tag:blogger.com,1999:blog-8161161431451849208.post9192309468444642670..comments2024-03-18T02:43:22.233-07:00Comments on Antediluvian Salad: Allosaurus - More of a Vulture Than a FalconDuane Nashhttp://www.blogger.com/profile/14467779935085970909noreply@blogger.comBlogger27125tag:blogger.com,1999:blog-8161161431451849208.post-26353248478260300062016-03-15T02:32:41.499-07:002016-03-15T02:32:41.499-07:00On tooth durability and theropod teeth being more ...On tooth durability and theropod teeth being more " thick and blunt compared to shark teeth". Are you sure of this? Carnivorous theropod teeth (exception being tyrannosaurid teeth) are characterized as being laterally compressed i.e. not thick and blunt Yes the tooth crowns could very likely get worn and broken. In fact there are loads of theropod teeth showing this exact attribute. As I mentioned several times in the post bone may not have been that high on the list of preferred food stuffs because dino bone may have altogether been more pneumatic and less marrow filled than mammal bone. "bone is extraordinarily tough" yes but when fresh still very wet and easily cut into. And the teeth got replaced eventually.<br /><br />Think about it this way: a theropod depending on the meal at hand has to make some value judgments on the friction and wear put on its teeth versus the benefits accrued from the meal. Young and small dinosaurs obviously had less meat and smaller bones than adult dinosaurs. So they were likely sliced and diced and eaten completely since the theropod did not have to cut through such thick/mature bone and it was hungrier anyways. But when we look at the bonanza of food that a 20,30,40 ton carcass provides, now we can be picky. When I have tons of high quality food to go through why gunk up my insides with relatively poor quality bone when I have all this meat, entrails, fat etc to eat up. Plus I can save my teeth from excess wear. This matches the fossil record too, especially for sauropods. Preserved adult and subadult sauropods but the young ones have been disappeared.<br /><br />On acidic stomachs in theropods. All the data we have suggest bone passed through theropod digestive systems relatively unscathed. All the shards and broken off splints of bone in theropods have sharp edges not the type you would expect from an acidic wash of the type you are implying. If theropods had the highly acidic stomachs compared to crocs we should see a pasty coprolite of dissolved bone not the jagged sharp bits we are seeing. In fact in a future post I will go more into the consistent occurrence of shards of bone in theropod poop. Shards of bone is a prediction that is met with the bonesaw hypothesis and I highly doubt it was gastroliths. For starters if gastroliths were so common in theropods we should find more of them especially the Cleveland-llloyd allosaur deposits.<br /><br />"used more against tough flesh and skin rather than bone..." I think you are thinking too narrowly. Dinosaur skin was often riddled with osteoderms. So if you are doing the bonesaw shimmy through dinosaurs skin you are in fact biting through bone. And if it is likely that theropods were eating tons of baby dinosaurs I doubt that they were - or even had the capacity - to delicately slice through and carefully avoid the bones in all those wee little dinosaurs. The laterally compressed, industrial strength teeth were powered by a laterally compressed head on the end of long and muscular neck which was the main source of power - or to put it better friction. The whole operation was based on speed and friction not really power as in the crushing power of a hyena bite. Which I am troubled with "bone-crusher" being the de-facto assumption as you seem to posit as well as everyone else. Ironic that in modern industrial animal processing it is speed and friction that processes animal carcasses not crushing power. Let go of the hyena mindset.<br /><br />I don't have or have seen any bone saw traces from sharks and vultures don't have the dental equipment. The main point of vulture part was to show the inspiration for the idea.<br /><br />Good questions and critiques, you keep me on my toes but I have uncovered other layers of evidence (future post) that have only bolstered my hypothesis. <br /><br />Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-1830130590014892452016-03-14T14:34:37.492-07:002016-03-14T14:34:37.492-07:00Hello again,
Although at first, I thought your ar...Hello again,<br /><br />Although at first, I thought your argument for a bone-saw-shimmy was perfectly plausible, I've done some thinking recently that's made me question some aspects of it. <br /><br />I think the first question to ask is: how well would theropod teeth stand up to such frequent use on bone with a sawing action? They're quite a bit more thick and blunt in nearly all cases compared to shark teeth, which I think would mean that they're not nearly as effective in the proposed sawing motion. I also wonder about the tooth crowns breaking from such a motion. I know that the denticles are unique in structure and last considerably longer than komodo dragon teeth (Brink et al, 2015). But, again, I don't know how they would stand up to the "bone saw shimmy". Bone is extraordinarily tough, after all, and if theropods were already adept at sawing bones, then why would we see Tyrannosaurids evolving a bone *crushing* bite, when the bones could already be sawed so easily? Hmmm....<br /><br />I also think the large coprolite could be explained by one, possibly two things: The first could be that the Allosaurus had already swallowed the prey (and prey parts) whole during feeding, and the resulting breakup of the bone is due to the digestive process. Bone eating vultures such as the Lammergeier have extremely acidic stomachs to help them digest bone, and they don't have a crop. (See: http://www.reed.edu/biology/courses/BIO342/2012_syllabus/2012_WEBSITES/IvyH.BeardedVultures.2012/mechanism.html ) Therefore, Allosaurus and other bone-consuming theropods almost certainly would have had a similar adaptation in place. <br /><br />Secondly, there's the fact that some gastroliths have been found associated with large theropod remains. See: http://dml.cmnh.org/1999Apr/msg00504.html Lourinhanosaurus was probably ecologically similar to Allosaurus, and I can't think of a reason that large theropods would have gastroliths other than to help their stomachs grind up bones! After all, these theropods probably weren't using it for buoyancy, and I don't think they would have possessed crops that needed cleaning out, either. (I've read that kestrels and some other small falcons will consume grit to rid their crops of a greasy lining from the insects they eat.) <br /><br />I also think the observed score marks on the bones could have simply been made by sheer bite force. Although Allosaurus isn't typically imagined as a bone-crusher, I'm sure that its jaws could produce enough force to bite through certain parts of bone. Perhaps its massive neck muscles could have also helped drive the tooth row into the bone and cause the marks we see? <br /><br />I'd also like to know if there's pictures of any bones that have been sawed by sharks, or vultures, etc. I'm curious as to what the marks look like and how they compare. <br /><br />-L. Walters<br /><br />P.S. I still think the sawing motion certainly seems plausible, but perhaps it was used more against tough flesh and skin rather than bone...Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-20028107724101664692015-11-12T16:21:09.071-08:002015-11-12T16:21:09.071-08:00Thanks for comment Darius Nau
While I think komod...Thanks for comment Darius Nau<br /><br />While I think komodo dragons are useful analogues for some theropods - esp carcharadontosaurids which lack long flexible necks - I prefer the action of vultures/giant petrels for many other theropods.<br /><br />If you compare a komodo dragon to say a dromaeosaurid like let's say Tsaagan (which I believe might fit the bonesaw shimmy model well) yes they do converge on serrated teeth but the komodo falls down in almost every other anatomical correlate to the theropod. Komodos don't have long muscular flexible necks; they are not bipedal; they don't strike downwards; and, as you mentioned, their skulls are broader. However in birds that feed on the bodies of large carcasses like new/old world vultures these modern avians converge on these anatomical correlates with the theropod. They only thing that the birds lack are the large/reinforced serrated teeth so that the damage that they can incur - esp. against live prey - is >much less< but I think that the general feeding/biting action had a lot of commonality. So much that I would consider vultures the best analogue among extant animals for several (but not all) carnivorous theropod lineages. And this is not so radical when you consider that vultures/giant petrels are derived theropods after all.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-32613489781521777502015-11-12T12:49:36.350-08:002015-11-12T12:49:36.350-08:00I think komodo dragons are perhaps the best extant...I think komodo dragons are perhaps the best extant analogue. <br /><br />Not only do they share the most similar tooth morphology of all extant animals, they also tend to engage in the same macropredaceous and even brontophagous activity. When feeding they rock their heads or entire bodies back and forth to power a drawing motion of their teeth, analogous in function to what you described here.<br />They even have that tendency to eviscerate their prey in this manner and start feeding while it’s still alive.<br /><br />Here are some examples:<br />https://www.youtube.com/watch?v=41tgpV1Z1Ug<br />https://www.youtube.com/watch?v=XPBiLXp5Uj8<br />https://www.youtube.com/watch?v=JIv-ASfimX0<br />https://www.youtube.com/watch?v=aQ1vbKm7BnE<br />https://www.youtube.com/watch?v=S5Syko2Yo4w<br /><br />Where they differ is that their skulls are broader and flatter. <br />Accordingly their feeding motion has more of a lateral, curved component (as does that of sharks), and less of the initial slash/strike motion (probably served to give the tooth rows an initial push and drive them deep into the flesh) Allosaurus is adapted for.<br />Darius Nauhttps://www.blogger.com/profile/01630359709576094063noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-79794716758465046822015-09-04T10:16:51.699-07:002015-09-04T10:16:51.699-07:00Interesting off the top of my head I recall recent...Interesting off the top of my head I recall recent chat that Ceratosaurus grew a lot larger than generally portrayed... A system perhaps dominated by loads of subadults, maybe a live fast die young ecoystem. A new ecology paper came out today pointing towards ecosystems with loads of adult herbivores have counterintuitively less predators than a system with less herbivores (but more young). If there was a lot of intraguild predation going on, rare adult sauropods pumping out tons of baby sauropodlets this could substantiate a predator heavy ecosystem.<br /><br /><a href="http://www.cbc.ca/news/technology/predator-prey-study-may-reveal-surprising-new-law-of-nature-1.3214839" rel="nofollow">predator Prey study may reveal surprising new law of nature</a><br /><br />Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-61585568343074648922015-09-04T08:09:03.436-07:002015-09-04T08:09:03.436-07:00I was referring more to the story you wrote (Mobil...I was referring more to the story you wrote (Mobile Sauropod Body Processing Units of the Morrison). Yeah the population curves seems to be skewed towards subadults, in fact it seems we don't have a single fully grown Allosaurus, Bybee et al. (2006) found no external fundamental system in even the largest specimens they examined (including AMNH 680 and AMNH 290). Anonymoushttps://www.blogger.com/profile/07366636690379139896noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-26639784969330485552015-09-04T00:01:23.591-07:002015-09-04T00:01:23.591-07:00Thanks for commenting HoveringAboveMyself
If you ...Thanks for commenting HoveringAboveMyself<br /><br />If you are referring to the disparity in size between the Torvosaurus and the Allosaurus in the pic that is because the allos are all small immature 1-3 years old while the torvo is only about 1/2 grown itself. Fair enough with the max size for both species matching up... I was always under the impression A. fragilis was generally a bit modest in size. But maybe the population curve was skewed towards subadults and full grown 10m+ adults were rare?...<br /><br />Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-36638171713653714942015-09-03T22:53:30.818-07:002015-09-03T22:53:30.818-07:00Really interesting read and hypothesis, sadly I do...Really interesting read and hypothesis, sadly I do not think I'm knowledgeable to comment much on it so I'm going to stick to what I know. <br /><br />Even ignoring the fragmentary relatives, grown adults of Allosaurus and Torvosaurus are actually similar in size. Specimens of Allosaurus like AMNH 680 and AMNH 290 approached 10m, with femora about 1 meter long (inferred for AMNH 290). In the side of Torvosaurus, the Dry Mesa material comes in two sizes, a "subadult" and 2 "adults" of similar size, we also have "Brontoraptor" which is similar in size to the small Dry Mesa specimen, using Hartman's skeletal as a guide the small ones would be about 8m long and the large ones would end up shy of 10m and based on "Brontoraptor" their femora would also be about 1m long. Edmarka rex isn't actually much larger than this, only about ~5%. <br />Anonymoushttps://www.blogger.com/profile/07366636690379139896noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-18767933793893361302015-08-18T18:17:43.215-07:002015-08-18T18:17:43.215-07:00Thanks for commenting Jaime, I know you said that ...Thanks for commenting Jaime, I know you said that you had trouble getting into the comments here so thanks for lending your thoughts. Well we might be at an impasse as it comes to both of our - what essentially boils down to - opinions on the strength of the papillae until further study. As I mentioned there is no studies on food processing as I have laid out here with vultures/petrels. All the work I can find on vultures is essentially having to do with carcass location/niche partitioning/conservation and this avenue of food processing is understudied. Be that as it may as you mentioned the much larger papillae in penguins serve to grasp the much smaller papillae in vultures serve to rasp. And if you watch closely the feeding behavior the choanal grinding as I have dubbed it occurs before the hook and pull. What I argue is that this friction augmented by the tongue and neck movements serves to weaken and disrupt the integrity of the meat. And here the small serrations would work better than larger papillae that the meat would get hung up on - keep in mind this all working very fast. After which - when the meat is softened up a bit - the leveraging hook and pull technique comes into play. And it is quite demonstrable that these carcass rendering birds differ substantially in their feeding mechanism than eagles/hawks/falcons so something is going on different here that much is for sure. I am open to other ideas but this seems the most logical. And did you not take note of the paper and pictures I referenced of the griffon vulture with a hole in its neck? Even though with the tongue lopping out of the neck it was still observed to ram back and forth when it was feeding. Therefore this behavior is so hardwired the bird is jamming its tongue back and forth even when it can't assist in food processing! This demonstrably discounts your suggestion that the tongue plays a smaller role in tongue assisted prehension than say penguins (which I admittedly know nothing about so feel free to illuminate me on how they are using their tongue) and is about as in vivo as we got right now. The theory as I laid out here best fits the observations.<br /><br />And no thoughts on the bonesaw shimmy? Yes it was inspired by watching the vultures but the two ideas can be looked at independently i.e. one is not dependent on the other.<br />Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-80179430608854310342015-08-18T17:05:19.387-07:002015-08-18T17:05:19.387-07:00I like your idea, Duane. However, my concern is th...I like your idea, Duane. However, my concern is that I do not think the oral papillae are durable enough to perform the behavior that you ascribe. Without knowing precisely what is being done here, we can assume a role for the tongue and oral papillae for some manner of prehension. When it comes to the much, much larger oral and esophageal papillae in penguins, sea turtles, and various other pelagic animals without teeth, we can assume that these assist in preventing slippage. Thus, they aid in prehension. But that in other birds seem smaller. Feeding behaviors differ. Ducks, geese, and flamingos use their lingual papillae and scrape inside their mouths, so lingual "ramming" back and forth might serve a process of managing small bits of food, or rendering, but never it seems very large bits. That's the function of the book and pull, after all. Of standing on the prey item and lifting up. As much as choanal grinding seems to make sense given the observed behavior, I am loathe to give it more concern without in vivo study of this behavior. As it is, we might rather expect these papillae to be advantaged when there are many of them, yet in these birds there are fewer. This suggests a smaller role in tongue assisted prehension than, say, penguins.Jaime A. Headdenhttps://www.blogger.com/profile/16010646866890414128noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-59531197418711977542015-08-18T17:05:01.786-07:002015-08-18T17:05:01.786-07:00I like your idea, Duane. However, my concern is th...I like your idea, Duane. However, my concern is that I do not think the oral papillae are durable enough to perform the behavior that you ascribe. Without knowing precisely what is being done here, we can assume a role for the tongue and oral papillae for some manner of prehension. When it comes to the much, much larger oral and esophageal papillae in penguins, sea turtles, and various other pelagic animals without teeth, we can assume that these assist in preventing slippage. Thus, they aid in prehension. But that in other birds seem smaller. Feeding behaviors differ. Ducks, geese, and flamingos use their lingual papillae and scrape inside their mouths, so lingual "ramming" back and forth might serve a process of managing small bits of food, or rendering, but never it seems very large bits. That's the function of the book and pull, after all. Of standing on the prey item and lifting up. As much as choanal grinding seems to make sense given the observed behavior, I am loathe to give it more concern without in vivo study of this behavior. As it is, we might rather expect these papillae to be advantaged when there are many of them, yet in these birds there are fewer. This suggests a smaller role in tongue assisted prehension than, say, penguins.Jaime A. Headdenhttps://www.blogger.com/profile/16010646866890414128noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-648461024326219962015-08-16T22:59:32.240-07:002015-08-16T22:59:32.240-07:00Exactly ! It doesn't take a great intellect to...Exactly ! It doesn't take a great intellect to figure out that if I do things a certain way and it yields a greater turnover then I'd best stick with that method of doing things, if Allosaurus was reaping a greater benefit from hunting together then it'd make sense that they'd be willing to tolerate one another, regardless of whether there being any form of emotional sentience within them. Robert Haannoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-33513393666468136312015-08-14T22:32:28.004-07:002015-08-14T22:32:28.004-07:00Indeed I want to elaborate more on social behavior...Indeed I want to elaborate more on social behavior in future posts. I actually think selfishness = as opposed to any kind of "mammalian" type empathy or emotional attachment was the glue that held these guys together. Basically if I run in cahoots with others of about my size we will have more feeding opportunities. I watch what my cohorts do and react in turn to what they see. Andrea Cau has been speaking of a similar nature for theropods for quite a while too so not a completely novel interpretation but one I tend to espouse. Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-48686707026734984182015-08-14T21:54:40.110-07:002015-08-14T21:54:40.110-07:00Interesting point of view, and one which has a leg...Interesting point of view, and one which has a legitimate backing of credibility to it. i especially like your take on the social aspect of allosaur behaviour, and i think you've highlighted this in your first few plesiosaur posts, just because an animal isn't hardwired to cohesive teamwork and complex coordination, doesn't exclude the possibility of some form, perhaps the most basic of cooperation between individuals towards a common goal. Too often we tend to shoehorn a particular animal into only fitting into a particular niche . I hope viewpoints like yours will be more common in the coming times .Robert Haannoreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-44360392563593760512015-08-14T08:11:38.011-07:002015-08-14T08:11:38.011-07:00Yes thank you Brian L for your insightful and stra...Yes thank you Brian L for your insightful and strangely prophetic comment. Yes, I too was worried about getting taken in by the whole "coolness factor" of it all - but hey, sometimes nature really is that cool. Nice to hear about your independent observations of vulture feeding. It happens so fast that I think that choanal grinding has been overlooked. And on prey capture by vultures this is a topic I want to go into more in my next post so stay tuned. <br /><br />On young vultures feeding at carcasses/various sized species feeding at once. I think a couple of factors are at play. The size of the carcass certainly dictates how many can feed at once. Smaller species/youngsters would certainly be more agile than older brutes. SInce theropods had more laterally facing eyes than mammalian carnivores this could allow them to feed and keep an eye on neighboring theropods. That being said there are loads of instances of even large mammalian carnivores or crocs/lions feeding side by side because the bounty of meat is so great fighting is just not worth it.<br />Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-14326688510870283082015-08-14T02:54:53.838-07:002015-08-14T02:54:53.838-07:00I must admit I am quite amazed by your post and, t...I must admit I am quite amazed by your post and, though that's not the best route to take, I hope you are (mostly) right about what you propose. It so happened that yesterday, I visited Artis zoo in Amsterdam where I got to have a look at the Griffon Vultures being fed. I have seen vultures eating before, but given the contents of your post I decided to use the opportunity to give them an extra good look and indeed, I could see the nibbling and hook-and-pull actions taking place, even if the vultures were fed dead rats rather than a big carcass. Of course, dominance was much in play too and for bonus points, the zookeeper mentioned to the watching crowd that despite all the squabbling taking place, young vultures are generally allowed to eat by the adults (presumably meaning their parents, mostly). Not too sure about that last thing, but certainly an aspect worth considering.<br />By the way, Griffon Vultures in Spain are also on record as having killed weakened calves and sheep by mass attacking them. This is taken as extreme behaviour due to lack of carcasses in recent years, but is nevertheless interesting behaviour that may or may not give insights to *Allosaurus*'s feeding methods. Certainly a mass attack on a live animal by vultures would be a very sordid and grisly affair.<br />A last thing worth pointing out, though you undoubtedly know this already, Lappet-faced vultures are also capable hunters of live prey in their own right, even if they mostly scavenge.BrianLhttps://www.blogger.com/profile/17880867575515761505noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-39763074875815537022015-08-13T20:11:53.196-07:002015-08-13T20:11:53.196-07:00Exactly Sean!! In fact I directly suggest that Tor...Exactly Sean!! In fact I directly suggest that Torvosaurus could have been the lappet-faced vulture of the Morrison, opening and dismembering large carcasses for other animals, in the paragraph after my diagram of bone slicing Allosaurus. Dominating small carcasses yeah, but if we are talking about a 20-50 ton carcass it can't monopolize all of it - especially against the much quicker and numerous Allosaurus.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-20484488875759315972015-08-13T13:35:01.476-07:002015-08-13T13:35:01.476-07:00Perhaps Epanterias or Saurophaganax morphs were li...Perhaps Epanterias or Saurophaganax morphs were like the lappet faced vultures in those first videos; they could walk up to a carcass being fed on by several allosaurs, and establish that he's in charge.Sean McCabehttps://www.blogger.com/profile/01638487125675179642noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-35441732323411774072015-08-11T12:59:35.590-07:002015-08-11T12:59:35.590-07:00No problem ^^. You truely are an intelligent perso...No problem ^^. You truely are an intelligent person, so I just had to tell you in case you thought otherwise ^^. Keep up the good work, especially on your new Theropod posts. I can't wait to see what you have in store next *cough* Phorusrhacoids *cough* ;).Iris-Katyayanihttps://www.blogger.com/profile/06188961246186305190noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-56210260104187519012015-08-11T11:10:36.363-07:002015-08-11T11:10:36.363-07:00Thanks so much for the kind words khalil beiting. ...Thanks so much for the kind words khalil beiting. Much of what you mentioned formed my impetus for this blog/my work. I was getting discouraged that "dinosaurus with laser beams coming out of their eyes" seems to be more of a trending topic in paleontology on facebook than my post here but some things take time to sink in and I am ok with a slow burn rather than an explosive fire. I have got enough encouraging words and interest here to keep me going - and so far no damning critiques - and your comment really made my day. Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-46224712158901009402015-08-11T08:13:41.299-07:002015-08-11T08:13:41.299-07:00Thanks, but just to let you know, I wasn't goi...Thanks, but just to let you know, I wasn't going to actually use your artwork. I was going to just make a scene similiar to the scene you vividly imagined. I was thinking of adding a few other animals, some speculative behaviour, maybe one or two speculative evolution species, etc. I'll definitely post a link to your work.<br /><br />Oh, and I can't wait for your next article ^^. You know, you are my favourite researcher in plaeontology. You make such excellent articles, with large amounts of evidence to back you up, all the while writing it in a way that's very intuitive and makes the reader really feel engrosed in your theories. The latter is something very lacking when it comes to the average formal paper, because those papers are usually boring and incredibly monotonous. They explain everything in a way that only a robot could truely understand. You on the other hand do a perfect job at informing and persuading by your drawings/guides, links to other modern day analogues that give a better understanding, etc. *Sigh* I wish other scientists were as good as you. Keep up the good work ^^.Iris-Katyayanihttps://www.blogger.com/profile/06188961246186305190noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-64413058231762647022015-08-10T19:14:43.244-07:002015-08-10T19:14:43.244-07:00Yes you can use my art it is all on deviant art an...Yes you can use my art it is all on deviant art and Creative Commons so use it and abuse it. Just specify what ideas are mine - and which are yours in your speculative project.<br /><br />I don't want to give too much away for my next post... just know that I have not played all my cards on this post and that several theropod lineages (possibly not all Mesozoic) are gonna get a little bit of a reboot here. Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-56527021922612535982015-08-10T16:39:17.511-07:002015-08-10T16:39:17.511-07:00Why thank you for the feedback. Like you, I can...Why thank you for the feedback. Like you, I can't look at the bones and everything so I've basically no clue on what is valid and what isn't. Also, is it true that Saurophaganax and/or Epanteris is only known from the upper morrison? If they're both only from the upper, than there's a slightly higher chance they might actually be valid. Them being a new species/genus/sub species/morph is another major question, but since neither of us actually have material to base off of, than I guess we just have to twiddle our thumbs and hope for a paper on either one of them.<br /><br />When it comes to mesopredators, intraguild predation, niche partitioning, etc., do you think you will do an article sometime in the future that talks/discusses them? You could even do a series like what you're doing with Plesiosaurs and Theropods, but I'd completely understand if you were busy. I'm only 16, so I have a lot of learning and research to do, so I jsut wanted to know if you would ever go in-depth with it.<br /><br />Oh, and could I re make your carcass scene for my spec evo project? I must mention though, this spec evo project of mine isn't really about an alternate time line like many other spec evo projects, but rather just about the ordinary Mesozoic. It has all of the animals we already have the fossils of, along with many species that aren't known, but that are possible (if not likely) due to our understanding of Archosaur evolution. I will also explore fossil sites with very little dinosaur fossils, therby making up new (likely and/or plausible) species, along with restoring already known animals in ways that are reflective of how modern day animals are all unique and/or strange (i.e. flamboyantly plumed giant Theropods, feathered Sauropods, Ankylosaur/ceratopsian omnivory, Hadrosaur inflatable nose/throat sacs, etc...you know what I'm getting at here ;)). I will also even make up new fossil formations that aren't known, like offshore islands, Appalachia in general, etc. So basically, I was wondering if in my feild guide, I could recreate a scene like what you wrote, except completely drawn in several slides that show the gradual proccess of the complete consumption of the carcass and how all of the Theropods biomechanically work. When (or if) I do this, I will upload it on DeviantArt, and if you allow me, I will give in the description a link to your blog, and the amazing article you did on Allosaurus biomechanics (along with any future reference you make on Theropod biomechanics).<br /><br />One last question, but do you already know what Theropod species/group you will do next? Iris-Katyayanihttps://www.blogger.com/profile/06188961246186305190noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-72615351764943901422015-08-10T15:39:33.730-07:002015-08-10T15:39:33.730-07:00Thanks and excellent questions. I am agnostic as g...Thanks and excellent questions. I am agnostic as goes Epanterias, Edmarka etc etc. They might just be large morphs of Allosaurus/Torvosaurus. And that question would be better addressed to the people who work first hand with the bones, have access to the specimens, and so on - which I do not. So I am going to decline to offer a staunch opinion either way because I don't have access to the specimens and I don't try to portray myself as a "taxonomy " guy any ways. I provide insight, ideas, and theories that might lead to future more rigorous testing. But my gut tells me that as the sauropods were getting bigger and bigger so were the theropods - whether or not this translated into bigger morphs or new species I don't know. And to tell you the truth ecologically it does not matter that much if those exceptional large theropods were different species/local variants/large morphs. The sauropods got bigger and so did the theropods.<br /><br />In theropod niche partitioning I tend to think that unless there is extreme reasons to infer a speciality in diet I tend to go with most carnivorous theropods having a lot of overlap in diet actually - complete with generous amounts of intraguild predation and cannibalism. For Marshosaurus I have not really looked at it too closely but the skull reconstructions suggests a pretty typical mesopredator - baby sauropods, young of other theropods, scavenging - probably fits the bill. My suspicion is that niche segregation occurred more on the landscape level than strong dietary differences. For instance maybe one species likes open plains, another closed canopy forest, another wetlands. This is how best you can achieve high diversity with lots of dietary overlap.<br /><br />In my speculative essay I implied a little partitioning between Ceratosaurus, Torvosaurus, and Allosaurus based on differential exploitation of large sauropod carcasses because I feel that this is where competition between the three is greatest. Torvosaurus is the best at breaking apart limbs, gaining access to large carcasses and it focuses on gnarly cartilage, skin, smaller bones, muscle. Ceratosauruss likes to poke deep inside carcasses after soft internal organs. And allosaurus exploits a ll aspects of the carcass, including the bones. And this wide feeding niche and inferred "mob" type sociality gives Allosaurus numerical dominance.Duane Nashhttps://www.blogger.com/profile/14467779935085970909noreply@blogger.comtag:blogger.com,1999:blog-8161161431451849208.post-38473455453035897562015-08-10T13:45:38.252-07:002015-08-10T13:45:38.252-07:00Well this is an astonishing article. This kind of ...Well this is an astonishing article. This kind of has to do with the carcass story, but what do you think Marshosaurus' niche/prey was? Also, since you mentioned Epanterias and Edmarka, do you think they are both valid, or are they just giant variants/morphs of Torvosaurus and Allosaurus respectively? Also, what do you think Saurophaganax's niche was (I'm assuming the role of "uber Sauropod slayer"). Now, one last question (sorry for all of the questions), do you think that I could "copy" your (amazing) carcass story for my spec evo project? I'd like to recreate/draw this scene in my Mesozoic Feild Guide (if I stop procrastinating of course ^^). Thanks and sorry for all of the questions.Iris-Katyayanihttps://www.blogger.com/profile/06188961246186305190noreply@blogger.com