Welcome Guest [Log In] [Register]
Welcome to Carnivora. We hope you enjoy your visit.


You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are some features you can't use. If you join our community, you'll be able to access member-only sections, and use many member-only features such as customizing your profile and voting in polls. Registration is simple, fast, and completely free.


Join our community!


If you're already a member please log in to your account to access all of our features:

Username:   Password:
Add Reply
Spinosaurus aegyptiacus v Tyrannosaurus rex
Topic Started: Jan 7 2012, 02:16 AM (459,198 Views)
Wolf Eagle
Member Avatar
M E G A P H Y S E T E R
[ *  *  *  *  *  * ]
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.

Posted Image

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).

Posted Image
Edited by Taipan, Apr 24 2015, 10:10 PM.
Offline Profile Quote Post Goto Top
 
Replies:
Jinfengopteryx
Member Avatar
Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
[ *  *  *  *  *  *  *  * ]
Vobby
Oct 16 2013, 06:41 PM
Uhm, do you have any scientific article, post or something criticizing Therrien & Henderson? I have no access to their study, but maybe I can understand it bettere reading someone who writes about it.
May I ask why you can't access it? Because it is freely available:
http://dinoweb.ucoz.ru/_fr/4/My_theropod_is_.pdf
Offline Profile Quote Post Goto Top
 
Vobby
Member Avatar
Omnivore
[ *  *  *  *  * ]
Jinfengopteryx
Oct 16 2013, 11:19 PM
Vobby
Oct 16 2013, 06:41 PM
Uhm, do you have any scientific article, post or something criticizing Therrien & Henderson? I have no access to their study, but maybe I can understand it bettere reading someone who writes about it.
May I ask why you can't access it? Because it is freely available:
http://dinoweb.ucoz.ru/_fr/4/My_theropod_is_.pdf
Oh thank you! For some reason google scholar gave me pages where I had to pay to read the article.
Offline Profile Quote Post Goto Top
 
Vobby
Member Avatar
Omnivore
[ *  *  *  *  * ]
Ok, I don't really get why they use the skull to estimate the body mass, while lenght is more clear. In the paragraph "estimating the body size of spinosaurids", where do you guys think are the mistakes? I don't see evident ones, but I probably just can't.

Edit: ok, i read the Mortimer's article, I should read it again to clarify some things, but I got whay you all dislike Therrien & Henderson study.

@theropod: about the "better, smarter" thing, in my opinion, Cau can freely and frankly disagree with other paleontologists if he wants, becouse he is a paleontologist, he can't do it from a position of equality. If I say that he is completely wrong, biased, lacking a decent methodology, then I'm doing it from a position of presumption, since I'm not equal to him in this matter. I would never say "this study is wrong", I prefer saying that I don't understand it, maybe that I'm not completely convinced or, better, point out that other scientist have criticized it. Just my opinion tough.
Edited by Vobby, Oct 17 2013, 12:29 AM.
Offline Profile Quote Post Goto Top
 
Jinfengopteryx
Member Avatar
Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
[ *  *  *  *  *  *  *  * ]
Vobby
Oct 17 2013, 12:18 AM
In the paragraph "estimating the body size of spinosaurids", where do you guys think are the mistakes? I don't see evident ones, but I probably just can't.
Theropod's link listed the mistakes. They used completely unrelated taxa and they tried to obtain a skull/size relationship for all theropods. This relationship is biased towards small, long tailed theropods and large, short tailed ones. Spinosaurus was large, but long tailed (like Barynonyx), so the relationship can't be used for it. Also, a 20 t Spinosaurus would be barely able to walk (but you already realized that the weight figures are stupid).
Offline Profile Quote Post Goto Top
 
Super Kaizer Ghidorah
Autotrophic Organism
[ *  * ]
The only skull and teeth much more lethal than this..
Posted Image

Is This!
Posted Image

This should answer this question. Will tyrannosaurus rex kill spinosaurus with with one deadly chomp? YES!
Edited by Super Kaizer Ghidorah, Oct 17 2013, 01:03 AM.
Offline Profile Quote Post Goto Top
 
Vobby
Member Avatar
Omnivore
[ *  *  *  *  * ]
lol

When I think about fight between giant theropods I just add some thousand of kilograms to the two opponents of this fight:




A long and cruel face biting struggle, whit pathetic use of the forelimbs. Here is a proper theropod fight for you! lol
Offline Profile Quote Post Goto Top
 
theropod
Member Avatar
palaeontology, open source and survival enthusiast
[ *  *  *  *  *  *  *  * ]
@vobby: I think Mortimer already made good points.

I can repeat the most important one: Why the hell should we assume Spinosaurs had similar proportions to Carnosaurs or Tyrannosaurs, let alone be correctly estimated when using the slope between Tyrannosaurs and compsognathids?

Cau can write whatever he wants, I've got no problem with him expressing his opinion. What I really don't get is why a bunch of people takes it at face value without any consideration, and basing on arguments against other studies that are even more applicable to Cau's himself. And there should be no such thing as "inequality" here. The methods Cau uses are not magic that only someone with a degree in earth sciences can do.
Offline Profile Quote Post Goto Top
 
Vobby
Member Avatar
Omnivore
[ *  *  *  *  * ]
Andrea Cau discussing Therrien & Henderson (nice post if you ask me):

http://translate.google.com/translate?u=http%3A//theropoda.blogspot.it/2013/10/diversi-modi-di-stimare-le-stime.html&hl=en&langpair=it|en&tbb=1&ie=UTF-8
Offline Profile Quote Post Goto Top
 
theropod
Member Avatar
palaeontology, open source and survival enthusiast
[ *  *  *  *  *  *  *  * ]
Very much to the point: it is easily falsifyable.

The best thing about it; it has already been falsified, even by themselves. Their estimates show consistent errors, so do their assumptions about skull lenght, weight and total lenght.

I can see the logic in favouring a method of estimate that is easy to falsify and yet has not been falsified. But by what logic should a method that has already been falsified have any value?

Better a method more difficult to falsify, but not falsified, than a method easy to falsify, and accordingly falsified. The former at least holds the possibility to be right.

One can also relativise the term of falsification by simply counting good arguments against of for a method. The same applies here.

Now, their estimate for Spinosaurus has not been falsified directly, due to the lack of remains, but all the points against their method are clearly indicating it is inaccurate.
Offline Profile Quote Post Goto Top
 
Vobby
Member Avatar
Omnivore
[ *  *  *  *  * ]
In the comments, Cau specifically said that his and Mortimer's critiques were moved to the results, not to the method itself. The method is good becouse its results can be easily verified, so confirmed or falsified. The method consists in finding a statistical, non necessarily linear, relation between the skull lenght and the body lenght of theropods. He is okay with the method, but he agrees with Mortimer when he said that different theropods should have been used in the study, with less arbitrary exclusions.
Offline Profile Quote Post Goto Top
 
Jinfengopteryx
Member Avatar
Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
[ *  *  *  *  *  *  *  * ]
A statistical relation maybe interesting, but how is it useful? Theropoda is a large clade and the variation is high, so it cannot be used for calculations.
Offline Profile Quote Post Goto Top
 
theropod
Member Avatar
palaeontology, open source and survival enthusiast
[ *  *  *  *  *  *  *  * ]
Using a single head-body function for all of theropoda is like using such a method for Mammalia. totally ridiculous.
Again, there's nothing good about being easy to falsify if a method HAS already been falsified in many regards. Being easy to falsify is an indicator of quality only if despite that a hypothesis has only been verified.
Edited by theropod, Oct 19 2013, 12:19 AM.
Offline Profile Quote Post Goto Top
 
thesporerex
Kleptoparasite
[ *  *  *  *  *  * ]
How many times have you people said falsified in the past 2 pages?
Offline Profile Quote Post Goto Top
 
theropod
Member Avatar
palaeontology, open source and survival enthusiast
[ *  *  *  *  *  *  *  * ]
Often, veeery often.
Offline Profile Quote Post Goto Top
 
Jinfengopteryx
Member Avatar
Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
[ *  *  *  *  *  *  *  * ]
thesporerex
Oct 19 2013, 12:56 AM
How many times have you people said falsified in the past 2 pages?
At least I didn't use that word that often. :D (in exchange I used two times "that" in a very short comment)
Edited by Jinfengopteryx, Oct 19 2013, 01:41 AM.
Offline Profile Quote Post Goto Top
 
2 users reading this topic (2 Guests and 0 Anonymous)
DealsFor.me - The best sales, coupons, and discounts for you
Go to Next Page
« Previous Topic · Dinosauria Interspecific Conflict · Next Topic »
Add Reply

Find this theme on Forum2Forum.net & ZNR exclusively.