Allosaurus vs Stegosaurus

[theropod]

That's why I wrote he should regard this argument from both sides. It becomes pretty irrelevant then.

[Godzillasaurus]

Indeed I suppose a well-placed bite by an Allosaurus (basicranium or anteriormost aspect of neck) could decapitate a Stegosaurus. I presume that or a bite severing the throat would be its quickest way of killing, and also the savest since it requires the least proximity to the tail. But given it could place it without sustaining severe injuries itself, almost any region of the postcranium would also be suitable (the best of course being the flank/abdominal region), including tights, calves, forelimb and tail-base.

Decapitation seems like a major overstatement, as the stegosaurus would have probably already been killed by then.

Epanterias likely even a little more, but we haven't cleared up what to use due to uncertainty on sample size and the largest Stegosaurus specimens.

It did, but that is still assuming that it was synonymous with the genus Allosaurus.

Allosaurids have very mobile necks and very wide gapes, it likely has the capability to bite the tail laterally, not dorsally, so that its bite could sever important muscles required for the defensive action of the tail and/or for locomotion.

Definitely, but a few bites, even regarding their potency, would not simply disable its tail. The theropod could definitely wound the herbivore this way, but I doubt that a few lateral bites would do the stegosaurus' tail in for good.

It could do so (similar to how Tyrannosaurus bit off the horn of Triceratops in one fossil), but this would be very dangerous, so it would be better to avoid the tail. I know that this is just the base, but attacking the flanks would still be the safest option.

Agreed

I think going for the neck, head or forequarters is even safer. In any case I think it would attack from the front or side, to avoid bringing its body in close proximity to the tail (as it inevitably would if it tried to run in from the back at too low an angle).

He was talking about the flanks in comparison with the tail/rear of the stegosaurus. But yes, overall, the head/fore parts of the herbivore are the safest areas to attack, considering the fact that its head was quite vulnerable and its beak was very blunt and rounded unlike the beaks of ceratopsians, so a bite is almost completely out of the question here.

He isn't actually angry, that's just his normal style of posting. Don't take it to heart.

I'm sorry, it is just that I think he goes way overboard sometimes.

If they really had a thermoregulatory function, they'd be filled with blood vessels and nerves, so a bite there would be at least quite painful.

A thermoregulatory function in stegosaur dorsal plates has actually been argued against, as their highly similar morphology to ankylosaur armor makes it unlikely. They were probably used more for display purposes and/or warding off predators.

[theropod]

Decapitation seems like a major overstatement, as the stegosaurus would have probably already been killed by then.

Considering the size and power in an Allosaurus' skull and neck, and how small the head of Stegosaurus is in relation to that, I think if Allosaurus bit that region and pulled, it would rip off the head. Of course that wouldn't really be necessary to kill but it might happen nevertheless.

It did, but that is still assuming that it was synonymous with the genus Allosaurus.

Which pretty much every scientist seems to agree it is.

Anyway the largest Allosaurus specimens besides AMNH 5767 are ~10m and rather 3-4 than 4-5t.

Definitely, but a few bites, even regarding their potency, would not simply disable its tail. The theropod could definitely wound the herbivore this way, but I doubt that a few lateral bites would do the stegosaurus' tail in for good.

Even a single bite may do severe damage to the tail flexors, we have to consider there's quite a bit of power behind it, plus the pulling motion, all of that very well designed to take a deep bite out of musculature. It would likely rip out a decent-sized chunk of flesh, which would disable or at least severaly limit the movement of the tail

But yes, overall, the head/fore parts of the herbivore are the safest areas to attack, considering the fact that its head was quite vulnerable and its beak was not sharp and/or hooked to a high degree unlike the beaks of ceratopsians, so a bite is almost completely out of the question here.

Indeed.

I'm sorry, it is just that I think he goes way overboard sometimes.

I'm afraid he doesn't think so, and I think telling him that will make him do so even more.

A thermoregulatory function in stegosaur dorsal plates has actually been argued against, as their highly similar morphology to ankylosaur armor makes it unlikely. They were probably used more for display purposes and/or warding off predators.

When and where was that morphology described? I agree a thermoregulatory function is unlikely, but the latest news I heard were the plates being quite fragile and non-solid.

Still they'd be a major hindrance for anything atacking the animal's back from above.

[creature386]

Dec 1, 2013 19:54:26 GMT 5 Godzillasaurus said:

If they really had a thermoregulatory function, they'd be filled with blood vessels and nerves, so a bite there would be at least quite painful.

A thermoregulatory function in stegosaur dorsal plates has actually been argued against, as their highly similar morphology to ankylosaur armor makes it unlikely. They were probably used more for display purposes and/or warding off predators.

From what I read in this article, it looks like this is one of the more robust theories (or at least more robust than the armor hypothesis):
www.jstor.org/discover/10.2307/2400518?uid=3737864&uid=2&uid=4&sid=21103031850681

[Godzillasaurus]

Considering the size and power in an Allosaurus' skull and neck, and how small the head of Stegosaurus is in relation to that, I think if Allosaurus bit that region and pulled, it would rip off the head. Of course that wouldn't really be necessary to kill but it might happen nevertheless.

Stegosaurus actually had a rather thick and muscular neck (at least in general) despite its small and slender skull.

Even a single bite may do severe damage to the tail flexors, we have to consider there's quite a bit of power behind it, plus the pulling motion, all of that very well designed to take a deep bite out of musculature. It would likely rip out a decent-sized chunk of flesh, which would disable or at least severaly limit the movement of the tail

I never thought about it ripping out any of the herbivore's musculature. In that case, a bite to the tail base seems a lot more effective now.

When and where was that morphology described? I agree a thermoregulatory function is unlikely, but the latest news I heard were the plates being quite fragile and non-solid.

They were definitely thin and fragile, I won't argue against that. But there can still be similarities between two different structures despite being totally different. We know that an armor purpose is definitely out of the question for stegosaurids, but that doesn't mean that stegosaur plates and ankylosaur armor cannot be very similar, as stegosaur plates were still made up bone material.

From what I read in this article, it looks like this is one of the more robust theories (or at least more robust than the armor hypothesis):

www.jstor.org/discover/10.2307/2400518?uid=3737864&uid=2&uid=4&sid=21103031850681

Thermoregulation purposes are much more probable than an armor purpose. It is just that, above all, they appear to have been adaptations more-so for display.

[theropod]

Stegosaurus actually had a rather thick and muscular neck (at least in general) despite its small and slender skull.

You think so?


It doesn't look like that region would be particularly resistant. The soft tissues would be quite easy to largely or fully sever with a bite imo, and then the head gets ripped off easily. I've seen nicely preserved specimens of Allosaurus and Stegosaurus in person

I never thought about it ripping out any of the herbivore's musculature. In that case, a bite to the tail base seems a lot more effective now.

What did you think of? That's pretty much what Allosaurus tooth and skull design is ideally suited for, deep bites into flesh.

They were definitely thin and fragile, I won't argue against that. But there can still be similarities between two different structures despite being totally different. We know that an armor purpose is definitely out of the question for stegosaurids, but that doesn't mean that stegosaur plates and ankylosaur armor cannot be very similar, as stegosaur plates were still made up bone material.

Well, we all know they were made of bone, and likely sheated in keratin. However that alone is not much of a similarity (it's like saying an elephant and a blue whale skull had many similarities because they were both made of bone).
Yes, they are likely homologues of Ankylosaur osteoderms, however this doesn't imply any greater similarity than those obvious points, at least not much of a functinally relevant one.

[theropod]

I'm wondering, have there been any hypotheses for Stegosaurus (specifically its dorsal plates) in "All Yesterdays" (I know, I should read that book...)?

[Fragillimus335]

Stegosaurus 65-75% win. Allo needs a precision head bite, Steg needs a hit anywhere.

[creature386]

^Why can't Allosaurus just bite the flanks?

[theropod]

Yeah, I wouldn't say Allosaurus is among those predators that are in a need for precision, it has quite a variety of regions to choose from that could all produce serious and fatal wounds.

[Runic]

Quick question that's been bugging me. Is stegosaurus bigger than dacentrurus? Cause I remember the latter being pitted against a T.rex yet stego is going against an allo, however I keep reading stegosaurus is the biggest stegosaur...

I'm afraid he doesn't think so, and I think telling him that will make him do so even more.

No, I just do it cause I love the emotional responses I get back lol

[creature386]

I have no idea. Keep in mind that there are different species, S. armatus is the largest one. I once found this:

The most common track morphotype from Quarry 5 ichnofacies range are wider medio-laterally than deep anterio-posteriorly, tridactyl with blunt digits ending in squared, hoof-like claws. Combined, these characters point to the pes of a single genus: Stegosaurus. Stegosaurus-morphotype tracks range in size from hatchling (estimated body mass 3kg) to adult animals (estimated body mass 6-8 tons). One talus block demonstrates adult stegosaur pedal track partially crushing a juvenile Stegosaurus-morphotype track, implying social behavior amongst juvenile and adult stegosaurs.

gsa.confex.com/gsa/2010AM/finalprogram/abstract_182427.htm
It has shown no source for that claim and it is no proper paper (just a conference abstract), so I wouldn't use it as a source, but it's interesting.

[Infinity Blade]

I think at 7 meters, Stegosaurus is 2-ish tonnes (if I remember correctly. I think from scaling from a 9m, 5t Stegosaurus once, forgot how to scale down though).

But I also cam across this.

fragillimus335.deviantart.com/art/Ten-Ton-Porcupine-398362307

Of course, it's not what one would call a reliable source, but Fragillimus is a knowledgable person.

[Godzillasaurus]

You think so?

Yes; it is still thin in shape, I'll give you that, but that does not mean it cannot be muscular and "thick" at the same time. A better answer for this would be that allosaurus would not just cut right through it like butter, as you are implying. A bite would certainly do a good amount of damage to it, but not to the point of the herbivore's head simply coming right off. Having a neck THAT weak would be a horrible adaptation for evolving alongside allosaurids (or any large theropods really). Having a thin neck does not mean that it is entirely weak; just look at sauropods and long-necked plesiosaurs. I guess the bottom line is that, despite being thin IN SHAPE, stegosaurus still had a relatively thick and quite muscular neck, hinting at a much greater resistance to allosaurid bites than you are implying.

It doesn't look like that region would be particularly resistant. The soft tissues would be quite easy to largely or fully sever with a bite imo, and then the head gets ripped off easily. I've seen nicely preserved specimens of Allosaurus and Stegosaurus in person

That is definitely the most vulnerable region of the animal, but that certainly does not mean that it is weak in general.

But even then, the herbivore's plates, despite not being used for defense purposes, would still serve as a major hinderance for a well-placed bite to its neck, as they would force the allosaurus to go for the sides of it as opposed to the top. This would certainly lead to a good amount of blood loss and/or (as you said) musculature being torn out, but it still would not be enough to simply rip the herbivore's head off.

What did you think of? That's pretty much what Allosaurus tooth and skull design is ideally suited for, deep bites into flesh.

I was thinking more in terms of blood loss and the "hatchet-bite" technique.

Well, we all know they were made of bone, and likely sheated in keratin. However that alone is not much of a similarity (it's like saying an elephant and a blue whale skull had many similarities because they were both made of bone).

Ankylosaurs and stegosaurs were MUCH more closely related to one another than elephants and whales are today, so that is irrelevant. Both groups of animals evolved unique dorsal characteristics. It is highly unlikely that stegosaur plates and ankylosaur armor evolved independently due to their close phylogenic relationship.

[Infinity Blade]

Ankylosaurs and stegosaurs were MUCH more closely related to one another than elephants and whales are today, so that is irrelevant.

That wasn't the point at all. The point was that being made of the same thing=/=being similar. Try Moeritherium and a modern elephant.