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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,195 Views)
Wolf Eagle
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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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Spinosaurus aegyptiacus
Spinosaurus is a genus of theropod dinosaur which lived in what is now North Africa, from the lower Albian to lower Cenomanian stages of the Cretaceous period, about 112 to 97 million years ago. Spinosaurus may be the largest of all known carnivorous dinosaurs, even larger than Tyrannosaurus and Giganotosaurus. Estimates published in 2005 and 2007 suggest that it was 12.6 to 18 metres (41 to 59 ft) in length and 7 to 20.9 tonnes (7.7 to 23.0 short tons) in weight. The skull of Spinosaurus was long and narrow like that of a modern crocodilian. Spinosaurus is thought to have eaten fish; evidence suggests that it lived both on land and in water like a modern crocodilian. The distinctive spines of Spinosaurus, which were long extensions of the vertebrae, grew to at least 1.65 meters (5.4 ft) long and were likely to have had skin connecting them, forming a sail-like structure, although some authors have suggested that the spines were covered in fat and formed a hump. Multiple functions have been put forward for this structure, including thermoregulation and display. Dal Sasso et al. (2005) assumed that Spinosaurus and Suchomimus had the same body proportions in relation to their skull lengths, and thereby calculated that Spinosaurus was 16 to 18 meters (52 to 59 ft) in length and 7 to 9 tonnes (7.7 to 9.9 short tons) in weight. The Dal Sasso et al. estimates were criticized because the skull length estimate was uncertain, and (assuming that body mass increases as the cube of body length) scaling Suchomimus which was 11 meters (36 ft) long and 3.8 tonnes (4.2 short tons) in mass to the range of estimated lengths of Spinosaurus would produce an estimated body mass of 11.7 to 16.7 tonnes (12.9 to 18.4 short tons).

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Edited by Taipan, Apr 24 2015, 10:10 PM.
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Megalosauroid
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blaze
Nov 19 2013, 02:48 PM
Megalosauroid
Nov 19 2013, 11:18 AM
Based on the proportions of Suchomimus, the overall length estimate of Spinosaurus turns out to be less than 14 m, at only 13.7 m, seeing the proportions of this specimen:

It yields 13.75 m, based on a 11 m long S. tenerensis with a 1.4 m skull

http://scotthartman.deviantart.com/art/African-Fisher-199803540


Based on Baryonyx, it yields 15.1 m, with a 9.5 m long body and a 1.1 m skull
Hartman's Suchomimus is actually 11.8m and his Baryonyx is 10m, you could cut them to 11 and 9.5 if you want but you'll be reducing either tail, neck, skull length or a mix of all three without actually affecting its overall size.

You can't just say it's skull was this long and the body was this long becase none of them is complete enough and both their skull length and overall length can vary depending on how you reconstruct them, for example, Gregory Paul recontructs Suchomimus at "only" 9.5m long but if you compare his skeletal with Hartman's what you'll see is that Paul restored the skull/neck/torso/tail much shorter than Hartman, not smaller, just less long, resulting in a much smaller total length but not considerably smaller in terms of overall size. Paul also restores Baryonyx much shorter, at only 7.5m.

The same goes for the skull of Irritator, since it's missing half of its snout, it is not certain it was 84cm long.
Hartmans Suchomimus based on the skull length is rather 10.6 m with streched tail and 11 m measured along the curvature of the spines, same with FMNH PR 2081 which measures 11.7 m and 12.3 along the curvature.

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Megalosauroid
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blaze
Nov 19 2013, 02:48 PM
Megalosauroid
Nov 19 2013, 11:18 AM
Based on the proportions of Suchomimus, the overall length estimate of Spinosaurus turns out to be less than 14 m, at only 13.7 m, seeing the proportions of this specimen:

It yields 13.75 m, based on a 11 m long S. tenerensis with a 1.4 m skull

http://scotthartman.deviantart.com/art/African-Fisher-199803540


Based on Baryonyx, it yields 15.1 m, with a 9.5 m long body and a 1.1 m skull
Hartman's Suchomimus is actually 11.8m and his Baryonyx is 10m, you could cut them to 11 and 9.5 if you want but you'll be reducing either tail, neck, skull length or a mix of all three without actually affecting its overall size.

You can't just say it's skull was this long and the body was this long becase none of them is complete enough and both their skull length and overall length can vary depending on how you reconstruct them, for example, Gregory Paul recontructs Suchomimus at "only" 9.5m long but if you compare his skeletal with Hartman's what you'll see is that Paul restored the skull/neck/torso/tail much shorter than Hartman, not smaller, just less long, resulting in a much smaller total length but not considerably smaller in terms of overall size. Paul also restores Baryonyx much shorter, at only 7.5m.

The same goes for the skull of Irritator, since it's missing half of its snout, it is not certain it was 84cm long.
Hartmans Suchomimus based on the skull length is rather 10.6 m with streched tail and 11 m measured along the curvature of the spines, same with FMNH PR 2081 which measures 11.7 m and 12.3 along the curvature.
11/1.4: 1/7.85 skull/body ratio

The Baryonyx is rather 10 m and has a 1.12 m long skull, the one meter bar is
2.4 cm long and the skull is 2.7 cm long, the specimen is 9.5 m long with streched tail and 10 m with fully straight tail.
1/8.92 skull/body ratio, again not 10
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Megalosauroid
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theropod
Nov 20 2013, 02:01 AM
Baryonyx is very close to a 1/10 ratio, the total lenght in Hartman's skeletal being 10m, with a 1m skull (the BMNH skeleton is 9.1m with a 91cm skull so no matter how you put it, its pretty close). Irritator/Angaturama postcrania are not known or reported thus far, and their skulls can only be estimated as well.

People should start to pay a bit of attention to how skull and total lenght estimates are derived and correlated with overall size, especially since Hartman elaborates his methods and provides estimates for Spinosaurus itself to check them with.

If one assumes Suchomimus/Cristatusaurus' skull to be a certain lenght, the top priority for Spinosaurus becomes to estimate its skull lenght in a compatible way, ie. not reconstruct one of the skulls extra-short and one extra-long. But 13.7m are made pretty unlikely by other reasons, that would require the holotype and MNSN to be pretty much the same size (ie. we have an animal with a 1m rostrum and a 75cm dentary...), and still below what the vertebral sizes indicate for BSPG...
The Baryonyx has a 1.12 m skull based on the scale bars, the 1 m bar is 2.4 cm and the skull is 2.7 cm.
The body length was 10 m so the skull body ratio is 1/8.92 or almost 9 but no way close to 10

According to Hartman, both holotype and MSMN specimens have a quite Little difference between their body lengths (about 1.6 m), which can be interpreted as a sign that suggests their differences are just a normal variation between adults of the same species, I did too an estimate for the holotype based on the vertebrae compared to Suchomimus and it yielded 12.8 m, wether or not it is accurate is a matter of more studies, but it fits well within the 1+ m difference between both specimens, could be a scaling error of course.

Based on the Milan specimens, the skull of MSMN V4047 can be somewhere between 1.6 and 1.75/1.8 m based on the cranial material.

Edited by Megalosauroid, Nov 20 2013, 07:50 AM.
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blaze
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You didn't measure his skeletal properly, the one in deviant art is 888px long from tip to tip and the femur is 86px long, since the femur is 108cm long then the tip to tip length of his reconstruction will be 11.2m long, axial length will be close to 11.8m as I've previously measured it.

How did you measure it to get only 10.6m from tip to tip?
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Vobby
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Megalosauroid
Nov 20 2013, 07:50 AM

Based on the Milan specimens, the skull of MSMN V4047 can be somewhere between 1.6 and 1.75/1.8 m based on the cranial material.

Paleontologists who have seen and touched the rostrum in Milan don't exacly agree with your estimate.
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Megalosauroid
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Vobby
Nov 20 2013, 08:54 AM
Megalosauroid
Nov 20 2013, 07:50 AM

Based on the Milan specimens, the skull of MSMN V4047 can be somewhere between 1.6 and 1.75/1.8 m based on the cranial material.

Paleontologists who have seen and touched the rostrum in Milan don't exacly agree with your estimate.
Posted Image

Using the proportions from this



Posted Image


and this.....



You get an estimated size from 1.57 to 1.75 meters for the skull.

An where did they exactly say the estimated 1.75 m for the MSMN V4047 specimen is wrong?
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Megalosauroid
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blaze
Nov 20 2013, 08:17 AM
@Megalosauroid
You didn't measure his skeletal properly, the one in deviant art is 888px long from tip to tip and the femur is 86px long, since the femur is 108cm long then the tip to tip length of his reconstruction will be 11.2m long, axial length will be close to 11.8m as I've previously measured it.

How did you measure it to get only 10.6m from tip to tip?
I took in account a 1.4 m skull.....

I will remake my estimate now based on the femur.
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Megalosauroid
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blaze
Nov 20 2013, 08:17 AM
@Megalosauroid
You didn't measure his skeletal properly, the one in deviant art is 888px long from tip to tip and the femur is 86px long, since the femur is 108cm long then the tip to tip length of his reconstruction will be 11.2m long, axial length will be close to 11.8m as I've previously measured it.

How did you measure it to get only 10.6m from tip to tip?
I remade my estimate, based on the femur it yielded 11 m?? and 11.4 m in axial length, and using the humerus it yields 10.7 m, but the figures are not larger than 11.2 m, and the 11.2-11.8 m difference assumes a really streched tail, but it seems quite straight compared to other of his skeletals, even the larger 12.3 m Tyrannosaurus Sue gets only 60 cm shorter with a moderately streched tail, so I would say 30-40 cm less for Suchomimus
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Spinodontosaurus
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When scaled by femur length Suchomimus comes out at a good 11.2 meters tip to tip... 11.4 meters in axial length is just not reasonable; it would be close to 11.8 meters as Blaze stated.

In any case, the exact axial length isn't that important, because all you are doing is scaling the entire skeletal up or down, so the skull length changes too.

And, once again, skull length is not the deciding factor in estimating Spinosaurus' size (and remember that no spinosaurid has a complete skull). Take Scott Hartman's skeletal, and alter it's skull:body ratio WITHOUT changing the relative size of preserved elements; i.e. don't change the size of the dentary, rostrum or vertebrae relative to each other. You will find that regardless of the ratio, the overall size isn't going to change much, because that is well constrained by the vertebrae.
What matters then is how you fill in the gaps between the known vertebral elements; that two professional skeletal reconstructioners (real word??) - Scott Hartman and Greg Paul - ended up with 14 meters for the type specimen says a lot.
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Megalosauroid
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Spinodontosaurus
Nov 20 2013, 10:43 AM
When scaled by femur length Suchomimus comes out at a good 11.2 meters tip to tip... 11.4 meters in axial length is just not reasonable; it would be close to 11.8 meters as Blaze stated.

In any case, the exact axial length isn't that important, because all you are doing is scaling the entire skeletal up or down, so the skull length changes too.

And, once again, skull length is not the deciding factor in estimating Spinosaurus' size (and remember that no spinosaurid has a complete skull). Take Scott Hartman's skeletal, and alter it's skull:body ratio WITHOUT changing the relative size of preserved elements; i.e. don't change the size of the dentary, rostrum or vertebrae relative to each other. You will find that regardless of the ratio, the overall size isn't going to change much, because that is well constrained by the vertebrae.
What matters then is how you fill in the gaps between the known vertebral elements; that two professional skeletal reconstructioners (real word??) - Scott Hartman and Greg Paul - ended up with 14 meters for the type specimen says a lot.
How do you get 11.2 m?? as far as I know, the femur appears to be 2.05 cm long and 1.075 m in real life, so:

107.5/2.05 cm equals a skeletal 55 times smaller than the real skeleton itself, multiplied by the length of the drawing (21.1 cm) it yields 1106 cm for the skeletal, which just does not match with the 11.2 m estimate in exact body length.

The 14 m estimate comes from Baryonyx, not from Suchomimus, so it might be less accurate than using as a base a more similar sized animal at all.
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blaze
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This is how I did it, copy his skeletal from deviantart (or his site) paste it into Photoshop/GIMP, créate a new layer from a selection that includes the femur and change its orientation to make the femur either totally vertical or horizontal, measure how many pixel it is in length, then measure how long is the skeletal from tip to tip,

I redid it and I think I might have been a little wrong but not too much, femur came out at 86px long in the skeletal from his site, the skeletal was 886px from tip to tip, thus 886/86*1.08=11.13m a little less than I previously measured it, very close to your new mesurement and both considerably more than your initial 10.6m.

Then I used my unorthotodox way of measuring axial length using google earth, verified that femur length and tip to tip length matched what I measured before and measured the axial length, I got at 11.67m or 11.7m rounded up.
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Spinodontosaurus
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Megalosauroid
Nov 20 2013, 11:14 AM
The 14 m estimate comes from Baryonyx, not from Suchomimus, so it might be less accurate than using as a base a more similar sized animal at all.

No I doesn't, it comes from using Spinosaurus itself. Sure, Baryonyx and Suchomimus were used to fill in the gaps, but overall size is somewhat constrained by the known elements of Spinosaurus. The only real way to get much lower than 14 meters is with a really dinky neck and tail - both of which are already on the short side to begin with. The torso size is much more certain, and it was big.
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spinosaurus rex
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i agree with spinodontosaurus. spinosaurus was definitely longer then 14 meters and i heard all about the big headed, short tail theory as a result of it becoming older. i just don't see it happening. spinosaurus was fully capable of reaching 16 meters at the least. i say somewhere around 17 to 17.5 meters are max. a spinosaurus with a big head and shot tail would be the outlier of its entire species.
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Megalosauroid
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Spinodontosaurus
Nov 21 2013, 05:23 AM
Megalosauroid
Nov 20 2013, 11:14 AM
The 14 m estimate comes from Baryonyx, not from Suchomimus, so it might be less accurate than using as a base a more similar sized animal at all.

No I doesn't, it comes from using Spinosaurus itself. Sure, Baryonyx and Suchomimus were used to fill in the gaps, but overall size is somewhat constrained by the known elements of Spinosaurus. The only real way to get much lower than 14 meters is with a really dinky neck and tail - both of which are already on the short side to begin with. The torso size is much more certain, and it was big.
It comes from using the proportions of Baryonyx scaled to the size of the vertebrae of the IPHG 1912 specimen, I guess we need a closer relative to Spinosaurus to do the estimate.
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Megalosauroid
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blaze
Nov 20 2013, 12:31 PM
This is how I did it, copy his skeletal from deviantart (or his site) paste it into Photoshop/GIMP, créate a new layer from a selection that includes the femur and change its orientation to make the femur either totally vertical or horizontal, measure how many pixel it is in length, then measure how long is the skeletal from tip to tip,

I redid it and I think I might have been a little wrong but not too much, femur came out at 86px long in the skeletal from his site, the skeletal was 886px from tip to tip, thus 886/86*1.08=11.13m a little less than I previously measured it, very close to your new mesurement and both considerably more than your initial 10.6m.

Then I used my unorthotodox way of measuring axial length using google earth, verified that femur length and tip to tip length matched what I measured before and measured the axial length, I got at 11.67m or 11.7m rounded up.
Was it really that long? the original figure by Sereno was 11 m, But 11.76 m is something close to AMNH 5027, even if this reconstruction is correct, it does not give you a 16-18 m long Spinosaurus as many claim.

The estimate based on the published skull size estimate gives you an animal barely 14.7 m, if w are using Suchomimus to estimate Spinosaurus you do not get something larger than 15 m.
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