Wayne Throop Feb2093 09:29PM : From: magney@cco.caltech.edu (Michael Agney) : MessageID: 1

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Wayne Throop Feb-20-93 09:29PM From: throopw@sheol.UUCP (Wayne Throop) Message-ID: <730276967@sheol.uucp> Newsgroups: talk.origins : From: magney@cco.caltech.edu (Michael Agney) : Message-ID: <1lq21gINNfhg@gap.caltech.edu> : While a lot of what Ted has to say (of what I've seen) seems unscien- : tific (at best), I don't know what the current ideas about sauropods : are. Were they land or sea creatures? If either, what of the problems : posed by Ted? They were land creatures. Some of the most convincining evidence of this is the trackway evidence from the American Midwest. I recommend glancing at the recent collection of papers _Dinosaur_Tracks_and_Traces_, edited by Gillette if I recall, and which seems available in most university libraries. For readings on the general area of sauropod limits and adaptations, see Alexanders' _Dynamics_of_Dinosaurs_and_Other_Extinct_Giants_. Ted's favored reference, McGowan's _Dinosaurs_Spitfires_and_Sea_Dragons, also provides good background (though apparently you have to read it more carefully than Ted to see this, since many of Ted's favorite puzzles, such as how sauropods could eat enough, and how they could hold their necks out straight, are explained in that book. Note also that Ted can't seem to get the spelling of McGowan's name right for two postings in a row, even after having this pointed out to him numberless times. He gets it right in his recent "sauropods" posting, but gets it wrong in his recent "rationale" posting.). Also consider Bakker's _Dinosayr_Heresies_. Ted often takes the lifestyle points and metabolic rate arguments from Bakker's work, and combines them with criticisims from McGowan's work to try to make it seem as if there is some contradiction or problem in the field. This is just mixing and matching points from conservative and radical camps in dinosaur studies, and the apparent contradictions Ted comes up with this way are essentially quotes out of context. And finally, Daltons and Waldens tend to have several recent books on hand, especially those that go along with recent PBS and cable presentations on dinosaurs, that give very good overviews, including some of the reconstruction work on the musculature and skeleton of brachiosaurs, as well as the family tree of the sauropods, explaining the differences between braciosaurids and diplodocids that Ted has had so much trouble with in the past. So much for reading material. For the rest of this post, I'll repost my own analysis of "Holden Numbering", as Holden's inaccurate use of square-cube scaling is often called in talk.origins, as well as a repost of some information about the largest dinosaur finds that shows they are all well within reasonable limits for strength, no attenuated gravity needed. ( Of course, Ted has already "refuted" this material. For comments on these refutations, see the companion posting on "Holden refutes his critics", coming to a talk.origins-carrying node near you. ) Subject: Holden Numbering Summary: explanation of the Holden Number, and why Ted gets it wrong Previous-Postings: 920727 920816 920928 921213 First, just what is the Holden Number? It is the weight in pounds-force over the square of the cube root of the mass in pounds-mass of any given creature. So lbs HN +--------------------- cat | 10 2.15 human | 200 5.85 elephant | 10000 21.5 brachiosaur | 150000 53.1 What does this calculation mean? It is a measure of force (the lbs weight) per available cross section (the lbs mass ^(2/3)). The lbs mass cube-rooted and then squared because the mass is a rough indicator of volume, and hence the ^2/3 power of mass is a rough indicator of cross section. Whence then the Holden Limit of 27? Well, if an animal is lifing more than its own weight, we can add the additional force to the top of the ratio, yielding a Holden Number which characterizes that lift. (This addition of weight plus load is invalid in detail, but arguably works moderately well as an adequate approximation.) Holden claims that Kazmaier's 1000 lb squat represents a limit of performance for animals Kazmaier's size or larger, and that the squat in general accurately models the act of standing up, and thus he calculates (1000 + 350) / 350^(2/3) ~= 27 to get a figure for the maximum possible Holden Number of any creature. Since this is pretty close to the actual Holden Number for the largest elephants, Ted then jumped to the conclusion that elephants are the largest creatures that can exist. There are many side issues, such as - other primates can sustain weights far larger - I've found references to three elephants larger than the one Ted uses for comparison - elephants in circuses have been reported doing acts with HN larger than 30 Ted has explanations for all of these points, but showing why he is wrong on all of them would be prohibitively tedious. Let's just address Ted's frequent claim that efficiency tends to go up with larger sizes. (One reason Ted often gives for this is the creature's "muscles binding together". He has also said in this connection that "Ants probably derive Holden numbers far above the 27 I mention". But why bother with "probably"? Let's take a really large ant, and give it tremendous strength: 1 gram of ant, lifing 100 times its weight. This loads the dice in Ted's favor. Yet the HN of such an ant is less than 15. Even such a goliath of an ant would have to lift 200 times its weight or so before reaching HN 27. And more reasonably sized ants would have to lift 500 or 1000 times their weight. Ted is definitely mistaken here. ( Note: Guiness mentions some beetles that come close, but you will note that those events don't involve lifting, but simply the point at which their exoskeletons crush. ) Ted also frequently claims that "[...]layers of thick muscles will begin to bind somewhat against each other" as size increases, and points to the fall-off of square-cube-scaled performance in weightlifting in the highest weight classes. Unfortunately, what Ted doesn't tell you is that his theory of "muscles binding" can't explain the whole story, because performance also falls off in the *lower* weight classes, and that can't be due to Ted's "muscle binding" theory. Again, Ted is definitely mistaken. So we can see that animals do NOT necessarily do worse on square-cube corrected scales as they get larger. Now let's concentrate on just why sauropod dinosaurs could do better than Kazmaier. 1) biped/quadruped differences 2) cross section differences due to non-proportional scaling 3) leverage differences due to non-proportional scaling We can correct the Holden Limit to apply to quadrupeds by simply adding the weight Kazmaier can lift with his arms to that he can lift with his legs to get a rough idea. That modifies the formula to (1660 + 350) / 350^(2/3) ~= 40 In the ballpark for a brontosaur, but still short of the HN for a brachiosaur. But we can account for proportional scaling differences between species by dividing by a more appropriate factor. We can't really determine what that factor is easily, but we can get a ballpark idea by using the bone thickness factor reported by Alexander and others of (1/2.73). Ted calls this a "mysterioso, non-real-world" fudge factor. Actually, it is based directly on observation, so it is, in fact, a non-mysterioso real-world factor, despite Ted's claim. Ted also says "bones don't lift weight, muscles do". Quite so, but I'm using Alexander's numbers on bone thickness to scale the whole limb, muscles and all. Note that this will give us a different scale completely, so we have to do the figure for both Kazmaier and the brachiosaur: (1660 + 350) / 350^(2/2.73) ~= 27.5 150000 / 150000^(2/2.73) ~= 24.2 ( By coincidence, the limit number here turns out to be much the same as the original Holden Limit. ) So, if we simply take nonproportional scaling into account, as Ted refuses to do, we can see that at least the brachiosaur is within the corrected limit. Finally, we can add a factor correcting for leverage to our formula by assuming that limb length scales as cube root of mass, while joint radius scales as 2.73 root of mass. Working it out, we get this (note that the limit this time is 22): (1660 + 350) / (350^(2/2.73) * (350^(1/2.73)/350^(1/3))) ~= 22.6 600000 / (600000^(2/2.73) * (600000^(1/2.73)/600000^(1/3))) ~= 22.6 That is, a better estimate than Ted's of the limiting size of an animal in 1G is about 600000 lbs. The largest plausible figures for sauropod masses are half that. At large sauropod sizes, this means that limbs only about 20 percent proportionally thicker than Kazmaier's are required. And such legs would, indeed fit under a sauropod. In fact, measurements made from human and dinosaur bones as reproduced in library references shows sauropod bones *at* *least* that much thicker (meaning that the leverage advantage is definitely there, and that the cross section advantage is plausibly there.) A more detailed posting of this fact was done some time ago. Now, Ted's resolution of this "problem" is different. Instead of taking into consideration a more detailed model, Ted persists with the oversimplified Holden Number, exploits his confusion between one of the slimmest of sauropods (diplodocus) and a rather more stout sauropod (apatosaurus, or brontosaurus), combines this with the mistaken impression that some of the larger mass estimates are calculated by force estimation instead of volume estimation, and comes up with the curious formula (against the original Holden Number scale remember, where the limit is 27, not 22): 150000 / 500000^(2/3) ~= 23.8 Both methods account for sauropods. Ted does it by assuming that sauropods were subject to 150000/500000 G effective acceleration, or about one-third gravity. Why Ted's attempts to supply a reduced effective acceleration fail, of course, is material for several additional posts. As for me, I can't see that the .3 gravity is required to solve the "problem", because the assumptions behind the Holden Limit at 10 tons or so in 1G are simply incorrect. Subject: Holden and the superhumongoreallybigosaurs Summary: Ted is basing his arguments on very scant evidence Previous-Postings: 921213 :: From: swf@tools3.teradata.com (Stan Friesen) :: Message-ID: <1590@tdat.teradata.COM> ::: Again, McGowan and others give out the weight for an ultrasaur as ::: 360,000 lbs, :: What others? : From: news@fedfil.UUCP (news) : Message-ID: <169@fedfil.UUCP> : Articles I've seen in newspaper and magazine accounts which, due to space : limitations, I cannot always keep... The Avon Field Guide to Dinosaurs. It is always well to remember that McGowan and others give out the weight for an ultrasaur as 180 or so tons based on the assumption that it is close to 100 ft long. But that is only the upper limit of a range of guesses at its length. :: In particular its accuracy is limited to the accuracy of the model. :: And just how accurate do you think a model based on *one* *leg* is going :: to be? (At the time McGowan wrote his book, only one leg from the :: ultrasaur has been exhumed, so that was all that was available for :: analysis). : I remember reading that collar bones, ribs, and other bones were : uncovered in the late 70's. McGowan's book is dated 1991. What exactly : are you talking about? Actually, the situation is worse than Stanley points out, though Ted is right that more than "a single leg" is known of Ultrasaurus. Sort of. Let's look at a very recent book (published 1992), organized around the major finds of currently active researchers, and containing interviews with them. The book is _The_Kings_of_Creation_, by Don Lessem. Let's see what there is to see about Ultrasaurus. From the chapter on sauropods, "Land of Giants", we have these points: In the summer of 1972, Jensen went to Dry Mesa on a headline-making hunt. "I was an obsessed man. I was going to find the oldest, biggest carnosaur [meat-eading dinosaur], the bigger the better, even though scientifically that means little." [...] He struck upon the shoulder blade of an enormous dinosaur [...] A little figuring, based on comparisons of this shoulder bone and vertebrae found nearby with those of other giant sauropods, put the length of the new animal at eighty-two to ninty-eight feet (or even 140 feet, if it proved to be related to the long-tailed Diplodocus, as Jensen believes) [...] That was the discovery of Supersaurus. In 1979, Jensen was again digging around the Dry Mesa site, [...] when he and his crew came upon another shoulder blade. This one was nearly nine feet long, and broader than that of Supersaurus. If not from an animal longer than Supersaurus, it certainly belonged to a far heavier animal. [...] That was Ultrasaurus. But... Jensen did not get around to formally dubbing Supersaurus and Ultrasaurus until October 1985 [...] Jensen didn't base his new genus on the intriguing giant shoulder blade evidence. Ranterh he used one of several vertebrae found nearby as his holotype -- the distinctive bone upon which hangs new species or genus identification. [...] Jensen called his own diagnostic skills into question in a 1987 paper. There he took the unusual step of withdrawing his assignment of a neck vertebra to Ultrasaurus. He redubbed it [..presumably this means the vertebra..] a diplodocid, in keeping with the backbone's forked spines. And Jensen noted, the biggest scapula from Dry Mesa should be the holotype for identifying Ultrasaurus. Now, however, he has changed his mind again: "That was wrong. I was pressured to publish a lot quickly. I assumed incorrectly it was Ultrasaurus." Now Jensen believes the shoulder blade belongs to an unidentified brachiosaur, but not Ultrasaurus. By this latest analysis the quary at Dry Mesa would contain at least four different giant sauropods. Not surprisingly, Jensen's reconsiderations of Ultrasaurus left other paleontologists puzzled and displeased. Several doubt that Ultrasaurus is an animal distinct from Brachiosaurus, and few think Jensen's description and naming will stand the test of time. But The Dry Mesa quarry is still producing new fuel for the dispute. [.. a gargantual pelvis and other finds, some attributed to Ultrasaurus by some, but nothing definitive..] So. We see that the size was guessed based on a shoulder blade, and a mismatched vertebra. Further, 100 feet long is only the longest of a range of guesses, just as for Supersaurus. (It is typical of Ted to take the longest of a broad and speculative range as definitive. Perhaps this is because he is viewing things through accounts in the popular press, which are in turn trying to make things sound as big and amazing as possible.) So, let's see what the best expert in the biz (after whom the Ultrasaurus species, "Ultrasaurus macintoshi" was named) has to say. McIntosh has examined all the bones in question. He was one of the first outsiders at Dry Mesa after the giant pelvis was found. He has worked with Gillette and has long been convinced of the worthiness of Gillette's claim that Seismosaurus is a new and singularly long animal. Of Ultrasaurus, he says, "It's known from so few bones. I'm skeptical." McIntosh is not convinced that Ultrasaurus is something new. Like other researchers, he thinks it might be just a big Brachiosaurus. Its huge vertebra with a high spike, used to name the animal, might belong to the rear end of a diplodocid. Nor did the shoulder bones excavated at Dry Mesa provide clear evidence for Ultrasaurus or Supersaurus in McIntosh's mind. "But I thought all three were different." Still, it's possible, says McIntosh, that "Supersaurus and Ultrasaurus might be the same animal." As for Supersaurus, McIntosh is more confident as to its identity, but not utterly convinced. "I'd say it's a diplodocid with a two-thirds' chance of being new. But I hate to speculate. [...]" Of the Seismosaurus site, Lessem has this to say: Unlike Jensen's Dry Mesa site, this one was not a jumble of bones from many species, but rather the largely intact remains of one animal. Of the seismosaur, there is no doubt: it is a diplodocid sauropod of 140 to 150 feet in length. It is by far the largest sauropod for which complete a complete skeleton is available (and even it isn't completely excavated, let alone prepared or mounted). :: Try reading some actual journal articles on dinosaur weight estimates, :: and you will see that they are generally considered to have about a 30% :: (or higher) confidence bound. This is *very* crude, little more than :: order of magnitude. : 30% Off from 180 tones is still 120 tons and more. He still can't : make it. Bill Kazmaier at that size would be able to lift less than : half his weight off the ground, and Kaz is the most powerful creature : his size or larger, lb. for lb. imaginable. Ted has a limited imagination indeed. And, as I've already pointed out, sauropods didn't have to be stronger "lb. for lb." (though Ted probably means square cube scaled strength instead of lb. for lb. as he actually says). But the main thing to note here is that Ted is missing the ponit. The point is, WITH A SKELETON the weight estimates can be off 30%. That's the best case, when a volumetric model made with full information, and only guessing at the density. With no skeleton, as in the case of Ultrasaurus, one is even guessing at the length. And the guesses of length span 20%, corresponding to masses from under 100 tons to 180 tons. As more information is known about Ultrasaurus, the estimates are tending towards the low end of the original range of guesses. Ted has claimed that this re-evaluation was based on trying to get the weights down under 132 tons, given by Guiness as a limit. But from above we can clearly see that this is not the case. The re-evaluations are based on featues of the bones themselves. So, far from interpreting the bones in light of an attempt to get a known result, new results are being arrived at because of newly noted features of the bones, or because of new finds altogether. : Archimedes' technique could not be improved upon, assuming you have a : good idea as to the general shape and size of the creature involved, : which we do. No, we do not, as I've amply demonstrated above. The bottom line is, the largest example for which a full skeleton is known is under 100 tons. Even the Ultrasaurus is plausibly under 100 tons, based on the 20% range of sizes in the original identification. Ted is basing his argument for masses over 100 tons on very poor evidence indeed. And, of course, Ted's unmodified square-cube scaling is invalid. -- Wayne Throop throopw%sheol@concert.net


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