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Post by Infinity Blade on Nov 26, 2015 7:44:52 GMT 5
This thread is for any discussion pertaining to any current debate regarding what soft tissue structures were present on the face of dinosaurs (e.g. theropod "lips" or even cheeks and what this could mean for other dinosaurs).
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Cross
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Post by Cross on Nov 26, 2015 11:07:51 GMT 5
Edmontosaurus regalis is known from comb-like soft tissue on the dorsal surface of the skull (Bell et al. 2013).  Edmontosaurus regalis with Preserved Soft-Tissue Structures
(A) Right lateral aspect of head and neck showing approximate orientation of the block on the body (gray part on inset silhouette) and inset of skull showing preserved elements (gray).
(B) Close-up of partial skull and comb structure. Skin overlapping the side of the skull is indicated by arrowheads. Anterior is to the right.
(C) X-ray of posterior part of skull and neck showing posterodorsal margin of the skull (arrowheads) and interior of comb. Image is rotated 45° anticlockwise relative to (C). Anterior is indicated by arrow.
(D) Close-up of neck scales demarcated in (A).
Scale bar increments in (B) and (D) represent 1 cm. Scale bar in (C) is approximate. bc, braincase; c, comb structure; cv, cervical vertebrae; dv, dorsal vertebrae; f, frontal (impression); h, hyoid; itf, infratemporal fenestra; o, orbit; po, postorbital; q, quadrate; sq, squamosal. Skull illustration is modified from Campione and Evans [12].The paper can be found here for free : www.sciencedirect.com/science/article/pii/S0960982213013948--Reference Bell, P. R., Fanti, F., Currie, P. J., & Arbour, V. M. (2014). A mummified duck-billed dinosaur with a soft-tissue cock’s comb. Current Biology, 24(1), 70-75.
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Post by Infinity Blade on Nov 26, 2015 17:35:32 GMT 5
What do you think of theropod "lips"? As of now, I don't agree with them, but I'm not going to explain why right now. Edit 8/18/19: now I do, but this doesn't necessarily mean gums completely covering the teeth ( as per GSP's latest renditions shown below; his rendition on the left or something like this-> is fine IMO). Such a condition isn't even seen in all squamates; you can still see teeth showing when the mouth is open ( 1, 2, 3, 4, 5, 6, 7, 8), and some theropods probably had proportionately much bigger teeth than the lizard examples I linked to here.  |
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Cross
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The biggest geek this side of the galaxy. Avatar is Dakotaraptor steini from Saurian.
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Post by Cross on Nov 26, 2015 18:09:39 GMT 5
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Post by Infinity Blade on Nov 26, 2015 18:36:23 GMT 5
I concur with no lips as well. Zach Armstrong makes a good argument for it here (hyperlink). There was even an SVP abstract that argued against theropod lips (as well as rhamphothecae) and supported tactile-faced creatures (similar to crocodilians). TACTILE FACED THEROPODSFORD, Tracy L., Dino Hunter, Poway, CA, United States of America, 92074 " For decades whether or not theropods had lips has been a hot topic for paleontology and paleoartists. Did they have lizard like 'lips' or were they lipless like an alligator? One of the arguments for lips are the numerous foramina on the premaxilla, maxilla and dentary. These foramina are theorized to have supplied nerves for the lips and muscles. The lips serve several functions: in squamata, the 'lips' protect the labial oral glands, hold food and retain water. In mammals, the 'lips' are for communication, food manipulation and water retention. Looking at extant animals, we can determine if theropods had lips. Both mammals and squamates have a limited number of foramina on the maxilla and dentary, which supplies nerves for their 'lips' and muscles, as well as nutrients. More importantly, the bone texture of the premaxilla, maxilla, and dentary is smooth in both mammals and squamates. This is caused by the constant interaction of soft tissue rubbing against the skull bones. Previous investigations have not taken this bone texture into account. Theropods have a rugose bony texture and numerous foramina, which indicates a lack of soft tissue for lips and facial muscles. This is best seen in the antorbital fenestra. Bones textures on the inside of the fenestra are smooth, which indicates the soft tissue has some movement, while the outside bone is rugose. There is a groove that extends from each foramina and it extends toward the jaw line. The foramina also have smaller grooves that extend in the opposite direction. This is best seen in older individuals. Crocodilians also have several foramina and a more rugose bone texture. The foramina do supply nerves for the facial region, which makes the face a tactile sense organ. The best use for this tactile face is for feeding/hunting in murky water. Another suggestion is theropods had a rhampotheca. In extant avians, the foramina supplies nutrients for a rhampotheca. Where the rhampotheca attaches in extant avians, the bone texture is smooth, i.e., the beak and claws. Therefore the skull elements in theropods with rough bone texture were incapable of having a rhampotheca. It is the conclusion of this study, using extant taxa as a baseline, that theropods lacked lips/facial muscles and a rhampotheca. This is based on the rough bone texture on the bone surface, which is in contrast to the smooth bone texture of animals with lips/muscles. It is also inferred that theropods had a tactile face
similar to that in crocodilians." vertpaleo.org/PDFS/39/39ad8cfa-19a3-4d99-a9fb-0dee66022922.pdf |
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Post by Infinity Blade on Apr 17, 2016 8:11:58 GMT 5
Do note that I'm open to anything being right on this subject. Whether or not theropods had oral seals doesn't keep me awake at night. I just want my curiosities here quenched. antediluviansalad.blogspot.com/2016/04/not-your-daddys-tyrannosaurus-rex.html'Nother interesting post by Duane Nash. I think he does a good job in refuting the whole jaw closure thing and the idea that the teeth would shred the lips, but I'm still not completely sure about the whole moisture argument. How then would we explain sabertooths?... Oh, and remember how I said this once? Well, 1 obviously doesn't work, as birds and crocodilians are in lieu of lips for specialization reasons. Not 100% sure on how much 2 or 3 would really matter anymore. 4, well, even if a theropod had particularly long teeth, I *guess* they could be counteracted with a deeper lower lip (just a guess)? 5, I'm guessing this may be counteracted with the lower jaw lips not completely sealing the teeth? 6, Nash still found the moisture thing lacking, but I still find the sabertooth thing lacking... I dunno....... |
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blaze
Paleo-artist 
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Post by blaze on Apr 18, 2016 15:43:20 GMT 5
The very first part of that post was decent but Nash then went crazy with the speculation, it looks like an eldricht abomination.
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Post by Infinity Blade on Apr 18, 2016 23:55:42 GMT 5
So would you agree with larger M. pterygoideus muscles?
I was also mostly concerned about the "theropod lips" part.
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Post by theropod on Oct 10, 2016 1:32:27 GMT 5
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Deleted
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Post by Deleted on Oct 10, 2016 8:10:39 GMT 5
So I should remove the exposed teeth in my large-toothed theropods then?
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Post by theropod on Oct 10, 2016 17:17:50 GMT 5
I for my part do agree with Witton, but he also makes it pretty clear that direct evidence is lacking.
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Deleted
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Post by Deleted on Oct 10, 2016 19:22:48 GMT 5
Witton seems to put up a really convincing case on why dinosaur teeth should be covered.
But how about spinosaurines? They have huge teeth, and are arguably in a similar situation as the plesiosaurs he brings up. Cau seems to restore Spinosaurus with full lips, but I have no idea how plausible it is...
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Deleted
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Post by Deleted on Oct 10, 2016 22:47:07 GMT 5
Witton seems to put up a really convincing case on why dinosaur teeth should be covered. But how about spinosaurines? They have huge teeth, and are arguably in a similar situation as the plesiosaurs he brings up. Cau seems to restore Spinosaurus with full lips, but I have no idea how plausible it is... Im not entirely sure, but if it is similar to crocodiles like some people say then I think there's a good chance of it having exposed teeth. |
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Post by spinosaurus1 on Oct 11, 2016 1:05:36 GMT 5
my favorite interpretation of a lipped spinosaur  really like the idea of spinosaurs being lipped up untill it get nears a notch. this of course is just personal views |
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Post by theropod on Oct 11, 2016 2:41:27 GMT 5
I think both versions are valid based on our current understanding, but I do think Spinosaurus’ major crocodile-homoplasies (notably in the sense-department) justify restoring it without lips. I don’t think the partially-lipped idea is new either, didn’t Greg Paul apply it to baryonychines?
Huge teeth alone aren’t enough imo. They certainly are huge, perhaps even longer than any other theropod tooth, but we’re at most talking about a couple of centimetres that they might be longer than the longest tyrannosaur or carcharodontosaur teeth, so that’s probably well within the plausible limits of soft-tissue covering (keeping in mind hippos can keep their teeth covered without problems).
The ecological and dental similarities to crocodiles, and the probable shared trait of pressure receptors are a lot more compelling though. Spinosaurs hunt similar prey, live in similar habitats and use their snout very similarly in at least two regards (in terms of prey capture and sensory perception), and it seems plausible that we should look for the reason why crocodiles lack lips somewhere among these traits.
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