
|
Post by theropod on Sept 6, 2013 22:50:12 GMT 5
That's a mathematical likelihood, basing on the circumstance that unless Giganotosaurus somehow had a population size that was orders of magnitude smaller, we know a much bigger part of T. rex' population.
I don't need a source for that, it is not elaborated by professionals because it is so obvious and there is no relevance justifying publication by a scientist. I already showed what Hartman wrote.
|
|
|
|
Post by Grey on Sept 6, 2013 23:24:31 GMT 5
In mathematical logic, 2 or 30 are nothing compared to the global populations in both that is obvious. Added to the fact the exact size of the second southern giant is not certain. I don't want to enter a new endless discussion with you on these kind of matters, you envision Giganotosaurus likely bigger, fine. I'm not interested in speculations.
|
|
|
|
Post by creature386 on Sept 6, 2013 23:47:23 GMT 5
But when talking about percentages it is a lot. For example if we assume both had a global population of 200.000 specimen (this is way too low, as the specimen we found are not from the same time, so it could be billions, but this is just an example), 2 specimen would equal to 0,0001%, while 30 would already equal to 0,0015%, that is a difference.
|
|
|
|
Post by theropod on Sept 6, 2013 23:55:26 GMT 5
Speculation is fine as long as it's the most likely thing. Everything else is also speculation, but less probable. Both samples are small compared to the total population size, but that doesn't mean one isn't still much bigger than the other.
That's like saying a mouse wasn't bigger than an ant because both are tiny. Or Carbondioxide was irrelevant to the climate change because it's percentage in the athmosphere was tiny. It's a feely-argument.
Yes, I envision Giganotosaurus as more likely bigger, based on probabilities I already explained (pneumatisation, sample size, observable size range). Many people do (Tom Holtz for example...) and there is nothing wrong with that.
|
|
|
|
Post by Grey on Sept 7, 2013 0:17:34 GMT 5
Tom Holtz opinion was before Hartman last works and I know he enjoyed it through his comments. Does he still considers Giganotosaurus the absolute bigger guy ? I'm not sure about that at all, I could ask him.
No, in the various blog posts and thoughts I've read about, most people don't expect one or the other to be bigger, merely in the same size range, with no real disparity.
Giganotosaurus and Tyrannosaurus are pretty similar. I don't like to claim one is bigger based on no hard data, only debattable expectation.
The pneumatisation does not appear a significant factor reading Hartman, the sample size is irrevelant (the Giga type is really bigger (in mass) than which Rex specimens ?), the observable data range : there is nothing to observe at this point. Both Giganotosaurus are in the size range of Tyrannosaurus rex, and you or I don't know if these specimens were quite large or quite small in their own species. I'll retract this once I see more substantial elements.
|
|
|
|
Post by Grey on Sept 7, 2013 0:30:41 GMT 5
Just asked to Hartman about the "likelihood" of Giganotosaurus being the bigger species :
That's a bad interpretation of probability. When you only have two samples it could just as easily be from the "big" end of the bell curve as from the small one.
Without a proper sample from a population of individuals, you are pretty much stuck just comparing specimens, not speculating as to what the entire species was like.
The original question :
|
|
|
|
Post by theropod on Sept 7, 2013 0:40:33 GMT 5
I'm not saying it's from the small end, nobody did, that assumption is unnecessary and too liberal for my considerations. Not sure what exactly you asked Hartman on that part, I'd recommend posting the linked comments and not just the answers, since I recall the question you once asked him about sauropod size was basically a reductio ad absurdum speaking of 300t animals...
Edit: I see you added it.
What I don't really understand is what contradiction you seem to see between my observations and a "comparison of specimens", since that's exactly what I'm doing-I'm just not comparing individuals with such vastly different probabilities but instead resorting to several ones and demonstrating how one might not edge out the biggest T. rex, but the majority of T. rexes.
Also, I suppose by fragmentary rexes you mean UCMP 137538, or what other specimen do you mean?
Based on Laplace the probability of a sue-sized T. rex in a sample of adults is at best ~1/20 (this is including that perhaps there is one other T. rex of similar size, otherwise it would be closer to ~1/40). The probability of finding a MUCPv-95-sized Giganotosaurus is 1/2. This is a clear difference in likelihood.
Sample size is even highly relevant, and the observable data range is that even if the biggest Giganotosaurus doesn't exceed the size of the biggest T. rex, the smallest Giganotosaurus definitely exceeds the smallest T. rex (and you could use smallest specimens just as well as the largest, that's just the same situation), meaning it has a higher size range based on the limited available data. Pneumaticity is not a totally certain point, but it was not rejected by Hartman, he appeared unsure about its impact. It has been implied in several publications (Janensch, 1947; Brochu, 2003; Bates et al., 2009 & Hutchinson et al., 2011) that T. rex is very pneumatic, even for a giant theropod.
But being completely conservative with the two Giganotosaurus specimens when already using them to compare to a much bigger sample at maximum size? Is that objective?
And Holtz was just an example of someone who argued this quite definitely, I already gave other examples of many who found Giganotosaurus to be bigger (and even published that), I even hope he has changed that opinion since it was MUCPv-Ch1 being the biggest described theropod skeleton (2004), an obviously unrealistic assumption, and that in an absolute standard work on dinosaur paleobiology. It's not really important but it's a justified opinion. Besides, I don't see everybody stating they were just the same size, this is a cautious opinion suggested in a few blog posts, as opposed to the at least equally widespread one of Giganotosaurus being bigger.
The Giganotosaurus holotype is obviously considerably bigger in every regard than Bobby, Bucky (which based on 8,4t "apneumatic" Sue would be <4,5t, and <3,8t with a density reduced to 0,8), MOR 009 or Black Beauty and may end up edging out several medium sized rexes such as AMNH 5027, Stan or MOR 555.
|
|
|
|
Post by Grey on Sept 7, 2013 0:47:27 GMT 5
Typically of you, you take too much advance : I've just asked to Hartman if Stan or the Carnegie were smaller, comparable or bigger than Giganotosaurus holotype; he responded that he'd have to calculate this to be sure but as guess, they are probably close.
The point remains that there is no reasonnable likelihood in all of this. Yes some Gigas were perhaps bigger than Sue. Yes, some rexes could be bigger than Sue. Perhaps Giganotosaurus was on average bigger than T. rex but the largest rexes specimens that existed were bigger than any Gigas. Or vice-versa. We don't know.
I wait for a response of Tom Holtz.
|
|
|
|
Post by theropod on Sept 7, 2013 0:55:02 GMT 5
Please, don't even start like that, you know what happens. I was not even including Carnegi, and my guess would be it weighs about the same as MUCPv-Ch1, perhaps even slightly more (and the T. rex holotype is indeed a pretty large and robust rex already, even Stan is, albeit short, which earned it the incorrect reputation of being particularly small). Also you might have noticed I put a "may" in front of the latter three (AMNH, Stan, Wankel), implying my uncertainity on them. You required examples (or more exactly you expressed doubt whether the Giganotosaurus holotype was bigger than any T. rex specimen, which is out of the question as I have shown you), I gave them to you. |
|
|
|
Post by Grey on Sept 7, 2013 0:58:56 GMT 5
And because of his works, I prefer Hartman responses and guess about it. Thanks.
|
|
|
|
Post by theropod on Sept 7, 2013 1:57:19 GMT 5
Broly: Shartman's response to him: Megalosaurid: Shartman's response to him: And why did you state you tought Stan and Carnegi were heavier than MUCPv-Ch1 here when you think it's so uncertain and I should not state they MAY be (not even including Carnegi!)? |
|
|
|
Post by Grey on Sept 7, 2013 2:15:04 GMT 5
1. I respect broly but he's nowhere a reference, especially when it comes to discuss Tyrannosaurus.
2. Yes so ? Irrelevant with his response to me.
3. Yeah, close, with Giganotosaurus perhaps heavier, why not. That does not change his point in the message I've copied above. And I recall he once expected the second Giganotosaurus to be larger than Sue. Not to say he's wrong at all, but as he said, he'd have to do some additionnal work.
I've not claimed anywhere that Stan or Carnegie were heavier. I've wondered and posted Hartman response.
Now believe what you want in your "counting the hit ignoring the miss" speculations. When it comes to such questions, I prefer real experts opinions, not yours.
Tyrannosaurus and Giganotosaurus are as far as we know similar in size and there's no reasonnable likelihood of larger species beyond that. The data is deficient that's all. Don't try to convince me or so, you definitely can't, sorry.
|
|
