tag:blogger.com,1999:blog-8161161431451849208.post218446750061842784..comments2024-03-18T02:43:22.233-07:00Comments on Antediluvian Salad: Not Your Daddy's Tyrannosaurus rex...Duane Nashhttp://www.blogger.com/profile/14467779935085970909noreply@blogger.comBlogger78125tag:blogger.com,1999:blog-8161161431451849208.post-63953870447681757252023-09-06T07:50:13.108-07:002023-09-06T07:50:13.108-07:00I think the large hanging lips would get in the wa...I think the large hanging lips would get in the way of a rapid, crushing bite. <br />They would also be likely to be pierced by the teeth.<br />These lips are primarily seen in animals with dull dentition, that hold onto their prey.<br />T rex would have simply bit them, and would not need these.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-59018187821021783822018-03-21T07:17:32.473-07:002018-03-21T07:17:32.473-07:00This comment has been removed by the author.New Moonhttps://www.blogger.com/profile/11479322264833082071noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-76204502923555994442017-04-06T15:28:27.326-07:002017-04-06T15:28:27.326-07:00Well Jason, I do not think he analyzed it properly...Well Jason, I do not think he analyzed it properly. We can see it in the very beggining: he puts many skulls of different creatures there and says that just because all of them have rugose skull texture the comparation with crocodiles is not a great one, however he simply forgot that, even tough rugose texture can be caused by many things, it is obvious that different causes will lead to different textures on the skull (muscle attachment changes the surface of the bone, but the marke are clearely not the same as those of crocodylian keratinized skin). Therefore his first point does not stand.<br /><br />He says that people like to compare T. rex with crocs because they are predatory, but this is simply not the case. We are talking about fossil data and accuracy, not a simple fan made comparation to make T. rex look cool.<br /><br />And if the iregular texture of T. rex's skull was due to bites from rivals, the paleontologists would have realized it. The teeth have a specific shape and thanks to this it is easy for an authority in the subject to identify tooth marks left by a rival of it's own kind (that is how it was Discovered that Sue had a parasyte on her jaws when it died), but the texture found resembled that of a crocodylian skull. All of this without mentioning that:<br /><br />- It was shown that the irregular surface goes almost all the way to the tooth row. It is nearly impossible for a T. rex to have had such an enormous area of it's snout bitten like that (just have the shape of the jaws in mind);<br /><br />- D. horneri, just like D. torosus, had thin teeth designed for slashing and cutting. Such jaws would have NEVER left marks like those seen in T. rex.PaleoKnighthttps://www.blogger.com/profile/14759160960102177697noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-60386094819805595452017-04-05T09:00:39.957-07:002017-04-05T09:00:39.957-07:00@Jaason Silveria My two cents: http://antediluvian...@Jaason Silveria My two cents: http://antediluviansalad.blogspot.com/2017/04/behind-your-bony-mask-of-face.htmlDuane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-50456979460443691252017-03-31T08:55:11.985-07:002017-03-31T08:55:11.985-07:00I understand this is a rather old post, but the &q...I understand this is a rather old post, but the "T. rex with lips" controversy came up again in Carr et al. (2017):<br />http://www.nature.com/articles/srep44942<br /><br />The long-awaited descriptor of the upper Two Medicine Formation tyrannosaur Daspletosaurus horneri includes a brief but noticeable discussion on facial musculature, using birds and crocodilians as analogues. It is hypothesized that the density of neurovascular foramina along the lipline, particularly at the pointed rostrum, supported sensory integument similar to modern crocodilians, and not unlike Bob Bakker's early skin-wrapped "lizard lips" reconstructions. I think this conclusion is premature. While crocodilian-like mechanoreceptors were undoubtedly part of the tyrannosaur facial musculature, I have issue accepting the lipless reconstruction with the teeth sticking out; the organs may have been keratinized, and thus flamboyantly ornamented and colored. Even the article states that similar (if less extravagant and sophisitaced) foramina are present in "lipped" tetrapods such as cane toads and moles.<br /><br />(Interestingly, the article also states that Daspletosaurus was to derived to be the ancestor of either Tarbosaurus or Tyrannosaurus. They all probably shared a more distant common ancestor in the form of Lythronax.)Jason Silviriahttp://sympanscience.wordpress.comnoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-22471426320418617252016-10-09T10:08:40.633-07:002016-10-09T10:08:40.633-07:00Found an interesting thing if you wanted to contin...Found an interesting thing if you wanted to continue this for animals such as Dunkleosteus. Because this-<br /><br />http://i.imgur.com/0Izd42a.jpg<br /><br />is the same type of animal as this.<br /><br />http://i.imgur.com/JXCHKcY.jpg<br /><br />Lungfish, man. Lungfish.Anonymoushttps://www.blogger.com/profile/06537056479288460350noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-66803740162544055672016-08-12T23:34:19.968-07:002016-08-12T23:34:19.968-07:00@Altair sky birds are dinosaurs, not the other way...@Altair sky birds are dinosaurs, not the other way around. he also directly addresses the point you make about mammals being too far outside the phylogenic bracket Anonymoushttps://www.blogger.com/profile/16487518223946522978noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-4920296052053468612016-06-01T10:21:08.871-07:002016-06-01T10:21:08.871-07:00I agree with basically all of your post, but If I ...I agree with basically all of your post, but If I have to land a small critique, I think you're comparing too much dinosaurs with today's mammals. Dinosaurs are birds so it makes sense to me that the T-rex could have had fleshy growths covering its face like a turkey's or a vulture have, and these structures could have formed lips because that could be an advantage, from an evolution point, but comparing these structures to a bulldog's lips I think it's kind of pushing it too far to be realistic.<br />https://s-media-cache-ak0.pinimg.com/736x/d5/b9/60/d5b9608b4226438cea1b7fca542c2a8a.jpg<br />http://lafeber.com/vet/wp-content/uploads/dragoon_head-bodlina-wikimedia-labeled.jpgAnonymoushttps://www.blogger.com/profile/11223201636901179815noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-31063224687977016082016-05-31T07:53:11.450-07:002016-05-31T07:53:11.450-07:00Just go google what "bless your heart" m...Just go google what "bless your heart" means in certain situations...Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-20574216072207195012016-05-31T07:16:47.140-07:002016-05-31T07:16:47.140-07:00Sarcasm I'm presuming.Sarcasm I'm presuming.D-mannoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-47840238412132017692016-05-29T23:14:38.059-07:002016-05-29T23:14:38.059-07:00Bless your heart DovahkiinHU3BR sweet child...Bless your heart DovahkiinHU3BR sweet child...Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-82267721392740976712016-05-29T13:32:00.191-07:002016-05-29T13:32:00.191-07:00Also by this logic of "this extinct animal ha...Also by this logic of "this extinct animal had the X characteristic, and modern animals that show X also show Y but not Z, so this extinct animal surely showed Y but not Z" is proven to be nonsense if we look at ceratopsians and hadrosaurs: modern animals that show beaks have no cheeks so this would mean that these groups were cheekless, but they also had teeth clearely made to chew food (hadrosaurs had many tiny teeth placed close to each other that would, together, act like molars and triceratops, for example, had thick and somewhat pointy molars, not sharp and thin teeth like those of iguanas) and the shape of the jaw close to the teeth is very similar to what we see in modern cattle, what would mean that they had cheeks. So we see that the ratiocination showed on those paragraphs would indicate that ceratopsians and hadrosaurs would have cheeks and be cheekless at the same time (what is obiously a complete nonsense).<br /><br />Also the fact that such lips would help to track scent while the animal hunted, because when the lips touched the ground they would bring scent with them and because the animal would be able to "taste" the smell, is nonsense because:<br /><br />1- Even dogs that do not show very long lips, like german shepherds, are very efficient in tracking scent;<br /><br />2- Dogs that show long lips like bloodhounds rarely open their mouths when tracking something unless they are tired and need to eliminate more heat trough the furless tissue of the mouth (also to keep the mouth open all the time like this would eliminate far more water than if it's mouth was lipless, or if it had small lips that only covered the gums, and closed, as only a small part of the upper jaw's gums would be exposed);<br /><br />3- For such lips to take the scent on the ground efficiently they would need to touch the ground, but T. rex was BIPEDAL and would lose balance far easier than quadrupeds. So it would certainly not touch the ground with it's mouth.<br /><br />And to end this: if T. rex had such long and hangy lips, they would caugh the attention of rivals during fights (as it would be a very soft and vulnerable part of the smout) and rivals would try to bite the lips off and we would gind clear tooth marks very close to the teeth and not only far from them, on the top pf the snouts.PaleoKnighthttps://www.blogger.com/profile/14759160960102177697noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-1777999586887774342016-05-29T13:31:19.785-07:002016-05-29T13:31:19.785-07:00WHAT? Seriously, these statements do not make sens...WHAT? Seriously, these statements do not make sense! Let's take a look: "There are some really mammalian things going on here" like foward facing eyes (let's forget about eagles, hawks and owls, for example), very proeminent nasal region (because vultures and kiwis find their food by using magic) and heterodont dentition (let's just forget that the teeth of a CROCODILE are longer and sharper when they are closer to the nostrils while those closer to the eyes are shorter and not as sharp as the front ones www.gettyimages.com/detail/pho…).<br /><br />Also your comparatuon makes no sense: "Furthermore when we look at terrestrial predators that share these same attributes of heterodont dentition, binocular vision, a dominant olfactory sensory apparatus - they don't have lizard lips, they have loose, draping, jowel like lips" because all of them are MAMMALS, not non avian theropods for f*ck's sake! Also as we can see on my previous paragraph: eagles have foward facing eyes, but no muscular lips; vultures and kiwis use their excellent sense of smell to find food, but have no muscular lips; and crocodiles are heterodont, but are completely lipless. If these characteristics, while isolated from each other, have nothing to do with muscular lips, together they will still to not have anything to do with muscular lips. Also if you look at the bone texture in tyrannosaurus the facial area is rough and has numerous foramina. Because there is so many foramina there is no room for soft tissue to attach to. In all animals with muscular lips the bone texture is smooth. That is because they have soft tissue (muscle) rubbing against the bone. In theropods, the bone texture is rough, there are no muscles rubbing against it, therefore they lacked muscular lips. PaleoKnighthttps://www.blogger.com/profile/14759160960102177697noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-42261355839748900522016-05-28T22:20:09.535-07:002016-05-28T22:20:09.535-07:00Also, T-Rex was closely related to birds and croco...Also, T-Rex was closely related to birds and crocodiles, not snakes, lizards, frogs, humans, bears, or dogs.Anonymoushttps://www.blogger.com/profile/13347340287346067084noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-40444218528826811012016-05-28T19:52:22.689-07:002016-05-28T19:52:22.689-07:00Ignore him guys, he's only trying to get a rea...Ignore him guys, he's only trying to get a reaction....Anonymoushttps://www.blogger.com/profile/13347340287346067084noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-886507936206727652016-05-24T08:58:29.437-07:002016-05-24T08:58:29.437-07:00Perhaps I wrote poorly, when I said that the beak ...Perhaps I wrote poorly, when I said that the beak is an extension of the underlying bone, I very much meant that it is more like lips than teeth. I'm not sure how to word this, but basically I was agreeing with you regarding beaks as not being a good example against lips because they are an unusual extension. As it were. Hence why I thought varanids might work better as an example.<br /><br />Beak evolution...perhaps you're right, but I think this might also be overcomplicating it. I just think that perhaps since they are heavy, teeth are reduced in size as flight becomes more important. To compensate, the lips/mouth edges become more heavily keratinized as a substitute. Things go on from there. In herbivores, tough plant material rubbing the edges of the mouth encourages keratinization here also, which then becomes rather helpful in clipping the plants. Mammals have highly flexible lips compared to these herbivorous dinosaurs so they don't have the same problem. This is just a random idea though.<br /><br />Varanids do hold onto struggling prey, even if it usually is smaller than themselves. Though I imagine the forces are usually rather low so moot point.<br /><br />Since theropods had breakable, replaceable teeth, would excess lateral forces be transferred to the teeth which are then just broken, hence reducing the need for lateral skull strength? Or is that totally wrong? Complete theory, I'm not exactly a physicist. Physics. Does this also help varanids and crocodilians when it comes to dealing with forces from struggling prey?<br /><br />Either way I think we can all agree that theropods would be taking something of a more tactical approach than just gouging their face into the nearest hide.<br /><br />To Anonymous:<br />I think some other lizards are also heterodont examples. Some varanids and tegus.<br /><br />Depends which ornithischians you're discussing. I'm fairly certain that hadrosaurs, with those complex tooth batteries, were doing significant chewing and needed cheeks of some sort (Duane used condors as an example before I think, looks good to me). But others have dentition more akin to that of Uromastyx, though arguably these lizards don't chew a great diet, just bite the food as they swallow it. Not really chewing like we do, for example.Zerox Z21https://www.blogger.com/profile/17869302742607157151noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-66329456021097736722016-05-24T08:52:02.526-07:002016-05-24T08:52:02.526-07:00@Pedro Bear fair enough on komodo dragon prey capt...@Pedro Bear fair enough on komodo dragon prey capture. I still maintain the vaguely incisor like dentition of tyrannosaurids would be aided by large lips that would "feel out" where the meat is on a bone, among other tactile uses that lizard lips simply don't provide to the same extent. A superior "environmental swab" that lizards simply don' need because their tongue does the trick of bringing sensory information into the oral region. Theropods would doubtless explore their world orally and an open and hanging "lip" region that exposes more surface area to sensory input is superior to the keratinized thin lizard lips that dominate our view.<br /><br />@anonymous please consider leaving a name next time. We obviously differ on the suite of characteristics arguments. For me I would discount aquatic predators (sharks and crocs) because water is a medium that transmits vibrations well and negates the need for lips and birds don't have heterodont dentition or dentition at all for that matter. Furthermore their keratinized beaks negate the need for "lip" like structures that are necessary to keep enamel rich teeth healthy in a salivary juice broth. Tusks and croc teeth are actually fairly low in enamel and not very mineralized.<br /><br />I happen to agree with ornithischians lacking cheek tissue having recently been swayed in this direction. Ironically the "rictal tissue" notion for what ornithischians had is exactly what I am implying for theropods. Take another look at my hellhound rex and you can see where I got the inspiration for that lip structure on the bottom jaw... people got a little caught up in the "mammal like lips" argument ( I never said that they were muscular) but instead are an extension of the rictal lining we see in birds today (albeit less keratinized). THey would do the same job that predatory mammal lips do but the exaptation is a little different.<br /><br />Anyways stay tuned for future posts on this topic...<br /><br />Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-78064921478591352802016-05-23T16:02:52.504-07:002016-05-23T16:02:52.504-07:00Amazing post, but I have to disagree with on the f...Amazing post, but I have to disagree with on the fact of mammalian lips. <br /><br />"Furthermore when we look at terrestrial predators that share these same attributes of heterodont dentition, binocular vision, a dominant olfactory sensory apparatus - they don't have lizard lips, they have loose, draping, jowel like lips."<br /><br />Just because something has all these qualities does not mean that it has big jangly lips. Crocodiles have heterodont teeth, Boomslang snakes, dromeosaurids, and modern raptors have binocular vision, turkey vultures, german shepherds, sharks, and albatross have a great sense of smell, but they all don't have jangly lips.<br /><br />"Too far outside the phylogenetic bracket" <br /><br />Although this correct to some extent, you do have to realize that squamates are closer to dinosaurs than mammals are right?<br /><br />http://66.media.tumblr.com/0fe30d921c8193e80dddb41681cdfaa5/tumblr_nubv5qBZ5c1ug05iuo1_500.png<br />http://blogs.scientificamerican.com/tetrapod-zoology/files/2012/07/amniote-cladogram-Tet-Zoo-July-2012-tiny.jpg<br /><br />As for ornithischian lips, as it turns out, they could have chewed perfectly well without lips. After all, lizards like Uromastyx do it and even if they had cheeks, they would not be mammalian cheeks, but rictal tissue.<br /><br />And to top it all off, neither birds nor crocs have cheeks and osteological correlates to of mammalian-like fleshy lips is not present in dinosaurs.<br />http://spinosaurus-the-fisher.tumblr.com/search/saurianhttp://<br />www.tandfonline.com/toc/ujvp20/17/sup003<br />http://www.tandfonline.com/toc/ujvp20/17/sup003#.V0OLfJMrJOw<br />http://www.tandfonline.com/toc/ujvp20/18/sup003<br /><br />Still a great post though (Totally agree with the neck boobs)<br /><br />P.S. You may not get the full abstract for the last 3 links, but I posted them anyway because you may be able to access them.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-3835777150647800662016-05-23T15:03:00.642-07:002016-05-23T15:03:00.642-07:00Duane, i have to disagree strongly with this sente...Duane, i have to disagree strongly with this sentence: "Because it is venomous it does not engage in prolonged skirmishes with large prey the komodo dragon is of limited utility in thinking about how the face and lips of a large terrestrial macropredatory animal handles bites."<br /><br />Komodo dragons will stay in prolonged skirmishes with struggling prey of similar size, at least thats what id say based on evidence:<br /><br />https://www.youtube.com/watch?v=JIv-ASfimX0<br /><br />https://www.youtube.com/watch?v=XPBiLXp5Uj8<br /><br />https://www.youtube.com/watch?v=nrg9hYjW8ts<br /><br />http://www.dailymail.co.uk/news/article-3513601/Incredible-moment-pair-massive-Komodo-dragons-catch-kill-unsuspecting-goat-Indonesia.html<br /><br />Also look at Bryan Fry's comments, which talks about how komodo dragons hunt and use venom:<br /><br />https://www.science.org.au/learning/general-audience/history/interviews-australian-scientists/associate-professor-bryan-fry#mythbuster<br /><br />"Komodo dragons naturally evolved to feed on 40 to 50-kilo prey animals like pigs and deer. When they feed on their natural sized prey, they kill 90 per cent of that prey in the first three or four hours. 75 per cent of the prey bleed out in the first 30 minutes and another 15 per cent continue bleeding and die within three or four hours."<br /><br />"The primary Komodo dragon weapon is actually the teeth. They have these very flat, large, double-serrated teeth. When they bite, they bite and they pull straight back, so they leave parallel deep cuts. It is like with a saw, each cut follows the other one and each notch goes a little deeper. It is the same thing with their teeth. It is basically grip and rip. The mechanical damage alone from the teeth wounds is enough to kill in some cases. For example, on Rinca, where we do a lot of our research, an eight-year-old boy was killed there a couple of years ago. He went and squatted in the bushes and a big dragon came up, got him and cut right here (indicates). The dragon sliced right through the boy’s femoral artery. That mechanical damage, the tissue damage, is enough to kill. The blood spurt was about two metres from his leg. But it was a little unclear whether he died from that or from when the dragon then grabbed him mid-body and smashed his head against a tree. That caved in his head and the dragon ran off with the body while being chased by the family."<br /><br />Sure, you can argue he talks about how prey can escape the initial attack and be weakened through blood loss after it, but based on the photos and videos i will argue that this isnt because the komodo dragon dont want to engage in a prolonged skirmishes, rather id argue the ideal situation for komodos is when prey dont run away, so that it can use its mouth and neck as a "can opener" of sorts.Duck of Doomhttps://www.blogger.com/profile/03242298622370195225noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-91254287657722537662016-05-23T11:21:07.644-07:002016-05-23T11:21:07.644-07:00I don't want to give too much away - as I am s...I don't want to give too much away - as I am saving it for a future post - but I would double check any assumptions implicit in, "because beaks are an extension of the bones and teeth of the jaws". Yes it is true that the bones of the skull in birds reflect the shape and usage of the beak. There is definite reasons for this. But to assume that the beak came about as a reflection of the underlying bony tissue might be getting it backwards. <br /><br />Something external to the skeletal system - a new way of feeding perhaps - incurred the changes that created a beak and then the underlying bony tissue was selected to optimize the mechanical workings of a beak. But some selective pressure had to have occurred that favored the evolution of beaks. And it did not happen just once in theropods but multiple times in flighted and non-flighted theropods. <br /><br />Regarding lizards and especially monitors. Here we have a rather limited and not too precise analogy in the komodo dragon. The rest of the clan hardly counts as top predators being generalist small game, scavenging, egg eating - hardly the type of prey that could do you in. Because it is venomous it does not engage in prolonged skirmishes with large prey the komodo dragon is of limited utility in thinking about how the face and lips of a large terrestrial macropredatory animal handles bites. Mammalian predators offer much more insight because they actually bite and hold onto struggling prey. And in all cases their lips envelope the bite area and act as sensory input device. This is of adaptive benefit because it allows better sensing of where to place the bite and also gives a warning to predator if the prey is going to tense up and retaliate/shake etc etc. This torsional load could be disastrous to mammalian predators as this puts their canines in jeopardy. For theropods lateral torsion could hurt their teeth however they can grow in more. More importantly for theropods their entire skull is weak in the lateral realm full of fossa and thin struts of bone. Large lips would provide an early warning to lateral torsion that could shake off the bite and club the theropod laterally causing sinuses, fossa, and struts of bone to collapse.<br /><br />The notion that theropods could simply walk up to and gouge out meter long swaths of flesh in fleeing, struggling herbivorous dinosaurs I don't take much stock in anymore. We are seeing more and more evidence that dinosaur skin was on a level of thickness in a class of its own. Literally an arms race of increasing thickness vs. increasing theropod biting ability.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-44137285840363860182016-05-23T09:57:37.295-07:002016-05-23T09:57:37.295-07:00I was rather caught up with the pictures, I'm ...I was rather caught up with the pictures, I'm afraid! I was definitely thinking of the bloodhound analogy more than wild mammals.<br /><br />My main point with beaks was that fleshy lips don't seem strictly necessary for sufficient tactile sensation with the jaws. I suppose this would apply to lizards handling food/prey also? Mainly thinking of varanids of course (which do also make the effort to maneuver prey in the jaws). For that matter they might be a better example because beaks are an extension of the bones and teeth of the jaws. I suppose this is what you're getting at?<br /><br />I absolutely know better about lizards using their tongue and am not sure why I said that, I definitely know varanids do it rather extensively. Do ALL lizards use their tongue for the majority of scenting? In species where scent really matters anyway. I know crocs are generally a poor example for this reason (I do wonder about the more terrestrial crocodilian species from the mesozoic era though, on a separate note), though crocs do often make their first strike and grab at prey above the waterline I suppose (relevant species of course)? Also mother crocs carefully handling nestlings on land must have good mouth sensitivity aside from the water based pressure pores to avoid harming them. And as for beaks, well, is there any chance that the simple flesh and skin around the mouth could be similarly innervated and tactile without being a hard bill?Zerox Z21https://www.blogger.com/profile/17869302742607157151noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-66964439169672532102016-05-23T00:49:10.807-07:002016-05-23T00:49:10.807-07:00Thanks for comment Fred:
"Birds with solid b...Thanks for comment Fred:<br /><br />"Birds with solid beaks seem to be able to sense things with their mouths perfectly adequately without extensive fleshy lips" What are beaks and why did they evolve? Why do some lineages of animals always grow beaks and other not? What tissue did the beak replace or better yet what was the precursor tissue of a beak?<br /><br />"I'd be curious as to why other animals have not evolved something similar" Other animals did evolve something similar they are called mammals. Don't get to caught up in the pictures they are mainly for shock and awe. Lippage on the order of wild canids, ursids, and hyaenas is quite adequate. <br /><br />BTW you and nearly everyone else seems to gloss over the rather obvious point I make several times. Lizards have a tight sealing mouth because their tongue flicks in and out to sense their environment. Theropods (like mammals, birds, crocs) have no such tongue so a more "open" oral region would work better as an environmental swab than a closed one. Birds beaks are actually highly innervated and very tactile (what did a bird beak evolve from?....) crocs live and hunt in a liquid medium where their pressure pores sense changes in the watery medium they live in so no need for lips. Mammalian carnivorans need adequate lips to protect their enameled teeth as well as using their lip regions for tactile sensing of prey. Theropods likewise. Lizards simply do not provide an adaptive model for theropods.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-30634341516252795542016-05-22T06:43:43.346-07:002016-05-22T06:43:43.346-07:00Many mammals seem to have a vomeronasal organ and ...Many mammals seem to have a vomeronasal organ and this also seems to be true for bears. They share an ancestry with dogs which have confirmed organs. It doesn't seem well studied but I found some investigation by a Benjamin Kilham into it so it does seem like they do to some degree at least, which would explain scenting the air with an open mouth. So not sure this translates well to Tyrannosaurus.<br /><br />As for the particularly extensive lips and jowls...if you think it plausible that Tyrannosaurus has them for the sensory reasons you discuss, I'd be curious as to why other animals have not evolved something similar. Birds with solid beaks seem to be able to sense things with their mouths perfectly adequately without extensive fleshy lips, and the same holds true for crocodilians (no lips at all but need to deftly handle large prey) and lizards (the usual style lips we see for theropods). If large jowly lips make so much sense, why do other animals not seem to have them? Even mammals don't, certainly no wild mammal does to the extent the man-made breeds such as bloodhounds do. I think an investigation into all the downsides would be interesting. I suspect there must be plenty, as otherwise sure we would see such structures in wild animals also.Zerox Z21https://www.blogger.com/profile/17869302742607157151noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-35539776816538050532016-05-21T13:48:21.196-07:002016-05-21T13:48:21.196-07:00Duly noted Robert Haan.Duly noted Robert Haan.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-58875887480000592332016-05-20T18:13:06.081-07:002016-05-20T18:13:06.081-07:00Well...... they do say its more of lizard lips but...Well...... they do say its more of lizard lips but its still something i guess ?RobertHaannoreply@blogger.com