Spinophorosaurus nigeriensis vs Acrocanthosaurus atokensis

[theropod]

The difference in thickness of the center and tip of the tail isn't extreme.

It is considerable, and the forther anterior we go, the thicker, stronger and heavier the tail will be (which relates to how much force a blow with said tail will generate)

Any impact would be very damaging to a much smaller predator; as long as the size difference is major, the whip-like morphology of diplodocid and titanosaur tails would be crippling.

Titanosaur tails aren’t really whip-like, they are relatively short and thick organs.

But of course the damage would be more sufficient against a much larger predator comparably, but I would not take away the possibility that a powerful enough tail strike to the skull of such a creature (especially in acrocanthosaurus' case, which obviously did not possess a very robust skull) could easily incapacitate it.

Depends on what size the sauropod is and what shape its tail is. I doubt an Europasaurus would incapacitate it, but the situation if different if, for example, said sauropod had a club or a set of thagomizers at its tail tip.

The vertebrae are designed to support the neck, but they do not make it up entirely.

Not entirely, mostly. researchers agree that immense amounts of soft tissues on those necks would make it impossible for the animal to support them, ergo the amount of muscle wasn’t very big compared to many other animals. Tendons would certainly play an important role here.

Sauropod necks are made up of immense amounts of muscle as well.

as I wrote, check the paper I linked→.

Well that is true. But depending on how tall it is compared to its prey (in this case, they were not that far apart in size), it seems highly unlikely that it would go in for the flanks if it were taller.

Not any less likely than an attack on any other place. Simply dependant upon the relative positions of their bodies. A similar-sized sauropods flanks are within comfortable striking range for a theropod. It is less likely to bite the lower belly tough.

True, but I was referring to the probability that the most damage done in such a scenario would be done with violent downward strikes of the creature's skull (axe-biting).

That implies damage tzo muscles, tendons and blood vessels first and foremost.

With enough precision, such a bite would easily be able to sever it.

In a similar-sized sauropod, that is conceivable (as I already mentioned, most dinosaur neural arches, especially in sauropod vertebrae, especially in cervicals, aren’t what one would call particularly robust bones), which doesn’t make it a necessity.

It is simply a very quick way to kill if you ask me.

it is, regardless of whether any damage to the spinal cord was inflicted in the process.

Could we just agree that whether a carnosaur bites a similar-sized sauropod in the neck, flanks or belly, it will be able to cause fatal damage in all likelyhood?

In addition, bites to the legs, tail base and back will probably, at least partially, immobilise the victim.

[Godzillasaurus]

Titanosaur tails aren’t really whip-like, they are relatively short and thick organs.

Have a look at the drawing I posted (I of course did not draw it). Many reconstructions show that titanosaur genera did in fact possess whip-like tails. 

Depends on what size the sauropod is and what shape its tail is. I doubt an Europasaurus would incapacitate it, but the situation if different if, for example, said sauropod had a club or a set of thagomizers at its tail tip.

It depends on the size of the sauropod in comparison to the predator. Especially something like allosaurus, which was not particularly large in size (it was probably only around 24-30 feet in length and maybe about 4 tons) and did not possess the strongest-built skull (again, very pneumatic and poorly designed for gripping), would be vulnerable to a tail strike from a considerably larger sauropod. For example, a tail strike from something like apatosaurus (which as we know was so much larger than allosaurus) would be likely very devastating for the predator's skeleton, regardless of where it actually hit. 

But the skull alone (which would be particularly vulnerable to heavy blows, unlike something with a much more robust and heavily-constructed skull like tyrannosaurus) would not be the only vulnerability here. It is perfectly conceivable to believe that a large sauropod in relation to a predator's own size would be able to devastate that said predator's ribs and whatnot. Again, it all depends on the size of the two creatures; if the predator is near or exceeding the size of the sauropod, a whip-like tail strike would probably only cause moderate to severe lacerations, like you said earlier.

That implies damage tzo muscles, tendons and blood vessels first and foremost.

I know. I am not claiming that severing the spinal cord was its primary method of killing, just that it is definitely possible with enough precision and power.

Could we just agree that whether a carnosaur bites a similar-sized sauropod in the neck, flanks or belly, it will be able to cause fatal damage in all likelyhood?

I do not disagree with this. But I was simply stating the fact that the most effective way to kill would probably be with powerful perpendicular insertion of its teeth into the back of the pray animal followed by (probably) very violent backward tearing. Allosaurus, based on what skull evidence we have, probably lacked a very powerful bite (but yet its entire feeding apparatus was in no need of such, as its skull simply needed to be particularly deep and its dentition needed to be able to cut flesh efficiently); so it seems logical to believe that this was the best way to kill at least somewhat forcefully

[theropod]

Have a look at the drawing I posted (I of course did not draw it). Many
reconstructions show that titanosaur genera did in fact possess
whip-like tails.

I am fully familiar with the skeletal, thank you. But this→ is a whip-tailed sauropod. of course every tail tapers posteriorly, that doesn’t automatically make it a whip. The tail tips of macronarians, at least those discovered so far, are not comparable to flagellicaudatans (I’m fairly certain the name tells you something), and those epitomize what is known as a "whip-tail" among sauropods.

Also, you should note that the vast majority of that skeleton is mere restoration, there is no such thing as a known Argentinosaurus tail, it is known from dorsal and sacral vertebrae and a partial hindlimb and hip. This Alamosaurus→ is far more complete.

It depends on the size of the sauropod in comparison to the predator.
Especially something like allosaurus, which was not particularly large
in size (it was probably only around 24-30 feet in length and maybe
about 4 tons) and did not possess the strongest-built skull (again, very
pneumatic and poorly designed for gripping), would be vulnerable to a
tail strike from a considerably larger sauropod. For example, a tail
strike from something like apatosaurus (which as we know was so much
larger than allosaurus) would be likely very devastating for the
predator's skeleton, regardless of where it actually hit. 

But
the skull alone (which would be particularly vulnerable to heavy blows,
unlike something with a much more robust and heavily-constructed skull
like tyrannosaurus) would not be the only vulnerability here. It is
perfectly conceivable to believe that a large sauropod in relation to a
predator's own size would be able to devastate that said predator's ribs
and whatnot. Again, it all depends on the size of the two creatures; if
the predator is near or exceeding the size of the sauropod, a whip-like
tail strike would probably only cause moderate to severe lacerations,
like you said earlier.

So? That’s basically what I said. But we were talking about sauropods and theropods with relatively small size disparities, not something like Apatosaurus and Allosaurus.

But I was simply stating the fact that the most effective way to kill
would probably be with powerful perpendicular insertion of its teeth
into the back of the pray animal followed by (probably) very violent
backward tearing. Allosaurus, based on what skull evidence we have,
probably lacked a very powerful bite (but yet its entire feeding
apparatus was in no need of such, as its skull simply needed to be
particularly deep and its dentition needed to be able to cut flesh
efficiently); so it seems logical to believe that this was the best way
to kill at least somewhat forcefully

Firstly, we are talking about Acrocanthosaurus here, not Allosaurus. Surely, the two have many features in common, but there are also many differences. For example, contrary to Allosaurus, Acrocanthosaurus has very tall neural spines–while those of Allosaurus are relatively low (albeit long), in order to allow for a large dorsal range of motion (which is probably related to head-striking-behaviour). So I wouldn’t assert they bit exactly the same way.

But we can be fairly confident, that given they both have laterally compressed skulls and teeth, they both actually did rely on posterior tearing motions. Such a bite on such scale and could fairly easily tear out an animal’s throat or guts if given the chance.

[Godzillasaurus]

I'm fully familiar with the skeletal, thank you. But this→ is a whip-tailed sauropod. of course every tail tapers posteriorly, that doesn’t automatically make it a whip. The tail tips of macronarians, at least those discovered so far, are not comparable to flagellicaudatans (I’m fairly certain the name tells you something), and those epitomize what is known as a "whip-tail" among sauropods.

Also, you should note that the vast majority of that skeleton is mere restoration, there is no such thing as a known Argentinosaurus tail, it is known from dorsal and sacral vertebrae and a partial hindlimb and hip. This Alamosaurus→ is far more complete.

Ahh, I see. I do not deny that diplodocids and related groups did in fact have particularly the most "whip-like" tails of the entire sauropoda group, but it seems likely that, when are least relatively enough, any sauropod tail could be used as a weapon. And the thicker tails of titanosaurs would in fact be more efficient at dealing out broader damage to larger predators too.

Firstly, we are talking about Acrocanthosaurus here, not Allosaurus. Surely, the two have many features in common, but there are also many differences. For example, contrary to Allosaurus, Acrocanthosaurus has very tall neural spines–while those of Allosaurus are relatively low (albeit long), in order to allow for a large dorsal range of motion (which is probably related to head-striking-behaviour). So I wouldn’t assert they bit exactly the same way.

It seems like I mixed up the names a bit. I tend to do that when I type fast (you know, like sometimes I call giganotosaurus "carcharodontosaurus" and such).

But while I do agree that the spine morphology could be a hinderance in terms of biting and killing style, it does not seem out of the question that at least both animals would have killed similarly, if not almost identically. They had very similar morphology in this region, so it is not logical to believe that they killed in "very different and unalike" ways. For example, both possess rather deep but yet not-so robust rostra that were studded with sharply-edged rear-facing dentition (a common trait in carnosauria), so the primary killing style of both would in fact be violent ripping (as opposed to stabbing. The hatchet-bite would more-so drive the teeth deeply where they would then work like a saw of some sort, ripping the creature's back and upper flanks apart). But still, depending on the leverage of acrocanthosaurus, the axe-bite theory does not seem completely out of here.

[theropod]

Ahh, I see. I do not deny that diplodocids and related groups did in fact have particularly the most "whip-like" tails of the entire sauropoda group, but it seems likely that, when are least relatively enough, any sauropod tail could be used as a weapon. And the thicker tails of titanosaurs would in fact be more efficient at dealing out broader damage to larger predators too.

I didn’t deny that–in fact I also think so. I was just saying that Titanosaur tails weren’t whip-like., contrary to what you claimed

But while I do agree that the spine morphology could be a hinderance in terms of biting and killing style, it does not seem out of the question that at least both animals would have killed similarly, if not almost identically. They had very similar morphology in this region, so it is not logical to believe that they killed in "very different and unalike" ways.

As I just explained there is a considerable morphological difference.

For example, both possess rather deep but yet not-so robust rostra that were studded with sharply-edged rear-facing dentition (a common trait in carnosauria),

Yes, that is a very basic similarity tough.

so the primary killing style of both would in fact be violent ripping (as opposed to stabbing. The hatchet-bite would more-so drive the teeth deeply where they would then work like a saw of some sort, ripping the creature's back and upper flanks apart).

Again, that is a very basic similarity which I didn’t question.

But still, depending on the leverage of acrocanthosaurus, the axe-bite theory does not seem completely out of here.

Cranial depression certainly was part of its bite, but its neck clearly tells us it was not specialised for the same thing Allosaurids were specialized in, otherwise we would not see these differences. The ranges of movement these two animals had must have been quite different. Not as if it mattered to the way they would most likely attack a small sauropod tough.

[Godzillasaurus]

As I just explained there is a considerable morphological difference.

In terms of spine shape/height and possibly skull size in relation to the rest of the body (I believe carcharodontosaurs had particularly large skulls in this regard. And most definitely in comparison to allosaurids, which had much smaller skulls proportion-wise). But aside from that, there are plenty of morphological similarities in terms of tooth shape, skull robusticity, and bite force (neither animals possessed very powerful based based on cranial studies, nor did they really need them to be efficient predators). And it is even wise to consider their specialization and prey type as awfully similar as well (both were finely adapted for hunting large animals, particularly those like large sauropods. Although I am unsure what sauropods specifically coexisted with acrocanthosaurus, but it seems likely that they were fairly dominant in that area during the Middle Cretaceous, as titanosaurs were fluent then)

Cranial depression certainly was part of its bite, but its neck clearly tells us it was not specialised for the same thing Allosaurids were specialized in, otherwise we would not see these differences. The ranges of movement these two animals had must have been quite different. Not as if it mattered to the way they would most likely attack a small sauropod tough.

I do not deny that allosaurids were far better structured for hatchet-biting, but that does not completely rule out the possibility of acrocanthosaurus being able to do so with enough leverage. Again, think about the feeding apparata of both animals: VERY SIMILAR.

[theropod]

In terms of spine shape/height and possibly skull size in relation to the rest of the body (I believe carcharodontosaurs had particularly large
skulls in this regard. And most definitely in comparison to allosaurids,
which had much smaller skulls proportion-wise).

Actually Acrocanthosaurus skull/body proportions are fairly similar to Allosaurus.
It’s just giganotosaurines that have giant skulls.

But aside from that, there are plenty of morphological similarities in
terms of tooth shape, skull robusticity, and bite force (neither animals
possessed very powerful based based on cranial studies

Actually both were never really compared in the literature.

And it is even wise to consider their specialization and prey type as
awfully similar as well (both were finely adapted for hunting large
animals, particularly those like large sauropods. Although I am unsure
what sauropods specifically coexisted with acrocanthosaurus, but it
seems likely that they were fairly dominant in that area during the
Middle Cretaceous, as titanosaurs were fluent then)

They certainly both hunted sauropods, in fact we have very good indications for that in both of them (relatively large amounts of trampled and bite-marked bones from the Morrison Formation, the Paluxy Tracksite…). I wouldn’t assert that their dietary specializations were exactly the same tough.

I do not deny that allosaurids were far better structured for
hatchet-biting, but that does not completely rule out the possibility of
acrocanthosaurus being able to do so with enough leverage. Again, think
about the feeding apparata of both animals: VERY SIMILAR.

That far better structured thing is the point, they are not "very similar". They show paralells, only logical congsidering they are relatively close phylogenetically. they also show differences, also logical considering they are different in terms of size, stratigraphy and habitat.
Regarding its actual capability in terms of "hatchet bite", that simply depends on what you define as a hatchet bite. Both head/neck ventroflexion and pulling must obviously have been part of both their bites, but the ways they applied them must have been somewhat different. Anyway Acrocanthosaurus was certainly fully capable of slicing its way deeply into the flesh of a prey item.

[creature386]

May 4, 2014 22:12:16 GMT 5 theropod said:

In terms of spine shape/height and possibly skull size in relation to the rest of the body (I believe carcharodontosaurs had particularly large
skulls in this regard. And most definitely in comparison to allosaurids,
which had much smaller skulls proportion-wise).

Actually Acrocanthosaurus skull/body proportions are fairly similar to Allosaurus.
It’s just giganotosaurines that have giant skulls.

I know, this is irrelevant, but haven't you argued that Acrocanthosaurus would at least be a valid analogy for Carcharodontosaurus?

[theropod]

Yes, I do.
Several recent works (e.g. Zanno & Mackovicky 2013, Canale et al. 2014) have Carcharodontosaurus outside the big-skulled Giganotosaurus+Mapusaurus+Tyrannotitan-clade, others have them form a polytomy, so they don’t refute it and I think its valid to say the big-skulled forms are likely a distinct clade.
I don’t see why Acrocanthosaurus shouldn’t be the more suitable analogy, since the giant giganotosaurine skulls constitute a derived trait (that neither Acrocanthosaurus nor Concavenator exhibit).

[creature386]

Yes, but given that you replied to a comment about Carcharodontosaurus, it appeared to me that you included it within your statement about giganotosaurines.

[theropod]

The comment was referring to carcharodontosaurs (=carcharodontosauria) actually. Carcharodontosaurus itself was not really part of the equation, since we lack an existent specimen that has both cranial and postcranial remains.

[Godzillasaurus]

Actually Acrocanthosaurus skull/body proportions are fairly similar to Allosaurus.
It’s just giganotosaurines that have giant skulls.

Acrocanthosaurus is a giganotosaurine, isn't it? I have read that somewhere

Actually both were never really compared in the literature.

Unless you have undeniable evidence of its biting strength, you can never know for sure. Carcharodontosaurus was compared to spinosaurus in terms of biting strength before (About 3t compared to about 2t of force). It was stated by some Japanese paleontologist before somewhere, but I can't remember. I keep looking it up but I can't find it. But either way, it seems probable that acrocanthosaurus and allosaurus are analogous in this regard, and it seems illogical to assume that their biting strengths would be exceptionally high.

They certainly both hunted sauropods, in fact we have very good indications for that in both of them (relatively large amounts of trampled and bite-marked bones from the Morrison Formation, the Paluxy Tracksite…). I wouldn’t assert that their dietary specializations were exactly the same tough.

Obviously not exactly (considering that titanosaurs were common during the Cretaceous and diplodocids and brachiosaurs were more-so Jurassic-restricted. Different groups of sauropods entirely), but it is safe to assume that at least both creatures (any member of allosauria in general) would have likely included sauropods as a staple part of their diet. Despite the obvious proportion and size differences among the two animals, they possess comparable morphologies and both coexisted with sauropods ultimately. Note that titanosaurs were more isolated during the later parts of the Cretaceous, and the dominant terrestrial herbivore niches were taken over by ornithopods, ceratopsians, and ankylosaurs (of which tyrannosaurus, with their more robust morphology and higher aptitude for powerful killing, were clearly better designed to hunt. Whereas the quite deepened but yet much more lightly-built skulls of allosaurs were not at all adapted for ANY sort of crushing or gripping). So thus, the attacking-of-flanks and ripping-apart-of-flesh hypothesis seems logical for all allosaurs really.

[creature386]

May 13, 2014 7:11:53 GMT 5 Godzillasaurus said:

Actually Acrocanthosaurus skull/body proportions are fairly similar to Allosaurus.
It’s just giganotosaurines that have giant skulls.

Acrocanthosaurus is a giganotosaurine, isn't it? I have read that somewhere.

Not really.

dx.doi.org/10.1371%2Fjournal.pone.0017932

dx.doi.org/10.1080%2F14772019.2011.630927

[Godzillasaurus]

Wow. I did not know that. So it was a completely different group from carcharodontosaurus too? Huh. Still though, it should be well-known that allosauria in general possessed characteristics that were not differentiated between the two creatures. It should be common knowledge (at least among those who study them) that allosaurs most likely did in fact kill with ripping and blood loss.

[theropod]

Not a completely different group.Acrocanthosaurus and Carcharodontosaurus share a more recent common ancestor than either does with Neovenator or Allosaurus, and while Carcharodontosaurus shares a more recent common ancestor with Giganotosaurines than with Acrocanthosaurus, Acrocanthosaurus doesn’t seem to form a distinct clade with anything else, based on the current state of knowledge. Acrocanthosaurussimply turns out as a slightly more basal carcharodontosaur in phylogenetic analyses that’s all that sets them apart.