Wednesday, November 16, 2016

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

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

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Friday, October 14, 2016

Night Stalker Rex Part II: Tyrant Tummy Tucks & Where the Rubber Meets the Road

As Khalil Beiting pointed out in my last post T. rex is actually not the only known barrel chested terrestrial theropod. Allosaurus, though certainly not displaying the thickness of T. rex, has a pleasantly plump countenance. And certainly all other tyrannosaurids display a thickened torso to varying degrees. In the case of Allosaurus a highly agile, cursorial nature need not be selected for - giant sauropod carcasses, sauropodlets, and stegosaurids are not winning any foot races. Having a little extra in your back pocket might come in handy for Allosaurus when wrestling teenage sauropods and intimidating/fighting over carcasses with rival mega-avepods. In the case of other barrel chested tyrannosaurids I believe this increasing girth - culminating in T. rex of course - speaks to a general trend of highly sensory adapted, nocturnal, stealthy, territorial, quick killing, and calculating predators.

Of course when I speak of "fat" tyrannosaurus or other theropods I am not implying that they are fat the way a super weaner elephant seal pup is. Obviously they probably carried some fat depending on the season and condition but this fat would be concentrated at the base of the tail, thigh, abdomen and hip near the center of gravity (kind of like a chicken). When I speak of "fat" T. rex & tyrannosaurids I mean that they are coming at you with the thickness. A professional football linebacker or a sumo wrestler are both athletes, are both powerful in any sense of the word, are both athletically gifted in any sense of the word, and they both  are carrying not a little, but a lot of fat. But these "girthy" athletes are probably in better shape than the average reader of this blog and one would hesitate to call them "fat" in the negative connotation of the word if they were within arms reach of you.  It is a bit paradoxical that such large athletes are rarely described as "athletic" even though they perform amazing feats of power and strength. The term "athletic" seems to be reserved for only the svelte, lithe, trim, and quick athletes in the pantheon of "attractive" olympic body worship culture.

pro-baseball player Prince Fielder

It is this bias I speak of - "what constitutes athletic?" - and how this concept intertwines with being slim, of low body fat percentage, and being of a culturally established level of physical beauty and attractiveness. It is this bias, I assert,  that creeps into and underpins our thought processes when imagining what constitutes athletic and attractive creatures of deep time and how they should look.

olympic athlete Holley Mangold
It is my contention that we want slim attractive theropods - especially tyrannosaurids - because this matches what we want to see in our own vaunted athletes. Slim equals beauty, success, athleticism, and adaptive superiority. Fat equals ugly, inferior, sickly, tired, slow, and headed towards the evolutionary dustbin. The notion of fat dinosaurs, especially fat theropods, also strikes a dissonant chord within us because this was the predominant past visage of dinosaurs prior to the dinosaur renaissance. And we all know that the past researchers of dinosaurs (pre-renaissance) got everything wrong, right?

Gorgeous George and some dumb duckbill. credit Archive of Field Museum

Above is the old - and now overhauled - predatory pose of Daspletosaurus dubbed affectionately "Gorgeous George" over some dumb duckbill at the Field Museum of Chicago (special kudos to DinoGuy2 from the dinotoyblog forum for jotting my memory of it). Although I never saw it in person I do remember this image vividly from my childhood. What I want to talk about is not the outdated vertical mount, or the tail dragging, or the pronated hands, or the dubious taxonomic status of this specimen. Go read this excellent write up The Glorious Journey of Gorgeous George if you want to learn more about the history of this mount. What I want to draw attention to is the gastralia in this mount that denotes a very thick and round countenance.

Gastralia are rarely included in mounts, even to this day, and I can't overstate the caveat that skeletal mounts sometimes get it wrong. On the other hand can anyone prove to me that the gastralia as depicted here did indeed get it wrong? As noted in the linked history of this mount the gastralia is not of the original bone. But it looks to be a pretty seemless transition of the gastralia from the pubic bone to the furcula. Based on articulated specimens of other theropods with intact gastralia this should be what to expect.

stolen form some creationist web page
What is interesting, and maybe it is just perspective playing tricks here, is that when we look at the refurbished mount of Daspletosaurus at the Field Museum, Gorgeous George looks like he has lost a few pounds.

Did you lose some weight Gorgeous George? credit Funk Monk CC2.0

It appears that Gorgeous George in his new dynamic posture has received a bit of a tummy tuck. Where  did this tummy tuck come from?

Well if you go back and read Predatory Dinosaurs of the World Gregory S. Paul advocated hollowed out bellies for theropods:

"...theropods probably looked lean, sleek, and a little bony, like big dogs and cats. "Plump" theropod drawings are certainly wrong." (Pp. 105)

"Predators gorge at a carcass, then fast until they are hungry again. The stomach is highly distensible so it can hold big meals. In accordance with this the abdominal "ribs" or more correctly gastralia, of predatory dinosaurs were poorly ossifiied, multijointed, and very flexible. So hungry theropods on the hunt should be drawn with hollow cat- or dog-like bellies. In some of the big mounted skeletons, the abdominal ribs are mounted to form a distended belly, which would be true only after feeding on a kill. A satiated theropod mush have waddled away from its meal!" (pp. 106)

His skeletals follow suit. Go peruse his theropod skeletals, especially of any large bodied forms, and you will note he gives a distinctive tummy tuck to the gastralia just after the pubic bone.* But is there any evidence for such a tummy tuck in theropods? Would the gastralia of a hungry theropod necessarily have formed such a hollow cavity or would a theropod belt - line been a bit more ample? I have not found any preserved specimens and I welcome any evidence supporting such a tummy tuck. Crocs don't seem to have it. I can't discern such a tuck in any of the remarkably complete specimens of theropods... you can connect the dots or the gastralia as you want BUT there might just be a bit of a modern day bias in trimming up theropod skeletals/mounts in some cases. Perhaps the ol' skool look had a little bit more truthiness to it than we might initially presume... I have not noticed the tummy tuck in Scott Hartman's skeletals but I do think his flesh outlines are too svelte.

*I am not suggesting that GSP ignored or misinterpreted data merely that his depiction of tummy tucked gastralia is consistent with his assertion of hollow bellied, svelte theropods.

Things seem a little equivocal on the exact neutral placement of gastralia but there is some work done go here. Instead of gastralia allowing a "tummy tuck" look as GSP asserts Classens advocates a more concave look for theropod gastralia:

"In ornithomimids preserved in situ the ventral outline of the abdominal wall as indicated by the gastralia is usually concave. Although this may be a taphonomic artifact, midventral shortening of the gastralial system would result in ventral movement of the abdominal wall (fig 16 A-C below). The ventral movement of the body wall during protraction would result in an increase in trunk volume"

(from Classens 2005)
Also form Classens 2005 it does appear that in crocs there is strong musculature linking the pubic bone to the gastralia seeminly negating the possibility that such a tummy tuck would be apparent in life. Instead the gastralia likely moved as one functional unit and might not "pinch in" to denote an empty stomach. Indeed if an empty stomach would cause the "tummy tuck" look to appear we should see lots of evidence of this look in crocs since they are ectotherms and often have empty stomachs. But do we see this "tummy tuck" in living crocs? Nope.

Chubster Tyrannosaurus from David Norman's Dinosaur! non tummy-tuck
Svelte Tummy Tuck Tyrannosaurus credit Gregory S. Paul used for educational purposes "don't sue me please"

As you can see adding the tummy tuck has a profound effect on how the rest of the gastralia line up, dramatically altering the profile of the animal. Classens cites a paper by Carrier & Fisher that during gastralial retraction the abdominal cavity could expand 14% in Allosaurus !!

non-tummy tuck T. rex postcard from London Natural History Museum taken from Don Glut
credit Neil Lloyd taken from Love in the Time of Chasmosaurus

Obviously the above image has some glaring issues - but maybe the rotund girthiness offers a lot more truthiness in it than we might be comfortable in conceding?

Where does the truth lie with regards to gastralia placement? Maybe a bit in between the Gorgeous George look and the GSP tummy tuck look? Or is that just a needless compromise? Personally I suspect past "chubster" depictions might offer a shade more truth than the more recent svelte, trim depictions. Perhaps we prefer our theropods svelte, trim,  and "athletic" looking just like we prefer our modern day "athletes" to look with respect to olympic body spartan hero kult skinny worship?

Think about balance for a second. Having the most rounded, heavy part of your body towards the center of gravity makes absolute sense for a horizontal obligate biped, especially one with a big head. Functionally theropods would be more stable in that configuration.

Did I just make all theropods - not just tyrannosaurids - "fatter" or phatter if you prefer? Yeah I said it, every svelte looking, skinny, tummy tucked theropod is OBSOLETE!!   ;')

CutiePie by Duane Nash

Weird enough for you?

Whiskers, of course it had whiskers. A big fat tail base because of the caudemofemoralis and fat storage, of course. Prominent pterygoideus flare just like in big crocs - why not for the strongest terrestrial biter ever?  Obscene tufts of thickened skin around the head, neck, and forequarters - biting into the neck of T. rex would be like biting into a flat big rig truck tire. But probably the first thing that catches your eye is dem big honking toes and feet, enough to give any pedicurist nightmares...

The feet of course are why this post is subtitled "where the rubber meets the road" because it is the feet that take much of the impact of the stresses and strains of a biped the size of a small whale. They would need cushioning - gel soles if you will - and lots of it. More so than is pretty much always depicted. In other words pretty much every image of large theropod feet is - OBSOLETE!!!   ;')

Because the feet of Tyrannosaurus and other - quite literally - mega-avepods have to react to the stresses incurred by high weights we should think about the ol' square cube law. Since volume increases faster than surface area large theropods should have relatively bigger, derpier, and more rotund toe and foot pads than their smaller brethren. Trackways confirm this.

Credit Rufous-Crowned Sparrow. Philmount Ranch new Mexico

Richard T. McCrea, Lisa G. Buckley, James O. Farlow, Martin G. Lockley, Philip J. Currie, Neffra A. Matthews, S. George Pemberton -

In situ tyrannosaurid Bellatoripes fredlundi Trackway A images. a) Print #2 of Trackway A (in situ) - PRPRC 2011.11.001 (right); b) Trackway A (in situ) view to the east of prints #1–3. Note the thick layer of kaolinite in the freshly excavated area in front of print #3.
There is also loads of examples of large theropod footprints getting confused with large ornithopod footprints and vice versa. Almost like there is some sort of biomechanical constraint imposing limits on the pedal morphology of giant bipeds? Hint, hint there likely is...

Also of note is the reported gigantic abelisaur footprint of recent news that features a positively gigantic foot pad. I have heard some chatter it might be from a sauropod back foot but when giant biped get their foot on it just may have looked like that...

Not only are giant theropod feet bigger, wider, and more plump than generally depicted, the claw itself was likely fairly elevated off the substrate in neutral position with only the tip contacting the ground and perhaps only when it pushed off. Think more like giant dog paws. YW Lee was kind enough to share this purported photo displaying massive toe pads on the feet of Concavenator. I honestly don't know if I am breaking some embargo here or if this should be taken down (let me know if so), but sheesh that padding is incredible.

Anyways make of these pics what you will, perhaps I severely underestimated the amount of toe padding in my illustration?!?

In any case there are good examples from present theropods that have toe pads to suggest that as bipedal terrestrial theropods get bigger the padding on their feet get relatively bigger to compensate for the exponential expansion of volume (i.e. weight).

Compare the foot padding on a turkey to an ostrich:

credit Malcolm Libury. turkey foot

credit Masteraah. CC2.0

For paleoartists wanting to draw large theropod feet with a bit more truthiness: draw them bigger, plumper, more elevated claws, more uglier, and just plain derpier than you see in all other depictions (including any and all "world renowned" professional paleoartists). It is quite interesting why big ol' toes and toe pads have not got a "footing" so to speak (bad pun is always intended) in theropod paleoart.  I have discussed the patently obvious issue of ignoring abundant large toe pads in dromaeosaurids before - which calls into question a tight grasp needed for the RPR model of dromaeosaur predation. We have had evidence suggesting as such for some time via these footprints. But in my estimation only a paltry foot pad is given and never do you see the claws actually raised off of the ground.

Big, gnarly, ugly toes and feet are simply not as attractive and sexy as the slender, refined, and petite toes and feet of modern theropod paleoart. We keep wanting to export our cultural baggage with us in our excursions into deep time.

So back to stalking technique and what big foot pads, chubby toes, and gel shoes meant for T. rex and other large theropods. What these attributes imply is that one of the most iconic scenes from Jurassic Park - the cup of water rippling at the approach of T. rex - is truly and utterly false. Not only that, such a noisy approach is diametrically opposed to the stealth mode that these animals operated in.

T. rex and other giant avepods would have been disarmingly quiet when walking around. Their huge and fleshy toes and foot pads smothering and muffling the sound of any snapping vegetation or substrate that might betray their presence. In heightened stealth mode - when they were actually stalking - they would have moved with the precision and care of a gigantic heron. Students of natural history should immediately think of the commonly observed silence that elephants can move with. An uncanny ability to slip into stealth mode is often attributed to these animals by hunters/poachers/naturalists as they can at will slip into the brush and disappear noiselessly.

Elephants are also useful in providing an example of unequivocally gigantic, stealthy, and strategic (plant) predators that make successful and repeated nocturnal raids on the subsistence farms of hyper vigilant but nocturnally ill - equipped hominins.

When T. rex and other tyrannosaurids were not out performing stealth raid operations at night what were they doing during the day? Probably a lot of lounging around on their big fat bellies, preferably in a morass of cooling mud or body of water like the self satisfied tyrants they were. Probably looking quite ridiculous while doing so. And yes they could lie down just as I depicted below. (Pp 199 Ch. 11 Rex, Sit: Digital Modeling of Tyrannosaurus Rex at Rest Stevens, Larson, Will & Anderson Tyrannosaurus Rex: The Tyrant King).

Cuz bad asses do what they wanna do and they don't care what you think about 'em or how ridiculous they look doing it.


From Amlaner & Ball 1983. encountered here


The Glorious Journey of Gorgeous George. Extinct Monsters

Classens, Leon P.A.M. (2004) Dinosaur Gastralia: Origin, Morphology, and Function. Journal of Vertebrate Paleontology 24(1) 89-106: March 2004 online

Paul, Gregory S. Predatory Dinosaurs of the World. 1988 New York Academy of Sciences. Sime & Shuster

"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

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