Recurved, serrated teeth in baryonychines: why?

[theropod]

I don’t see how striking from above contradicts an open-mouthed fishing style.

[creature386]

Maybe he wants to say that using the snout to break through the water is easier with a closed mouth.

[theropod]

But it would have to open it anyway. The only difference is that here is already lies in wait with a gaping mouth. Of course that is not the only way for it to catch prey, but it is the way to reach the deepest while still being able to breathe, so I figure it will be its preferred method for reaching fish or lurking for it.

[Godzillasaurus]

No no, it would not be going in with a closed mouth (striking-wise, it would have its mouth already open when entering the water, where it would then clamp down on the fish), just that theropod's theory about it going in with its rostrum parallel to the water seems "off".

Simply, striking downward is logical considering not only its stance, but also its adaptations. It is not going to be sitting there with its mouth open waiting for fish to swim in (or in this case, it would not be trying to bite down that way). Depth aside, striking downward (but remember, probably not completely all of the time) is the most efficient and quick way to hunt most likely

[theropod]

So, why then do you consider raised nostrils to have any importance, if you think it did not actually lie in wait with any part of its snout already in the water?

All I was proposing was that if it did so, it would do that with an open mouth and its upper jaw close to the surface, since it would be that way it could reach deepest and have the best odds of securing a hold on prey. So there would not really be any need to stick its rostrum in for extended periods of time the way sometimes shown in documentaries, also eliminating the need for adaptions of the respiratory system. The position of its nares could thus be more of a coincidence resulting from the shape of its premaxillae than anything else.

I was not saying I considered it most likely that it had its mouth already in the water when hunting at all, I can just as well see it holding it above the surface. But sticking just its mandible in is just as viable as doing so with its whole snout in that case (skimmer vs heron) while it is more likely (just skimmer) if it actually held it into the water while lurking.

[Godzillasaurus]

It would still allow for easy breathing. The bottom line is that the animal was bipedal and hunted aquatic creatures, so how would raised nares NOT count as a necessary adaptation?

[theropod]

First please explain me why they necessarily do iyo
I already demonstrated it can reach into water more easily and deeper with just its lower jaw, which would make such a feature rather redundant. And you just stated it would not have its mouth in the water for more than a short strike for prey anyway. Do herons breathe while they strike fish?

Just as in a heron, the raised position of the nares is more likely a result of a selective pressure for snout elongation, in which the part anterior to the nares got longer and the toothrow got displaced rostrally, than a result of a selective pressure for high-set nostrils.

And how do you explain that baryonychines have their nares situated further rostrally if not by this?

[Godzillasaurus]

And you just stated it would not have its mouth in the water for more than a short strike for prey anyway. Do herons breathe while they strike fish?

That's a good point... But would that be the way it always killed? No- just that it would be striking from above most of the time as opposed to going in parallel most likely. I do agree that it would make such a feature partially unnecessary in this regard, but would that feature be unnecessary considering the fact that its ecology would make it relevant as a whole? If it were to go into the water and have a struggle before raising its snout out, THAT would be the moment for which the raised nares would make sense. Simple, if it was adapted to hunt fish this way, why would raised nares NOT be evolved?

And how do you explain that baryonychines have their nares situated further rostrally if not by this?

Think about the point of this topic: why did baryonychines and spinosaurines differ so much? At first, I believed that their evolutionary snout characteristics (aside from elongation) were evolved independently; but then you told me that baryonychines were much older, thus making me wrong (at least in part). In this case, it would make sense why baryonychines would possess more typical theropod characteristics, because they were fundamentally less specialized for piscivory than spinosaurines and possessed more typical megalosaur characteristics as opposed to the more unique ones of spinosaurus.

[theropod]

That's a good point... But would that be the way it always killed?

You tell me. I just don’t think any of its probably hunting methods would really require raised nares.

I do agree that it would make such a feature partially unnecessary in this regard, but would that feature be unnecessary considering the fact that its ecology would make it relevant as a whole?

It cannot be unnecessary and "relevant as a whole" at the same time…

If it were to go into the water and have a struggle before raising its snout out, THAT would be the moment for which the raised nares would make sense.

Not really. Anything big enough to give it a real struggle would likely require it to open its mouth pretty far, therefore raising the upper jaw to surface -leven even if it initially attacked by sticking its whole snout in.

Simple, if it was adapted to hunt fish this way, why would raised nares NOT be evolved?

There is no response to that question, all I was saying is that they are a sort of by-product of other developments going on in the spinosaurid skull, and not really an important adaption for their killing style by themselves.

At first, I believed that their evolutionary snout characteristics (aside from elongation) were evolved independently; but then you told me that baryonychines were much older, thus making me wrong (at least in part). In this case, it would make sense why baryonychines would possess more typical theropod characteristics

Such as less elongated premaxillae, and, by inference, lower-set nares. Now I don’t think both groups had exactly the same hunting methods and dietary specializations, but I am fairly confident we can consider both to have been mostly piscivorous, so they must have had some way of both catching fish and breathing.

[Godzillasaurus]

It cannot be unnecessary and "relevant as a whole" at the same time…

WOULD it be unnecessary if its ecology would make it ideal? That is what I was asking

There is no response to that question, all I was saying is that they are a sort of by-product of other developments going on in the spinosaurid skull, and not really an important adaption for their killing style by themselves.

The animal was still a bipedal piscivore that plunged its jaws into water, so by-product or not, it would make sense if it possessed them

Such as less elongated premaxillae, and, by inference, lower-set nares. Now I don’t think both groups had exactly the same hunting methods and dietary specializations, but I am fairly confident we can consider both to have been mostly piscivorous, so they must have had some way of both catching fish and breathing.

Evolutionary-speaking, baryonychines seem to have been more primitive and basal, which YOU convinced me of. Thus, it is possible that, yea, they may have evolved more typical piscivorous characteristics such as the more slender snout and hooked premaxilla,, but they still possessed more typical megalosaur characteristics than spinosaurines, which were pretty much EVOLVED to hunt fish morphologically.

[theropod]

WOULD it be unnecessary if its ecology would make it ideal? That is what I was asking

The only relevant thing for a structure supposedly used in predation is its functional anatomy. If it is unnessesary functionally, it is unnecessary overall.

I’m not saying raised nares are any more disadvantageous than they are beneficial, I’m just saying they are neglegible and result from other, actually important adaptions.

The animal was still a bipedal piscivore that plunged its jaws into
water, so by-product or not, it would make sense if it possessed them

We are running in circles. First you suggest they make sense, then you basically explain why they would be unnecessary, then you say they make sense…

Thus, it is possible that, yea, they may have evolved more typical
piscivorous characteristics such as the more slender snout and hooked
premaxilla,, but they still possessed more typical megalosaur
characteristics than spinosaurines, which were pretty much EVOLVED to
hunt fish morphologically.

The point is that I don’t really see much of a difference between both as regards the "plunging the snout into water" thingy, do you (and if so, what might it be?)?

Thus (as well as because of the uncertainty regarding the actual position of the fleshy nostril despite what may seem to make sense) the assumption seems natural that the raised nostrils of spinosaurines were not an important adaption for their feeding style.

[Godzillasaurus]

We are running in circles. First you suggest they make sense, then you basically explain why they would be unnecessary, then you say they make sense…

They would make sense in the fact that its ecology would make them useful. But still, I can see why they would be considered unnecessary if you take away the idea that it sat there with its mouth open. Does that help?

The point is that I don’t really see much of a difference between both as regards the "plunging the snout into water" thingy, do you (and if so, what might it be?)?

Is the general consensus as of now NOT that baryonychines are geologically much older and are much more similar to the most primitive spinosaurids? Evolutionary features take millions of years to fully develop, and thus now it makes sense why spinosaurids are simply more differentiated and unique among theropods, because other megalosaurs possessed more typical macrophagous theropod qualities, which baryonychines possess as well aside from the supposedly much larger forearms, hooked snout tip, and generall slender snout.

[theropod]

I cannot "take away" the idea that it sat there with its mouth open, I don’t, and nobody else does, know how exactly spinosaurs hunted. And a scientific discussion about an animal’s likely behaviour isn’t some sort of bargain. If you can see something from a scientific point of view, then accept it, if you can’t then don’t, but there are most certainly no conditions linked to whatever you accept or reject in the form of me retracting an argument.

As I already wrote it might not be the most likely behaviour. It would be anatomically possible and I can see it being employed, entirely depending on the situation of course. I can also wholeheartedly agree with it plunging its snout into water more like a heron, those two are not excluding each other.

Is the general consensus as of now NOT that baryonychines are geologically much older and are much more similar to the most primitive spinosaurids?

I’d consider it a fact that they are more plesiomorphic, as I explained that is likely the reason why their teeth still have denticulated carinae. But it has nothing to do with that, all animals need to breathe and I think I saw you agree that baryonychines were also piscivorous.

[Godzillasaurus]

I cannot "take away" the idea that it sat there with its mouth open, I don’t, and nobody else does, know how exactly spinosaurs hunted. And a scientific discussion about an animal’s likely behaviour isn’t some sort of bargain. If you can see something from a scientific point of view, then accept it, if you can’t then don’t, but there are most certainly no conditions linked to whatever you accept or reject in the form of me retracting an argument.

Again, this is just what I think. I am sorry if it sounds like it is coming off as a definite

I’d consider it a fact that they are more plesiomorphic, as I explained that is likely the reason why their teeth still have denticulated carinae. But it has nothing to do with that, all animals need to breathe and I think I saw you agree that baryonychines were also piscivorous.

I do agree that they too were piscivorous. It seems as if piscivory is a common trait among the spinosauridae family. But the more developed features of spinosaurines would not necessarily be present in all of spinosauridae, especially in the genera that were much older/more basal. If a certain group of animals evolves certain physical traits, those do not appear suddenly. Take cetaceans for example (I know, this analogy again. But it works!); modern forms have ancestors that were dog-like terrestrial predators, looking nothing like their forms today (a common example is pakicetus). But yet soon that more wolf-like form soon became more accustomed to life in the water with a more crocodile-like form (ie. ambulocetus), and soon enough that group became fully aquatic, with a few less necessary traits becoming slowly more redundant (such as the hind legs, which were still found in basilosaurus but were very small and useless). Over time, they completely disappeared.

Baryonychines may have been piscivorous, but YOU were the one who convinced me that they simply existed in the earlier parts of the Cretaceous (with the very first spinosaurids evolving in the Jurassic), while spinosaurines evolved much later, in the middle Cretaceous. Simply put, their piscivorous features may not be quite as prominent and unique as those of spinosaurines, because they had not yet adapted them.

[theropod]

They actually aren't as prominent. Just that there appears to be absolutely no requirement for raised nares in any of the fishing styles either of us considered likely, and those types of behaviour apply equally to baryonychines and spinosaurines.
If raised nares where important, they could literally have wandered to the top of their heads during spinosaur evolution (as they did in the only animals in which we know that they are, cetaceans) instead they remained on their rostra, which all make me think them being not at the snout tip is rather coincidential than a functional adaption for their diet.