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Saurophaganax maximus v Tyrannosaurus rex
Topic Started: Dec 15 2012, 10:02 PM (59,202 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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blaze
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Didn't thought you'll have it there, sorry

mmm I still don't think ichnotaxons are a good reference for size, I'm reading the Moroccan track paper and they're "debunking" some of the sizes reported for the tracks that they showed in Fig. 10, noting that the inclusion of hallux+metatarsal should not be counted and that several of them are underprints(?)

For example, the Tyrannosauropus petersoni tracks, which one of them is 110cm long:
Quote:
 
Según los autores mencionados la longitud de la pisada 1 es de 87 cm y de la pisada 2 (que es la que se reproduce en la Fig. 10) de 110 cm. Si se mide la parte digitígrada de las icnitas su longitud sería de 50 y 65 cm respectivamente.
Translation: According to the authors the length measurement of track 1 is of 87cm and that of track 2 (reproduced in Fig. 10) is of 110cm. If the digitadrade part of the tracks is measured their length would be 50 and 65cm respectively.

They said that tracks over 70cm when not including hallux+metatarsal are very rare.
Edited by blaze, Jan 2 2013, 05:36 AM.
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blaze
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They did mention a 90cm track but this is what they said about it:

Quote:
 
La icnita intermedia es la más larga de las tridáctilas de la zona (90 cm). No se puede medir la anchura porque una parte de ella no aflora. La marca del dedo IV está bajo la roca, la del dedo III es redondeada y la del dedo II no es simple y parece que es resultado del movimiento del dedo durante las fases de la formación de la pisada. El paso, ángulo de paso y la zancada son los mayores de los descritos en este trabajo.
La altura de la extremidad se ha deducido para un dinosaurio terópodo. No obstante tal atribución está limitada a las observaciones sobre una sola icnita que además no muestra con claridad la terminación de los dedos.
The intermediate footprint is the largest of the three toed ones in the site (90cm). The width can't be measured because un part of it doesn't surface. The mark of digit IV is under the rock , that of digit III is rounded and that of digit II is not simple(?) and looks to be the result of the movement of the digit during the formation of the footprint. The step, angle of step and stride length are the largest of those described in this work.
The height of the hind limb has been estimated. However such attribution is limited to the observation of a single footprint that does not show with clarity the edges of the digits.

This footprint was found alone, while all the others were found as part of trackways over 200m long, those of the trackways were averaged to 75cm and 77cm. I think an average is better than a single measure, it more ore less cancels out possible deformations.
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theropod
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Thanks for the translations. In any case these prints are still gigantic. Of course ichnotaxa are not really a reliable evidence, but I think the abundance of really huge footprints from the upper jurrassic shows that an animal like this might have existed.

There are also ones from Spain: http://www.topix.com/forum/science/dinosaurs/TQSQ8JOGCMHH0QPDG
Quote:
 
http://onlinelibrary.wiley.com/doi/10.1111/j....
"The giant sized theropod track with a total length of 79 cm is tentatively referred to Torvosaurus which, with a body length of 8–12 m, was the largest theropod in the world during the Upper Jurassic. An almost completeTorvosaurus maxilla, 63 cm long, from an animal with an estimated skull length of 158 cm was found in the Lourinha˜ Formation in 2003 (Mateus et al. 2006), and limb bones from a similar sized animal has previously been found in the area (Mateus et al. 2006). Following the formula suggested by Alexander (1976), that the hip height of a dinosaur can be estimated as four times the length of the foot, the animal responsible for the large track stood 3.5 m tall at the hips. A theropod track with an estimated total length of 82 cm found in the Upper Jurassic of Asturias, Northern Spain (Garcı´a-Ramos et al. 2006) is morphologically different, in that the digit impressions is longer and more slender than in the Portuguese specimen. This suggests that more than one type of giant theropod existed in Europe during the latest Jurassic. The Upper Jurassic theropod tracks from Portugal and Spain are the largest Jurassic theropod tracks in the world, and only the tyrannosaur track Tyrannosauripus pilmorei from the Maastrichtian of New Mexico is larger, being 86 cm long and 64 cm wide (Lockley & Hunt 1994). However, if the additional length of the metatarsus impression is included in the specimen from Porto Dinheiro, then the total length of the track is 96 cm. When including the length of the metatarsus, the large theropod track from Asturias is 103 cm long (Garcìa-Ramos pers comm. 2009)."


I think including all the remains a really really huge allosaur seems likely.


Grey has asked me between the lines to do this:
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It is not perfect of course, appearantly scientists don´t bother to make sideview shots of their teeth, or even more likely, I just didn´t find them. This was the only one I found. It is probably not a very thick Megalodon tooth, seeing it is not thicker than my Otodus tooth, but sufficient to show my point; the teeth of C. megalodon are (for a shark) pretty similar to those of T. rex, but even more similar to those of some carnosaurs in terms of functional morphology.
I´m not suggesting Allosaurus or Saurophaganax could have sawed thorugh bony regions the same way a (highly specialized) tiger shark saws through turtle shells (or human limbs), what I´m however suggesting is that the skull, teeth and neck of Allosaurus had the necessary power and resistence to deal lots of damage, sufficient to decide a fight with another similar sized theropod (which after all alltogether have rather elongate proportions and hollow bones) quickly.

PS: note the strong variability in those allosaurus teeth, as I noted earlier, some are much thicker than others, soem are serrated on one side, some on both, some are much longer or more curved than others...
Allosaurus is just as heterodont as T. rex.
Edited by theropod, Jan 2 2013, 06:16 AM.
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blaze
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Going by Boutakiout et al. (2009), the Asturias track is an underprint, anyway I agree this tracks indicate the existence of some giant theropods from the Later Jurassic, I just don't think they come from animals dissimilar in size to the largest we know from fossils. 12-13m.

About the 158cm Torvosaurus skull, I haven't researched it myself but I've been doubting their conclusion for some time because of this comment on Wikipedia:

Steveoc86
 
I was reading the recent 2006 paper describing the European specimens (the 630mm maxilla), in that paper they say that the skull would have been around 1.58m. However looking around the internet at torvosaurus skull reconstructions (including GSP’s torvosaurus and the skull reconstruction in the paper) the maxilla seems to nearly half the total length of the skull. When I scaled the reconstructions to have a 630mm maxilla I get a skull size of around 1.20m. Using GSP torvosaurus the animal would be only about 9.5m long. Smaller than other specimens that I’ve herd of . On Mortimer’s site he mentions an individual (Paratype BYUVP 2003) with a skull of 1.31m this would approach 11m. ) He doesn’t give any other measurements for that animal so I cant check it. One has a Ischium of 736mm (BYUVP 2015) this would also approach 11m. (asuming GSPs reconstructionis correct) The paper mentions the skull that is 118cm long with a maxilla that is 470mm, could it be that the maxilla is incomplete? (only preserved for 470mm)? thanks


I do need to research it myself though.
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theropod
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I daresay it is possible that the comment was left by mantis shrimp, but whoever wrote it obviously didn't know logical conclusions are misplaced in wikipedia. Anyway, I'd love to debate that, and maybe I'll do some more detailed analyses of the evidence soon (I want to make a torvosaurus skull reconstruction anyway).

back on topic, here's a paper on V.komodoensis' feeding mechanism:
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0026226

it largely fits what is presumed for allosaurs, but there are some major differences; allosaurus cranium is not laterally but vertically reinforced (maybe an indicator for a stronger downwards-motion but a shorter time of contact?), and of course the bipedal stance and the neck musculature. I think this points out to the motion in allosaurus being more of a neckmuscle powered downward strike, followed by acaudally directed pull, while in komodo dragons it is rather first a traditional bite and then a pulling motion with most of the body involved but less confined to one plane. In addition the jaws of allosaurus where ignificantly narrower, that could have helped focusing the generated force on a small area. Overally I'd say the mechanism in allosaurus appears to be even more derived than in varanus.
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blaze
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I just found out that he got to the same conclusion this past september but that comment was made in may 2007, I don't think mantis is Steveoc86.
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bone crusher
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theropod
Jan 2 2013, 02:07 AM
Posted ImagePosted Image
http://carnivoraforum.com/blog/entry/3823033/45167/

as one can see above the jaws and teeth of T. rex do totally put those of a 13m Saurophaganax to shame, I have to agree with verdugo lol
You do realize the cubic dimension of T Rex skull and it's robust design still totally obliterate those other two do you? In a head to head ram contact the Allosaurid's skull would shatter like biscuits.
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theropod
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funny, I forgot about theropods giving rise to pachycephalosaurs. in the plane important for the skull to deliver forces, the vertical plane, the skull of MOR 693 already withstands forces that can easily match those of a similar sized T. rex (1,9t with Mf and Cf applied, 5,5t without them). It is laterally far less reinforced of course, but that only matters for an animal that wants to hold onto its prey to restrain it or shake it.
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bone crusher
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theropod
Jan 3 2013, 08:39 PM
funny, I forgot about theropods giving rise to pachycephalosaurs. in the plane important for the skull to deliver forces, the vertical plane, the skull of MOR 693 already withstands forces that can easily match those of a similar sized T. rex.
Er no it doesn't. A similar sized T Rex would be a youngster which would have a far less developed skull than a fully grown specimen like Sue. Scale up MOR 693 to the same length as Sue or much longer if you must, you would see the difference is world a apart.
Also I used head to head ramming as an example, it really just shows T Rex could do tons more damage per hit given the opportunity.
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theropod
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A similar sized T. rex when scaled to the same weight, or if you want, the same lenght. wouldn´t matter, the skull of allosaurus can match T. rex in a vertical plane without much trouble. See the FEA Rayfield performed on the (rather elongate and narrow even for allosaurus standarts) skull of big al. This "tons more damage per hit" sounds as if you where in a videogame, and it is total BS.
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bone crusher
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Let's say the skull could but it doesn't have the immense neck muscle to output nearly as much power or durability. Also no sauro weighs the same as Sue, even if it does the weight distribution would be make it a far slender animal proportionally speaking. There's simply no way Sauro would deliver as much damage per bite or per charge etc as T Rex could, but keep on believe what you want.
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theropod
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At the same weight I would say it could without too many problems, but of course a 5,5t Saurophaganax with a slightly shorter skull won´t deal as much damage as a 1t heavier, accordingly stronger T. rex. And there is nothing suggesting saurophaganax didn´t have immense neck muscles, they where actually perfectly adapted for downward strikes and going by the msucle attachment very strong. There is no reason to suggest absolutely speaking at equal weights T. rex would be able to deal more damage, unless we are talking about a skull bite (but then we might just as well talki about Saurophaganax biting the torso, an area T. rex couldn´t bite).

However T. rex definitely doesn´t totally outmatch saurophaganax in this regard like you claim.
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theropod
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updated the comparison, now there´s a dorsal view for Saurophaganax:
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please not it bases on big al, the most narrow skulled specimen I know (see Snively et al. 2006 or Rayfield et al. 2001 for dorsal view pictures). a large animal like Saurophaganax might have had a broader skull like these:
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQLusQIGv4ZK_IxPphP5giG03BRiCbhRh2j3r5dIvdnUYXW0-sR6g
http://www.thefastertimes.com/dinosaurs/files/2011/03/allosaurus.jpg
Snively et al. 2007

Not as if that would matter for the biting style of Allosaurus, but I know for certain some people will favour T. rex (or do it already) merely because of its much broader skull.
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bone crusher
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I'm not saying Sauro doesn't have a strong neck, but by T Rex's standard it's still comically slender even at the same weight. You really should go back to the comparison, any man with common sense would tell you which one has the more powerful neck. Your idea of both animals at the same weight would somehow nullify any structural advantages is just weak. In fact at equal weight it would all comes down to proportion and better structure or design. This is almost as good of an example as how a Jaguar would easily overpower a puma at equal weight. The narrow skull of Sauro alone should be enough to tell you which animal is more frontal heavy and powerful.
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theropod
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Firstly, a jaguar certainly wouldn´t "easily overpower" a cougar of the same weight.
Then, Saurophaganax doesn´t need to carry a skull as heavy as that of T. rex, no wonder its neck is more slender. The additional force in T. rex´ neck is needed to support the skull. If you had a look at the functional variation of neck muscles... paper you´d know at parity allosaur necks do not look "comically slender".

I´m not talkign about anything nullifying structural advantages, but as a matter of facts Saurophaganax has them as well, while your only argument is: "T. rex has a broader skull, thus its better!". If that isn´t a weak argument I have to find the new definition of that word. How come you presume T. rex would be able to deal significantly greater damage and claim it to be a structural advantage, and each time I tell you about the structural advantages Sauropahganax has you think I was somehow trying to "nullify" structural advantages?

It is not my problem if you don´t acknowledge that other theropods also had equally formidable weapons, and really, in a fight between similar sized animals which both are well armed macropredators the advantages either has tend to be slight. You are however sticking to the believe of a wider skull being a deciding factor that somehow magically tells you T. rex was the superior one and no advantage of Saurophaganax would matter any more.
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