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Majungasaurus crenatissimus v Megaraptor namunhuaiquii
Topic Started: Jan 18 2012, 09:47 AM (7,965 Views)
Wolf Eagle
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Megaraptor namunhuaiquii
Megaraptor was initially described as a giant dromaeosaur, known primarily from a single claw (about 1 ft/0.30 m long) that resembled the sickle-shaped foot claw of dromaeosaurids. The discovery of a complete front limb, however, showed that this giant claw actually came from the first finger of the hand. The hands were unusually elongated, bearing sickle-shaped claws even more recurved than those of spinosaurids. The hand is quite distinct from other basal tetanurans, so it was not initially clear whether Megaraptor was an allosaurid, a carcharodontosaurid, a spinosauroid, or something else entirely. Subsequent studies, as well as the identification of close relatives with similar large claws on the forelimbs (see below), have helped identify Megaraptor as a highly advanced and lightly-built allosauroid, and a member of the family Neovenatoridae.

I read here that Megaraptor reached about 26 feet and weighed 1-2 tons. I don't know if it's a reliable source though.


Posted Image

Majungasaurus crenatissimus
Majungasaurus (pronounced /məˌdʒʌŋɡəˈsɔrəs/ mah-JUNG-gə-SOR-əs "Mahajanga lizard") is a genus of abelisaurid theropod dinosaur that lived in Madagascar from 70 to 65 million years ago, at the end of the Cretaceous Period. Only one species (M. crenatissimus) has been identified. This dinosaur was briefly called Majungatholus, a name which is now considered a junior synonym of Majungasaurus. Like other abelisaurids, Majungasaurus was a bipedal predator with a short snout. Although the forelimbs are not completely known, they were very short, while the hindlimbs were longer and very stocky. It can be distinguished from other abelisaurids by its wider skull, the very rough texture and thickened bone on the top of its snout, and the single rounded horn on the roof of its skull, which was originally mistaken for the dome of a pachycephalosaur. It also had more teeth in both upper and lower jaws than most abelisaurids. Majungasaurus was a medium-sized theropod that typically measured 6–7 meters (20–23 ft) in length, including its tail. Fragmentary remains of larger individuals indicate that some adults reached lengths of more than 8 meters (26 ft). Scientists estimate that an adult Majungasaurus weighed around 1,875 lbs. (850 kilograms).

Posted Image

____________________________________________________________

7Alx
Jan 18 2012, 03:22 AM
Megaraptor vs Majungasaurus


Here it is!
Edited by Taipan, Nov 17 2016, 04:40 PM.
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LionClaws
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Ausar
Oct 4 2016, 06:02 AM
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This conclusion is even more impressive when we take into account the fact that Tyrannosaurus could abduct its femur from 0o to 45o, allowing it to take three-meter sideways strides with ease.
Is there a reference for this femur abduction figure I can see? It sounds interesting.
Yeah, it's from "Analysis of hindlimb muscle moment arms in Tyrannosaurus rex using a three-dimensional musculoskeletal computer model: Implications for stance, gait, and speed" by Hutchinson et al.

At my college, I can access it here. Not sure about everybody else, though, so I'll reproduce the relevant table here.

Table 1
JointMotionMinimum Joint Angle Maximum Joint Angle
HipFlexion/Extension-65o45o
HipAbduction0o45o
HipMedial/Lateral Rotation-30o30o
KneeExtension/Flexion-10o90o
AnkleFlexion/Extension-90o0o
Metatarsaophalangeal (Toe)Flexion/Extension-45o90o
Interphalangeal*Flexion/Extension-45o0o
Foot-GroundMedial/Lateral Rotation-45o45o


"TABLE1. Ranges of joint motion allowed in the Tyrannosaurus rex musculoskeletal model. Asterisk indicates that inclusion of the interphalangeal joint is optional (see Appendix 2). To convert these angles to the angles used in Hutchinson and Garcia 2002; also Hutchinson 2004 a,b, for the hip joint subtract 90o from the angle here, for the knee subtract the angle here from 180o, for the ankle add 180o to the angle here, and for the toe add 90o to our metatarsophalangeal joint angle. For all joints, 0o was fully straightened, so the columnar reference pose has all joint angles set at 0o."

I'm not 100% sure what "Medial/Lateral Rotation" at the "Foot-Ground" "Joint" means, but the rest are pretty self-explanatory.
Das Dinosaurier
Oct 4 2016, 06:09 AM
Thanks Lion Claws!
I also think abelisaurs would have been good mouth-grapplers,not only because of the strong neck and skull,but I also think the relatively high degree of flexibility in the lower jaw,which is not exclusive to Majungasaurus in the Abelisaurids,should help it.
That's interesting. Do you have a citation for that I can look over? Sounds interesting.

More regarding mouth grappling in Majungasaurus:

Therrien et al.'s "Bite Me" paper applies beam theory to theropod mandibles. According to it, Majungasaurus (then called Majungatholus) had a mandible fairly similar in construction to that of a Komodo dragon. Therrien suggests that Majungasaurus and Carnotaurus would have behaved similarly to the giant varanid: more or less a slashing bite. This would count as evidence against our supposition that the Abelisaurids would have been handling prey with their mouths.

We may need to look at the skull architecture of Majungasaurus in greater detail to resolve these seemingly contradictory indications.

Quote:
 
As for the femur abduction in T.rex:Interesting.Perhaps it was using it not only to bigger side steps,but also for the use of legs for subduing prey or hold onto carcasses?

My guess is that T. rex wasn't using its feet to subdue prey like an Allosaurus or Tyrannotitan (say) would have, though it surely would have delivered a fairly stern kick if it got the opportunity (just like all animals will).

Looking at the femurs of T. rex and Tyrannotitan, my mammalian-oriented mind thinks "there was a tradeoff between flexibility and strength, and T. rex is firmly on the strength side of the divide." The bone just generally looks more rugged and gnarled (plenty of spots for muscles to attach), but the big indicators (imo) are 1) the femoral heads, and 2) the "crest" about 1/3 of the way down the bone.

Before we get into why exactly I think that the two animals represent different ends of a tradeoff between flexibility and strength, I should probably explain why there's a tradeoff in the first place.

Back when I was active here four years ago, Ursus Arctos (one of the moderators here, he still posts, but is far less active) had just discovered an interesting biomechanical fact: flexibility and strength are inversely related.

You see, the force output of a muscle is proportional to two factors: cross-sectional area and leverage. So:

Force Output ~ (muscle mass/muscle fiber length)*(moment arm length/total limb length)

Where "~" means "is proportional to," and "moment arm length" describes the distance from a joint to the muscle insertion point on the associated bone. In mammalian forelimbs, the relevant insertion point for shoulder muscles is the deltopectoral crest.

Now, the range of motion a particular joint has is directly proportional to the length of the muscle fibers, and inversely proportional to the moment arm length of that joint:

Range of Motion ~ muscle fiber length/moment arm length

Notice that increased muscle fiber length, while it increases the range of motion, decreases the force output of the limb (assuming all else is held constant). Likewise, while increased moment arm length results in increased force output, it also results in decreased flexibility (again, assuming all else is held constant). The only ways to make a limb "better," full stop, are to increase the muscle mass and decrease the length of the limb. Which is why I tend to assume that the following relation holds:

"Usable Strength" ~ muscle mass/total limb length

which you can derive simply by multiplying the relations for "Force Output" and "Range of Motion" and canceling out like terms. This basically describes how much force a limb can apply over its total range of motion, or (another way to think about it) how much total energy a limb can apply through its full range of motion (energy = force*distance).

Regarding femoral heads, I'm basically drawing an analogy to the humeri of carnivorians:
Posted Image
First posted by Ursus Arctos

The limbs of animals like ursids are optimized for flexibility, and you can see that their humeral heads are less acutely "bent" off of the bone, and form less of a "projection" towards the joint, than the bones of other animals (they're also significantly larger in size with more surface area, but that's less relevant for our purposes). On the other hand, the humeral head of the wolf (which is, relative to its muscle mass, more optimized for strength) comes off at a sharp angle, projecting towards the joint. To me, it looks like the wolf's humeral head is more deeply entrenched in the shoulder joint, reducing its flexibility.

As dangerous as analogies to a different bone in a taxonomically distant taxon may be, Tyrannotitan's femur appears to be clearly on the "bear" end of the spectrum, whereas T. rex's femur appears to be somewhere on the "wolf/lion" end of the spectrum.

Likewise, since I assume that the aforementioned "crest" is for muscle attachment, the fact that T. rex's crest seems to make up a larger proportion of his femur than Tyrannotitan's would appear to indicate that T. rex had a relatively longer moment arm, and therefore, relatively less range of motion in the hind limb (though I haven't measured pixels in the image, so take that with a grain of salt).

I'm afraid I have to get going again, I'll edit this post with conclusions regarding T. rex's use of the hind limb and responses to other things you said in your reply when I get the chance. Please do not respond to me until then.
Edited by LionClaws, Oct 4 2016, 09:11 AM.
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Okay, so in my last post, I explained why I thought that T. rex was on the "strength" end of a strength-flexibility tradeoff when compared to Tyrannotitan. Now I'll describe my current thoughts on what that means for function, especially in the context of certain other anatomical differences between the two animals.

First, the arctometatarsalian condition:
Posted Image

T. rex foot on the left, Allosaurus foot on the right. Look at the metatarsals. See that rexy's middle one is "pinched" at the top? That's the "arctometatarsalian condition." It basically let those bones in T. rex's foot act as a single unit. Regarding it, Snively and Russel 2003 had this to say:
Quote:
 
The tensile keystone model differs from kinematics likely evident in the foot of Allosaurus or other theropods with three largely autonomous metatarsals. As with humans (Kerr et al., 1987), footfall loadings would cause their outer metatarsals to splay beyond their resting orientation, essentially spreading the foot apart. During deviations from linear locomotion, metatarsals would experience increased bending loads individually, rather than as part of a single structure, as predicted for the arctometatarsus (Fig. 6). Broad-footed theropods are not uniform in metatarsus morphology (Snively, 2000). None of these animals, however, display plantar constriction of MT III consistent with distal unification of the metatarsals, which would occur in the arctometatarsalian pes under the tensile keystone model.

The probable multiple origin of the arctometatarsus (Sereno, 1999; Holtz, 2000) suggests it was not a legacy morphology, which was simply retained with no contemporary utility. Instead, it may have conferred a selective or performance benefit. Developmental and immediate functional advantages are not mutually exclusive. The correlation between a constricted third metatarsal and proportionally long metatarsus (Holtz, 1995) suggests a developmental correspondence. Unfortunately, developmental hypotheses of this type are tenuously ad hoc. Perhaps the ontogenetic program for lengthened separate metatarsals reciprocally invoked proximal and plantar constriction of MT III in coelurosaurs, but tensile keystone dynamics evince more for the tyrannosaurid arctometatarsus than simply a developmental contribution to the lengthened foot.

Another possibility is that the tensile keystone morphology conferred heightened agility for a given body mass. As such, the arctometatarsus may have been broadly analogous to the stiffened tails of dromaeosaurid coelurosaurs (Ostrom, 1969), which have been suggested as dynamic stabilizers. Because there was no anteriorly propulsive component to the elastic rebound of ligaments, third metatarsal constriction did not directly avail increased speeds. Instead, the unifying and shear-resisting properties of the arctometatarsus may have absorbed forces involved in linear deceleration, lateral acceleration, and torsion more effectively than the feet of other theropods. These forces are limiting factors to combat performance in humans (Snively: pers. obs. in open hand and weapons sparring) and the arctometatarsus may have imparted momentarily excessive construction (Gans, 1974) for selectively crucial behaviors, such as predation or escape.

However, while the potential may have been present the employment and utility of increased agility in tyrannosaurids are no more directly testable than ontogenetic hypotheses. As with the evolutionary correlation between cursoriality and pursuit predation in theropods (Carrano, 1998), alternate hypotheses must be explored. In addition, the tensile keystone model cannot be taken to indicate that tyrannosaurids behaved more dynamically than Allosaurus. Whether tyrannosaurids used the potential for higher maneuverability during prey capture, and how close these animals operated to safety limits, are untestable by observation. Consequently, definitive statements about comparative agility in theropods are premature. However, the tensile keystone model demonstrates, in one aspect of hindlimb function, potential benefits to agility in large arctometatarsalians.


They hedge their bets like good scientists, but they make it crystal clear that the potential for higher maneuverability was there. I think that there are good reasons for ceratopsian-specialists to be more adapted for lateral motions and torsion than sauropod-specialists, so this does make sense. There's plenty of uncertainty, but I think we can be far more certain about the implications of the arctometatarsalian condition than we can about my speculations regarding the implications of theropod femoral structure.

Now, in addition to having a better reinforced femur overall, a femoral structure adapted to strength over flexibility, and foot bones better capable of handling lateral, torsional, and backwards stresses, T. rex had comically thick vertebral centra:
Posted Image

As you can see, T. rex's vertebrae are far larger than Tyrannotitan's vertebrae. This is very odd, because the two animals were more or less comparable in size. Sue might have been a bit bigger, but she wouldn't have been twice the size! My guess would be that this is an adaptation to handle high compressive loads sustained during prey capture.

My belief is that Tyrannosaurus used its heavily built skull and powerful neck in prey capture. The strength in its hind limbs would have allowed it to generate extremely powerful postcranial forces, and its thick vertebrae would have allowed it to transmit these forces all the way to the mouth.

The image you should have in your head when I say that is one of a Tyrannosaurus rex dragging a Triceratops around by the horns. In short, Tyrannosaurus was a mouth-grappler. Probably the most effective one in the history of terrestrial carnivores.

By contrast, Tyrannotitan's (relative) lack of turning agility and the impressive flexibility of its hindlimbs (combined with its ludicrously huge mouth and blade-like teeth) make me expect that it would have been adapted for two things: hit-and-run attacks against large but less maneuverable prey items, and overwhelming ambush attacks (whether by kick or bite) on medium-sized prey. This is an animal designed not to have to worry about maneuvering or manipulating its prey. Against prey of similar size, I'd expect it to charge up alongside it and kick. Hard. Follow that up with a bite to the abdomen, and the hunt is over. Against larger prey, I see it flesh-grazing when possible. Of course, an "over-grazed" sauropod would probably end up dead.

They're both extremely formidable and impressive animals, though for very different reasons. I tend to prefer animals that can handle extended contact with an opponent over ones that rely on an all-powerful first strike (*cough* lion vs tiger *cough* ursid vs felid *cough cough*), but I can understand when other people disagree.

At this point, we're quite a ways off topic, but at least we're having fun!

Quote:
 
Regarding the leg strength:Caudofemoralis muscles pulls the thigh bone backwards when contracted,so it is indeed important in leg strength and on the dinosaur's running abilities,particularly short-burst sprinting,although it likely didn't had a direct use in combat.However,I'm not sure if Majungasaurus had these muscles so well developed as we see in Carnotaurus,since the authors of the article "Dinosaur Speed Demon" only compared Carnotaurus' caudofemoralis to other abelisaurs of south america,and didn't mentioned Majungasaurus.I think its possible that the later would have well developed caudofemoralis since,like Carnotaurus,it is a very derived abelisaur,though Majungasaurus likely didn't needed sprint ability like that of its cousin.However,I think the proportional size of the leg of the megaraptoran should let its leg musculature be,well,proportionally bigger,fact that should make it easier to "carry its body",although,as you said,it wouldn't help much in the leg strengh used for combat("Leg grappling").

I'd like a little bit of clarification on what "leg strength used for combat/leg grappling" is supposed to mean.

I think that having some detailed images of Neovenatorid and Abelisaurid hindlimb elements would be helpful if we can find them.

I also think that a scale showing the two animals would be quite useful.

Quote:
 
Regarding you 'pet theory':I think your theory that the carnosaurs were unleashing sideways kicks at prey items could be rigth,considering that the foot structure of carnosaurs were thick and strong when compared to tyrannosaurs and the claws were specially sharp.I think that this wasn't limited to carnosaurs and tyrannosaurs could do it as well,but less frequently,and monstruous footed theropods like Torvosaurus perhaps were specially adapted to do that.I also think that they could use them to subdue prey,as I said before.

Again, what I've said about "kicking" has more to do with the structure of the femur than it does with the size of the foot. If the above image of Allosaurus and Tyrannosaurus feet are anything to go by, T. rex is the one with the larger/more rugged feet (though if T. rex does indeed have larger feet, my guess would be that it's an adaptation for traction, not for kicking). However, Allosaurus feet are notoriously pathological - further evidence that they were used to knock over medium-sized prey? It'd be nice to see an image of Allosaurus' femur...
Edited by LionClaws, Oct 6 2016, 09:49 AM.
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"That's interesting. Do you have a citation for that I can look over? Sounds interesting."

Yes:CRANIOFACIAL ANATOMY OF MAJUNGASAURUS CRENATISSIMUS (THEROPODA:
ABELISAURIDAE) FROM THE LATE CRETACEOUS OF MADAGASCAR. link

Here is an excerpt:

"The lower jaws of Majungasaurus and
other abelisaurids possess a greatly enlarged external mandibular
fenestra, with specialized contacts between the dentary and
post-dentary elements
"

"[...]In contrast, the
lower jaws of Majungasaurus and other abelisaurids (and perhaps
noasaurids; Carrano et al., 2002) appear better equipped for
some form of intramandibular movement (Mazzetta et al., 2000).
Morphology consistent with this interpretation includes: (1)
greatly enlarged external mandibular fenestra, marked in particular
by reduction of the dentary; (2) peg and socket articulation
between the surangular and dentary, almost certainly involving
synovial joints
; (3) reduced contact between the dentary
and angular; and (4) a broad, platform-like articulation between
the splenial and angular largely caudal to the dentary
."

The authors also infers that that feature was used as a shock absorver during stuggle:

" However, the degree of movement at this
joint, as well as its function, is not clear for most theropods. It has
been argued that this system allowed for “some flexion in multiple
planes...” so as to serve “. . . as a shock absorber to
dampen the forces generated by the acquisition, manipulation,
and/or consumption of large prey” (Holtz, 2003:331).
"

However,the same features were found in the skull of another derived theropod:Carnotaurus,and the function infered was an increase of oral gape,in order to swallow small prey whole.

In my opinion,both were using the same tools for different purposes:Carnotaurus had longer and more slender teeth,as well as a narrower skull and ligther leg bones,which suggest a small game hunter,and likely used the flexibility in the lower jaws mainly to swallow small prey.
Majungasaurus,by the other hand,had more ossified,thicker skull,with shorter and thicker teeth as well as stockier leg bones,which suggests a big game hunter,that likely used the same lower jaw mainly as a shock absorver during prey struggle.

"Therrien et al.'s "Bite Me" paper applies beam theory to theropod mandibles. According to it, Majungasaurus (then called Majungatholus) had a mandible fairly similar in construction to that of a Komodo dragon. Therrien suggests that Majungasaurus and Carnotaurus would have behaved similarly to the giant varanid: more or less a slashing bite. This would count as evidence against our supposition that the Abelisaurids would have been handling prey with their mouths."

Ah,that analogy.Komodo dragons have a peculiar way of tearing flesh:1º)They bite prey with a not-so-powerful bite.2º)use postcranial forces(mostly neck muscles) to drive its teeth into prey.3º)They pull their skull,causing blood loss.This method curiously have been also proposed for allosaurs like Allosaurus itself:using a muscle-powered bite to cause blood loss.However,there are more characteristcs in Majungasaurus skull that suggests a bite-and-hold method rather than the bite-and-pull(with some characteristics being quite the opposite we see in allosaurs).Here are the arguments the article's authors said in favor of the bite-and-hold method:

"(1) broad
skull (resisting torsional bending); (2) abbreviated skull (reducing
the moment arm of resistance at the atlanto-occipital joint
caused by rostrally placed loads, and thereby facilitating stabilization
of the head using neck musculature; this feature may also
have reduced the moment arm of the lower jaw, permitting increased
bite forces at the tip of the snout); (3) surprisingly high
bite forces (based on the mandibular biomechanics of Therrien
et al. [2005]); (4) tendency toward hypermineralization and fusion
of skull elements, including more intricate and robust contacts
between skull elements (thereby strengthening the skull so
as to resist torsional forces); (5) fused and pneumatized nasals
(transforming these elements from a relatively thin strut into an
elongate tube that would have been more effective in resisting
torsional forces); (6) expanded occiput and neck musculature
(for stabilizing, and perhaps retracting, the head); (7) shortcrowned
teeth (given that longer-crowned teeth would be more
prone to breakage during extended biting); (8) robust premaxillary
teeth (necessary since these were likely the primary weapons
in bite-and-hold behavior); (9) enlarged external mandibular
fenestra (permitting intramandibular accommodation movements
through reduction of squamous contacts and concentration
of articular surfaces at well-formed, probably synovial joint
surfaces)
"




"Again, what I've said about "kicking" has more to do with the structure of the femur than it does with the size of the foot."

That is true in my opinion,but I'd expect a creature that often uses the leg in figths against prey have thicker and stockier feet than the opposite.With that in mind,I think the structure of the foot is an important indicator of a creature that uses its legs in figths(although it isn't the main thing to consider).

Regarding the 'kicking carnosaurs":You could be rigth,but shouldn't creatures that are adapted to kick have massively built ilium and femur(in order to sustain more kicking muscles)?Although carnosaurs like carcharodontosaurids have robust appendicular skeleton,the femur and ilium musculature likely were small when compared to tyrannosaurids!That said,I think the legs could do kicks,but I think theropods like Tyrannotitan were mainly using the legs to 'manipulate'and subdue prey with its apparently good leg flexibility,while the feet claws "rake" the flesh out of their prey in the process(my English isn't very good,so pardon me if I'm using the wrong expression).Pretty much like a bear would use its paws,thoguh the theropod would be using the legs.

"My belief is that Tyrannosaurus used its heavily built skull and powerful neck in prey capture. The strength in its hind limbs would have allowed it to generate extremely powerful postcranial forces, and its thick vertebrae would have allowed it to transmit these forces all the way to the mouth. "

Indeed,studies in the neck musculature of tyrannosaurids suggests that it used its neck to do very forced movements of the head in order to tear the flesh of the bitten prey,so it is very likely that postcranial forces played a significant role in prey capture,although I think the extremely large leg muscles were mainly evolved to overcome the dinosur's bulk in order to run(or walk) fast.

Curiously,Duane Nash(paleontologist) proposed a "vibrational" feeding for dromaeosaurs,which seems alike your belief.

"Tyrannosaurus was a mouth-grappler. Probably the most effective one in the history of terrestrial carnivores."

I personally disagree with this.I think Majungasaurus was even more adapted to do that ;D

"I'd like a little bit of clarification on what "leg strength used for combat/leg grappling" is supposed to mean."

Sorry,I think I choosed the wrong words there.I wanted to meant that "useful strength" you talked about earlier would be in Majungasaurus favor(since the legs are very massively built but short-stocky,overall),which makes me think it was using the legs in combat a bit more than Megaraptorans since,as you said:"grappling ability in the forelimbs is effectively determined by the muscle mass powering the limb divided by the length of the limb".

"I think that having some detailed images of Neovenatorid and Abelisaurid hindlimb elements would be helpful if we can find them."

Unfortunately,I couldn't post pics of Majungasaurus' hindlimb material,but take a look at this: https://repository.si.edu/bitstream/handle/10088/7636/paleo_Carrano_07b.pdf?sequence=1&isAllowed=y

There,you can see,in page 6,what its ilium looks like.

Now,look at this:

Posted Image
(Murusraptor fossil material)
Posted Image
(Aerosteon ilium)

If you compare the ilium of Majungasaurus and those that I posted here(that are from megaraptorans),you can see that the former is nowhere near as massive as the later(s):the megaraptorans' ones are much taller in the central part,and thus could likely support a bigger amount of leg muscles.With that in mind(and having in mind that the megaraptorans had much larger legs when compared to the rest of the body),it would be logical that they would be more capable of moving its body at speed,rigth?Well,while it is sure thing that neovenatorids were speedier than Majungasaurus,there are more things to consider in the agility departments:

Posted Image

All the bones in the image above are abelisaurs tibiae.Noticed something weird?If you thought that all of them have large "knees",you're correct:Abelisaurs had abnormally large cnemial crests,and Majungasaurus was not an exception.But what does this means?Take a look at this excerpt from:The Appendicular skeleton of Majungasaurus Crenatissimus:

"The pronounced cnemial crest is associated with a prominent
medial femoral epicondyle in other abelisauroids, and such a
structure may also have been present in Majungasaurus. This
marks part of the origin of Mm. femorotibiales, which contributed
to the knee extensor tendon(s) that inserted on the cnemial
crest. The possible elaboration of Mm. femorotibiales, but not
other, more proximal knee extensors (such as Mm. iliotibiales
and M. ambiens) suggests enhancement of the knee extension
moment. The extensive lateral fossa on the proximal tibia may
have housed a large M. tibialis anterior as well
."

This large knee extensor condition,together with the (possibly) specially large caudofemoralis(that gave the leg an extra power),may had given Majungasaurus increased propulsive speed of the leg, an advantage seemingly more suited to lunging than for pursuit running(which suggests an ambush hunting behaviour for that animal).That said,I think that megaraptorans would have the advantage in overall speed(due to the larger pace and increased muscles in the ilium),but abelisaurs like Majungasaurus would likely have the edge in leg propulsion and,thus,possibly acceleration.

"I also think that a scale showing the two animals would be quite useful. "

Unfortunately,I don't know how to make these,but there is one on page 1 of this very thread.




Now I finished posting and you can reply my post
EDIT:

" It'd be nice to see an image of Allosaurus' femur..."

Here it is
In page 125,there are many femurs of Jurassic theropods,where Allosaurus is included.That was the best I could find...
Overall,it looks a lot like that of Tyrannotitan,but is more curved in lateral view.

Edited by Carnotaur, Oct 28 2016, 05:11 AM.
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Ausar
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Quote:
 
That is true in my opinion,but I'd expect a creature that often uses the leg in figths against prey have thicker and stockier feet than the opposite.That said,I think the structure of the foot is an important indicator of a creature that uses its legs in figths(although it isn't the main thing to consider).
Cursorial animals known to kick with their limbs have distal limb portions that are particularly gracile, but they don't have a problem with this when they kick in fights. So in the context of kicking, I have doubts that it really matters as long as the limbs can take the stress incurred from kicking (which is evidently the case in living examples, and of course, no reason to think the opposite for a tyrannosaur).

Oh, not related to the thread, but "that said" means "however"; it's meant to indicate that the sentence it starts has some sort of opposing view to the previous sentence, not to complement it with some sort of agreement.
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"Oh, not related to the thread, but "that said" means "however"; it's meant to indicate that the sentence it starts has some sort of opposing view to the previous sentence, not to complement it with some sort of agreement. "

Thanks.I'm not from an english country.
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Omnivore
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I'll get to this eventually. I might make a new topic for it, since we're covering a lot of ground that just has nothing to do with Megaraptor vs Majungasaurus, but is still fun to talk about.
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Carnotaur
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Saprotrophic Organism
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^Okay.I think the whole comparison between the carnosaur and tyrannosaur and things related should be moved,but the other things(that are related to either abelisaurs or megaraptorans)should be debated in this thread.
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Soopairik
Carnoferox's sex toy
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I think this can go either way.
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GallirallusAustralis
Autotrophic Organism
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Megaraptor wins 7/10, it's claws and jaws are much stronger than Majungasaurus's.
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Thalassophoneus
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Pelagic Killer
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GallirallusAustralis
Nov 24 2017, 02:40 PM
Megaraptor wins 7/10, it's claws and jaws are much stronger than Majungasaurus's.
Megaraptor had narrow jaws whereas Majungasaurus had wide jaws, if I am not wrong.
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Carnotaur
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Saprotrophic Organism
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GallirallusAustralis
Nov 24 2017, 02:40 PM
Megaraptor wins 7/10, it's claws and jaws are much stronger than Majungasaurus's.
Out of the few skull and teeth material we have for megaraptorans, none of them suggests very strong jaws, as far as I know.

Posted Image
(Dentary of Australovenator)

Posted Image
(Juvenile Megaraptor's possible skull shape)

By the other hand, majungasaurine abelisaurs have some of the broadest and most ossified skulls out of the Theropoda.

The abelisaur almost certainly outclasses Megaraptor in jaw and neck strength, although the latter's more well developed forearms and claws could give it the edge. I am still not sure on which of the animals would win most of the time.
Edited by Carnotaur, Nov 25 2017, 05:14 AM.
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Daspletosaurus
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Heterotrophic Organism
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Abelisaurids (for the most part) were adapted for biting and gripping, their jaws could take side to side pressures and their necks were well adapted to holding prey still or thrashing side to side with pray, they were masters of attrition, out lasting there struggling pray.
(this is my opinion based on what I have researched and my own observations, nothing more)
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Drift
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High Spined Lizard
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Soopairik
Oct 17 2017, 08:25 AM
I think this can go either way.
Agreed, this one is very close.
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