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Post by Infinity Blade on Oct 11, 2016 5:39:06 GMT 5
A little off topic, but what does this now mean for machairodonts? If I read Witton's post correctly, then "enamel covers the teeth" isn't really justification for lips anymore, but it doesn't necessarily rule them out for Smilodon et al., right?
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Post by Deleted on Oct 11, 2016 12:21:37 GMT 5
It doesn't. It just makes it more indeterminate. I think an extreme form of the condition found in clouded leopards is most plausible.
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Post by spinosaurus1 on Oct 11, 2016 20:48:51 GMT 5
^  |
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Post by Infinity Blade on Oct 13, 2016 6:13:00 GMT 5
If having highly developed sensory organs is what may be the reason why crocodilians don't have "lips", what about the "tactile faced theropods" abstract I posted in the previous page? 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 Is there a rebuttal against it? |
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Post by Infinity Blade on Mar 31, 2017 16:58:33 GMT 5
Daspletosaurus horneri allegedly shows evidence for the same tactile face seen in crocodilians. This suggests no lips, at least in tyrannosaurids. www.nature.com/articles/srep44942
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Post by Supercommunist on Mar 31, 2017 19:58:32 GMT 5
Yes! **** U LIPS. CROCODILE MOUTH FTW!
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Post by theropod on Sept 7, 2018 0:15:51 GMT 5
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Post by theropod on Apr 25, 2019 23:56:51 GMT 5
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Post by Infinity Blade on Mar 31, 2023 5:04:22 GMT 5
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