Kaprosuchus Bodily Proportions

[Godzillasaurus]

BTW, a saltwater crocodile's average is far lower than 15 ft, I have shown the relevant link in the saltwater crocodile vs walrus thread.

I didn't use 15 feet as an absolute. When I said "or so", I was talking about its size being somewhere around there. I was talking about male salties in my post, not just in general if that helps. The average size for males is somewhere around 15 feet in length. Different sources will say different things though, so it is easier to use ranges. 10 feet seems way to small for a male average. A lot of sources point to 17 feet in length as being the male average.

What I mean; You consider it very likely it was differently proportioned, but you give nothing regarding the implications (will it make the animal smaller or larger or change the size at all?).

Well if the argument that it was a mainly terrestrial predator is true, that could likely make the animal's head smaller in proportion to its body length than in aquatic crocodylomorphs. Again, we have no evidence that its head was proportionally smaller, but it is a direct possibility. That would thus have made this specific specimen larger than 3-4 meters in life. There are two notable kaprosuchus reconstructions. This:



And this:



In all honesty, I would like to acknowledge that the second reconstruction appears to be the more inaccurate of the two, considering that it was based more-so off of the anatomies of modern crocodilians and its head construction is way off, putting no consideration on the keratinous shield on the tip of the snout (in other words, the bulbous premaxilla of the animal) and the dip from the crania area to the tip of the upper jaw. Its head looks far too gracile in build anyway than the skull of the real animal. Again, it is only a drawing, but it is still inaccurate.

Without any such data, it is the best bet we have to consider it 3-4m in lenght, not astronomic 5-6m, thus it is roughly comparable to large extant crocodilian species.

That is probably the best conclusion for now. There were still enough differences though in its skull structure from modern crocodilians, however.

[theropod]

The only really notable difference is actually that it had those extremely long teeth.

We cannot tell anything about its body structure. There are plenty of extinct animals with crocodyliform morphology that had both proportionally bigger and proportionally smaller skulls than extant crocodilians.

While I acknowledge the top one looks more lifelike and detailed, I cannot say its bodily proportions are necessarily more likely. Also, both are big skulled, it just seems Tamura made the skull a bit too elongate (if we consider it's in anterolateral view), thus oversizing it.

[Godzillasaurus]

The only really notable difference is actually that it had those extremely long teeth.

But they were laterally compressed and were yet in perfect correspondence with the animal's snout shape and bite force, heavily indicating high reliance on bite force and their ability to also pierce deeply to kill prey. They were not designed for gripping solely like the teeth of crocodilians (members of the order Crocodylia).

Other differences include a deeper profile (talking about its skull), a long yet blunt snout, a more bulbous premaxilla, a keratinous shield on the tip of the upper jaw, eye positions that imply a terrestrial lifestyle, and a less subtle dip from the crania to the premaxilla. There are plenty of differences.

We cannot tell anything about its body structure. There are plenty of extinct animals with crocodyliform morphology that had both proportionally bigger and proportionally smaller skulls than extant crocodilians.

Just the reason to not use the American alligator as a base

While I acknowledge the top one looks more lifelike and detailed, I cannot say its bodily proportions are necessarily more likely.

Well as you just stated, its head is much more accurate, putting more features from the animal's real head into consideration than the latter.

[creature386]

Nov 16, 2013 19:23:49 GMT 5 Godzillasaurus said:

BTW, a saltwater crocodile's average is far lower than 15 ft, I have shown the relevant link in the saltwater crocodile vs walrus thread.

I didn't use 15 feet as an absolute. When I said "or so", I was talking about its size being somewhere around there. I was talking about male salties in my post, not just in general if that helps. The average size for males is somewhere around 15 feet in length. Different sources will say different things though, so it is easier to use ranges. 10 feet seems way to small for a male average. A lot of sources point to 17 feet in length as being the male average.

Given that only 25 out of 600 "adult" saltwater crocodiles were longer than 4 m, this is highly unlikely:
huntnetwork.net/modules/wfsection/html/crocodylus_porosus_mp.pdf
10 ft is of course not the average we should use in an interspecific conflict thread (it's like the 23 kg komodo dragon), but we should do so if we want to compare it to Kaprosuchus (because we don't know the gender of the Kaprosuchus specimen and we neither know anything about it's age), as only this would allow a fair comparison.

[theropod]

Godzillasaurus: yes, but that doesn't change both are likely equally inaccurate regarding the postcranial proportions. That you favour the former is not because it's actually more accurate in these regards, and it doesn't imply less-crocodile-like proportions.

The (non-dental) differences in cranial built are quite subtle. As you yourself demonstrated, it's dorsal head shape is somewhere intermediate between Alligator and Crocodylus, nothing too outlandish. Yes, its rostrum and premaxilla are a bit deeper than the average extant Crocodile (and they can also be quite robust in Crocodylus or Alligator, not to mention Caiman), but not as massively as you make it sound, not beyond the scope of variation one would consider normal;
you make it sound as if this was a totally specialized terrestrial predator with completely different proportions from its relatives, while many features in its skull architecture suggest similarities to extant crocodilians, and Mahajangasuchids don't imply anything different.

This is still a large taxon, large as in "comparable to Crocodylus porosus or niloticus", which pretty much means what was also originally stated. But this specimen cannot match the largest specimens, that is apparent from all the data we have.

[Godzillasaurus]

Given that only 25 out of 600 "adult" saltwater crocodiles were longer than 4 m, this is highly unlikely:

Were they all male? Because I was only talking about male crocodiles.

yes, but that doesn't change both are likely equally inaccurate regarding the postcranial proportions. That you favour the former is not because it's actually more accurate in these regards, and it doesn't imply less-crocodile-like proportions.

If I read your post correctly, then I would like to acknowledge that the first drawing is probably more accurate because of the (probable) idea that kaprosuchus was a primarily terrestrial predator. The second one puts too much emphasis on it being a semi-aquatic animal, which, as I already stated, is unlikely. As of now, the former drawing appears to be the more anatomically accurate one. Plus, wasnt't was drawn by Sereno (who was the one who studied kaprosuchus in the first place)?

you make it sound as if this was a totally specialized terrestrial predator with completely different proportions from its relatives, while many features in its skull architecture suggest similarities to extant crocodilians, and Mahajangasuchids don't imply anything different.

I never said that it lacked similarities altogether from modern crocodilians, but that it was a lot different than what a lot of people think.

This is still a large taxon, large as in "comparable to Crocodylus porosus or niloticus", which pretty much means what was also originally stated. But this specimen cannot match the largest specimens, that is apparent from all the data we have.

Of course. Until we can find more fossil evidence from kaprosuchus, 6 meters in highly unlikely.

[creature386]

Nov 17, 2013 6:03:42 GMT 5 Godzillasaurus said:

Given that only 25 out of 600 "adult" saltwater crocodiles were longer than 4 m, this is highly unlikely:

Were they all male? Because I was only talking about male crocodiles.

I don't know (there was no gender specified), but as I said, this is not relevant here, because we don't know the gender of the Kaprosuchus specimen and I would like to compare both. I also said that this is not the average size we should take in an interspecific conflict thread involving the saltie.

[theropod]

If I read your post correctly, then I would like to acknowledge that the first drawing is probably more accurate because of the (probable) idea that kaprosuchus was a primarily terrestrial predator.

And there's the problem; is this really probable or was this just an idea fabricated from insufficient evidence?

As of now, the former drawing appears to be the more anatomically accurate one. Plus, wasnt't was drawn by Sereno (who was the one who studied kaprosuchus in the first place)?

That's a picture drawn by Todd Marshall, who often seems to ilustrate Sereno's discoveries. Even if Sereno himself had drawin it, I don't see what difference that's supposed to make, the postcranial skeleton is unknown, its exact habits are as well, and even assuming it was terrestrial that doesn't automatically mean it had a proportionally smaller skull.

I never said that it lacked similarities altogether from modern crocodilians, but that it was a lot different than what a lot of people think.

Well, we can see the description and the photos of the skull. Primarily it overlaps extant crocodilians, with a few differences as can be expected considering its part of an extinct family and lived during the Cretaceous. But none of its characters clearly attest to a terrestrial lifestyle, and even less to necessarily different head-body-proportions
Thus the basis on which to speculate on its proportions is thus far very small, with the best being to assume roughly crocodile-like morphology as long as nothing better pops out (which could be new, more complete fossil remains of this creature, or of a close relative).

[Godzillasaurus]

And there's the problem; is this really probable or was this just an idea fabricated from insufficient evidence?

Their isn't an ultimate surplus amount of evidence for a terrestrial lifestyle, but there is still enough to imply that it probably did not fill the same semi-aquatic niche as modern crocodilians.

That's a picture drawn by Todd Marshall, who often seems to ilustrate Sereno's discoveries. Even if Sereno himself had drawin it, I don't see what difference that's supposed to make, the postcranial skeleton is unknown, its exact habits are as well, and even assuming it was terrestrial that doesn't automatically mean it had a proportionally smaller skull.

Oh, ok. I watched that documentary about the unusual North African crocodylomorphs last week and it implied that Sereno himself drew it. 

But none of its characters clearly attest to a terrestrial lifestyle, and even less to necessarily different head-body-proportions

What might those characteristics be? Its skull and tooth structure indicates a killing style revolved less around gripping.

[theropod]

And a killing style "revolved less around griping" automatically means the animal was terrestrial? Is it so outlandish to assume a crocodilian with similar habitat might adapt to a different diet and/or feeding and killing style, as we know some other crocodilians from the same description (eg "pancake croc"/Laganosuchus) to have done.

[Godzillasaurus]

Nov 18, 2013 0:51:10 GMT 5 theropod said:

And a killing style "revolved less around griping" automatically means the animal was terrestrial? Is it so outlandish to assume a crocodilian with similar habitat might adapt to a different diet and/or feeding and killing style, as we know some other crocodilians from the same description (eg "pancake croc"/Laganosuchus) to have done.

Not necessarily. But its longer dentition and differently-structured jaws from modern crocodilians in conjunction could definitely imply a terrestrial lifestyle, don't get me wrong. I would like to just acknowledge that it is probably more likely that kaprosuchus was a terrestrial predator, based on evidence that we have now.

[creature386]

Why does a slicing bite indicate a terrestrial life style? It only shows that it probably didn't focus that much on drowning dinosaurs and maybe hunted more aquatic animas.

[theropod]

There are plenty of ziphodont aquatic reptiles. The mere presence of labiolingual flattening and carinae doesn't automatically mean the tooth belonged to a terrestrial animal. The tooth shape of crocodiles belongs to the exact killing style of crocodiles, one of many killing styles an aquatic predator can employ, nothing more.

[Godzillasaurus]

@creature, a slicing bite is not a characteristic of a terrestrial predator as a whole, as there are fully aquatic crocodylomorphs (dakosaurus for example) with that kind of dentition and killing style. Not only do its teeth imply a terrestrial life, but its skull does too (as I have already explained).

theropod, as I just stated in this post, I am fully aware that a tooth shape and structure designed for slicing and ripping is not restricted to terrestrial crocodylomorphs.

The main thing that needs to be realized is the fact that kaprosuchus had a very rugose and quite non-streamlined skull which would be a horrible adaptation for mainly hunting smaller aquatic animals. Its dentition is one thing, but its skull is another, and it's thick and rugose characteristics do not imply a primarily aquatic lifestyle. Aquatic and semi-aquatic crocodylomorphs have/had more streamlined skull structures, which would be much better for quick bursts of speed in a marine environment. If its thick snout was used in hunting, that would further prove it to be a primarily terrestrial animal.

[blaze]

Sarcosuchus has a much more oversized snout end but no ones saying it was a terrestrial animal, Kaprosuchus skull is not rugose all over, just a mustache shape at the end of its snout, is not as this mattered much as living crocs don't have exposed skull bones, overall the skull is not that particularly thick or robust for a a crocodilian skull, it's rostral proportion ratio (width at midlength of snout/snout length) is 0.48, comparable to the mean of the nile crocodile.

To drive that point further I tried to compare its lateral view with another croc but lateral view photographs of croc skulls are lacking so I had to use one from a scientific paper of an extinct species.