Tyrannosaurus rex had lips

[andrewsaurus rex]

I didn't realize there was an actual rule against it.  I thought it wasn't occurring just because everyone here has common sense. 

[Aerosteon]

Ford cannot prove anything, just like this study, the only thing that can prove that theropods had lips is to find remains of these oral structures, putting lips on theropods is speculation since nothing of these structures has been found Same as in Jurassic Park they put a ball around the neck of the Dilophosaurus.

the same study acknowledges in their own words "Some recent research on theropod rostral neurovasculature has argued that direct data and evidence for extraoral tissue reconstructions are lacking"

I find it funny how purists jump into the pool head first when a new studio comes out, like when they showed the spinosaurus on all fours. Did spinosaurids also have lips? Did Majungasaurus also have?

[stargatedalek]

Ford cannot prove anything, just like this study, the only thing that can prove that theropods had lips is to find remains of these oral structures, putting lips on theropods is speculation since nothing of these structures has been found Same as in Jurassic Park they put a ball around the neck of the Dilophosaurus.

the same study acknowledges in their own words "Some recent research on theropod rostral neurovasculature has argued that direct data and evidence for extraoral tissue reconstructions are lacking"

I find it funny how purists jump into the pool head first when a new studio comes out, like when they showed the spinosaurus on all fours. Did spinosaurids also have lips? Did Majungasaurus also have?

Putting eyes on theropods is speculation since there has never been a preserved dinosaur eye found. We infer the presence of eyes due to skeletal features that support them, such as sclerotic rings, and from analyses based on living animals (almost all vertebrates have eyes, and those that don't have eyes exhibit secondary adaptations indicating the lack of eyes).

We can similarly infer the presence of lips based on skeletal features that support them, like tooth wear, foramen patterns, and even jaw shape and jaw posture. As well as by analyses of modern animals, almost all of which have oral tissues that cover their teeth when their mouths close (aka lips). Those that don't show very specific adaptations that enable them to get by without lips, as even most aquatic animals still have them! And theropods do not share those adaptations (such as teeth that are round in cross section).

In paleontology the term "speculation" doesn't just refer to something that isn't 100% proven. We do not normally say theropod eyes are "speculation". It's generally used to refer to an element of a reconstruction (appearance or behaviour) that lacks significant evidence in its favour. So we wouldn't say lips are speculative. Nor would feathered or non-feathered Tyrannosaurus be speculative (small pet peeve), as there is decent amounts of evidence for either-or. But Tyrannosaurus having the ability to change colour, or Tyrannosaurus relying heavily on crustaceans as a food source when young, would be speculative.

Global warming is also not speculative, as you earlier claimed. That one's not even inferred, it's one hundred percent proven fact.

A lot of people have been in favour of lipped theropods for decades. I never found the 90's-2000's era of shrink-wrapping and exposed teeth very believable. Exposed teeth in theropods is an artistic fad that was never highly backed by scientific reasoning, it's just only now people are bothering to dispute it as the visual trope has become highly ingrained.

I see no reason to assume Spinosaurs or Abelisaurs would not have had lips, though Spinosaurs could go either way. Spinosaur teeth are noticeably more round in cross section than other theropods so they at least show what could be taken as evidence of being exposed, Majungasaurus absolutely does not show this evidence and should be depicted with lips.

[Faelrin]

Watched a video on this topic from Raptor Chatter last night, and he mentioned there was an abusive member on the team that published this paper? Anyone got more dirt on this? I'm curious.

Aside from coming here to sharing that, this whole paper has got me thinking, why did crocodilians evolve to not have lips, since like the majority of extant vertebrates do? I know from the paper their foramina is rather different in positioning due to their special sensory organs as an aquatic ambush predator (most of the time), and I did check out the abstract of the one paper explaining that they have keratinized skin on their faces that cracks as they grow, which is also rather different from most other extant reptiles. Is it just something in particular with the niche they adapted to? Are there any other species in a similar niche with a similar lip-less adaption? It very clearly isn't because of teeth size if the paper is anything to go by with the provided examples of various Varanus monitor lizard species.

[Aerosteon]

The comparisons of this study, in my opinion, are quite absurd and crude, since it compares totally different animals, with different ways of living and different biologies, comparing teeth and foramina, ignoring other anatomical structures of the skull and uses of these teeth.

We have four samples for figuring out how flight works to make a jet. We have penguins, bees, Hatzegopteryx, and bats. According to you, we should not use any of these to figure how flight works because they are not living similar lifestyles and have different wing setups. That is what you are suggesting and I am putting it in this simple of an example because I want you to understand why that idea does not work.

A study shows that it is strong trying to see its weak points and seeing what it kills, such as the replacement time of the teeth in theropods, which in T.Rex was 777 days but in Majungasaurs it was 56 days or in Allosaurus of 104 days but the study only focuses on T.Rex because it is the most popular and extrapolates all its results to all theropods.

The reasoning for lips is not to secure teeth within the mouth when biting, but to avoid them drying out too much from the air around them. Animals with exposed teeth typically have stronger layers of enamel or live in aquatic habitats where the concept of drying out is impossible because there is water surrounding them. Animals with lips typically have layers of enamel that are lighter. The point of the study was to test that with Tyrannosaurid teeth such as Tyrannosaurus rex and Daspletosaurus by comparing the enamel layers in the teeth to living monitors and crocodilians since they are the closest living relatives to Dinosaurs without beaks. One is heavily aquatic unlike Tyrannosaurids and one is land-based like Tyrannosaurids. If the enamel is similar, that points to the mouth covering likely being similar. The study found that Tyrannosaurid enamel matches up closer to the monitors than it does to crocodilians. This indicates that we should consider the monitor lips more likely.

Neither penguins have wings, nor do they fly, nor do bees have t-shirt feathers, not to mention the type of flight (unless we are talking about a hummingbird, and even so, bees have 4 wings that are active in their flights). ) and the anatomy is totally different from that of a bird, neither Hatzegopteryx had a bone structure similar to that of a bird to develop a similar flight, nor the structure and proportions of a bat is comparable to that of birds.

All these comparisons do not teach you anything about what a bird's flight is like, nor how it uses its t-shirt and rudder feathers, nor what its sailboat flight is like, nor how these wings beat in an upward flight.

Once again you assume something that is not true, animals with exposed teeth have almost no enamel layer, the most important thing in the teeth of elephants or wild boars is the dentin.
In the case of theropods such as Majungasaurus or Allosaurus, the renewal time of the teeth was 56 days on one and 104 days on the other, which is not enough time for the tooth to deteriorate. This could be a problem for animals with teeth that were not renewed. In the case of crocodiles, the teeth take approximately 365 days to renew, crocodiles share neither a habitat nor dental morphology with theropods, so their teeth are exposed to greater wear in the external area than an animal that lifts. his head more than 2 meters above the ground. The only thing that theropods and lepidosaurs share in the words of the study: "In particular, both in these lizards and in theropod dinosaurs, the teeth are aligned parasagittally with the vertical plane of the skull and do not slope outward as in present-day crocodiles" by what is not comparable the wear that is between theropods and crocodiles.



One of the arguments of the study to indicate the presence of lips is the line of foramina and it gives example photos. But what happens when these foramina are not present? as it happens in chameleons. In fact these foramina are also present in birds that do not have lips.




Another argument is that exposing the teeth to a dry environment would make them more fragile due to the lack of hydration, which exists due to glandular secretions in the mouth, but it turns out that this is not true of crocodiles since their teeth are exposed in some cases to extended times without hydration and therefore do not lose resistance, even if they are subjected to more wear.

It is curious how little by little dinosaurs have been differentiated from lizards, which at first were given the qualities and traits of giant lizards and come to see them more similar to birds, so that now the reference for oral structures are scaly lips of lizards and we do not find another explanation more in line with the evolution of the ranfotheca of birds, they directly went from scaly lips and glands in the gums to beaks.

[Aerosteon]

Ford cannot prove anything, just like this study, the only thing that can prove that theropods had lips is to find remains of these oral structures, putting lips on theropods is speculation since nothing of these structures has been found Same as in Jurassic Park they put a ball around the neck of the Dilophosaurus.

the same study acknowledges in their own words "Some recent research on theropod rostral neurovasculature has argued that direct data and evidence for extraoral tissue reconstructions are lacking"

I find it funny how purists jump into the pool head first when a new studio comes out, like when they showed the spinosaurus on all fours. Did spinosaurids also have lips? Did Majungasaurus also have?

Putting eyes on theropods is speculation since there has never been a preserved dinosaur eye found. We infer the presence of eyes due to skeletal features that support them, such as sclerotic rings, and from analyses based on living animals (almost all vertebrates have eyes, and those that don't have eyes exhibit secondary adaptations indicating the lack of eyes).

We can similarly infer the presence of lips based on skeletal features that support them, like tooth wear, foramen patterns, and even jaw shape and jaw posture. As well as by analyses of modern animals, almost all of which have oral tissues that cover their teeth when their mouths close (aka lips). Those that don't show very specific adaptations that enable them to get by without lips, as even most aquatic animals still have them! And theropods do not share those adaptations (such as teeth that are round in cross section).

In paleontology the term "speculation" doesn't just refer to something that isn't 100% proven. We do not normally say theropod eyes are "speculation". It's generally used to refer to an element of a reconstruction (appearance or behaviour) that lacks significant evidence in its favour. So we wouldn't say lips are speculative. Nor would feathered or non-feathered Tyrannosaurus be speculative (small pet peeve), as there is decent amounts of evidence for either-or. But Tyrannosaurus having the ability to change colour, or Tyrannosaurus relying heavily on crustaceans as a food source when young, would be speculative.

Global warming is also not speculative, as you earlier claimed. That one's not even inferred, it's one hundred percent proven fact.

A lot of people have been in favour of lipped theropods for decades. I never found the 90's-2000's era of shrink-wrapping and exposed teeth very believable. Exposed teeth in theropods is an artistic fad that was never highly backed by scientific reasoning, it's just only now people are bothering to dispute it as the visual trope has become highly ingrained.

I see no reason to assume Spinosaurs or Abelisaurs would not have had lips, though Spinosaurs could go either way. Spinosaur teeth are noticeably more round in cross section than other theropods so they at least show what could be taken as evidence of being exposed, Majungasaurus absolutely does not show this evidence and should be depicted with lips.

anillos escleróticos

What I find most amusing about this discussion is the insistence on attributing to theropods qualities of lizards and not thinking that the oral structures may not have been the scaly lips that lizards have, since if we know the evolutionary trend that the lizards have had birds, it does not even occur to us to think that instead of scaly lips they could have a horny cover as a ranfoteca or something in between.
The sclerotic rings are sufficient proof to say that the anatomy of an eye may be more like an animal that currently has it than another.
  What happens with this study is that it is based on the examination of a single tooth and the anatomical comparison of the T.Rex that is very popular (that does not smell good at all), to affirm that all theropods had lizard lips.
Why haven't they chosen the skull of a Majungasaurus or a Carnotaurus? Why haven't they compared the teeth of a Spinosaurus? Why haven't they gotten a cast sample of more teeth and only taken one from a Daspletosaurus? Is the study comparing the anatomy of the mandibles of current theropods and lizards and how they fit together in the two cases?

These are things that I ask myself and that the study does not explain.

[Bread]

Watched a video on this topic from Raptor Chatter last night, and he mentioned there was an abusive member on the team that published this paper? Anyone got more dirt on this? I'm curious.

A youtuber by the name of E.D.G.E also touched up on this abusive member, Robert Reisz.

I won't comment on anything regarding that said member, but I'll say that it does not contribute to the lip debate. Even if this scumbag is part of it, there shouldn't be a reason to discredit the others involved with the paper.

@Aerosteon I am pretty sure the reason and use of Tyrannosaurus is due to tooth size and popularity. Again, I've noted this about Tracy Ford's opinion, scientist are not presenting lizards associated with any relations to therapods. Simply using them to describe the similar lip structures that therapods would have to lizards. I don't think there is anything wrong with that given the acknowledgment of lizards not being related to therapods, etc. If anything, it is more important to acknowledge that crocodilians although related to dinosaurs, should not present the case that their relatives possess the same or similar characteristics and so on.

[Faelrin]

@Bread Thanks. I'll look into that. I absolutely agree with you there that the hard work of the rest of the team shouldn't be dismissed because of the actions of the few, or one particular individual, nor the evidence presented itself, unless there was something wrong with the methodology. That said it is unfortunate something of this nature has occurred. It definitely reminds me of some of the other ethical issues that have come up over the years with this field, like the thing with Robert DePalma that came out last year, the Burmese amber (such as the whole thing Oculudentavis a while back), the thing with "Ubirajara", etc. Raptor Chatter also made some good points in his comment section that such abusive actions can turn people away from pursuing the field. I think it can also hold us back from making more progress as well.

[Fembrogon]

I'll just add that Mark Witton also addressed this issue about the author in question on Facebook, following an inquiring comment. The paper was basically too far down the pipeline to change by the time the allegations arose.

[Faelrin]

@Fembrogon Thanks. I just checked out his response on the subject matter, and also saw Ford and Witton had a go at it too. I do agree with Witton's points. Like has Ford not seen what the inside of a Komodo Dragon's mouth is like? Their own teeth are ripping and tearing their own gum tissue up. How would that be any different if the same applied to a non-avian theropod then? Plus plenty of animals grow and shed their teeth, and yet still have lips. I just don't think those are very good counterpoints to what the paper raised. I don't think the other points raised from the anti-lips crowd hold much weight, especially when comparing non-avian theropods (except spinosaurids perhaps?) jaws and teeth to extant crocodilians, whose form and function seems to be quite different. Alligators for example have sockets on their upper jaws where their teeth on their lower jaws can slot into when they close their mouths. Crocodiles typically have teeth that interlock. Again from the supplementary material included with the paper it seems non-avian theropod jaws (or at least for Tyrannosaurus) couldn't close in such a manner without breaking.

Again I'm still wondering how spinosaurids fit into this. The paper made good points about non-avian theropod jaws aligning on a vertical plane, and extant crocodilian teeth leaning outwards. Nevermind the foramina placement, and difference between the enamel. There's so many factors at play here that we need to be taking a look at I guess. Or least I'd like too, assuming this sort of information is accessible. The reason I'm particularly interested in this, as for one thing the Mesozoic Life Spinosaurus has lips. Additionally this may be helpful to have an idea for future reconstructions of spinosaurids (such as from BotM, etc).

Like I think that paper only just recently scratched the surface, because of its limited scope. It's really got me questioning a lot, and I've been pro-lip for a while because I think it just looks more natural to me I guess. I hope this was all coherant. I am going to bed very soon lol (it's past 2:20 am for me atm).

Edit: One more thing. In the supplement material for the paper (or on Witton's blog post), they discuss the "crush closed" position being impossible for at least Tyrannosaurus, if not other theropods. Looking at the Yutyrannus specimens (in the paper and its supplement material) it seems some were preserved with its jaws like this though? Could it be a result of how it died, such as a post death muscle reaction, and/or the millions of years of fossilization that occured? It does seem to have similar foramina placement to say Tyrannosaurus, from what I can gather. Working on finishing up my Beasts of the Mesozoic Yutyrannus review which is why I'm wondering about this one in particular. Edit 2: Holotype ZCDM V5000 is a good example of this. Seems to have some post death and/or fossilization teeth slippage going on too. Skeleton seems to be flattened and crushed from fossilization which might contribute to all this too.

[Faras]

Rather not take a side in this debate, though personally I think dinosaurs probably had something (be it lips, beaks or scales) that fully or partially covered teeth. This paper left much to be desired however, my untrained eyes don't find their arguments too convicting:

1. Alligators live in somewhat murky waters. Particles in currents may cause constant wear on labial side of teeth (e.g. excessive brushing can break human teeth). Need to rule out dirty currents wear via comparative study of exposed fish teeth or teeth from domesticated alligators living in clear water.

2. One major factors for enamel damages is swift, often uneven dehydration caused by sun or wind in my experience of teeth collecting. Sunbathing behaviour means alligator teeth are frequently hydrated and dehydrated, which could result in extra micro cracks on labial side of enamel, making it prone to erosion. Most theropods probably wouldn't go in and out of water several times a day, how would this affect teeth wear in comparison with alligator?

3. Dead teeth may endure several years without obtaining visible cracks in humid regions. I'd like to see study of teeth wear of other species in the same formations.

4. The paper didn't mention (or I was being blind...) how much use the Daspletosaurus tooth went through. "No evidence of any substantial wear" - did the animal die shortly after growing that tooth? Need to study more teeth.

[DinoToyForum]

@Sim While checking the paper's supplementary material today, I saw the Daspletosaurus was listed as D. sp. So it is from a species that has yet to be described.

In that context "sp." usually just means that the species cannot be determined from the material. It doesn't mean it's a new species.

[DinoToyForum]

Watched a video on this topic from Raptor Chatter last night, and he mentioned there was an abusive member on the team that published this paper? Anyone got more dirt on this? I'm curious.

A youtuber by the name of E.D.G.E

That's @E.D.G.E. (PainterRex) , they're a member here as well 

[Leyster]

@Faelrin about Yutyrannus, you have to keep in mind that fossils from that formation, while beautifully preserved, are often flattened due to taphonomic processes. When they're excavated, they're basically found "opening in half" as impression and counter-impression, which sometimes has funny results ("Archaeoraptor" tail, if I remember correctly, is actually the counter-impression of the tail of a Microraptor). Another example of taphonomic distorsion (not from that formation, but similary flattened) is Scipionyx which looks like it has a nasal crest, but it's really the nasal bones splayed due to compression.

[Faelrin]

@DinoToyForum Thanks for the correction there. I forgot that was the case.

L @Leyster Thanks for explaining all that. I kind of had a feeling that might have been the case.

[Sim]

Thoughts I have:

1. In his blog post about this paper, Mark Witton shows Qianzhousaurus has depressions in its upper jaw which it seems its lower jaw teeth could fit into, like what Faelrin described is seen in alligators.  If I'm remembering right, PNSO has saif Tyrannosaurus has them too.  All things considered though, I still think Qianzhousaurus and Tyrannosaurus had lips.

2. Does the Mesozoic Life Spinosaurus have lips?  From what I've seen of it, it doesn't appear to?

3. I'm surprised to hear Robert Reisz has been abusive, since he was a consultant for Doug Watson...  It reminds me of how Matthew Baron, Aaron Van der Reest and Nick Longrich have also behaved badly: https://michael-balter.blogspot.com/2021/07/paleontology-alleged-sexual-harasser-is.html

[Faelrin]

@Sim Hmm. I missed that on my first reading of it. Guess I'll need to go back and check that out. Granted the positioning of the teeth, and how far the jaws could close seem to be important factors here as well. And of course the enamel.

No you are right. It doesn't. I misremembered, sorry. I'll correct my above post later. Might have also gotten the wrong impression, since the sculptor of the model, Jake Baardse, tends to give the rest of his sculpts lips (when applicable).

[Aerosteon]

"The neurovascular canal with branching pattern as complex as that of the extant crocodilians and ducks, suggests that the trigeminal nervous system in Tyrannosaurus rex probably functioned as a sensitive sensor in the snout."

"It must be noted that the sensitivity of the snout in Tyrannosaurus rex may not have been as enhanced as that of the crocodilians because Tyrannosaurus rex lacks the thick neural tissue occupying the neurovascular canal unlike extant crocodiles."

https://www.sci.news/paleontology/tyrannosaurus-rexs-jaw-tactile-sensor-09986.html

[Aerosteon]

https://www.google.es/url?sa=i&url=https%3A%2F%2Fpalaeo-electronica.org%2Fcontent%2Fpdfs%2F1178.pdf&psig=AOvVaw2PdFUCtizcN13e4fB_msNt&ust=1680819962855000&source=images&cd=vfe&ved=0CBEQjhxqFwoTCPivw7rkk_4CFQAAAAAdAAAAABAD

[Faelrin]

@Sim Okay so I've been re-reading Witton's blog post, and I am at the part with the Qianzhousaurus skull that you mentioned. If I'm understanding correctly, they argue against those spots in the skull being used in such an extant crocodilian like manner, because other parts of the skull couldn't close all the way, without breaking. So that does leave me the question of what were those spots used for then? Or what were they even?

Here's the relevant section quoted:

We are not the first people to ponder this issue, and dinosaur literature has contrasting views on how far theropods could close their jaws. Some authors propose that theropod mandibles could be pulled way up into the cavity of the upper jaw and have even identified landmarks for the resting position of the lower teeth (below). These include depressions in the walls and roof of the upper oral chamber that seem suited to act as socket-like structures for receipt of the lower dentition (e.g. Molnar 1991; Ford 1997; Currie 2003; Hendrickx et al. 2014). Others, most notably Tyler Keillor (2013) in his excellent book chapter on restoring the face of the "Jane" Tyrannosaurus, have questioned this idea on grounds that theropod mandibles can't close so tightly without literally bashing into problems.

Reconstructing the face of T. rex for our paper saw us agreeing with Tyler's conclusions. At a certain point of mouth closure, theropod lower jaws collide with bones under the eye socket (specifically, the ectopterygoid) so that further adduction either requires the jaws to literally crush themselves shut, or else the bones of the posterior skull act as a hinge, swinging the jaw tip into the mouth but dislocating the jaw joint. Ford (1997) proposed that a notch in the ectopterygoid accommodated the closed lower jaw during mouth closure but we don't think this is plausible. Theropod ectopterygoids can be complex shapes and yes, some have regions that superficially look like they could nestle the lower jaw, but these were almost certainly filled by deep jaw muscles in life (e.g. Gignac and Erickson 2017). There are, of course, theropod skulls preserved with their jaws tight shut in the fossil record but we have to be careful assuming these represent in vivo conditions, given how routine processes of decay and fossilisation can pull and crush carcasses into unnatural configurations.

That also seems to answer my questions regarding the Yutyrannus skull in the sort of "crush closed" position I asked about last night, aside from what L @Leyster posted above.

@Aerosteon Thanks for sharing that. Very interesting information within, particularly as it concerns the famous Sue specimen. At the end of the paper, if I'm understanding correctly, it seems like they don't lean one particular way or the other on this debate, but rather that more data is needed to test either hypothesis. I wonder what the authors of this particular paper, think of this new one by Cullen et al?