tag:blogger.com,1999:blog-8161161431451849208.post3024644286032453452..comments2024-03-18T02:43:22.233-07:00Comments on Antediluvian Salad: Sinking Ornithoscelidians: Sitting Ducks, Water Chevrotains & Ceratopsid Death BedsDuane Nashhttp://www.blogger.com/profile/14467779935085970909noreply@blogger.comBlogger34125tag:blogger.com,1999:blog-8161161431451849208.post-35370942070078711702017-05-17T13:20:37.584-07:002017-05-17T13:20:37.584-07:00Umm…. wut? I think you misread me, I did not call ...Umm…. wut? I think you misread me, I did not call Coelophysis aquatic I merely depicted it opportunistically diving after a dicynodont carcass at the bottom of a flooded pool. More to the point I wanted to depict how the buoyant nature of such theropods would make diving somewhat laborious - they would probably pop right back to the surface. Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-62661215745924021922017-05-11T14:54:36.677-07:002017-05-11T14:54:36.677-07:00I was just recovering from the shock of an aquatic...I was just recovering from the shock of an aquatic Liaoningosaurus and then here you come along and shock me with more nonsense about aquatic Coelophysis! Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-30768968170954198702017-04-19T10:13:11.158-07:002017-04-19T10:13:11.158-07:00Worth noting is that downy feathers are only known...Worth noting is that downy feathers are only known from Coelusauria. Downy feathers vastly improve thermoregulation, especially when you compare it to more basal feathers. Maybe the reason why Coelurosaurs aren't predominantly scaly is because down feathers (combined with the out layer) is as beneficial if not more so than SIGILs. Hence the general loss of SIGIL, yet is a mainstay in the rest of Dinosauria (and is a constant in many lineages).Iris-Katyayanihttps://www.blogger.com/profile/06188961246186305190noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-20476277110326681442017-04-19T06:58:27.331-07:002017-04-19T06:58:27.331-07:00No post as of yet in those regards I pretty much p...No post as of yet in those regards I pretty much put all that stuff into the SIGIL post. I know it is not en vogue but I don't think feathers were ancestral to dinosaurs but more of a croc-like dermal pedigree. Other stuff then got added on top.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-59367853512586717012017-04-19T03:51:43.126-07:002017-04-19T03:51:43.126-07:00Oh I know it's completely speculative once you...Oh I know it's completely speculative once you use hypotheses to back up your own hypotheses. I just typed down what flowed in my mind. Will you expand on this odd way of thermoregulation in another post?<br /><br />Also, I've had the same question bugging me for YEARS now. Why is it that everything that is a Theropod, basal Ornithischian (looking at you Tianyulong) or a basal Neornithischia (Kulindadaromeus) is uber fluffy, but everything else is scaly even in the exact same conditions? I have assumed in recent years that feathers were a basal trait and that various lineages implored some other forms of integument as time went on for various reasons. If SIGIL is true then feathers and SIGIL are more or less basal to Dinosauria, but because they are BOTH ancestral then different lineages had more options on how to tackle thermoregulation and even defense in the form of quills, armor, etc. Maybe feathers weren't necessarily better than SIGIL and vise versa. Maybe the use of either depended on other factors not necessarily for thermoregulation. Like how SIGILs would be better for armor/defense from predators. Or how shaggy feathers might be better for a predator that is trying to break up its body outline while hiding/stalking prey. Who knows for now. All I know is that something weird was going on with Dinosaurian integument, and all this means is that there are WAAAAY more ideas and hypotheses that can be played around with in paleoart. I used to be the feather nazi in recent years, but now I'm really liking the idea of even some Theropod lineages being primarily or almost completely scaly. Still not as speculative as an uber feathered Sauropod (nothing to say against basal Sauropodomorphs though), but either scenario is still plausible.Iris-Katyayanihttps://www.blogger.com/profile/06188961246186305190noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-40594687574992810882017-04-18T10:01:03.128-07:002017-04-18T10:01:03.128-07:00@Khalil Indeed I've often pondered that scenar...@Khalil Indeed I've often pondered that scenario. Respectable scientists, however, would be aghast at piling on multiple speculative hypotheses on top of one another like that. SIGIL plus negative buoyancy, plus rear fermenting compost heat, plus aquatic ankylosaurs, plus fleeing volcanoes into the water. Not saying you are totally wrong but just don't expect the vast majority to go with you (or me) into those realms, Too tenuous.<br /><br />My thoughts drift in the same direction and it is indeed peculiar that if there is anywhere we should find fully feathered ankylosaurs and ceratopsians it is Liaoning. The mere fact that we have reportedly hundreds of specimens for these guys from these deposits, beautifully preserved, and they don't have coats of insulating filaments while the theropods from the same environment and of about the same size DO have preserved insulatory coats should give us moment to pause? What were these ornithischians doing differently? I do suspect it is a combination of SIGIL, countercurrent heat exchange, and rear-fermenting heat production.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-78305903610098226942017-04-18T07:31:28.534-07:002017-04-18T07:31:28.534-07:00This is Khalil. I'm at school so I can't l...This is Khalil. I'm at school so I can't log into my account.<br /><br />On the matter of thick skinned Psittacosaurus, could the thick skinned also serve a thermoregulatory purpose? I imagine a thick hide could keep in heat during the winter months and cold rains of Liaoning. It would also explain why Psittacosaurus isn't fuzzy like it's ancestors and relatives. Maybe for the need to grow a thick dermis for defense (and possibly for aquatic capability like you have suggested), feathers were opted out for a thick dermis for retaining heat and SIGIL's for better regulation/physical defense. Combining the rear gut fermenting within the body cavity creating heat, Psittacosaurus might have been rather comfy in it's own (fat) skin even in the winter. The only feathers remaining on an adult Psittacosaurus might have been the defensive bristles on the tail. <br /><br />Speaking of Liaoning, remember that baby specimen of Liaoningosaurus that was preserved in what was once a riverine or lacustrine? It's presence there could have easily been accidental, but with the likely habit of escaping danger by lunging to the bottom of the water, it raises questions about if it's placement was accidental. Speculation of course but it makes sense knowing their anatomy/biology. From what we know about Cretaceous Liaoning, volcanic activity was a major cause for fossilization, so maybe the young Thyreophoran lunged into the water, scared from the loud blasts of the volcano, the resulting forest fires, etc. The fish in it's guts probably have nothing to do with this of course ;)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-8339110786006016212017-04-17T12:07:54.683-07:002017-04-17T12:07:54.683-07:00Hi Magpie thanks for reading and comments.
On moo...Hi Magpie thanks for reading and comments.<br /><br />On moose & underwater grazing evidence: No evidence that I know of. Got me thinking about what would count as evidence - gut contents maybe but most underwater plants are, generally speaking. a lot less fibrous than terrestrial ones so might not preserve too well… <br /><br />On hadrosaurs: for now I would count them as likely to float with at least their head above water. They do have thick skin but lack all that other gear - especially the heavy head gear - of ankylosaurids and ceratopsids. Their heavy and thick caudal musculature and tail would probably slightly tip the anterior of the body towards the surface in water getting the nose or mouth topside, unlike the case in ceratopsids where the only study on their buoyancy (which again is good except for omission of the skin as another source of density) dips the head downwards in the water. Quite a cumbersome design for an animal that - on the low lying coastal floadplains of eastern Laramidia - would encounter bodies of water daily.<br /><br />Footprints of punting dinosaurs might be another line of evidence to look for - maybe showing a gliding phase as hippos display underwater in underwater punting - as well as buoyancy studies that infer a level of skin density on par with what<br />psittacosaurus shows.<br /><br />It is also interesting to think that not too long ago there was a wider diversity of large, thick-skinned, and sometimes armored mammals - giant sloths, glyptodonts, various rhinos, toxodonts - some of these guys may have been underwater punters too, but not necessarily aquatic by habit. <br /><br />Best, duane Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-3929021892520361492017-04-17T08:07:28.960-07:002017-04-17T08:07:28.960-07:00Ah, now that I've actually read this post, I h...Ah, now that I've <i>actually read</i> this post, I have to say I agree with you. Bottom punting does seem like a likely conclusion, especially considering all that gear. Also, I like the emphasis on skin--it is not just a covering, it's one of our most vital organs, and it dictates how we live. <br /><br />Now that we're here, though, I do have some questions. First of all, I got to thinking about moose, which spend some time underwater grazing. Do we have any evidence for such a dinosaur? Second, you only briefly mentioned hadrosaurs (and their de facto skinlessness, for the most part.) To clarify: are you suggesting that they <i>were</i> able to keep their heads above water?<br /><br />Thanks for another great read.magpienoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-70623329780853118622017-04-17T01:22:24.537-07:002017-04-17T01:22:24.537-07:00Perhaps you could mention armadillos as an analogu...Perhaps you could mention armadillos as an analogue? They're dry-to-desert IIRC and they don't eat aquatic matter but their punting is pretty famous.Anonymoushttps://www.blogger.com/profile/06537056479288460350noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-84555456257697954872017-04-16T23:31:25.780-07:002017-04-16T23:31:25.780-07:00Like I said , He's often overlooked . :pLike I said , He's often overlooked . :p<br />Robert Haannoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-35683793816668109972017-04-16T19:43:30.192-07:002017-04-16T19:43:30.192-07:00Thanks Robert. Again, as I mentioned several times...Thanks Robert. Again, as I mentioned several times above, I am not making the argument that ceratopsians or ankylosaurs were especially aquatic merely that bottom punting may be in fact be how these animals moved in the water. I am not totally against it either but that was not my intended argument (though some it seems have taken it this way). Actually first I have heard of Anchiceratops, thanks for reading.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-43681859245374993742017-04-16T11:54:32.610-07:002017-04-16T11:54:32.610-07:00Great post Duane ! Some interesting points made, i...Great post Duane ! Some interesting points made, it should be noted that a case has been made for the much overlooked ceratopsian Anchiceratops as being a somewhat well adapted to a semi aquatic lifestyle.Robert Haannoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-57435862674193921682017-04-15T01:50:12.008-07:002017-04-15T01:50:12.008-07:00nothing in particular planned in those regards.nothing in particular planned in those regards.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-1604628751360529522017-04-14T15:55:48.923-07:002017-04-14T15:55:48.923-07:00Yeah I didn't mean to skew your words. I clear...Yeah I didn't mean to skew your words. I clearly see the meaning in your words. And yes I was worrying people were gonna misquote you. I see it often with your work and with the works of many others and especially the major news. I remember when people kept saying that you said that Dinosaurs had mammalian lips or bulldog lips in the unironic sense. Even I said bulldog lips but simply as a metaphor in personal conversation. But hey, that's human behavior to sum up information, even when it gets too simplified.<br /><br />Do you plan on any posts about possible semi-aquatic candidates? As others have said Lurdusaurus is obvious, but I'm betting some Ankylosaurs with their small, delicate teeth could have at least sometimes foraged and grazed in water.Iris-Katyayanihttps://www.blogger.com/profile/06188961246186305190noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-88880337681393715602017-04-14T15:39:07.446-07:002017-04-14T15:39:07.446-07:00Thanks Khalil. I didn't want to get into what ...Thanks Khalil. I didn't want to get into what species may or may not have been semi-aquatic - I didn't want that controversy today. Some people are already misinterpreting my thoughts as suggesting "all ornithischians were semi-aquatic" which is not what this about.<br /><br />"ankylosaurs and some ceratopsians were semi-aquatic similar to hippos" Possible, but again that is not what I am claiming or even suggesting in this piece but I fear…. ughhh I can already see the trouble I got into a bit and how people are going to misquote and paraphrase this piece… "Duane Nash said ceratopsians and ankylosaurs were like dinosaur hippos" No, mainly terrestrial and possibly moved through the water like a hippo as a consequence of heavy and thick armor & skin that was evolved for terrestrial protection.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-58953569391058180732017-04-14T12:06:53.113-07:002017-04-14T12:06:53.113-07:00Great post Duane. I've been wondering for year...Great post Duane. I've been wondering for years why Ornithischians lack the beneficial air sacs found in the rest of Dinosauria. I hadn't really heard any good hypothesis why they lost them either, but this makes perfect sense and is honestly very likely. So various small to medium sized Ornithopods were very similar to modern Waterbuck, Kob, Chevoratain, Tapir, Capybara, etc. I wouldn't be surprised if some Ankylosaurs and some Ceratopsians were semi-aquatic similar to Hippos. At the least I could easily see them often sleeping and resting in water.Iris-Katyayanihttps://www.blogger.com/profile/06188961246186305190noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-48047863809659371682017-04-13T17:21:56.260-07:002017-04-13T17:21:56.260-07:00Guys you should read what I say more carefully.
A...Guys you should read what I say more carefully.<br /><br />After the first paragraph I write "It is a contention of mine and this piece that just because an animal is not explicitly aquatic does not negate the potential for water to still shape and inform significant aspects of its biology and anatomy."<br /><br />@Robert Gay Points taken regarding taphonomy and nowhere was I implying that ornithischians that might bottom punt or sit low in the water necessarily lived in rivers, bodies of water full time etc etc. Likewise small antelope, deer, chevrotains that hide in water are not necessarily aquatic but in fact spend most of their time foraging and living on land. Water is just a medium to hide in just as burrows and dense foliage are as well. As prey species I am arguing that these earliest ornithischians would dispense with air sacs in order to not buoy up to the surface in water and be such an easy target. Hence air sacs are lost and all subsequent ornthischians inherit a reduced or nonexistent air sac system because of the cryptic adaptations of the early small ornithischians.<br /><br />"Just because you have ceratopsids preserved in a river channel doesn't mean they were living in a river."<br /><br />I'm trying to figure where you got that impression that I was suggesting that from this piece. I really want to know because you are not the first to misinterpret what I was saying. Was it the picture I made of the bottom running centrosaurs? With regards to ceratopsians and ankylosaurs having a hippo-like negative buoyancy in the water I mentioned that this was potentially a byproduct of a thick hide evolved under a regime of saw toothed predators and combative conspecifics. The hippo like water movement I am suggesting is a byproduct of terrestrial adaptations. <br /><br />@Robert Gay The reason I omitted mention of Lurdusaurus (which is quite probably an aquatic animal) is that this post is specifically about terrestrial prey animals that >sometimes< hide or move through water, hence the water chevrotain emphasis. And how picturing early ornithischians as roughly equivalent to small ungulates, chevrotains, and large rodents that routinely forage on land but seek refuge in water might serve as a useful hypothesis for why air sacs were lost. You can't really hide in the water if all those air sacs are floating you above the surface of the water. Lurdusaurus may well be past the point of being a mainly terrestrial animal that sometimes seeks shelter in water. It could have been primarily aquatic both in foraging and habit.<br /><br />Ot let me simplify things:<br /><br />1) Early ornithischians are small cryptic animals. They hide in thick foliage, burrows, and in water. The evolutionary pressure to sit low in the water necessitates loss of extensive air sac system i.e. so that they don't float like a duck.<br /><br />2) Subsequent ornithischians inherit the reduced air sac system - regardless of how often they use water to hide in.<br /><br />3) Some ornithischians (marginocephalians & thyreophorans) increase in skeletal and integumentary density. Potentially they no longer just sit low in the water, but sink right down and are negatively buoyant. Their movement in the water would thus resemble tapir, hippos and other thick skinned mammals that bottom punt. However this method of movement in no way is indicative of a reliance on the water or that it is their preferred habitat. It is merely a byproduct of their anatomy and offers the best way to move through it as they can no longer swim.<br /><br />4) If these animals are in fact negatively buoyant it can offer an explanation for the repeated documentation of ankylosaurs in marine sediments (they got swept away into deep water where they could not reach the surface) and mass ceratopsian death beds due to oceanic intrusions. The got in water that was too deep and drowned.<br /><br />5) Also potential biogeographic implications i.e. ceratopsids not able to colonize eastern North America until the western interior sea withdrew.<br /><br />I hope that clarifies.<br />Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-84744479452722457622017-04-13T16:13:20.842-07:002017-04-13T16:13:20.842-07:00@RobertGay: The notion of semiaquatic ankylosaurs ...@RobertGay: The notion of semiaquatic ankylosaurs in particular is poorly founded; although they could certainly swim, it's impossible to say if any were hippo-like in their nautical habits. The supposed evidence for aquatics and carnivore in hatchling Liaoningosaurus, for example, is extremely sketchy. An equally likely taphonomic scenario is that the baby ankylosaur's corpse simply sat upon an already dead fish on the Yixian lakebed.<br /><br />Interestingly, Duane doesn't mention the iguanodont Lurdusaurus, which IS very hippo-like in general proportions. I can't remember the exact study, but it was demonstrated that the lurdusaur's bone density was much higher than other dinosaurs and equivalent to modern marine mammals, suggesting it may have had a hard time supporting itself on land.Jason Silviriahttps://www.blogger.com/profile/11086785734795609818noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-24698010570142041592017-04-13T14:34:43.083-07:002017-04-13T14:34:43.083-07:00Just because you have ceratopsids preserved in a r...Just because you have ceratopsids preserved in a river channel doesn't mean they were living in a river. The preservational environment is not the same as the environment of death or even the animal's preferred environment. In fact there's naturally going to be a bias towards water-based deposits in terrestrial environments because you don't have much else making rocks. Here in Western Colorado we've got a whole articulated <i>Camarasaurus</i> skeleton preserved on display in a river channel sand. I wouldn't base much of my interpretation of this animal's life mode on the fact it was found in a channel sand. This poor creature could have just ended up on a riverbank to drink when a flood hit.<br />I'd be surprised if there weren't dinosaurs doing what you're suggesting here. I think it is a bit of a stretch to apply it to all of Ornithischia, or even just ankylosaurs and ceratopsians.Anonymoushttps://www.blogger.com/profile/11914892485880621750noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-73227366514233057572017-04-13T12:59:35.312-07:002017-04-13T12:59:35.312-07:00Another possibility is a mosasaur getting involved...Another possibility is a mosasaur getting involved....BKhttps://www.blogger.com/profile/03759189747932749283noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-5401335978987359092017-04-13T11:18:14.552-07:002017-04-13T11:18:14.552-07:00It's just occurred to me that any water-puntin...It's just occurred to me that any water-punting ornithischians near the Western Interior Seaway might've found themselves sharing the water with Deinosuchus. Makes you wonder what sort of interactions a submerged ceratopsian or ankylosaur might've had with a giant alligator!Dmyersnoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-82011947595653630832017-04-12T22:58:35.331-07:002017-04-12T22:58:35.331-07:00Ha Ha oopsHa Ha oopsDuane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-67945565593369188372017-04-12T21:37:19.838-07:002017-04-12T21:37:19.838-07:00The Brachiosaurus painting is a Burian, not a Knig...The Brachiosaurus painting is a Burian, not a Knight. (His signature is in the bottom right of the picture.)Andrew Raymond Stückhttps://www.blogger.com/profile/12080621275951453768noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-51577925944862827512017-04-12T20:21:53.962-07:002017-04-12T20:21:53.962-07:00Thanks for the kind word DMyers, very encouraging....Thanks for the kind word DMyers, very encouraging. I'm glad you get something from it.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.com