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Austroraptor cabazai v Utahraptor ostrommaysorum
Topic Started: Feb 6 2012, 07:12 PM (9,139 Views)
Taipan
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Utahraptor ostrommaysorum
Utahraptor (meaning "Utah's predator" or "Utah thief") is a genus of theropod dinosaurs, including the largest known members of the family Dromaeosauridae. Fossil specimens date to the upper Barremian stage of the early Cretaceous period (in rock strata dated to 126 ± 2.5 million years ago). It contains a single species, Utahraptor ostrommaysorum. The holotype specimen of Utahraptor is fragmentary, consisting of skull fragments, a tibia, claws and some caudal (tail) vertebra. These few elements suggest an animal about twice the size of Deinonychus. Like other dromaeosaurids, Utahraptor had large curved claws on their second toes. One claw specimen is preserved at 22 centimetres (8.7 in) in length and is thought to reach 24 centimetres (9.4 in) restored. The largest described U. ostrommaysorum specimens are estimated to have reached up to 7 m (23 ft) long and somewhat less than 500 kg (1,100 lb) in weight, comparable to a grizzly bear in size. Some undescribed specimens in the BYU collections may have reached up to 11 m (36 ft) long, though these await more detailed study.

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Austroraptor cabazai
Austroraptor ("Southern thief") was a genus of dromaeosaurid dinosaur that lived about 70 million years ago during the Cretaceous period in what is now modern Argentina. The type species for the genus, Austroraptor cabazai, was described in late 2008 by Fernando Novas of the Museo Argentino de Ciencias Naturales. The fossil specimen was discovered in the Late Cretaceous deposits located in the Río Negro Province of Argentina. The species was named in honor of Alberto Cabaza, who founded the Museo Municipal de Lamarque where the specimen was partially studied. Considered large for a dromaeosaur, Austroraptor cabazai measured around 5 metres (16 ft) in length from head to tail. It is the largest dromaeosaur to be discovered in the Southern Hemisphere. Particularly notable about the taxon were its relatively short forearms, much shorter in proportion compared to those of other members of its family. The relative length of its arms has caused Austroraptor to be compared to another, more famous short-armed dinosaur, Tyrannosaurus. Weight: 365 kg (810 lbs).

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Dracorex128
Feb 6 2012, 04:56 AM
Utahraptor vs Austroraptor
Edited by Taipan, Dec 6 2013, 09:42 PM.
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Fragillimus335
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Utah has size, hunting ability, weapons, forearms. and a better bite. Utah 90%
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Superpredator
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Fragillimus335
Sep 10 2012, 02:10 AM
Utah has size, hunting ability, weapons, forearms. and a better bite. Utah 90%
What do you mean "hunting ability"? Both were hunters.
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theropod
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it has been theorized that austroraptor was a fish eater because of it´s long snout and conical teeth. imo it could also be an adaption for restraining struggling prey tough.
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Carcharadon
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Utahraptor, simply due to being larger
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SpinoInWonderland
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Utahraptor wins due to size advantage...
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Carcharadon
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Actually i will probably go as far as saying this is a straight mismatch in favor of utahraptor

Austroraptor had long, narrow weak jaws and proportionally had smaller arms than other dromaeosaurs, and is more gracile in build, as well as it is smaller.

I think achillobator would be a better match
Edited by Carcharadon, Apr 20 2013, 06:31 AM.
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Spinodontosaurus
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Jaime Headden's restoration of Achillobator would put it as far too small to face Utahraptor, unless you meant to pit it against (the also larger) Austroraptor.
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Big G
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Utahraptor wins easily for size and weapons
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Carcharadon
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Spinodontosaurus
Apr 20 2013, 07:51 AM
unless you meant to pit it against (the also larger) Austroraptor.
Yea i meant to face it against austro
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Jinfengopteryx
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Dark allosaurus
Apr 20 2013, 06:28 AM
Austroraptor had long, narrow weak jaws
Weren't Utahraptor's premaxiliary teeth comparable to Velociraptor (which were described to be weak, in the 2010 paper about the Velociraptor vs Protoceratops fossil)?
So, even with strong jaws, it won't be helpful, because if the teeth were weak, they could break at a high stress.



References:

"New Information on the Anatomy and Relationships of Dromaeosaurus albertensis (Dinosauria: Theropoda)"
Philip J. Currie
Journal of Vertebrate Paleontology
Vol. 15, No. 3 (Sep. 14, 1995), pp. 576-591

"New evidence for a trophic relationship between the dinosaurs Velociraptor and Protoceratops"
David Hone, Jonah Choiniere, Corwin Sullivan, Xing Xu, Michael Pittman and Qingwei Tan (2010
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theropod
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^Velociraptor's teeth are so sharp they really wouldn't need to be very strong. Like in sharks or komodo dragons, they would slice through an oponents tissue without difficulties.

have a look at Austroraptor: http://fc09.deviantart.net/fs39/i/2008/364/8/e/Austroraptor_Skull_composite_by_Qilong.jpg

This is a different story. The dentary is the first one I see among non-avian theropods that I would actually compare to a gharial. As far as I know the teeth are cone shaped, so they don't have the slicing power to make up for the jaws not being so robust.

In the jaws department, Austroraptor stands no chance. It is also outsized here, and Utahraptor likely is superior in most other regards as well, as its morphology must have enabled it to sucessfully hunt large prey, even tough they are not known of Austroraptor.
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coherentsheaf
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theropod
Apr 20 2013, 10:16 PM
^Velociraptor's teeth are so sharp they really wouldn't need to be very strong. Like in sharks or komodo dragons, they would slice through an oponents tissue without difficulties.

have a look at Austroraptor: http://fc09.deviantart.net/fs39/i/2008/364/8/e/Austroraptor_Skull_composite_by_Qilong.jpg

This is a different story. The dentary is the first one I see among non-avian theropods that I would actually compare to a gharial. As far as I know the teeth are cone shaped, so they don't have the slicing power to make up for the jaws not being so robust.

In the jaws department, Austroraptor stands no chance. It is also outsized here, and Utahraptor likely is superior in most other regards as well, as its morphology must have enabled it to sucessfully hunt large prey, even tough they are not known of Austroraptor.
Fowler's RPR paper disagrees with varanid comparison:

The peculiar teeth of Dromaeosauridae (with the possible exception of Dromaeosaurus) differ from typical theropods in that the denticles of the posterior carina are particularly elongate, distally hooked towards the tooth apex, and much larger than those of the anterior carina [66]. This character is particularly pronounced in derived Late Cretaceous taxa (e.g., Velociraptor, Saurornitholestes); indeed anterior denticles may be entirely absent in some Saurornitholestes teeth [66], [67]. Denticle reduction on the anterior carina would enhance a piercing function, but the peculiar hooked shape of the posterior denticles would not appear well-suited for tearing through flesh, suggesting behaviour that deviates from more typical theropods.
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theropod
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Oh, I wasn't aware of that. But what's that "may be totally absent" supposed to mean? Aren't the teeth well preserved enough to tell this for sure?
I cannot imagine that in Velociraptor this wouldn't be known for certain.

If this really holds true, it wouldn't be that unuausl at all. Have a look at a lateral and an anterior tooth of Allosaurus and tell me they aren't radically different...and still the lateral teeth seem perfect for slicing, in shark or varanid fashion, a paralell that has been drawn in scientific papers.

Looking at my Velociraptor skull replica (but it appears less detailed than the original, all the teeth don't show the serrations, even tough msot had them, the anterior ones jsut don't seem as laterally flattened: http://commons.wikimedia.org/wiki/File:Velociraptor_skull_cr%C3%A2ne_2.png) the anterior teeth seem almost needle like. If the jaws couldn't fulfill a slicing function, why are all the other teeth in both Allosaurs and dromaeosaurs perfectly adapted for this?
Maybe the premaxillary teeth played some role in securing prey with the first bite, while the slicing was done by the lateral ones. The anterior teeth are pretty small compared to the others, so I cannot imagine them to be much af a hindrance. Or they might be some sort of anchor to prevent loosing the prey item after a slashing bite.
No idea whether my scenarios are realistic, but I doubt this had negative effects on the jaw function.
Edited by theropod, Apr 21 2013, 06:45 PM.
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Black Ice
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coherentsheaf
Apr 20 2013, 10:34 PM
theropod
Apr 20 2013, 10:16 PM
^Velociraptor's teeth are so sharp they really wouldn't need to be very strong. Like in sharks or komodo dragons, they would slice through an oponents tissue without difficulties.

have a look at Austroraptor: http://fc09.deviantart.net/fs39/i/2008/364/8/e/Austroraptor_Skull_composite_by_Qilong.jpg

This is a different story. The dentary is the first one I see among non-avian theropods that I would actually compare to a gharial. As far as I know the teeth are cone shaped, so they don't have the slicing power to make up for the jaws not being so robust.

In the jaws department, Austroraptor stands no chance. It is also outsized here, and Utahraptor likely is superior in most other regards as well, as its morphology must have enabled it to sucessfully hunt large prey, even tough they are not known of Austroraptor.
Fowler's RPR paper disagrees with varanid comparison:

The peculiar teeth of Dromaeosauridae (with the possible exception of Dromaeosaurus) differ from typical theropods in that the denticles of the posterior carina are particularly elongate, distally hooked towards the tooth apex, and much larger than those of the anterior carina [66]. This character is particularly pronounced in derived Late Cretaceous taxa (e.g., Velociraptor, Saurornitholestes); indeed anterior denticles may be entirely absent in some Saurornitholestes teeth [66], [67]. Denticle reduction on the anterior carina would enhance a piercing function, but the peculiar hooked shape of the posterior denticles would not appear well-suited for tearing through flesh, suggesting behaviour that deviates from more typical theropods.
Black Ice
 
Fowler et al. (2011) discuss the elements of prey acquisition, but also of processing, especially in the manner in which raptors consume their prey. Because dromaeosaurs lack a beak (a subject I discussed here) their processing must be done with teeth (a thing I’ve been told that they have). Dromaeosaur teeth are characterized by particularly large denticles on the distal carina as well as occasionally having apical hooking of the denticles, a feature that varies in the degree of “hookedness”. They can be either extremely sloped in some teeth, essentially angled towards the crown apex, or outward (Currie et al., 1990). Denticles are useful for many purposes: As denticles, they produce both a point along the crown where pressure from the crown as a whole is imparted, focused toward small separate portions rather than as a whole if the carina were not a single ridge; they also provide slots (or kerfs) between which tissues such as ligament or muscle fibers may be caught, increasing the tearing and thus rendering power of the tooth (Abler, 1992, 2001). Shape of the denticles varies, with some denticles having a largely rounded aspect, others with a sort of tilted-peak, and still others more triangular than squared as well as the inverse. Most denticles are typically hooked, having the aspect of a square with one corner extended, and this corner is always the apical edge of the denticle; thus, the denticles always have a peak that points apically, even when the angle varies (Currie et al., 1990).
Posted Image
Fowler et al. argue that the hooking of the denticles (which as can be seen above point outward in a general 45° angle from the angle of the crown of this tooth) is related to the posture of the head, which when in mantling behavior would be nearly or sub-vertical, nose pointed down and between the legs. Thus the angle of the teeth would be horizontal and create pressure using gravity to assist in tearing of the flesh; in this manner, the denticles would be pointed not posteriorly but close to vertically, as they are generally oriented toward the back of the mouth, now upward. Such a model proposes that gravity would then pull engaged flesh downward against the denticles. Fowler et al. support this model by noting that the jaws are “not particularly robust,” citing work by Therrien et al. (2005) and Sakamoto (2010). These studies show that dromaeosaurid jaws act as simple levers, indicated by a largely level force profile along the jaw, and more suited to quick nip and pull motions than prolonged periods where the teeth are embedded in flesh, which is indicated by high force profiles in the back of the jaw as is seen in stouter jaws such as in Allosaurus fragilis, or Gorgosaurus libratus. The subjectivity of “robustness” aside, this suggests that the thin jaws, thin teeth, where slashing teeth. As such, the denticles are merely suited for quick pulls, nipping bits of flesh apart, rather than prolonged prey engagement, and the same is true for the broader-jawed, broader toothed Dromaeosaurus albertensis (see Therrein et al., 2005, for discussion).

The morphology of some dromaeosaur teeth differ strongly from the hooked denticles of taxa noted by Fowler et al. (2011). Note, above and below, the presence in Saurornitholestes langstoni (after Currie et al., 1990), that while the morphology of the “main” body of the denticle (or corpus) is hooked, each denticle is paired with a apical and a basal “keel,” which converge into the diaphyses between denticles (in some teeth, this diaphysis, the space between denticles, terminates in a narrow slot with a rounded bottom, called a cella. These keels afford the denticles less of a elongated, slender profile and more of a rounded, hump-like one, and can substantially alter the effect the hooking provides when the teeth are engaged in a substrate. It is interesting enough that one can treat the morphology of denticles as miniature teeth — so that each crown has it’s own “jaw” of teeth along the edge — and thus infer a general model that they might act like saw blades or a method of distributing compression force along the carina. Such a model may seem useful, but is certainly untested when it comes to predatory theropod dinosaurs, just as such a model might come under fire when adapted to ornithischians, or sauropods, or a range of denticulated, ziphodont or non-ziphodont dentition in Archosauria, mammals, etc.

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coherentsheaf
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Apr 24 2013, 02:47 AM
Jaime A. Headden
 
[\color]Fowler et al. (2011) discuss the elements of prey acquisition, but also of processing, especially in the manner in which raptors consume their prey. Because dromaeosaurs lack a beak (a subject I discussed here) their processing must be done with teeth (a thing I’ve been told that they have). Dromaeosaur teeth are characterized by particularly large denticles on the distal carina as well as occasionally having apical hooking of the denticles, a feature that varies in the degree of “hookedness”. They can be either extremely sloped in some teeth, essentially angled towards the crown apex, or outward (Currie et al., 1990). Denticles are useful for many purposes: As denticles, they produce both a point along the crown where pressure from the crown as a whole is imparted, focused toward small separate portions rather than as a whole if the carina were not a single ridge; they also provide slots (or kerfs) between which tissues such as ligament or muscle fibers may be caught, increasing the tearing and thus rendering power of the tooth (Abler, 1992, 2001). Shape of the denticles varies, with some denticles having a largely rounded aspect, others with a sort of tilted-peak, and still others more triangular than squared as well as the inverse. Most denticles are typically hooked, having the aspect of a square with one corner extended, and this corner is always the apical edge of the denticle; thus, the denticles always have a peak that points apically, even when the angle varies (Currie et al., 1990).
Posted Image
Fowler et al. argue that the hooking of the denticles (which as can be seen above point outward in a general 45° angle from the angle of the crown of this tooth) is related to the posture of the head, which when in mantling behavior would be nearly or sub-vertical, nose pointed down and between the legs. Thus the angle of the teeth would be horizontal and create pressure using gravity to assist in tearing of the flesh; in this manner, the denticles would be pointed not posteriorly but close to vertically, as they are generally oriented toward the back of the mouth, now upward. Such a model proposes that gravity would then pull engaged flesh downward against the denticles. Fowler et al. support this model by noting that the jaws are “not particularly robust,” citing work by Therrien et al. (2005) and Sakamoto (2010). These studies show that dromaeosaurid jaws act as simple levers, indicated by a largely level force profile along the jaw, and more suited to quick nip and pull motions than prolonged periods where the teeth are embedded in flesh, which is indicated by high force profiles in the back of the jaw as is seen in stouter jaws such as in Allosaurus fragilis, or Gorgosaurus libratus. The subjectivity of “robustness” aside, this suggests that the thin jaws, thin teeth, where slashing teeth. As such, the denticles are merely suited for quick pulls, nipping bits of flesh apart, rather than prolonged prey engagement, and the same is true for the broader-jawed, broader toothed Dromaeosaurus albertensis (see Therrein et al., 2005, for discussion).

The morphology of some dromaeosaur teeth differ strongly from the hooked denticles of taxa noted by Fowler et al. (2011). Note, above and below, the presence in Saurornitholestes langstoni (after Currie et al., 1990), that while the morphology of the “main” body of the denticle (or corpus) is hooked, each denticle is paired with a apical and a basal “keel,” which converge into the diaphyses between denticles (in some teeth, this diaphysis, the space between denticles, terminates in a narrow slot with a rounded bottom, called a cella. These keels afford the denticles less of a elongated, slender profile and more of a rounded, hump-like one, and can substantially alter the effect the hooking provides when the teeth are engaged in a substrate. It is interesting enough that one can treat the morphology of denticles as miniature teeth — so that each crown has it’s own “jaw” of teeth along the edge — and thus infer a general model that they might act like saw blades or a method of distributing compression force along the carina. Such a model may seem useful, but is certainly untested when it comes to predatory theropod dinosaurs, just as such a model might come under fire when adapted to ornithischians, or sauropods, or a range of denticulated, ziphodont or non-ziphodont dentition in Archosauria, mammals, etc.

First of all since you definitely are not the author of this text (Jaime Headden is: http://qilong.wordpress.com/2011/12/19/dromaeosaurs-are-terrestrial-hawks/) do not quote yourself on it, quote him, else you are committing plagiarism.

Second the first sentence you highlight discusses the general properties of serrationts, it does not specifically concern itself with the denticles of Dromaeosaurs. Fowler et al. point out that the serrations of Dromaeosaurs are different as you can see by reading the text I quoted!

The second part you highlight is actually in support of Fowler's hypothesis, the whole section describes Dromaeosaurs as using gravity and their specialized teeth to nip off small pieces of flesh, similar to modern eagles that hold their prey down while ripping off small strips. This is not comparable to sharks or giant monitors, both being designed to deal large structural damage to struggling prey.

In short: The passage you highlight is in support of the notions of Fowler et al. A more important quote from it would have been: As such, the denticles are merely suited for quick pulls, nipping bits of flesh apart, rather than prolonged prey engagement, and the same is true for the broader-jawed, broader toothed Dromaeosaurus albertensis (see Therrein et al., 2005, for discussion).
Edited by coherentsheaf, Apr 24 2013, 04:40 AM.
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