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Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,254 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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SpinoInWonderland
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Grey
Jan 31 2013, 09:57 PM
Regarding the color, that's not important and a factor of its technical and scientific accuracy, but I don't have any problem with that particular color.
The flesh hasn't been preserved so the dorsal structure is just as speculative as the color...

But going by the spines, a sail is the least likely. Stromer actually speculated a hump from his observations...
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SpinoInWonderland
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theropod
Jan 31 2013, 09:49 PM
The spinous processes of the holotype are lost and cannot be examined.
And the one who described them, came up with the idea of a hump...
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Grey
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Yes, the purpose is that this color is no worse than any other and that's far to be the main issue at this point.

Interesting that Stromer speculated himself at the time. Now this back almost 100 years ago and you know how much paleontologists of the time were wrong and later corrected in many works. In modern days I did not see something conclusive. I would not bet on it.

Viewing its semi-aquatic lifestyle, a large sail is more credible than a heavy hump to me.

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SpinoInWonderland
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Grey
Jan 31 2013, 10:27 PM
Viewing its semi-aquatic lifestyle, a large sail is more credible than a heavy hump to me.

A meaty crest(like in Planet Dinosaur) or a ridge would also help, and actually would be more useful since they would be sturdier and thus would be more resistant to the drag and other forces it may experience when swimming...
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theropod
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My point was that not everything shown in a model can be evidenced or is more than educated guess, this incloudes things like the color, but also things like it´s spines which are a matter of controversy.
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Grey
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I'm certain we'll have the final word anyway.

Already, this model is 15,8 m long, despite Cau, not a supporter of upper sizes, is standing with it.
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Jinfengopteryx
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brolyeuphyfusion
Jan 31 2013, 11:00 AM
Jinfengopteryx
Jan 31 2013, 02:43 AM
But maybe the sail indeed was just an equivalent to Elephant ears.
That's even more unlikely than a Dimetrodon-like sail...elephant ears can be moved and have no bones, Spinosaurus can't even move it's spines and has broad bones in it!

And again, a sail is the least likely...
No, I didn't mean in appearance, I ment in function. To have more surface for loosing heat (some people critisize the sail, because Spinosaurus wouldn't need extra heat).

EDIT: I haven't seen MysteryMeat replied already a few pages back. Anyway, for that function, it doesn't have to be Dimetrodon like, PD like would be enough. I don't know what it was, but everything would be possible. It could have been for storing fat (tough it would have to be very heavy than aswell, what's unlikely), but that's again just a possibility. I don't think it would have absorbed more heat than vice versa. Elephant ears too have lot's of blood vessels, but they don't make the elephant overheat, same with fennec ears.
Edited by Jinfengopteryx, Feb 1 2013, 12:44 AM.
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MysteryMeat
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brolyeuphyfusion
Jan 31 2013, 07:12 PM
MysteryMeat
Jan 31 2013, 02:04 PM
brolyeuphyfusion
Jan 31 2013, 11:00 AM
Jinfengopteryx
Jan 31 2013, 02:43 AM
But maybe the sail indeed was just an equivalent to Elephant ears.
That's even more unlikely than a Dimetrodon-like sail...elephant ears can be moved and have no bones, Spinosaurus can't even move it's spines and has broad bones in it!

And again, a sail is the least likely...
I think you misunderstood him completely...
Jinfeng meant sail could have had thermo regulatory properties like elephant ears, not fanning like ears...
The issue with that is that it's not likely to be a sail at all...

Why is it that people try to keep defending the sail above all others?
Who says only a sail can be thermo-regulatory??
I am not defending anything, sail, hump or ridge...
Whatever it is, it greatly increase the surface area of t he animal, so it's good for cooling and heating.
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MysteryMeat
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theropod
 
the model also displays the animal at a specific color it might not have had either, it being displayed doesn´t imply there is any reason to believe it. The facts are, it is not known and mere speculation.
The spinous processes of the holotype are lost and cannot be examined. Unless they made substantial new findings of vertebrae, there is no material to suggest anything that has more weight than the already proposed speculations.
That model is just a model in many, I too know a model of Arizonasaurus that displays the structure as a crest/ridge, that doesn´t necessarily mean it has any credential in this regard.
As long as there is no info an whether there is actual new information or whether it is just hypothesis, I don´t think the model is important in this regard


Now you are just arguing for the sake of argument. Restoring skin color is more speculative than restoring muscles, I think you can assume we all know that. No one is taking the skin color on a dinosaur like the holy doctrine of god.

Also please tell me why a well constructed model by highly-skilled artist working closely with paleontologist has no credential. Can't believe you just take a great piece of work and dismiss its scientific value like that.



brolyeuphyfusion
 
The flesh hasn't been preserved so the dorsal structure is just as speculative as the color...

Hardly.
Muscles attach to the bones, your skeletal structure defines it.
When you have fossilized bones, you can still work out how the muscle is constructed on the animal. On the other hand, skin color is usually based on modern animals, no solid fossil evidence, definitely more speculative than reconstructing muscles.
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Maelstrom
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I am not sure if this has been posted here but Andrea Cau seems to believe that Spinosaurus had a quick and powerful bite:

http://theropoda.blogspot.co.uk/2009/01/spinosaurid-paleobiology-more-than-just.html

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According to him its bite was used to impale prey and near the bottom of the page he suggests that spinosaurs also used their claws for impalement.
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Godzillasaurus
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Maelstrom
Feb 1 2013, 03:04 AM
I am not sure if this has been posted here but Andrea Cau seems to believe that Spinosaurus had a quick and powerful bite:

http://theropoda.blogspot.co.uk/2009/01/spinosaurid-paleobiology-more-than-just.html

Posted Image

According to him its bite was used to impale prey and near the bottom of the page he suggests that spinosaurs also used their claws for impalement.
That does not seem too hard to believe. What would be the point of long, conical teeth if they weren't for piercing the flesh of prey? A similar kind of dentition is seen in long-snouted crocodilians such as the Indian gharial. The teeth of a spinosaurus would have been very deadly weapons during the Cretaceous.
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Maelstrom
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Godzillaman
Feb 1 2013, 08:01 AM
That does not seem too hard to believe. What would be the point of long, conical teeth if they weren't for piercing the flesh of prey? A similar kind of dentition is seen in long-snouted crocodilians such as the Indian gharial. The teeth of a spinosaurus would have been very deadly weapons during the Cretaceous.
The main part was:
Andrea Cau
 

bite relatively quick AND powerful


Some people seem to think that Spino had a quick but weak bite.

Also Spino's elongated rostrum increases the moment of the force exerted by the muscles in the mandibular at the end of the rostrum. The cross section of the rostrum is triangular, the presence of the long nasal dorsal ridge served as a point of discharge to the forces, the presence of the long secondary palate - which acts as a mechanical expedient to resist torsion and the entire region infront of the nasals was made of solid bone with no cavities or soft spots.

All these seem as adaptations to support the intense stress caused by a powerful bite. A 2-3 tonne bit sounds more reasonable now.
Edited by Maelstrom, Feb 1 2013, 05:21 PM.
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Jinfengopteryx
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Maelstrom
Jan 30 2013, 04:28 AM
EDIT: I found the Seebacher method is quite conservative and might actually underestimate Suchomimus, because it gives the following results:

Tyrannosaurus: 6650 kg
Carcharodontosaurus: 6173 kg
Giganotosaurus: 6594 kg
Spinosaurus: 7981 kg (at 17m)
Seebacher said the method gave realistic weights for 95% of the tested animals.
The only dinosaurs where he said there were problems were small Coelurosaurs. There were no problems with Spinosaurids. The problem groups seem to be Ankylosauria and Stegoauria:
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6,6t was not for Sue BTW. The other weights match with the published estimates and he didn't show any estimate for Spinosaurs (as I have already said).
MightyMaus
Jan 30 2013, 07:15 AM
I dont trust the Seebacher method, not because of the method, but the starting assumptions. In the table they seem to drastically overestimate some dinosaurs, and underestimate others. For instance they have a Velociraptor at 3.1 meters and 44kg, and a Deinonychus at 3 meters and 104kg.

Also:

Dicraesaurus at 12.0m and 4.4 tons.

Haplocanthosauru at 14.0m and 14.5 tons.
Seebacher hasn't made any length estimates, only weight estimate, the lengths wereby other palaeontologists. As said, some Coelurosaurs culd be overstimated. I think we don't have to worry about the 3,8t estimate for Suchomimus.
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Godzillasaurus
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Spinosaurus probably shook large prey items in its jaws to help kill them, and fundamentally, dismember them.

Similar behavior is seen in modern crocodilians. When a crocodile attempts to kill and eat something too large to be swallowed whole, they normally shake their heads when that said item is clamped in their jaws. This violent maneuver can kill and easily rip apart large animals. Why do crocodilians do this? Well, they don't have carinae (cutting edges) on their teeth, unlike a large handful of various raisuchians and other prehistoric crocodilians.

I own the fossil of a spinosaurus tooth. The tip is non-present, and the tooth is rather short. However, when I examine it closely, I see what appears to be distinctive carinae. Similar features are seen on the teeth of crocodiles. However, this "carinae" is non other than a simple ridge. Nothing more, nothing less. It is not very sharp. This is a clue to how spinosaurus may have killed. Their teeth are very similar to those of modern crocodiles, and they appear to have adapted to a similar lifestyle.

My main point is that, although spinosaurus teeth lack the sharp cutting edges of carnosaurs, their similar morphology to those of modern crocodiles would surely make them a very dangerous animal in the Cretaceous Sahara.
Edited by Godzillasaurus, Feb 2 2013, 09:07 AM.
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dinosaur
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Seriously, and i am not trying to annoy anyone. Tyrannosaurus wins like this:
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Or this:
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Or this:
http://theozzex.deviantart.com/art/T-Rex-kills-Spino-179510533

Or this:
Posted Image
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