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Saurophaganax maximus v Tyrannosaurus rex
Topic Started: Dec 15 2012, 10:02 PM (59,199 Views)
DinosaurMichael
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Saurophaganax maximus
Saurophaganax ("lizard-eating master") is a genus of allosaurid dinosaur from the Morrison Formation of Late Jurassic Oklahoma (latest Kimmeridgian age, about 151 million years ago). Some paleontologists consider it to be a species of Allosaurus (A. maximus). Saurophaganax represents a very large (13 metres (43 ft) long). Saurophaganax was one of the largest carnivores of Late Jurassic North America. Ray even gave an estimate of the body length of fifteen metres and Chure of fourteen, though later estimations have been lower. The fossils known of Saurophaganax (both the possible New Mexican material and the Oklahoma material) are known from the latest part of the Morrison formation, suggesting that they were either always uncommon or appeared rather late in the fossil record. Saurophaganax was large for an allosaurid, and bigger than both its contemporaries Torvosaurus tanneri and Allosaurus fragilis. Being much rarer than its contemporaries, making up one percent or less of the Morrison theropod fauna, not much about its behavior is known. Stovall in Oklahoma also unearthed a considerable number of Apatosaurus specimens, a possible prey for a large theropod.

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Tyrannosaurus rex
Tyrannosaurus is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex (rex meaning "king" in Latin), commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the Maastrichtian age of the upper Cretaceous Period, 67 to 65.5 million years ago.[1] It was among the last non-avian dinosaurs to exist before the Cretaceous–Paleogene extinction event. Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to the large and powerful hindlimbs, Tyrannosaurus forelimbs were small, though unusually powerful for their size, and bore two clawed digits. Although other theropods rivaled or exceeded Tyrannosaurus rex in size, it was the largest known tyrannosaurid and one of the largest known land predators. By far the largest carnivore in its environment, Tyrannosaurus rex may have been an apex predator, preying upon hadrosaurs and ceratopsians, although some experts have suggested it was primarily a scavenger. The debate over Tyrannosaurus as apex predator or scavenger is among the longest running in paleontology. Tyrannosaurus rex was one of the largest land carnivores of all time; the largest complete specimen, FMNH PR2081 ("Sue"), measured 12.8 metres (42 ft) long, and was 4.0 metres (13.1 ft) tall at the hips. Mass estimates have varied widely over the years, from more than 7.2 metric tons (7.9 short tons), to less than 4.5 metric tons (5.0 short tons), with most modern estimates ranging between 5.4 and 6.8 metric tons (6.0 and 7.5 short tons). Packard et al. (2009) tested dinosaur mass estimation procedures on elephants and concluded that dinosaur estimations are flawed and produce over-estimations; thus, the weight of Tyrannosaurus could be much less than usually estimated. Other estimations have concluded that the largest known Tyrannosaurus specimens had a weight exceeding 9 tonnes.

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Edited by DinosaurMichael, Dec 15 2012, 10:02 PM.
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theropod
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blaze
Jan 6 2013, 01:26 PM
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It's based on Allosaurus specimens from the Cleveland-Loyd quarry and is evident if you scale his DINO and Big Al to the same head body length, or femur length that the tails are almost equal, which I didn't did when I used to claim that his Big Al had a shorter tail and I have to apologize for that, I went by looks and spread misinformation... So yeah, his Big Al could have a tail that's a bit too long, but even then is "only" ~7.2m long, head body length was some 3.5m.

I think from the Arizonasaurus case we can't confide in what Museums say, or even with Sue, making a 12.3m long mount but claiming it was 12.8m, even now that they've updated it they have 12.9m as the conversion of 40.5ft...

About Big Al two, the skeletal in the link I provided and the page which provides the link are actually conflicting, in the page it says 8m long and 2.4m tall at the hips, on the PDF it says 2.5m tall at the hips (but is supposed to be a conversion from 8ft which is ~2.4m) and it does say 7.6m long but by the looks of it it's from tip to tip which doesn't make it impossible that it was 7.9m along the curves (I just noticed that 8m was rounded up in the page), then again... I'm not fond of the skeletal... the skull does seem to scale to ~80cm roughly the claimed figure but the femur is ~97cm mmm, I think I spoke to soon, this is complicated!  :'(

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Hartman's Big Al skull superimposed with the skull in "Rayfield et al. (2001) Cranial design and function in a large theropod dinosaur" to the same scale, because it says they based it on Big Al, said skull is ~79cm in greatest length but I think I saw that same reconstruction in Madsen (1976).

Also, I found something that might interest you for your skull reconstructions.
I didn´t check that either. Then Big Al is just taller and maybe has a deeper body.

The 7,2m probably fit a 7,5m animal when the posture is taken into account.

Well, in this case the skeleton is virtually 100% complete, I think it lacks ten small bones. Even the most unreliable museum couldn´t make drastic errors in its size estimations.

This is indeed all very complicated, we should wait for some better info imo
Until then, view my skull comparison as a possible size for the skull of a 13m saurophaganax.

here´s a question I asked at Askabiologist concerning an overlapping subject: http://www.askabiologist.org.uk/answers/viewtopic.php?pid=21222#p21222

Thank´s a lot for that link!

PS: My Allosaurus skull was based on the scanned model Rayfield used when it differed from the reconstruction.
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bone crusher
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The difference really isn't that great and certainly doesn't yield a 3 tons decrease in weight. In fact Hartman's drawing has much bulkier neck and calves muscles which should balance out a few things too. The tail should actually be as thick as the 3d model according to a recent bulky tail study. So the rest is just the ribcage, there's no way the excess amount would be as much as 3 tons. Sue would weighted at least 9 tons, 10 tons or more if being well fed during a full season.
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theropod
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Appearantly the results Greg Pauls model yielded where that much lower...
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theropod
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oh, I think it should be easy to see Hartmans version here is simply bigger than the model, look at the head size. scaling to height won´t work, the legs of the model are near collumnar while those of Hartman are in a lifelike position. if you scale them correctly it is not surprising that the weight would be quite a bit lower than 9t.
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bone crusher
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OK, this should be accurate now, the hips length are exactly the same. Still I don't see a huge difference. Hartman's Sue literally doesn't have any fat content on its body area which is unnatural and not good for estimating a live weight. Again things would balance out if taking into account the much bulkier neck and calves in Hartman's Sue.
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SpinoInWonderland
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bone crusher
Jan 6 2013, 08:37 PM
Hartman's Sue literally doesn't have any fat content on its body area which is unnatural and not good for estimating a live weight.
How are you assuming that dinosaurs have a large amount of fat at all? Many birds today can be quite lean, and they're dinosaurs...
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theropod
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Much better, now it is obvious the weight would drastically decrease with a corrected spine curvature and rib posture. If the weight decreased that much when Greg Paul checked it I honestly don´t see why we cannot assume that Hartmans estimate is about right.

I think I now get a better idea of why the weight estimate from the study was too high; first of all, the model has virtually no spine curvature, which makes the torso longer than it should be, then it has cranially swept ribs and the resulting larger ribcage filled up with what I have called "additional tissue" earlier. Keeping in mind that the real torso, what you see in Hartmans skeletal, should be highly pneumatic, it is not surprising that removal of the exagerated parts would drastically decrease weight. Sues mount just isn´t really accurate, that´s it.
Edited by theropod, Jan 6 2013, 08:49 PM.
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theropod
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oh, and imo it is far more unnatural to assume a significant amount of fat added to the animal. It is an active predator, additional bulk wouldn´t be beneficial for hunting!

and be honest bony, which reconstruction would you favour, a T. rex looking like this:
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or one looking like this:
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You all know the corresponding image manipulations for allosaurus and torvosaurus, so no need to post them again.

If you favour the latter, all you are favouring is a large amount of additional fat around the torso.
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bone crusher
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In reply to Greg's complain, Hutchinson JR has mentioned that they've already removed the excessive weight from the expanded ribcage for their 9.5 tons data. So in essence what you ended up getting is in fact something along the line with Hartman's drawing. Also the concave gastralia from Greg's drawing is not accurate as seen in Hartman's drawing where the gastralia is a convex line.
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bone crusher
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I don't favor excessive amount of fat at all, nor do I favor a bone thin animal either. It would probably be more ideal for a T Rex to carry some fat content to cope rainy days just like how bears and crocodiles do often times.
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theropod
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Hartman however states the estimates centered around 6t, his own estimate is 6,4t. A bit more than the estimate greg paul made, that´s why I´m using it.
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bone crusher
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Just what method did Hartman use to get his estimation anyway? I trust his skeleton drawings and all but nailing down the weight is another thing, I hope he can collaborate with Hutchinson's team next time on 3d scans.
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theropod
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I don´t know, but you could ask him. Greg Pauls model-in-water-based weight estimate seems very conservative and I would prefer one that is a bit higher. Also Hartmans skeletal seems to be the most accurate that we have, so he is certainly aware of the rib posture etc.
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blaze
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The 7.2m for Hartman's Big Al is along the curves, its 6.9-7.0 from tip to tip. But you're right, let's wait for more info.

Getting back to Sue, theropod, have you read the response Hutchinson et al. gave to Greg Paul to that comment? they listed most of the reasons why Paul models are emancipated and, at least to me, it was pwn worthy lol

The reason that image of the model seems to have a very small head and in fact, might be messing with us by comparing it to Hartman's skeletal, according to Hutchinson et al. answer to Paul, they're not in Orthographic 2D view, like skeletals, they have a perspective added to them by Blender, it wasn't intentional though but this only affects the images.


Images in ortographic view are here but sadly, there isn't one for the minimum model of Sue.

btw: I don't know if Hartman writes it but in Ontograph Studio in the Sue skeletal it says "large individuals could attain 8 tonnes" or something along those lines. And isn't the 6.4 tonnes before the bulky tail study?
Edited by blaze, Jan 7 2013, 07:00 AM.
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theropod
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I'm on my tablet at the moment, and it's very late so I'll repond on it later. They used blender? wow, I should read those studies more carefully...

no idea on the tail, i don't even know which exact study you are referring to, but I asked Hartman recently and he still sais it centered around 6t, with the stronger pneumatisation making up for the more massivetail, so he is certainly aware of it.
Edited by theropod, Jan 7 2013, 08:59 AM.
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