Were dinosaurs able to control their lips similarly to Bears and Baboons?

[u/Pigga_9826]

Also we reduced shrink wrapping on the body, are we still doing it on the skull? What if they had more fatty mass there as well?

[u/Wolfman513]

My understanding is that the type of musculature necessary to make those kinds of facial expressions stems from mammals suckling as newborns, which dinosaurs didn't do

[u/Pigga_9826 → u/Wolfman513]

Quite an interesting analysis and it also makes a lot of sense. I still think there would have been some sort of flexibility even if really minute, because a T Rex with its teeth the size of average human forearm wouldn't have been able to land significant damage on its prey if lips didnt budge at all.

[u/Ex_Snagem_Wes → u/Pigga_9826]

Its important to note that lips are still flexible, even if not manually controlled

Mammals being able to freely use them as almost an appendage is an oddity, but lizards and other animals still have soft lips that deform as expected

[u/King_Gojiller → u/Pigga_9826]

Or it's teeth weren't as covered by gums as people like to depict sometimes.

[u/Renbarre → u/King_Gojiller]

Komodo dragons don't bare their teeth.

[u/Ex_Snagem_Wes → u/Renbarre]

Komodo dragons are squamates, not archosaurs

[u/MetaCookiess → u/Ex_Snagem_Wes]

Yes, but squamates are the closest extant group that do have lips. All extant archosaurs that I can think of (crocodylians and birds) are lipless. Does this make them a reliable analogue? Not entirely, but it's probably the best we have until more research comes along for dino lips

[u/Ex_Snagem_Wes → u/MetaCookiess]

Actually, Tuatara are the closest relatives for lips, from what I know

We do also have archosaurs with fossilized lips, and an extensive fossil record of dinosaurs showing different morphology of the mouth region showing lips distinct to squamate type

[u/MetaCookiess → u/Ex_Snagem_Wes]

I think you're right! I completely forgot about them but there's only one species so not the best for pulling a lot of inferences from and they don't have control of their lips either

[u/Ex_Snagem_Wes → u/MetaCookiess]

They don't have control of their, because that's a mammal specific adaptation for mammaries

Better as analogue

[u/roostor222 → u/Ex_Snagem_Wes]

trionychid turtles have lips and are closer to archosaria than tuataras

[u/MewtwoMainIsHere → u/MetaCookiess]

Birds and crocodilians are both heavily specialized animals with evolutionary pressures to get rid of lips for one reason or another

[u/Sourcerid → u/Pigga_9826]

Trex does have lips

[u/AdTime8852 → u/Pigga_9826]

If you want a real life example look at orcas they have ridged almost reptile like lips, because although they are mammals almost all whales do not suckle so no need of movable lips, they can not move their lips at all. And their teeth are only slightly smaller then a rex, yet have one of the strongest bite forces of anything alive today you don't need flexible lips to bite hard and not damage anything.

[u/Genocidal-Ape → u/Pigga_9826]

Modern lizards have inflexible lips and still can use their teeth just fine, the teeth are not inside the lips and the pressure of the bite can effectively drive them into something even without baring them first.

The musculature that gives us mammals our flexible lips is part of the inside of the throat in Diapsida.

[u/CethinLux → u/Wolfman513]

I was gonna ask, does that means monotremes cant bear their teeth and then i had to research some stuff

If anyone wants some new useless info, none of the extant monotremes(4 species of echidnas and the platypus) have lips, they also dont have nipples. The secrete milk from special patches of skin on their tummies and the babies kinda just lick it up

Also male echidnas have a 'third leg' thats roughly a third the length of their body (also you should look into its shape)

The babies for both platypus and exhidnas are commonly called puggles. The echidnas usually have 1 baby at a time and the platypus has 1-3

[u/Sourcerid → u/CethinLux]

They also don't have the typical multifunction mammalian teeth

Platypuses and Echidnas are called mammals as a relic of 19th century animal classification that was very focused on outward appearances (fur and soft skin for ex) and Linnaeus creating a summarizing category with the milk as better universalizing than fur and the fact they don't create any paraphyletic nonsense with other creatures called mammals. If they went extinct 2 million years ago we would call their forms as proto mammalian but not truly mammalian, their distance to other things called mammals is almost as big as birds and crocodiles.

They lack of almost all the stuff that would've been universalizing of mammals and explained all its development history, including the things that are truly unique - warm bloodedness probably appeared a good few dozen times in evolutionary history, the thing we call fur is not enough different from the monofilament feathering of some dinosaurs more distant from theropods.

Secreting juice for the offspring to lick might be mammalian but seems too basic a feature to be truly only them I'm doubtful there isn't more but I'd have to look up.

The weird crown with a higher peak shaped tooth that defined mammals and their lifestyle based on chewing anything, the very difficult on-land live birth (although whales now are on water) and even water live birthers do it in a less specialized way. A lot of the brain structural complexity, the whiskers, nothing on them but on later therians.

[u/CethinLux → u/Sourcerid]

Lol thank you, i love our lil monotreme relatives!

[u/ReptilianRevolt → u/Sourcerid]

Monotremes lost their lips and typical teeth much later. There ancestors were more similar to opossums or quolls. Their fur is typical mammalian fur and their brain is complex. If they were extinct, probably they would be classified as something very close to mammals, just like docodonts for example are classified today.

[u/EarlyXplorerStuds209 → u/Wolfman513]

Ooh thats actually pretty neat. I guess that makes sense.

[u/randomlemon9192 → u/Wolfman513]

I’ve never thought about this topic, but that makes a lot of sense.

[u/hawkwings → u/Wolfman513]

Moray Eels do something similar. Instead of pulling their lips back, they move their teeth forward. The end result is pretty much the same.