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Post by tomhet on Jan 29, 2008 3:55:16 GMT
Old reproductions of mosasaurids used to have some kind of crests, even the Carnegie Mosasaurus has them, where did the artists get the idea from? Is it invalid now?  |
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Post by piltdown on Jan 29, 2008 9:45:42 GMT
Mosasaurs were depicted with frills because of an erroneous description in 1899 of some throat bones of Platecarpus, which were misinterpreted as a fringe along the top of the neck. The writer corrected his mistake, but the paleoartists ignored him and continued portraying mosasaurs with crests. Of course they may have had some sort of soft-tissue ornamentation, but none has been preserved. As for the Carnegie mosasaurus, well, so much for the notion of the accuracy of 'museum quality' figures approved in consultations with experts ;D
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Post by nobs on Jan 29, 2008 17:55:32 GMT
I always did love those lil crests on the top!
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Post by tomhet on Jan 30, 2008 18:10:33 GMT
Mosasaurs were depicted with frills because of an erroneous description in 1899 of some throat bones of Platecarpus, which were misinterpreted as a fringe along the top of the neck. The writer corrected his mistake, but the paleoartists ignored him and continued portraying mosasaurs with crests. I can't believe it, there are books written 60 years later that still reproduce the same mistake  |
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Post by Dinotoyforum on Jan 30, 2008 18:32:40 GMT
Mosasaurs were depicted with frills because of an erroneous description in 1899 of some throat bones of Platecarpus, which were misinterpreted as a fringe along the top of the neck. The writer corrected his mistake, but the paleoartists ignored him and continued portraying mosasaurs with crests. I can't believe it, there are books written 60 years later that still reproduce the same mistake Such is the power of pop culture... Of course, there are also books written 60 years later that do not reproduce the error too. |
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Post by Dinotoyforum on Apr 19, 2008 10:07:15 GMT
 The specimen in question. The 'throat bones' Pitdown alluded to are actually cartilaginous tracheal rings, seen here at the bottom of the picture. |
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brad
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Post by brad on May 10, 2008 15:37:44 GMT
Another issue that comes up with restoring mosasaurs is whether or not to give them forked tongues, like their living relatives monitors and snakes. I was disappointed when the recent National Geographic IMAX film restored them with unforked tongues. Is there any hard evidence on the matter, or just implications from phylogeny?
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Post by Dinotoyforum on May 10, 2008 15:42:27 GMT
Implications from phylogeny. Discussed in detail in:
Schulp, A.S., Mulder, E.W.A. and Schwenk, K. 2005. Did mosasaurs have forked tongues? Netherlands Journal of Geosciences / Geologie en Mijnbouw, 84(3), p. 359-372.
They did have forked tongues. And we all know the purpose of forked tongues right?
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Post by crazycrowman on May 13, 2008 4:21:35 GMT
"They did have forked tongues. And we all know the purpose of forked tongues right?" To look really bad@ss as collectable figures, right ? No, I know better :-) Just like thier modern day relatives, like Jakarta the water monitor here, to make sure that they don't miss anything smelly, good, or bad, and allowing them to make particularly good use of thier jacobson's organ to do so.  |
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Post by crazycrowman on May 13, 2008 8:06:23 GMT
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Post by sbell on May 13, 2008 12:49:46 GMT
"They did have forked tongues. And we all know the purpose of forked tongues right?" No, I know better :-) Just like thier modern day relatives, like Jakarta the water monitor here, to make sure that they don't miss anything smelly, good, or bad, and allowing them to make particularly good use of thier jacobson's organ to do so. But would a forked tongue actually work underwater? It seems that a tongue would be a fairly inefficient way to 'taste' underwater, since it is based on being moistened (in the mouth) then contacted by the smell particles. If everything is always wet, would it still work? And if so, why aren't there any tongue-based tasters in the oceans now? Further, how efficient would it be to swim along swiftly, then stick a tongue? Unless they stopped moving, the force of a wall of water against tongue tip--particularly a thinner tongue tip of the forked variety--would probably just get pushed back against the mosasaurs' nose, which probably wouldn't be that helpful. Plus, forked tongues work by not only moving in and out, but by waving around in order to get better directionality. Or is this thought to be more of a holdover/plesiomorphic trait that mosasaurs would have had because of their ancestry? On another topic, in the same vein, I read somewhere a while ago that researchers discovered that most lizards, in particular monitors and iguanas, actually are venomous, we just couldn't tell because it is eother weak venom or we blamed bacteria for the effects from bites www.newscientist.com/article.ns?id=dn8331which are supposed to be close relatives of mosasaurs. I believe that is also true of more snakes than we previously realized. Therefore, is it safe to extrapolate that mosasaurs, because of a close relationship with monitors and snakes, may also have had saliva that contained venom? |
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Post by Dinotoyforum on May 13, 2008 16:39:43 GMT
"They did have forked tongues. And we all know the purpose of forked tongues right?" No, I know better :-) Just like thier modern day relatives, like Jakarta the water monitor here, to make sure that they don't miss anything smelly, good, or bad, and allowing them to make particularly good use of thier jacobson's organ to do so. But would a forked tongue actually work underwater? It seems that a tongue would be a fairly inefficient way to 'taste' underwater, since it is based on being moistened (in the mouth) then contacted by the smell particles. If everything is always wet, would it still work? And if so, why aren't there any tongue-based tasters in the oceans now? Further, how efficient would it be to swim along swiftly, then stick a tongue? Unless they stopped moving, the force of a wall of water against tongue tip--particularly a thinner tongue tip of the forked variety--would probably just get pushed back against the mosasaurs' nose, which probably wouldn't be that helpful. Plus, forked tongues work by not only moving in and out, but by waving around in order to get better directionality. Or is this thought to be more of a holdover/plesiomorphic trait that mosasaurs would have had because of their ancestry? On another topic, in the same vein, I read somewhere a while ago that researchers discovered that most lizards, in particular monitors and iguanas, actually are venomous, we just couldn't tell because it is eother weak venom or we blamed bacteria for the effects from bites www.newscientist.com/article.ns?id=dn8331which are supposed to be close relatives of mosasaurs. I believe that is also true of more snakes than we previously realized. Therefore, is it safe to extrapolate that mosasaurs, because of a close relationship with monitors and snakes, may also have had saliva that contained venom? Interesting thoughts. I'll have to puzzle over these for a while. May I copy your post for a marine reptile forum I'm a member of? - I'll get some mosasaur experts on the case. |
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brad
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Post by brad on May 13, 2008 16:39:50 GMT
But would a forked tongue actually work underwater? It seems that a tongue would be a fairly inefficient way to 'taste' underwater, since it is based on being moistened (in the mouth) then contacted by the smell particles. If everything is always wet, would it still work? And if so, why aren't there any tongue-based tasters in the oceans now? Further, how efficient would it be to swim along swiftly, then stick a tongue? Unless they stopped moving, the force of a wall of water against tongue tip--particularly a thinner tongue tip of the forked variety--would probably just get pushed back against the mosasaurs' nose, which probably wouldn't be that helpful. Plus, forked tongues work by not only moving in and out, but by waving around in order to get better directionality. There are living marine reptiles with forked tongues. Wikipedia's article on sea snakes says: " As it is easier for a snake's tongue to fulfill its olfactory function under water, its action is short compared to that of terrestrial snake species. Only the forked tips protrude from the mouth through a divided notch in the middle of the rostral scale." |
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Post by Dinotoyforum on May 13, 2008 16:41:58 GMT
divided notch huh? I wonder if Mosasaurs have such a structure on their rostrum...
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Post by sbell on May 13, 2008 17:32:35 GMT
But would a forked tongue actually work underwater? It seems that a tongue would be a fairly inefficient way to 'taste' underwater, since it is based on being moistened (in the mouth) then contacted by the smell particles. If everything is always wet, would it still work? And if so, why aren't there any tongue-based tasters in the oceans now? Further, how efficient would it be to swim along swiftly, then stick a tongue? Unless they stopped moving, the force of a wall of water against tongue tip--particularly a thinner tongue tip of the forked variety--would probably just get pushed back against the mosasaurs' nose, which probably wouldn't be that helpful. Plus, forked tongues work by not only moving in and out, but by waving around in order to get better directionality. Or is this thought to be more of a holdover/plesiomorphic trait that mosasaurs would have had because of their ancestry? On another topic, in the same vein, I read somewhere a while ago that researchers discovered that most lizards, in particular monitors and iguanas, actually are venomous, we just couldn't tell because it is eother weak venom or we blamed bacteria for the effects from bites www.newscientist.com/article.ns?id=dn8331which are supposed to be close relatives of mosasaurs. I believe that is also true of more snakes than we previously realized. Therefore, is it safe to extrapolate that mosasaurs, because of a close relationship with monitors and snakes, may also have had saliva that contained venom? Interesting thoughts. I'll have to puzzle over these for a while. May I copy your post for a marine reptile forum I'm a member of? - I'll get some mosasaur experts on the case. Sure, I would be interested to know the opinions of others on this--the idea has kind of bounced around in the back of my head since first hearing about the venom thing. |
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Post by sbell on May 13, 2008 17:47:05 GMT
But would a forked tongue actually work underwater? It seems that a tongue would be a fairly inefficient way to 'taste' underwater, since it is based on being moistened (in the mouth) then contacted by the smell particles. If everything is always wet, would it still work? And if so, why aren't there any tongue-based tasters in the oceans now? Further, how efficient would it be to swim along swiftly, then stick a tongue? Unless they stopped moving, the force of a wall of water against tongue tip--particularly a thinner tongue tip of the forked variety--would probably just get pushed back against the mosasaurs' nose, which probably wouldn't be that helpful. Plus, forked tongues work by not only moving in and out, but by waving around in order to get better directionality. There are living marine reptiles with forked tongues. Wikipedia's article on sea snakes says: " As it is easier for a snake's tongue to fulfill its olfactory function under water, its action is short compared to that of terrestrial snake species. Only the forked tips protrude from the mouth through a divided notch in the middle of the rostral scale." Okay, I was just thinking it out there. The use of a tongue also relates to how the animal moves--sea snakes, from what I've seen and read, tend to poke around in holes and crevices when hunting; sticking a tongue out when near a hole would be practical and safer (as opposed to sticking a whole head in)--I am arguing that a mosasaur was probably a pursuit hunter, which would have swam in more open environments--sticking out a tongue, even a short portion, does not seem like an efficient technique--it would be easier to have water flow directly past the Jacobson's Organ, and guide the animal that way (as sharks and many fish do). But they may still have had the forked tongue, if nothing else, than as a vestige of ancestry. |
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Post by crazycrowman on May 13, 2008 23:00:28 GMT
"But would a forked tongue actually work underwater? It seems that a tongue would be a fairly inefficient way to 'taste' underwater, since it is based on being moistened (in the mouth) then contacted by the smell particles. If everything is always wet, would it still work? And if so, why aren't there any tongue-based tasters in the oceans now? Further, how efficient would it be to swim along swiftly, then stick a tongue? Unless they stopped moving, the force of a wall of water against tongue tip--particularly a thinner tongue tip of the forked variety--would probably just get pushed back against the mosasaurs' nose, which probably wouldn't be that helpful. Plus, forked tongues work by not only moving in and out, but by waving around in order to get better directionality. " They are not called water monitors because they live in deserts :-) Many monitors, specifically Varanus salvator and V. dumerili are well documented for this. As is the Mertens Water Monitor. Those species are excellent swimmers and many hunt out at sea, or in other open water reguarly.  Monitor tongues work fine in the water. They are not flaccid weak structures either, and can be directed one way or the other quite efficently. The article suggest that the slightly forked tongue of the helodermas would have been more similar to that of the mosasaurids. forked tongue would have been helpfull for follwing prey, hunting hidden prey, under the sand at the sea floor or amidst rocks/vegitation, or for hunting prey above the water, say, birds or pterosaurs. "it would be easier to have water flow directly past the Jacobson's Organ, and guide the animal that way (as sharks and many fish do" Except for the fact that sharks and fish, are...well...Fish. Fish, due to the way that they breathe can open thier mouths and let water continuiously flow through, and over the associated structures. Monitors, being a reptile can not do that. That does bring us to an interesting question though....I wonder, did mosasaurids have a palatal valve like crocodilians, allowing them to open thier mouths underwater and keep them that way to hunt, while not drowing ? (Sea reptile experts, do you know this one ?) As for the venom, much like the feather issue in dinosaurs, it would/could depend on where the venomous ancestor of snakes and the other living lizards who are venomous evolved and split off. |
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Post by sbell on May 14, 2008 5:13:50 GMT
I guess the main gist of my disagreement stems from the assumption that, unlike sea snakes, monitor lizards, or marine iguanas (or sea turtles, or various crocodiles...I think that covers the living large marine reptiles) the mosasaurs were obligated swimmers, were probably higher speed, cruising and pursuit oriented pelagic animals--there are no modern reptilian analogues anymore. Particularly in the later forms (I'm sure there were transitions) I highly doubt that mosasaurs could even come onto shore to breed, they would have simply been too heavy and awkward.
Stemming from those assumptions, I am simply stating my doubts that a tongue would be the best sensory equipment for a higher speed, cruising, pursuit hunting, fully aquatic animal. I am not saying that their tongues were not forked; I am simply stating that it is likely that evolution would have directed mosasaurs to a more conservative form that would direct senses in other ways--sound (including sonar) and sight tend to be popular for pelagic cruisers (whales, dolphins, seals, most large bony fish), but nostril-based smells also work (particularly in sharks) although sound/vibration is also very important. Alternatively, the forking of the tongues, if it persisted, may be vestigial.
And I realize that fish & sharks (not the same!) are differently adapted for life in the water, the point I wished to make (made very badly--I lost my train of thought) is that (as far as I am aware) external olfactory organs are not seen in the aforementioned high speed pursuit and cruising animals, only in ambulatory swimmers (e.g. polypterids) or reef and bottom dwellers (e.g. moray eels). In these instances, the nostrils function like the sea snake tongue--the animal can get closer to a potential location of prey without actually putting the head completely in harm's way. And I refuse to believe that mosasaurs, particularly the largest among them, spent their time rooting about in reefs and mounts.
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Post by crazycrowman on May 14, 2008 22:57:23 GMT
"the mosasaurs were obligated swimmers, were probably higher speed, cruising and pursuit oriented pelagic animals--there are no modern reptilian analogues anymore" While several species of sea turtles are cruising and pursuit oriented pelagic animals, (I am thinking Leatherback, specifically) and indopacific crocodiles to a degree, though they can go on land with no trouble, neither are close relatives, so there are no directly close modern analogues, true. I am very aware that sharks and fish are not the same, what is the same, and what I was making the likeness for was that neither of those animals are "air breathers". "I am simply stating my doubts that a tongue would be the best sensory equipment for a higher speed, cruising, pursuit hunting, fully aquatic animal." That could be true. They could have had vestigial tongues, or they could have had a well developed and stronger, possibly reinforced tongues that allowed them to use it as their modern relatives do, to test, and then pursue. Monitors often run down prey. They get a bead on where it is, sniff, sniff, RUN (or swim, as its fascinating to feed them fish in a pool in captivity) and strike. One of the few modern reptiles that hunt this way. I guess what I am saying it a reinforced tongue probably does not take any more "evolutionary imagination" for reconstructions as something as mammalian as "sonar" in a reptilian animal. I personally think it more likely that the tongue would be used, simply because it is in all modern mosasaur relations.  Maybe like modern crocs they had electro-sensory type pits ? I know crocodilians can hunt in complete darkness by using those pits to detect movement/changes in the water, much like a lateral line. (the ones in the image are on an alligators snout)  Many modern snakes have heat detecting pits, and they are present in all of the "primitive" boas and pythons...... Then again, mosasaurs could have just had very good vision ;D Hearing we could probably get some who is more familiar with mosasaur anatomy/biology to let us know....what was their auditory ossicle/quadrate bone like, and what animal today is it most like ? I really am not well versed in extinct marine reptiles. I believe that I read in the past that it was most like that of modern monitor lizards, but, I could be wrong there. "And I refuse to believe that mosasaurs, particularly the largest among them, spent their time rooting about in reefs and mounts." I am inclined to agree there, though, the use of a monitor/helodermid/serpentine tongue structure would also be of use in an active predator. |
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Post by crazycrowman on May 17, 2008 4:35:53 GMT
Just a couple of photos I found interesting.  Water monitor skull.  Platycarpus Skull.  "Prognathodon" |
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