Wednesday, November 16, 2016

The Allosaurus Magical Underwear Death Kvlt: Following the Path at #2016SVPSLC

Follow the path with my book Dinosuar Enlightenment: Piercing the Veil on Kaiju Dinosaur in an Age of Disruption now available on Amazon as an ebook and soft cover!! Get twisted!!

I could have wrote just another hunky dory, look at how happy we are in paleo land, so inclusive and so progressive, color by the numbers write up of my experience at SVP2016 but then I thought to myself "do people really come here for that?" and how disingenuous  would I be in writing such a piece? I would imagine that by now if you have kept following this blog you yourself might be a little left of center; a little bit of an envelope pusher; a little bit of a black sheep. In fact, you might be all those things and still disagree with a lot of what I say - all the better but you have to give me this - I do force you to think. Or you might be someone who genuinely dislikes me and what I have to say but keeps coming back anyways, in that case thanks for the page views.

"This ain't no fucking Bon Jovi concert."

Despite my seeming mockery of Mormonism and religious thought imbued in the title of this post and the blog title itself I do think a certain amount of spirituality or strengthening of the spirit is of benefit to people. A personal, spiritual, and cosmological reckoning of one's place in the universe. Are you walking the path? I do place some attention on "meaningful coincidences" or "synchronicities". I don't overanalyze them or really try to persuade other people of their merit or that they happen to me. I simply take note of them, realize the universe is giving me an "atta boy" and carry on. I also take note of happy accidents. For example upon arriving at LAX I learned the plane was oversold and my seat was bumped - I had no seat! At first they tried to bribe someone off of the plane for a 200$ dollar voucher. I waited. They rose it to 400$ and I quickly swooped on it. I just had to wait three more hours for my upgraded first class seat. Poor me. Upon arriving in Salt Lake City I had covered my travel expenses and had a good rum n' coke buzz to boot! I knew I was walking the path. Such meaningful coincidences probably have no place in "rigorous scientific discussions" indeed many might read this and see it as just another reason to dismiss me... but I bet there are at least some reading this who have met with series of inexplicable coincidences or experienced a sense of "synchronicity" that they can't dismiss. Even scientists.

And it was one such meaningful coincidence that caught my attention in SLC that strengthened my resolve and resolution that I am on the path. There was a break in the talks or maybe it was just a couple of boring ones that I didn't care for. I was walking around the Grand American hotel where the convention was held mulling over my place in the paleo game - something I think a lot of people do. Do my ideas make a difference? should I just concede that no one will take me seriously as a blogger, non-accredited, non peer-reviewed, shoot from the hip, overly speculative, not playing by the rules and somewhat coarse artist? It was with these thoughts dancing around in my head that I came upon a harpist playing in the lounge... yes a fucking harpist. After seeing that I felt the need to get some fresh air out in the real world. As I stepped out of the bubble world that is SVP, cocooned in another bubble of bougy harp playing wankery, I came upon an item that shocked me back to reality and at the same time gave me the perfect contrasting image to the harp playing world I had just stepped out from.

A used intravenous needle with a small smear of blood still decorating it, just lying in the well manicured grass bordering the ritzy Grand American hotel. A poignant reminder that the world can be a desperate, ugly, brutal, and flawed place - even Salt Lake city. The perfect antithesis to the Grand American hotel, harp playing, and the playing along to get along atmosphere of SVP. The question was laid out before me, not literally but figuratively, am I with the harp or am I with the needle?

You can guess which item resonates with me more (figuratively of course)... but as ugly as it is it offers a more resolute and resounding ring of raw truth to it.... "this ain't no fucking Bon Jovi concert."

All right enough of this soul-searching emo crap. I'm boring, dinosaurs are cool that's what you came here for right?

Daspletosaurus neck throttles some dumb horned dinosaur
Ughhh full disclosure, although this is my third SVP I do admit a certain hesitancy on attending these events. It costs a lot; it is usually pretty far away; you gotta take time off work; arrange travel times; sitting in cramped airplanes and speeches gives me back pains; ugghh academic types annoy me a bit; I'm a bit of a weirdo loner and don't have a clique I can do stuff with. But with all that bitching and moaning I invariably leave knowing full well it was worth it. The reason I feel this year was extraordinarily worth it was not just for what I learned, but for several key speeches that bolstered and reinforced ideas I have been arguing for and developing here at antediluvian salad. Coming across independent lines of evidence that converge and intersect with developing hypotheses is always very exciting and vindicating. Sharing such passion is something that I will not hesitate to express on this blog. Because, yes, scientists need passion, excitement, and ultimately an emotional plea in their expressions because, well, other less endearing methods of looking at the world are winning the war for how humans view and interpret the world.

I splurged a bit this year and attended the Morrison formation field trip. Hey, when in Rome, right? Given that the Morrison and it's ecology/dinosaurs is something I delve into on the regular here I thought it right to at least visit the place - given that my travel expenses got taken care by synchronicity event #1 it proved justifiable. I also experienced synchronicity event #2 & #3 when I landed in the van with Joseph Peterson of University of Wisconsin-Oshkosh who is engaged in a pretty intense reevaluation of the Cleveland-Lloyd quarry and shot-gun seat opened up for me. You know I leaped on that opportunity!! So I got to pick Joe's brain a bit about Cleveland-Lloyd and I got to stretch out in the front. Win-win.

Our first stop, after a rather picturesque drive, was the hallowed ground of Cleveland-Lloyd. What a place!! I honestly did not know that there was even a visitor center here with skulls and mounted skeletons. Pretty cool but a bit off the beaten path, if you plan a visit make sure to 2x check its open.

Michael F. Leschin gave a pretty engaging introductory talk on the rough-shod history of the place. I made a rough-shod video to boot:

Joseph Peterson then took us into the two quarry rooms where he gave us a little bit on what his group have been finding:

What do we get from this? Cleveland-Lloyd is a mess. It was a mess back in Jurassic and it is a mess now. It is a sloppy, complicated crime scene in which multiple CSI jurisdictions analyzed the scene of the crime and they did not even use proper collection technique. They trampled over everything and crapped on everything. The researchers and the dinosaurs.

Here are some interesting tid-bits that I gleaned from my visit; disarticulated skeletons with some association; evidence of some orientation of long bones and therefore an incipient current; some bones show evidence of trampling - many do not; some bones show evidence of feeding traces - many do not;   often characterized as a "predator trap" CL is abundant in only one predator, Allosaurus, others are rare; with the exception of Allosaurus most skeletons represent adult morph dinos; charophytes, aquatic algae, are present indicating standing water at least some times; abundant shed Allosaur teeth; heavy metals and arsenic are present and relatively abundant; CL sits next to a much larger lake; eggshell has been found, anecdotally said to have been found fairly commonly, but discarded due to misidentification.

For me, it is possible to discard some hypotheses. The fact that CL sat at the edge of a much larger lake allows us to discount CL representing the last water feature on a drying landscape. It was not a dying ground for dinosaurs seeking water, the lake itself would hold water much longer. I think it also possible to discount the idea that the bones washed into the site. The reason I would discount this hypothesis is: why so many allosaurs? Even if you suggest that there is a potential allosaur nesting site why dead allosaurs of so many size classes? Something was killing allosaurs of all size classes in this area.

Here is my working hypothesis and it is necessarily complex due to the fact that an intersecting  convergence of complex factors may have created the picture coming into focus...

What type of body of water/fluvial or lacustrine system was CL? I think Joe is partially right in his assessment of the site as an "ephemeral pond" in the above video. I do think water flow was just enough at times to create an incipient orientation in long bones, while at other times water was stagnant, and at other times it was bone dry. I think CL represents the terminal entrance of a somewhat ephemeral stream/arundo/wash into a larger lake system. During some years substantial flow would allow charophytes to grow and enough of a current to create some long bone orientation. During drought conditions CL would dry out, creating the condition for dinosaur mediated trampling of bone. We see a complex taphonomic record and clues because the setting was very dynamic.

credit Mark Peters CC2.0

Dinoturbation is a thing and CL might just represent a dinosaur mud wallow. Q: What large animals in hot climates don't enjoy a good mud bath? Answer: None. Of course we should expect that large dinosaurs, especially gigantic naked skinned sauropods would enjoy a cool and refreshing mud bath. We should also not be surprised given the size of the bathers involved that in digging in and maintaining such wallows whole stream beds could be affected. Just look at the type of mud wallows that modern pigs can create and size that up to hefty camarasaurids. Now... imagine if you will a small creek or wash, as it loses velocity going down its channel and it approaches the lake the streambed flattens out. This allows all of the small bits of sediment - the fine silt, muds, and clays - to fall out of the water column. These fine particulate sediments i.e. mud would be the ideal candidate material to attract dinosaurs in for a good mud bath. That skeletons show disarticualtion but some association may in fact be due to the dinoturbation of large bodies churning up the sediment.

Old and ailing animals went to die in a place of comfort. Animals when they are dying, they know it. They want to do it as painlessly and as comfortably as possible just as we do. Hospice care for any large, ailing, injured, or sick mega-dinosaur would have been provided for in a stinky, goopy, comforting, morass of mud. The spot on the landscape that provided them with much comfort during life would see them off in death. This notion of large dinosaurs coming to CL to die is consistent with the dominance of mature sized individuals represented at CL. Even the Torvosaurus and Ceratosaurus are gigantic. From what I have gathered there are few immature specimens except for one species.

Enter Allosaurus. The CL visitor center has a neat display of an Allosaurus skull in between the daunting skulls of the larger Ceratosaurus and Torvosaurus pulled from the quarry. Which begs the question: "what set Allosaurus apart from these other intimidating predators that allowed it such numerical dominance in the Morrison?"What type of magical underwear was Allosaurus wearing? Personally I don't suspect it was a wider, more generalized feeding envelope, I'm not convinced that all of these theropods were not supreme opportunists. Indeed when it comes to the diapsid brain and prey it usually boils down to "can I overpower it?" if yes, then I eat it. If no, move on.  All three species seem pretty well pat on weaponry. For me I suspect that what set allo apart was a more adept, flexible, and efficient reproductive strategy. Allo did not outfight the competition, it simply outbred them. And is that not the dinosaurian way? Dr. Bakker has done much work on Allosaurus feeding sites and his interpretation is that Allosaurus fed its hatchlings at feeding lairs, literally dragging sauropod carcasses across the landscape to feed their somewhat altricial young. As evidence Bakker has noted that teeth of young allosaurs coincide with shed adult teeth - they were feeding on the same stuff in the same area. The idea is evocative. But what is easier and more simple than dragging giant sauropods across the landscape to feed your hatchlings? Bringing your hatchlings to the dinner party. What is even more simple than that is laying eggs at the dinner party - or at least in an area dinner should soon arrive at.

credit San Diego Zoo blog

Could Allosaurus have literally colonized giant sauropod carcasses like theropodian tarantula hawks? Laying eggs at the scene giving hundreds of allosaurus hatchlings a competitive edge via a nice feeding opportunity upon hatching? Given that some weeks/months of incubation had to have happened there is a more practical question of is this lifestyle feasible would the carcass be around when the eggs hatched?... However if there is a certain locality that tends to congregate large dead and dying dinosaurs perhaps just laying eggs in that locality on the likely chance that a body might just show up is benefit enough.

All this speculation aside I will be waiting to see if more evidence of eggs/nesting shows up at CL but I do suspect something different regarding reproductive strategy was going on in Allosaurus that allowed it the competitive edge...

What is the killer? For me any holistic appraisal of CL has to invoke a mechanism for "what killed the allosaurs?" I am not so intrigued with what killed all the other dinosaurs - as I mentioned earlier we might in fact be looking at a long standing dinosaur mud wallow that served as a comforting "hospice care" locality for old dinos on their way out. What is intriguing is that allos are found here in all size classes. I am not satisfied with the answer that they were getting washed in as this would still not explain the predator prey disparity and variety of age classes. I do think that they were here in all size classes, that they ate here, and that they died here. The killer in my estimation is something very close to avian botulism or perhaps a deeply nested Mesozoic theropod version of avian botulism.

Many are familiar with the argument that a "poisoning event" created CL. However I think fewer have actually looked into what types of potential poisoning events match the crimes scene and I suspect fewer still have really investigated avian botulism.

I first came across a likely case of avian botulism while walking around the Santa Clara estuary - a visit I documented in these two posts Life & Death in a Southern Californian Estuary parts 1 & 2. If the present is the key to past ( or at least a clue) I can't think of any better culprit than avian botulism to have created the situation at CL.

Ideal Environment. Avian botulism thrives in warm, shallow, oxygen poor water, with abundant protein substrate. CL as an ephemeral pond or dinosaur wallow is well poised to foster avian botulism. That dinosaur carcasses occurred with regularity provides the protein substrate.

Transmission & Hosts. Let's suppose CL hosted avian botulism - how did it infect allosaurs? A large sauropod dies at CL of natural causes. It's drinking water, maybe ingesting some charophytes.   Ultimately it does not die of avian botulism but once it dies the bacterium swarms on this abundant food source. Carrion insects colonize the carcass. The insects ingest the bacterium (Clostridium botulinum) but they too do not die from it. However their bodies do concentrate the neurotoxin produced by the bacterium. Allosaurs arrive at the carcass and consume it. As they consume the carcass they incidentally ingest the insects that have colonized the carcass and in doing so ingest the highly concentrated neurotoxin. Since avain botulism is paralytic disease the allosaurs that become infected go into paralysis at or near the spot of ingestion. They are then either killed by conspecifics or other theropods due to their paralysis and furthering the outbreak. Modern outbreaks of avian botulism can kill thousands of waterfowl. In modern waterfowl they get it through eating of infected fish or invertebrates that have concentrated the toxin. Allosaurus most likely would have got infected through incidental ingestion of carcass colonizing insects i.e. "maggot" type insects as it scavenged.

Now we may never get the hard physical evidence of avian botulism from the fossil record. Sometimes all we have in paleontology are competing explanations... As an explanatory hypothesis I think that the intersection of ideas I have presented here as some resonance - enough to at least store in your back pocket for future reference...

The rest of the spots we went to on the field trip: Fruita, Mygatt-Moore, Riggs-Quarry they were all right but did not offer the type of addicting questions that CL did.

Some pictures:

Mormon Tea the ephedra plant at CL. similar gymnosperms would have lived here in the Jurassic
cryptic desert fern CL
L-R Torvo, some croc,  Allo, Cerato. Scale is sort of hard but that Torvo skull is easily a meter long
Stokeosaurus? and Torvo CL
Some beardo weirdo next to the LOLzy mispelled BrachYosaurus type specimen locality Riggs Hill
some Camarasaurus stuff is in there, really. from Mygatt- Moore

All right, enough playing around as Jr. paleontologist - how about the conference itself?

Well I don't have the time, space, or effort to really give a full run down on the talks and posters I saw. But I do have the time, space, and effort to go into the presentations I saw that dovetailed with many of the developing ideas and hypotheses I present here at antediluvian salad. So yeah, it really is all about me ;') - if you want more of a general run-down and review - check out some of the other blog posts about SVP2016.

Semicurcular Canals, Lifestyle and the Theropod Agility Spectrum

The first talk that really resonated with me was by James L. King who is looking at the anatomy of the semi-circular canal in both extant and extinct theropods as a method to infer trophic lifestyle.

I provided the summary above for your reference and mine. What is not included here and what was discussed at length at the talk is that King did resolve a cluster in morphospace indicative of agile, predatory life histories in theropods. Allosaurus, several tyrannosaurids, dromaeosaurids clustered in this group. Who was the outlier? Who fell out from this grouping? Andalgalornis - a phorusrhacid and good ol' sexy rexy himself T. rex. Long time readers of this blog should recognize that I do have a bit of a history with these interesting and imo often misunderstood predators. In Terror Birds Cometh: A New Hypothesis Unlocking Phorusrhacid Feeding Dynamics & Ecology I vehemently argued against the recent interpretation of phorusrhacids as agile pursuit predators of small game (Degrange et al. 2010) that delivered precise downward blows to the back of the neck of small game from the beak tip. Instead I offered that the bite and ecology of phorusrhacids is most similar to giant scaled up vultures and petrels - they were arch predator-scavengers, not small game specialists. Serrated tongues and papillae - just like we see in modern carcass rendering birds - allowed them prime access to the diverse, ponderous and large paleo-mammals they shared the continent with. If Andalgalornis was indeed a "rabbit killer" we should expect semi-circular canals congruent with other agile, predatory theropods. The preliminary data of King does not suggest high agility in Andalgalornis, suggesting that my interpretation of phorusrhacids as macabre ground vultures on steroids - not rabbit killers - may in fact be the more likely lifestyle for these birds. I would also interject that the likely appearance of these birds - often depicted as fully, feathered, regal, and attractive - was most likely ghoulish, nightmarish and full of ewww factor. People tend to forget that humans are animals too and what disgusts and offends us will likely disgust and offend other animals - such as competitors at the carcass of a giant sloth.

It also should not be too much of a surprise why I think that the work of King so far in showing that T. rex is falling out of the "agile" group of predatory theropods brings a big smile to my face. Now King himself at the talk lamented this fact and felt that some in the audience might be a little disappointed that rex fell out as an "agile - hunter" theropod, I guess the assumption being that if rex was not an agile hunter it was not a hunter at all. However King was certainly not referring to me when he made that comment, indeed  if he glanced over at me during this part of his speech he would have seem me beaming with pleasure. As I have been making the case for in the last couple of posts - the (not yet finished) "Nightstalker Rex" series - T. rex had perfected a unique nocturnal method of prey capture. In T. rex speed and agility were not selected for but instead a super - senses equipped predator that could detect, infiltrate, and abduct dinosaurs as they slept allowed ol' sexy rexy to balloon to preposterous girth and size and exploit the complete spectrum of contemporary prey types and sizes.

The Revenge of the Ugly, Fleshy-Faced, Caruncled, Wattled, Snooded, Nightmare Inspiring Theropod with Flesh Antlers

Now, you  know, I just got to do a little victory dance for this one. Especially since I took my share of criticism for it back when I started pushing this view of theropod facial soft tissue structures: What Do Face Biting Birds - Including Turkeys - Tell Us About Face Biting Theropods?  As you can see from the comments this assertion that fleshy facial structures in theropods were widespread and even should be expected was met with a variety of responses - some positive, some equivocal, and some highly skeptical. Now my beef, and my gloating attitude, is not aimed at the people who brought good arguments and points against this notion. Instead, and let me be crystal clear, it is aimed at the people who ridiculed, mocked, harassed, and discounted this idea purely from a place of incredulity, emotional attachment, and group think.

Several parts bear repeating:

"Although the bony feature (frontoparietal fossa) is ultimately lost during avian evolution, homologous vasculature and sometimes carunculate skin remain."

"The frontoparietal fossa reached enormous proportions in large theropod taxa such as Tyrannosaurus, suggesting that theropod dinosaurs may have emphasized the temporoorbital vessels for a physiological role, potentially cephalic thermoregulation, and/or to support soft tissue ornamentation or display structures on their skull roof."

Did you catch all that? Display structures on the roof of the skull? It may well turn out that the skin and flesh derived display structures that I have been arguing for and adorning my theropods with for some time might in fact be on the conservative side!! I should - indeed we should - go a bit further with the extravagance, audacity, and sheer spectacle of theropod skin/flesh derived facial structures. What gives me confidence in this work and its implications is the name Witmer at the tail end of the author list. Lawrence Witmer has, if nothing else, put together quite the cottage industry in churning out high quality anatomically informed papers. Although he is the last author on the authorship his name brand recognition alone should make this topic a worthwhile area for discussion. From what was revealed at the talk; these structures were not muscular insertions as the mechanical leverage was all wrong and no sesamoid bones; lots of vasculature present; homologous structures in other diapsids. I have a lot of confidence in this work shattering how we imagine and depict theropods.

dorsal and ventral view of Allosaurus skull

At the end of the talk Holliday implored paleoartists - indeed he pretty much laid it out there - that T. rex and other theropods with large temporal fenestra and excavated frontoparietal fossa should be depicted with snoods, hoods, and other types of soft tissue structures. He neglected to mention caruncules - seems that everyone hates caruncles - but the point was not lost on me. Indeed I would take this notion of theropod cranial soft tissue structures a step further: if you look at the placement and size of these structures you are left with the observation that there is a lot of freakin' piping available to support soft tissue structures. Indeed what we might be looking at is the potential for soft tissue structures that can be engorged with blood. This could literally create structures - functionally and anatomically congruent with antlers - that would dramatically change in size, shape, and color depending on the mood of the animals. Condors can dramatically engorge the tissues on their head and they don't even have the piping that non-avian theropods did!! A great tool for sexo-social display - especially for rival intimidation/fights over carcasses. I never really bought the idea that the crests, ridges, and hornlets on the heads of theropods were their primary display organs - just too small and lacking in that wow!! factor. Instead bring on the flesh antlers.

Lythronax argestes dorsal view, credit Lukas Panzarin. note large and extensively excavated fossa around dorsotemporal fenestra 

Paleoartists need the courage, audacity, and freedom to eschew notions of what a typical theropod "looked like". Indeed this whole argument of what is accurate paleoart and what is fantasy should in part be blown up. Do I expect any of the premiere, commercial, "world renowned" paleoartists to start depicting theropods with diverse and wild soft tissue structures on their head? If history is anything to go by, probably not (I would love to be proven wrong though). Remember, well if you are under 30 you probably can't remember, that when Gregory S. Paul started aggressively feathering theropods it was not like the Doug Hendersons and Mark Hallets of the world immediately jumped on board with him.

Hopefully some budding paleoartist on deviantartist will take the bait and get some inspiration from these rough sketches I put down while waiting at the airport for my plane home. Remember kids, fortune favors the bold!!

Speaking of Gregory S. Paul I could not stop running into him at SVP... I mean like everywhere... even at museums, at the hotel... just another synchronicity? Sort of like when I was in the urinal thinking about asking Bakker about the anomalously high predator/prey ratio of T. rex in Hell Creek and then guess who pops in next to me in the urinal... I didn't have the nerve to get into it with him while taking a piss but I swear this happened!!

For the third and final talk that I want to get into - which also btw let me know full and well that I am following the path - is the one on Limusaurus and its very interesting ontogeny. By now you have probably heard the gist of the story. Limusaurus - a beaked ceratosaur that most likely was herbivorous or omnivorous - started out life toothed. Not only was it toothed it started with veritable face daggers.

Now why is this talk by Shuo Want so important to me? It is not crucial for anything I have put out yet, but for something I will in the future. This ontogenetic change from a toothed omnivorous youngster to an eduntulous, herbivorous adult complete with gastric mill encapsulates quite succinctly a change that occurred in many lineages of dinosaurs - including of course birds. What I will be arguing is that a concurrent soft tissue change occurred as well in this transition from predator to omnivore/herbivore.

I can't spill the beans as of yet but I want to build a little suspense for this upcoming project. And I want you to have fun with it too. The answers are already laid out in front of us, we just have not been asking the right questions. So if you are a person who likes exploring, likes new ideas, is open to new ways of thinking about things I ask you this:

Why grow a beak?

Don't answer too quickly.. let the question stir in your mind a bit. Realize that it is a quite simple question but one which has not been asked or answered in any sort of quantitative or qualitative manner. There is an answer and it is embedded in the fossil and evolutionary history of the animals that did grow beaks and those that didn't.

Just think about it a bit...

"A Long habit of not thinking a thing wrong, gives it a superficial appearance of being right, and raises at first a formidable outcry in defense of custom". Thomas Paine

Support me on Patreon.
Like antediluvian salad on facebook. Visit my other blog southlandbeaver.blogspot
Watch me on Deviantart @NashD1Subscribe to my youtube channel Duane Nash.


Nick Fonseca said...

I thought you mike like this.

I was inspired in part by your posts about dino skin, and obviously the Cassowary.

Duane Nash said...

Very cool. I would like to use that image or an image of that when it is done. Indeed theropods that started fully scaled and then became fully feathered and then became naked skinned in many places give us a lot of play for skin display devices. Just as many birds show us today. We have just been way too conservative in our choices from the panoply of modern bird display structures. If there is one pattern to glean it is that the larger the bird and the hotter the environment the more naked skin on the head, neck, and forequarters occurs. Not always but often. Large theropods in hot environments would definitely fall into this pattern of large patches of naked skin on the head, neck, and forequarters.

Iris-Katyayani said...

Amazing post Duane. There's so much in it I can't quite say all of what I want to! But I can say this; I hope there will be a minor revolution in the way we portray Theropods from now on. Now people can't really give the excuse of "it's to speculative", when it's speculative if not wrong to NOT give them something funky on their heads. There's a wide spectrum of uses as well; thermoregulation/heat transfer, display, intimidation, protection and also simply to just look healthy and strong. And that's a great idea about Allosaurus and the reason for such mass grave sites.

Andrew Raymond Stuck said...

I think this most recent Tetzoo article on ceratopsians dovetails nicely with your musings on theropod soft tissue displays:

Duane Nash said...

@khalil indeed shying away from such soft tissue structures or giving the "it's too speculative argument" is not so defensible with osteological correlates coming to light. The soft tissue revolution keeps on going and takes no prisoners. Like I said in the post people are going to be tentative and conservative at first in depictions of soft tissue structures on theropod heads - but that is the wrong attitude to take. The whole point of display structures is to stand out, be flamboyant, attract attention - the WOW factor.

@Andrew Raymond Stuck I'm telling you synchronicity strikes again!! I read it and I'm glad Darren threw caution to the wind and got behind the idea of inflatable nose pouches in ceratopsians.

D-man said...

There was actually an SVP study talking about T.rex locomotion. It said that T.rex and its relatives were very adept at speed (on par with derived ornithomimids). There was another that said T.rex was better at covering longer distances than carnosaurs of similar size.

Also, I had a friend that went to the SVP. The scientist behind the theropod face coverings said T.rex only had a large vein just behind the skull, unlike with Allosaurus which has carnaculed face

Duane Nash said...

I take any speed estimate with a grain of salt - especially with T. rex. All we can really get at is rough approximations. No one can really prove that T. rex was actually faster than Ankylosaurus, and it most certainly was not as agile. The lower range of speed estimate for T. rex 15 mph or so is well within the range of speed that a hippo can achieve and there is no reason to assume ankylosaurs can not go as fast as a hippo so it is quite possible that ol' rexy was no faster and certainly less agile than an ankylosaurus.... that is why I keep going back to agility as a better index of behavior than speed estimates (which are inherently wide ranging and will probably always be). The preliminary work on semi-circular canals seems to posit rex as not inherently agile.

"I had a friend that went to the SVP" Well he must have misunderstood the talk or gave you faulty info. I don't recall anything as precise as what you say "allosaurus has a carnaculed (sp?) face" being posited. I think you mean caruncles? And a " T. rex had a large vein just behind the skull" ummm what? The talk was on supratemporal fenestra and how they could conceivably foster brain cooling and soft tissue structures - so probably potential for lots of large veins sprouting out of the supratemporal fenestra. Not necessarily mutually exclusive and no there was no distinction drawn between Allosaurus and T. rex in those terms. Unless your friend spoke privately with the "scientist behind the face coverings" who has a name and it is Casey Holliday. If you look at the size of supratemporal fenestra in the pics I posted above you can see that both the allosaurus and the tyrannosaur have large holes. I don't see how the conclusion your friend drew or thought was being drawn can be supported.

What can be said and what Holliday was making a point about in his talk is that these holes were not for muscular attachment as always assumed. That leaves the possibility for brian cooling and/or soft tissue structures. Both uses are possible and not mutually exclusive. The soft tissue structure radically alters our traditional image of theropod appearance. I don't know where the confusion is coming from.

However I do find it interesting that this potentially radical work has gotten little too no attention in paleoart or the online paleo community. It's like some people go into denial mode at the mere suggestion that theropod skulls when covered in flesh did not look like mirror images of the skeleton. I also find it very telling that Darren Naish's nose balloon ceratopsian post has got all kinds of attention and noise while this - more rigorous study - has got hardly any noise...

Related Posts Plugin for WordPress, Blogger...