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
Carcharodontosaurus saharicus v Tyrannosaurus rex
Topic Started: Jun 8 2012, 05:34 PM (130,013 Views)
Taipan
Member Avatar
Administrator

Carcharodontosaurus saharicus
This huge meat eater was 45 feet long (5 feet longer than T-rex) and weighed 8 tons, making it one of the largest carnivores that ever walked the earth. This African carnosaur had a gigantic 5’4" long skull and enormous jaws with 8" long serrated teeth. It walked on two legs, had a massive tail, bulky body and short arms ending in three-fingered hands with sharp claws. Carcharodontosaurus is one of the longest and heaviest known carnivorous dinosaurs, with various scientists proposing length estimates ranging between 12 and 13 m (39-43.5 ft) and weight estimates between 6 and 15 metric tons. Its long, muscular legs, and fossilized trackways indicate that it could run about 20 miles per hour, though there is some controversy as to whether it actually did, a forward fall would have been deadly to Carcharodontosaurus, due to the inability of its small arms to brace the animal when it landed. Carcharodontosaurus was a carnivore, with enormous jaws and long, serrated teeth up to eight inches long.

Posted Image

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

_________________________________________________________________________________

Blue orca
 
Tyrannosaurs Rex vs Carcharodontosaurus
Edited by Taipan, Apr 24 2015, 10:18 PM.
Offline Profile Quote Post Goto Top
 
Replies:
Ursus panthera
Member Avatar
Artiodactyla
[ *  *  *  *  * ]
Joking lol
Offline Profile Quote Post Goto Top
 
theropod
Member Avatar
palaeontology, open source and survival enthusiast
[ *  *  *  *  *  *  *  * ]
yigit05
Nov 14 2012, 01:42 AM
theropod
Nov 12 2012, 12:32 AM
always those paws...
carchadontosaurus have large claws.damage to any size trex
The point is that the hands of a theropod are not called paws. they have large claws, but their purpose was rather gripping and positioning, not primarily doing damage
Offline Profile Quote Post Goto Top
 
Verdugo
Member Avatar
Large Carnivores Enthusiast
[ *  *  *  *  * ]
theropod
Nov 14 2012, 01:03 AM
Being slender can be advantageous for agility, that´s obvious, and there I have not seen evidence why a tyrannosaur should be more agile than other theropods. Both an explanation on the arctometatarsus and the knee joint would be interesting tough.

jingoferx: I thought holtz stated it was larger in his private communication with grey? anyway, 12m is definitely lower bound and the majority of estimates are higher than that. Mortimer gives C. saharicus 12,7m and basing on various reconstruction it could also be ~13-13,5m (I remember a comparison of skeletals on the forum)

lorg od the allosaurs, I´m looking forward to an explanation on the knee joint thing, and I agree about your points.
Man, Tyrannosauridae is more agile than a same sized Carnosaur due to being arctometatarsal. I have cited like thousand times =_= -_-

And being slender doesn't equal more agile, you just over-simplifying. I wouldn't say a gray wolf is more agile than a cougar because it is slender you know
Edited by Verdugo, Nov 14 2012, 03:21 AM.
Offline Profile Quote Post Goto Top
 
theropod
Member Avatar
palaeontology, open source and survival enthusiast
[ *  *  *  *  *  *  *  * ]
there is a great difference between grey wolves and cougars because wolves are cursorial.

But what about explaining why being arctometatarsal equals being more agile? isn´t that oversimplyfying, especially when you can´t even find an explanation stating why it is advantageaous to have a strangely shaped mid metatarsal kind of jammed between the others?
Offline Profile Quote Post Goto Top
 
Verdugo
Member Avatar
Large Carnivores Enthusiast
[ *  *  *  *  * ]
Quote:
 
there is a great difference between grey wolves and cougars because wolves are cursorial.

Cursorial doesn't equal less agile
Quote:
 
But what about explaining why being arctometatarsal equals being more agile? isn´t that oversimplyfying, especially when you can´t even find an explanation stating why it is advantageaous to have a strangely shaped mid metatarsal kind of jammed between the others?

Andrea Cau
 
The tyrannosauridi are distinguished from previous large theropods predators (ceratosauri, carnosaurs and dromeosauridi) for the bringing together of a skull specialized to bite powerful and torsion-resistant with a hind limb arctometatarsale, which allows speed and agility impossible for the previous theropods predators (although the vulgate media say that the dromeosauridi are among the fastest dinosaurs, the proportions in the leg bone and the absence of arctometatarso indicate that were not particularly suitable for running: this is in accordance with the anatomical data and taphonomic, which highlight their specialization "brontofagica", or to attack prey lens but significantly larger than themselves: this applies to the huge Utahraptor as for the small to medium sized Velociraptor).

The anatomy of the "base" of tyrannosauridi (particularly evident in taxa of medium-sized and Alectrosaurus Albertosaurus) allowed these animals to be faster than their prey and their possible competitors non-arctometatarsali to have a potentially areal foraging larger (and thus limit what competitors), and allowed them to minimize the competition between different age groups (juvenile body proportions show more cursorie adults, implying that they could be predators of other theropods arctometatarsali unlikely accessible for adults, relatively slower): all these factors not only strongly limited the possibility of expansion of other large theropods predators (preventing the establishment of a "triumvirate asiamericano" similar to that gondwaniano) but formed of one of the main tyrannosauridi " engine "of the morphological evolution of the other dinosaurs their contemporaries.

The apex of the potential of the predator arctometatarsale it has precisely with Tyrannosaurus: in this taxon dell'arctometatarso the advantages have allowed it to evolve a size comparable to those of giant gondwaniani (spinosauridi and carcharodontosauridi) but with a relatively longer limb, and a foot capable a decent agility (because it is less subject to mechanical torsion).

In conclusion, it is plausible that the arctometatarsali (tyrannosauridi, ornithomimidi, troodontidi, mononykini, avimimidi and elmisauridi) were relatively faster and more agile of their non-arctometatarsali. Also (especially important for large animals), they could slow down the motion in a dynamically less dangerous, absorbing better "braking" and change direction, as compared to other dinosaurs of the same size. Thus, even assuming that it was not a runner, a giant Tyrannosaurus as it should be, precisely because of the advantages conferred dall'arctometatarso, faster and more agile than other giants without arctometatarso.


Edited by Verdugo, Nov 14 2012, 03:58 AM.
Offline Profile Quote Post Goto Top
 
theropod
Member Avatar
palaeontology, open source and survival enthusiast
[ *  *  *  *  *  *  *  * ]
still no proper analysis of the mechanical properties, just a deduction without describing why an arctometatarsal should be that much better...
Offline Profile Quote Post Goto Top
 
Black Ice
Member Avatar
Drom King
[ *  *  *  *  *  *  *  * ]
Have they done that same study on other carnosaurs etc. to finalize it? Sounds like they made the assumption based off one type of theropod.
Offline Profile Quote Post Goto Top
 
Verdugo
Member Avatar
Large Carnivores Enthusiast
[ *  *  *  *  * ]
theropod
Nov 14 2012, 04:14 AM
still no proper analysis of the mechanical properties, just a deduction without describing why an arctometatarsal should be that much better...
Man, you seriously need an comprehensive explanation ?. I believe that is quite substantial

Andrea Cau clearly stated that T rex is more agile,
Offline Profile Quote Post Goto Top
 
Black Ice
Member Avatar
Drom King
[ *  *  *  *  *  *  *  * ]
Did he test it on other carnosaurs?????
Offline Profile Quote Post Goto Top
 
theropod
Member Avatar
palaeontology, open source and survival enthusiast
[ *  *  *  *  *  *  *  * ]
No, he did state it was plausible, without an analysis or further explanation, just a blog post (whose exact meaning might not even have been translated correctly). That´s a big difference.

Exactly, before believeing something I want a proper explanation, a mechanical test or a logical explanation, not a claim that it is generally said like that or it would probably have better properties. Is there a paper explaning on the advantages of an arctometatarsal for being more agile than other animals with a generally less bulky built?
Offline Profile Quote Post Goto Top
 
theropod
Member Avatar
palaeontology, open source and survival enthusiast
[ *  *  *  *  *  *  *  * ]
http://www.bio.ucalgary.ca/contact/faculty/pdf/russell/274.pdf
Quote:
 
If so, agility enhanced by the arctometatarsus may
have been beneficial in acquiring prey, although the
evidence is sparse and indirect.
The foregoing discussion parsimoniously corrobo
rates agility associated with predation as an initial
selective impetus for the arctometatarsus. This con
clusion rests on accepting the hypothesis of increased
agility in arctometatarsalians and upon a secondary
extrapolation that carnivorous coelurosaurs were pre
daceous. While alternatives are conceivable, the link
between the arctometatarus and predatory agility is
the most probable scenario.
CONCLUSIONS
1. Description and shape analyses indicate that
the arctometatarsus is morphologically distinct
from other theropod metatarsi but variable in
some details of form and thus function between
tyrannosaurids, ornithomimids, troodontids, and
caenagnathids.
2. Differences between arctometatarsalian mor
phologies are consistent with homoplasy, revealed
by independent character evidence (Sereno, 1999;
Holtz, 2000; Clark et al., 2002) and best docu
mented by Holtz (2001). The present study sug
gests a minimum of four origins. The structure’s
developmental expression was possible in coeluro
saurs but apparently not in other theropod taxa.
3. Proximal intermetatarsal ligaments were probably
a prerequisite to the developmental cascade
responsible for the arctometatarsus (including the
appearance of extensive distal ligaments).
4. If the arctometatarsus enhanced agility, its proba
ble selective benefit was likely related to predatory
performance in carnivorous taxa. Biological roles
associated with intra- and interspecific competition
and escape were probable at various stages in a
possessor’s life history.


Clear what I mean? the whole thing is not more than a hypothesis, there is obviously no direct evidence for enhanced agility. It might jsut be a different shape that evolved as a more elongated shape like it is typical for small and gracile animals. Tyrannosaurs then retained this trait, that doesn´t mean they have better agility because of it.
Offline Profile Quote Post Goto Top
 
Black Ice
Member Avatar
Drom King
[ *  *  *  *  *  *  *  * ]
I'd love to see that paper too. As the legs aren't the only thing that contributes to agility. You still have the hip placement, ankle sockets and joints etc. you can't just say t.rex is more agile because it has acrometatarsal only. That's not the only thing contributing to agility, even then the term agility is used as an extremely general term.
Offline Profile Quote Post Goto Top
 
theropod
Member Avatar
palaeontology, open source and survival enthusiast
[ *  *  *  *  *  *  *  * ]
A longer leg is not necessarily beneficial for agility, a longer metatarsal in particular ought to make the whole animal less stable is at all. Shorter legs and a less bulky body allow better accelleration (the leg muscles remain similar but the leverage is better). We´ll see about the details of which one is more agile, but claiming T. rex was is premature.
Offline Profile Quote Post Goto Top
 
Verdugo
Member Avatar
Large Carnivores Enthusiast
[ *  *  *  *  * ]
Quote:
 
A longer leg is not necessarily beneficial for agility,

A slender body isn't either
Quote:
 
Shorter legs and a less bulky body allow better accelleration (the leg muscles remain similar but the leverage is better).

Shorter legs doesn't equal quicker acceleration, why don't you tell that to the cheetah ?

And if you notice, T rex has shorter femur => shorter fiber length; more muscular legs which would make it easier to exert its strength and therefore accelerate faster.
Quote:
 
We´ll see about the details of which one is more agile,

And you don't have a single proof to prove that Carnosaur is more agile than same sized Tyrannosaurid ?. At least i still have one, directly claim from scientist, and if you remember, Gecko has showed that Hartman also claims the same thing as Cau
Quote:
 
but claiming T. rex was is premature.

Probably, but claiming Carchar is more agile is unreasonable since there is NO proof, scientist claims or paper to prove that
Edited by Verdugo, Nov 15 2012, 12:09 AM.
Offline Profile Quote Post Goto Top
 
theropod
Member Avatar
palaeontology, open source and survival enthusiast
[ *  *  *  *  *  *  *  * ]
I have, it is not as bulky, but I´m not the one making the claims here. A shorter femur means you have a shorter lever on the one end, and which do you think takes more force to move and thus longer to accellerate, a shorter or a longer lever?
Offline Profile Quote Post Goto Top
 
2 users reading this topic (2 Guests and 0 Anonymous)
ZetaBoards - Free Forum Hosting
Create a free forum in seconds.
Learn More · Register Now
Go to Next Page
« Previous Topic · Dinosauria Interspecific Conflict · Next Topic »
Add Reply

Find this theme on Forum2Forum.net & ZNR exclusively.