Dinosaur lips?

[AcroSauroTaurus]

What I'm wondering is why a terrestrial predator like Daspletosaurus need sensory pits for detecting underwater vibrations. I don't think a Daspletosaurus is going to stick its snout in the ground to detect the footsteps of a prey animal... unless they were for predicting an ambush from a crocodilian while drinking. Or it would stick its snout in thick vegetation near a herd of herbivores and when the pits felt an individual getting close the Daspletosaurus would launch its head through and ambush the prey animal.

[Loon]

From what I've been reading in this thread, this sounds really interesting. I'm not familiar with obtaining journal articles, so if any one could point me in the right direction, it would be very much appreciated. I don't agree with a lot of the claims I've heard about this paper proving all theropods, and by extension, all dinosaurs, didn't have lips. I think it's important to remember that tyrannosaurs are very specialized animals and that a trait in one species of one family shouldn't always apply to an entire clade. By that thinking, all dinosaurs would have feathers because some coelurosaurs have them.

[Dyscrasia]

From what I've been reading in this thread, this sounds really interesting. I'm not familiar with obtaining journal articles, so if any one could point me in the right direction, it would be very much appreciated. I don't agree with a lot of the claims I've heard about this paper proving all theropods, and by extension, all dinosaurs, didn't have lips. I think it's important to remember that tyrannosaurs are very specialized animals and that a trait in one species of one family shouldn't always apply to an entire clade. By that thinking, all dinosaurs would have feathers because some coelurosaurs have them.

http://www.nature.com/articles/srep44942

The paper is open access.

[Loon]

http://www.nature.com/articles/srep44942

The paper is open access.

Thank you

[Nanuqsaurus]

Yeah, I'm not buying this. Just got used to seeing theropds with lips and now they come up with this. It just doesn't make a lot of sense to me that they compare two entirely different animals that fill entirely different ecological niches, and somehow draw a conclusion from that. And that reconstruction is just terrible.

[Neosodon]

What I'm wondering is why a terrestrial predator like Daspletosaurus need sensory pits for detecting underwater vibrations. I don't think a Daspletosaurus is going to stick its snout in the ground to detect the footsteps of a prey animal... unless they were for predicting an ambush from a crocodilian while drinking. Or it would stick its snout in thick vegetation near a herd of herbivores and when the pits felt an individual getting close the Daspletosaurus would launch its head through and ambush the prey animal.

Sensing magnetic fields would be the most sensible use I'm thinking.

[stargatedalek]

Crocodiles don't even have scales on their mouths, they have hard skin.

I hope your referring to inside a crocodiles mouth.

I don't know what your image is of, but I couldn't even find it among results for "crocodile mouth".

What I'm wondering is why a terrestrial predator like Daspletosaurus need sensory pits for detecting underwater vibrations. I don't think a Daspletosaurus is going to stick its snout in the ground to detect the footsteps of a prey animal... unless they were for predicting an ambush from a crocodilian while drinking. Or it would stick its snout in thick vegetation near a herd of herbivores and when the pits felt an individual getting close the Daspletosaurus would launch its head through and ambush the prey animal.

Sensing magnetic fields would be the most sensible use I'm thinking.

That isn't of any more use out of water than sensing vibrations. The most likely explanation is that these patterns are simply a preservation artifact or even bone disease, but if they were sensory apparatus they probably rooted "feather barbels".

[suspsy]

From what I'm seeing on Facebook, a number of paleontologists are skeptical of Carr's conclusions about lips or the presumed lack thereof, Mark Witton and Matt Martyniuk being two of them. And John Conway has declared that he won't be changing any of his paintings.

[Doug Watson]

From what I'm seeing on Facebook, a number of paleontologists are skeptical of Carr's conclusions about lips or the presumed lack thereof, Mark Witton and Matt Martyniuk being two of them. And John Conway has declared that he won't be changing any of his paintings.

Is the debate on Facebook in an open forum I would love to check it out?

[Neosodon]

Stargetadalek, I typed in crocodile undersides to get my picture.  I curious how you get your information. What makes you think  that crocodiles didn't have scales on their mouth. The pictures you posted are not as close up as the one I posted but you can still see the scales if you look closely. They are flatter so they are harder to see but you can still see the lines in between were they connect. Here is a dwarf crocadile. If you are thinking my first picture is not real here is another one that you can clearly see the scales on.

[CrypticPrism]

Crocodiles don't have scales on the sides of their mouths. That's hardened skin.

[suspsy]

From what I'm seeing on Facebook, a number of paleontologists are skeptical of Carr's conclusions about lips or the presumed lack thereof, Mark Witton and Matt Martyniuk being two of them. And John Conway has declared that he won't be changing any of his paintings.

Is the debate on Facebook in an open forum I would love to check it out?

It's on Mark Witton's Facebook and Twitter. I don't know if you're Friends with him, but here's the link:

https://www.facebook.com/mark.witton/posts/10154234692491433

[stargatedalek]

If any hardened surface that isn't a single plate is scales than I suppose rhinoceros are also scaled.



Look closely at the structures, they aren't scales, they're hardened skin that forms into semi-random segments.

[Neosodon]

If any hardened surface that isn't a single plate is scales than I suppose rhinoceros are also scaled.

Look closely at the structures, they aren't scales, they're hardened skin that forms into semi-random segments.

To you it looks like hardened skin that happens to resemble scales. To me it looks like scales. Unless you can get information from a crocodile expert this won't be resolved.

[Tyto_Theropod]

I'll finish with a quick PSA: PLEASE, people, can we not have drama over a discovery. Reasonable criticism and well-founded arguments in favour/against is fine, and in fact I'd encourage it. Getting fanatical about it is not, and I've seen far too much of it on the forum lately. Please, DTF, stay special and don't descend to the level of all my other internet hangouts!

Just because I wasn't a ray of sunshine doesn't invalidate my argument or mean my skepticism isn't well-founded. This claim is absolutely preposterous for very many reasons.

They openly admit to only bothering to make comparisons to crocodiles. There is not one bit of mention of the animals being of entirely different ecological niche, nor of other animals that display similar patterns. Crocodiles don't have exposed teeth because of these sense organs (are they organs? receptors?) but rather because they're aquatic.

They name-dropped Horner. Doesn't matter if he's barely even quoted, dropping his name is already a bad sign.

The accompanying reconstruction shows a lack of finesse or awareness of the subject. And no, the reconstruction is not the be-all-end-all of a claim, but this clearly isn't bad because it was rushed, but rather because of a lack of understanding of the animals anatomy. Big difference between a rushed sketch being bad and a commissioned reconstruction being inaccurate.

I wasn't specifically talking about you and I'm very sorry that you've chose to take it that way. In fact, I was thinking more about the whole Ornithoscelida business. Also, you seem to have assumed that I am endorsing the paper's correctness, which I am not. Although I am becoming increasingly sceptical of this study, at the time of my original post I was keeping an open mind until more commentary was made by other palaeontologists.

I don't agree with a lot of the claims I've heard about this paper proving all theropods, and by extension, all dinosaurs, didn't have lips. I think it's important to remember that tyrannosaurs are very specialized animals and that a trait in one species of one family shouldn't always apply to an entire clade. By that thinking, all dinosaurs would have feathers because some coelurosaurs have them.

This is exactly what I've been saying all along. If Tyrannosauroids were lipless of course, a fact of which I am increasingly doubtful.

[stargatedalek]

I wasn't specifically talking about you and I'm very sorry that you've chose to take it that way. In fact, I was thinking more about the whole Ornithoscelida business. Also, you seem to have assumed that I am endorsing the paper's correctness, which I am not. Although I am becoming increasingly sceptical of this study, at the time of my original post I was keeping an open mind until more commentary was made by other palaeontologists.

I don't agree with a lot of the claims I've heard about this paper proving all theropods, and by extension, all dinosaurs, didn't have lips. I think it's important to remember that tyrannosaurs are very specialized animals and that a trait in one species of one family shouldn't always apply to an entire clade. By that thinking, all dinosaurs would have feathers because some coelurosaurs have them.

This is exactly what I've been saying all along. If Tyrannosauroids were lipless of course, a fact of which I am increasingly doubtful.

Aah sorry, I didn't mean to make that sound like I thought you were talking about me specifically. Rather I just wanted to reiterate my response in case it had been iced over because of any perceived aggression.

[The Atroxious]

Anatomy trumps genetics, and behavior trumps anatomy.

If we want to use genetics for every inference we should be reconstructing all dinosaurs with either full coats of feathers and bills or with armored crocodilian scutes. Similarly if we use solely anatomy for every depiction all dinosaurs should be flat. A certain degree of inference is required in reconstruction, and this means cross referencing an animals probable (or in some rare cases proven) behavior with its preserved anatomy to interpret a realistic appearance, then using genetics only to fill in the unknowns after that.

Crocodiles have exposed teeth for very specific reasons. It has nothing to do with the sensory organs on their snouts, crocodiles have exposed teeth because they spend the vast majority of their time with their teeth underwater. A land-based animal can't do this without its teeth being damaged by exposure to the air, we see this in tusked mammals, but not in dinosaurs. And in case someone thought they were going to be smart, most fish don't have exposed teeth because it makes them less hydrodynamic, which is unimportant for an ambush predator like a crocodile.

I'm no longer going to directly reply to anyone who just suggests crocodiles were the best reference for Tyrannosaur anatomy because Suchomimus has a skull superficially and convergently similar to crocodiles in profile shape. I'm low enough on aspirin as-is.

You yourself mention tusks immediately before discounting a similar possibility in dinosaurs. The truth is that there are, in fact, several types of animals that have exposed teeth, and while it's uncommon, it's clearly possible. I'm very much in the camp that exposed teeth were an archosaur peculiarity, and until there is clear, unequivocal evidence one way or another, I feel it's safer to infer a lack of lips, just like most find it safe to infer some kind of plumage on tyrannosaurines.

This thread has gotten really aggressive really fast. I understand having a preferred hypothesis, but are dinosaur lips really that much of a hot button issue?

Oh my god I'm dying, you said birds don't have lips.





You know how there was that whole thing on smilodon having big, floppy jowls? That's because teeth can ROT. Prolonged exposure to air can cause tooth rotting. Crocs are safe from this because they're semi-aquatic, and usually only have short times walking around on land. Dinosaurs were completely terrestrial, which means rotting would happen over and over. And no, there's no "well they just regrew them like sharks" because sharks are RIDICULOUSLY distant from dinosaurs. Birds have lips. Therefore they probably got them from their DIRECT ancestors, theropods. The only reason spinosaurs are depicted as lipless is because it would get in the way of snagging fish. Land theropods would not have this because the lips would swing back when biting prey, therefore keeping them safe from damage. Your defenses completely ignore the flat logic we put up against it.

Pretty sure those are called cheeks. You know, like the whole stegosaur/ornithopod/therizinosaur cheek discussion. What's seen in the bird is the same structure those other dinosaurs are postulated to have when talking about cheeks in dinosaurs.

Also, regardless of sharks being distantly related to dinosaurs, the fact that dinosaurs and crocodilians also regrow teeth shouldn't be discounted. Correct me if I'm wrong, but I don't know of any other extant animals that can regrow lost teeth, which suggests that the only animals we know of that can share the trait of having exposed teeth. Maybe there's something to this? Just an idea.

[Halichoeres]

Geckos continually replace teeth, but they keep their teeth nice and humid, so fun trivia but not very informative on this particular debate.

[Doug Watson]

From what I'm seeing on Facebook, a number of paleontologists are skeptical of Carr's conclusions about lips or the presumed lack thereof, Mark Witton and Matt Martyniuk being two of them. And John Conway has declared that he won't be changing any of his paintings.

Is the debate on Facebook in an open forum I would love to check it out?

It's on Mark Witton's Facebook and Twitter. I don't know if you're Friends with him, but here's the link:

https://www.facebook.com/mark.witton/posts/10154234692491433

Thanks, ironically I was just reading an article from Mark Witton's blog from 2016 where he is still open to the idea that some theropods could have been lipless. He raises the question that I did earlier here about toothy Pterosaurs and he also brings up the interesting fact and I quote "that several crocodylians species 'hibernate', or more accurately aestivate, for months at a time in dry underground burrows during the hottest summer months (Grigg and Kirshner 2015). During these intervals they do not access water at all. Other, South American species spend dry spells as fully terrestrial carnivores, abandoning aquatic habits and obtaining water largely from the prey they kill (Grigg and Kirshner 2015)."
I haven't finished the article yet.

[EarthboundEiniosaurus]

Monitor lizard teeth are replaced throughout their lifetime as well, and they have a similar lip covering as is proposed for theropods. As for the "lips" on birds, it is known as the rictus and it does seem plausible that it could be a reduced version of what would have been found in non avian dinosaurs (that whole idea was put forth by Duane Naish however, so take it with some salt). As for tooth rot, i'm not entirely sure the argument that enamel degrades when not kept moist is entirely valid, as there are a number of extant animals with tusks that have at least a partial enamel covering and show no problems. In my very much unprofessional opinion I believe we should be very cautious when suggesting a certain organism (or even a group of organisms) did not posses some sort of tooth covering, as it seems to be the default condition for tetrapods, although it may be that some tooth exposure is plausible as enamel seems to be more versatile than once thought.