Thursday 15 December 2022

Tetzoocon 2022 - Day 2

Go here if you have not read part 1 yet. If you want to listen to Me and C.M. Kosemen talk about our experience at the con, you can also check out our two-part podcast on the event:


These podcasts are also available on most RSS-based platforms. Anyway, let's just jump right into things:

The morning of day two was all dedicated towards our favorite flying reptiles, the bir... I mean pterosaurs. Unfortunately, I arrived too late to listen to Elizabeth Martin-Silverstone's presentation on why you should (or shouldn't) CT-scan a pterosaurs. By the title alone I bet it was interesting. I did come in time for Natalia Jagielska's talk about how to describe your own pterosaur. This was much more than her just retelling how her description of Dearc went. Instead it was an actual how-to guide on what to do and what the steps are from the moment of a fossil's discovery all the way up to publishing its description in a scientific journal. Especially notable is the frustration many go through with the process of peer-review (which, in its current form, I hear many paleontologists say nowadays, has become somewhat antiquated), as well as the fact that not everyone may have the financial means to publish their findings. As you can see here, Natalia also made excellent use of memes in her presentation.

After that was the pterosaur roundtable discussion where Jagielska, Martin-Silverstone, Witton, Conway and Naish all sat together and collectively dunked on "the two Daves", also known as David Martill and David Unwin, who have gained a bit of infamy thanks to their dubious claims in recent years around pterosaur biology. Especially telling was Martin-Silverstone's account of how one of the Daves simply tried to evade the discussion when told that fossilized melanosomes were found inside pterosaur pycnofibers, which is pretty conclusive evidence that these fibres were fuzzy epidermal structures on the outside of the body. At the end of the session I actually had a question for the presenters, but there was unfortunately no time for me. I did the next-best thing and asked Darren Naish on his blog afterwards and he gave me a pretty helpful reply. Through Memo I have also heard that John Conway also disagrees with Paul's idea on pterosaur locomotion, at least when it comes to azhdarchids. 

After that was Steve White's presentation on his new Mesozoic Art, the quasi-part-three of his Dinosaur Art book series, but now under a new publisher. White told about all the trouble he went through to get these books published and I think the main take-home message I got from his talk is that nowadays, unless you are a big name or dealing with children's media, it is best for paleoart- or paleontology-themed books to be self-published, something I will have to keep in mind (*wink*wink*).

After lunch and a signing event by everyone at the con who contributed to Mesozoic Art (it was a lot), came another rountable discussion, about something completely different. C.M. Kosemen, Gert van Djik, Jennifer Colbourne, Joschua Knüppe, Adrian Tchaikovsky and Dougal Dixon all sat together to talk about designing alien life. Especially Dixon I felt shined during this event thanks to his sheer enthusiasm. He quipped some funny but also thoughtful comments about the production-constraints on alien designs and also told us more about his novel Greenworld, which still has not gotten an English release! Especially fascinating was his statement that he thinks that real alien life will probably look nothing like what he or the other presenters designed and might resemble more something from Stanislaw Lem's Solaris, which I actually somewhat agree with. Then he surprised everyone when he whipped out his... model of a Greenworld character riding on an alien insectoid creature. It does not go mentioned enough that Dixon is also a pretty great 3D-artist who does an excellent job at turning his speculative creatures into models. The next surprise then came for the whole audtitorium when Spencer Drake, the grandson of the Frank Drake, happened to sit in the audience and asked the presenters their opinion on OG Drake's claim that, due to the constraints of evolving intelligence, most spacefaring aliens will happen to look vaguely humanoid enough that, if you encountered them at night wearing a trenchcoat, you'd probably mistake them for a human. Even though I also disagree with this assessment (I am firmly of the opinion that, when we finally do find extraterrestrial life, even intelligent forms, it could be so different that we might not recognize it as alive at first. I am actually somewhat frustrated with my own alien designs being still too similar to things one might find on Earth, but it is of course difficult to imagine things beyond any of your own frames of reference), I still thought some of the responses to Spencer were a bit too blunt and harsh. Especially Knüppe just saying that he hated it (without elaboration), to the point where he made a parody of the concept where a species evolved a humanoid body shape but happens to have the intelligence of a cockroach (an admittedly fun take, but to take some wind out of his sails, H.G. Wells already did that subversion over 120 years ago).

Then came John Conway's presentation on his new book A History of Painting (With Dinosaurs), which basically sprung up from the question of what would have happened if Renaissance artists and other famous painters, from Dali to Monet and Warhol, had painted dinosaurs. What followed were Vermeer oviraptors and cubist ankylosaurs. Notably, Conway presented the book and each painting as a trial-and-error experience, the whole endeavour basically being an experiment in what styles work and do not work for dinosaur illustrations (and it of course also asks the question what dinosaur art should even be like and if it even needs a specific use to “work”). After All Yesterdays and hyper-realistic paleoart by the likes of Julius Csotonyi and Andrey Atuchin, I believe Conway here crystallized what might very well become the next big paleoart-movement, which I think had already been brewing in the background for a couple of years: A shift away from trying to be photo-realistic and more towards stylisation and experimentation with what methods and styles are useful, both for artistic as well as scientific purposes. And I can already see various areas to expand on where other arists could experiment. Conway restricted himself only to European/western art history from the Renaissance onward, but of course people all throughout the world have developed vastly different and intriguing art-styles since prehistory. How would dinosaurs look through the painting methods of East Asia? How would the Ancient Egyptians have depicted dinosaurs in their tomb reliefs?

Finally came Mark Witton and Ellinor Michel's presentation on The Art and Science of the Crystal Palace Park, a great book I have already written about. Witton and Michel talked about what drove them to write this book, as well as some anecdotes. Very fascinating was Michel's story of how, due to being restricted by her wheelchair, she was forced to stare at the park's alleged Megaloceros fawn for an extended amount of time while Witton and others were closely investigating the main statues, which led to her noticing that it did not at all look like a deer. After further investigation it turned out that this was not meant to be Megaloceros, but actually the last surviving member of a family of four Xiphodon that were originally on the Tertiary Island. As the authors note, such a massive mistake in the park's long history of restructuring makes one wonder what else might be missing from the park's original iteration. Having read the book beforehand, I already knew about the missing Xiphodon, but it was a nice detail to know how exactly Michel and Witton made that discovery.

At last then came the Tetzoocon Quiz. I got only nine out of thirty points, though according to Naish the average is four, so good for me I guess. I definitely appreciated the question about what plot did not happen in the tv show Primeval. I am always happy when people remember that one, but the question made me realize how bizarre this show must have been for people not into it.

And that concludes the first ever Tetzoocon I was able to attend. Laughs were had, merchandise was bought, friends were made. I got to photograph Dougal Dixon being proud of his dinosaur tie (and also bought from him the new 40th anniversary edition of After Man). I hope I made some people tune into the CMTK Podcast and also read Har Deshur. On the day after there was also a guided tour by Naish through the Crystal Palace Park, but I was unable to attend that because then we already had to fly back. However, I did go to the park by myself the day before the convention, and that story shall soon also be told.

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Thursday 8 December 2022

Tetzoocon 2022 - Day 1

Well guys, I have done it. I have managed to attend Tetzoocon for the first time! As you know, I am not from the UK, so this was part of a wider London vacation, during which I also visited the Natural History Museum and the Crystal Palace Geological Court, as well as a bunch of non-zoology related stuff (like the pretty awesome War of the Worlds Immersive Experience), but those stories I will tell in future posts. Before I begin telling you about the first day of Tetzoocon in this post, here are a few climatological and anthropological observations I made during my first visit to the UK in over a decade:

  • You know how in Breaking Bad any scene that is meant to take place in Mexico is tinted with a yellow filter? I felt like the same happened in real life as soon as I stepped out of the plane, but with the colour grey. I have never seen such greyest of greys as I did in London.
  • During a bus tour at night to see the Christmas street lights I noticed that the skyline gives the grey night sky quite an alien glow. In front of this backdrop, this gave the London architecture quite a sinister appearance. 
  • The British have technologically advanced enough to have already invented the traffic light. However, nobody in this remote part of the world has apparently had the idea yet that these lights are on occassion supposed to turn green for pedestrians, creating a peculiar culture of ritualized jaywalking. Perhaps the constantly grey environment has led an aversion to the colour green. 
  • Fish and chips taste the best when the restaurant-owner is a Turkish man.
  • This is the only country I know where law enforcement and other state employees dress like they purposefully do not want to be taken seriously.
  • The public transport system could use some work.
  • Everyone was very nice.

Day 1 of Tetzoocon began early in the morning with everyone arriving and the presenters setting up the stalls. One of the first people I got to talk with by coincidence was Gert van Dijk, who is a pretty nice dude. He asked me how I solved the problem of a convincing tripod walk-cycle with my Hellasic Dyles, to which I sheepishly had to answer that my aliens are tripods more out of Martian genre obligation rather than biomechanical sense. He certainly got me there. I also got to meet my friend C.M. Kosemen for the first time in person, which was pretty great. He even brought some memento-cards for our podcast. Memo and his wife were a bit late to the event so Me and my girlfriend helped them set up his stall before going into the first presentation. 

The event was of course opened by Darren Naish himself, no surprise there, who quipped some jokes and explained some things to newcomers.

The first proper presentation was then given by naturalist Jack Ashby, who gave a talk about his book Platypus Matters: The Extraordinary Story of Australian Mammals. It began with some fun facts about platypodes, some of which were certainly new to me, such as the venom produced by the animal's ankle spur being able to cause pain for months. Many of these amazing facts about the platypus Ashby then used to ask the question of why, when we talk about Australian animals, we use such traits as a reason to describe them as weird or primitive, while animals more familiar to western audiences with equally unique traits get called amazing or magnificent. From here Ashby went into the colonial history of othering Australian animals and how this not only has a lasting effect today but also how inaccurately viewing Australia as an evolutionary backwater has had a tremendously negative effect on trying to preserve the continent's fauna. Overall, a great presentation. As I myself have written about the othering of certain animals, Ashby said a lot of things that resonated with me and he definitely convinced me to buy his book.

Hana Ayoob's planned talk unfortunately had to be cancelled, so next up was Dean Lomax talking about Locked in Time, a book on paleoethology which I had already read and can thus highly recommend. Lomax went into the history of what inspired his book and presented some of his favorite examples of fossilized behaviour. Pretty standard, but Lomax's energy and enthusiasm made it a very enjoyable talk.




After that was already book signing and lunch pause, where I helped Memo out at his stall and got to talk to more people. There was an interesting guy who bought three whole original drawings made for All Yesterdays, among which was Memo's version of Johann Jakob Scheuchzer's Homo diluvii testis. Working for the museum where most of Scheuchzer's original collection is stored (though the original salamander fossil is unfortunately still in Haarlem), I told the man some facts about that story, which led to him wanting to record my voice because apparently I was the first German-speaking person ever who could tell him the correct pronunciation of Scheuchzer's name. Pretty bizarre experience. Edit: As it turns out, the person in question was zoologist Paul Stewart.


Then came the big talk where Kosemen, Naish and Conway reminisced on the anniversary of All Yesterdays. Most of it was Naish retelling the story of how the book came to be, with some added details by Kosemen and Conway. I felt like I had heard most of it already and wished they had gone more into detail about the different reactions to the book and the movement it started, as well as what direction they thought paleoart might be heading into in the future. But hey, I will probably ask Memo that directly in the podcast.

Sitting at the talk were also these chaps from a little known website called Love in the Time of Chasmosaurs. Maybe you have heard of them.

The next presentation, of which I unfortunately forgot to take pictures, was Jennifer Colbourne talking about tool use in animals and if certain non-bird theropods could use tools as well. The different classifications of tool-use were interesting to learn about and there is nothing disagreeable with her assessment that, if troodontids did use tools, it would have been only a very basic, biologically pre-programmed practice. I did disagree however with her statement that there is no way fish could use tools.

Then came Cassius Morrison with his presentation about Ecological niche partitioning among non-coelurosaur theropods. The things he talked about were very interesting, among which being the idea of using megalosauroids, whose diets are pretty well-known, as a sort of rosetta-stone for various Mesozoic ecosystems, as well as the realization that megalosauroids may have already had strongly water-adjacent diets even before the evolution of spinosaurids. This might mean that giant carnivores like Torvosaurus should be imagined more as ecologically bear-like rather than as apex-predators. The problem was just that the way Morrison presented all this felt very long-winded and dragging. I think he could have summarized many things more concisely and I believe he also went noticeably overtime.

At last was Darren Naish's talk on the often overlooked herpetofauna of Britain, which was pretty good. Naish went into the fossil history of reptiles and amphibians of the British Isles, as well as many unfortunate mistakes in assessing the true herpetological diversity of the country, such as when pool frogs were for a long time mistaken as an introduced species, leading to their British population going extinct before it was realized they were natives all along. There is apparently also still a debate over whether treefrogs were ever native to the area or not. The presentation then took a surprising turn when Naish revealed that there were various Victorian societies that purposefully tried to integrate exotic animals into the native British ecosystem, which today has in some cases made it difficult to say which lizards living over there were ever native or introduced. Really fascinating stuff and presented by Naish in a very engaging manner. I also have a suspicion that he came across some of these things while earlier researching the phenomenon of British big cats.









After the presentations came the art gallery where I think everyone had a great time conversing with each other. Dougal Dixon signed my original German copy of After Man, Miranda was infatuated with Gert van Dijk's alien art...


...and I got to meet Mr. Biblaridion of Alien Biospheres fame himself. Fantastic guy, I must say. We talked about the joys of mass extinction in spec-evo, languages and the regrets we have for some of our older content. Afte the event, Memo, Michael and Me went together to a Chinese restaurant and had a nice evening.

But that is not all of course, since the event continued the next day and we will get to that soon.

If you liked this and other articles, please consider supporting me on Patreon. I am thankful for any amount, even if it is just 1$, as it will help me at dedicating more time to this blog and related projects. Patrons also gain early access to the draft-versions of these posts.

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Sunday 27 November 2022

I am coming to Tetzcoon 2022!

Almost forgot to mention it anywhere. This December 3rd and 4th I will be attending Tetzoocon. This will be the first time ever where I attend the convention and also the first time in over a decade that I visit London and Great Britain again. 

I will be there only as a visitor, but C.M. Kosemen, with whom I am hosting the CMTK Podcast, will obviously be a guest speaker at the All Yesterdays Retrospective presentation. For the convention he will actually be bringing little, signable memento cards with his Snaiad and my Har Deshur creatures on them, so look out for those!

There is not much else I can say. I am obviously not a big name in this scene, so most people will not care about my presence (which I somewhat prefer). But if any of you readers look forward to meeting me in person and don’t know what I look like, you can identify me by the unreasonably large amount of dinosaur pins I will be wearing on my sweater.

Saturday 12 November 2022

Diplodocus: A history of reconstructions - Part 2

Here we are back again with a history of Diplodocus reconstructions! Last part we looked at the very first reconstructions of the genus, its predecessors and the fame and controversy that came with the various Dippy mounts. Today we will look at what happened after, as well as the many, sometimes weird ideas that have been made about the genus.

From Water to Land

Fig. 1

Starting from the 1920s onward, Diplodocus, like all sauropods, was interpreted as an erect-legged, but tail-dragging and mostly aquatic animal, with some researchers, such as William Diller Matthew, even going as far as saying that they never left the water by giving birth to live young. The most common interpretation about their diet was that they fed on soft aquatic plants, as their teeth seemed highly unsuited for chewing anything tougher. It was also thought that the head was too small to gather enough food to feed the giant body in bulk, hence why they were restricted to a very slow metabolism. But even back then, some questions about their diet came up, especially in relation to the bizarre, pencil-like teeth of Diplodocus with their blunt tips. In 1924, William Jacob Holland, the same man who supervised the Dippy mounts, proposed that Diplodocus may have actually primarily fed on mussels and other shelled animals, using the teeth to pluck them from rocks. The poor clams were then swallowed whole and crushed in a gizzard by gastroliths. Although he was the one proposing it, Holland himself was skeptical of the idea, as he correctly observed that no one has ever found mollusc shells in the stomach region of any sauropod skeleton. The idea still interestingly foreshadows some modern suggestions that Nigersaurus may have been a freshwater filter-feeder (Hallett & Wedel 2016).

Fig. 2

In the 30s, new specimens were being discovered, such as the Smithsonian’s USNM V 108655, adding to our knowledge about the genus. This specimen was originally assigned to the type species D. longus, but seems to more likely have been part of Diplodocus hallorum (Tschopp et al. 2015), which you might know better as “Seismosaurus”.


Fig. 3 & 4

The view of Diplodocus and other sauropods as aquatic grazers prevailed well into the 40s and 50s, as can be seen by these two paintings, the top one made by Mathurin Méheut for the French University of Rennes and the bottom one by none other than Zdeněk Burian.

Fig. 5

Already in the 50s, doubt began to appear about the classic watery sauropods. Kenneth Kermack’s (1951) studies showed that the laws of physics would have prevented them from using their long necks as a snorkel, like here in this Burian reconstruction of Brachiosaurus, as the water pressure on a fully submerged sauropod would have compressed its lungs so much that it would have been impossible for it to draw in air through its windpipe. If you want to test this yourself (though mind you that this is pretty unsafe), drop to the bottom of a pool and try drawing in air through a two-metre straw. Unfortunately, Kermack’s conclusions were either ignored by the paleontological community or dismissed by Edwin Colbert with the argument that whales can breathe while in the water just fine (Desmond 1975), ignoring the fact that whales do not have long necks and have to come very close to the water surface with nearly the whole body in order to take in air.

Fig. 6

In the late 60s, much change was on its way. In his influential paper The superiority of dinosaurs, Robert Bakker (1968) readdressed Kermack’s results and found various other flaws with the idea of sauropods having hippo-like lifestyles. Their hollow bones meant that they would have awkwardly floated on the water’s surface, whereas hippos and whales have heavy, solid bones in order to better sink. The feet of sauropods were also not adapted for muddy environments and, perhaps most importantly, many of their fossils were found in sediments that implied a very arid environment. Bakker reinterpreted the sauropods not only as fully terrestrial animals that ate the leaves of tall plants like giraffes do today, but also as metabolically highly active creatures, which used their bizarre teeth to rake off coniferous plant matter in massive bulk to then digest it in a gizzard (if sauropods truly used gastroliths to break down their food has come into question over the years (Wings & Sander 2007) and pure hindgut fermentation through a specialized caecum may be more viable (Hallett & Wedel 2016)). While not Diplodocus, Bakker used close relative Barosaurus to provocatively illustrate this new vision of sauropods, showing the animals with a proudly high-held neck, the tail well above ground, striding into the prehistoric savannah like giraffes. This roughly still remains the default interpretation of sauropod lifestyle, as many subsequent studies have confirmed its validity. But it was certainly not the end of mystery and debate around the life appearance of these animals.

Much noise about a nose

Fig. 7

One of the first questions trying to be unravelled during the Dinosaur Renaissance was that of the sauropod face. Most sauropods, especially Diplodocus, have their nares (the bony holes for the nostrils) on top of their skull right above the eyes. Classically, the nostrils were therefore placed right there as well, giving these animals a whale-like blowhole, which of course perfectly lined up with their original aquatic interpretation. With the knowledge that sauropods were actually land dwellers, the position of the nostrils became an intriguing mystery during the Dinosaur Renaissance. A sober take by McLoughlin (1979) was that the “blowhole” instead developed to more easily breathe while the mouth was submerged deeply in the spiky canopies of conifer trees. Giraffes, gerenuks and other high-browsing mammals of today also have retracted nostrils to not get stung in the nose by tree needles and in recent times this has even been put forth as an explanation for the sauropod-like skulls of litoptern mammals like famous Macrauchenia (Croft 2016).

Fig. 8

However, the most infamous take was of course that there never was a blowhole. Coombs (1975) was the first to argue that the retracted nares were actually evidence for a proboscis, based on the fact that animals like tapirs or elephants also have retracted nares to give a strong base for their trunks. Coombs himself did not illustrate this, but many after him did, such as Bakker (1986) above, who was open to the idea, but seems to have preferred the classic blowhole, with the explanation that the on-top nostril-position may have instead been useful for sound production. The sauropod trunk became a recurring phenomenon throughout many 70s and 80s books, mostly aimed at general audiences (read: children) to illustrate the degree of uncertainty in paleontological reconstructions. A trunked alternate history sauropod even appeared in Dougal Dixon’s The New Dinosaurs. Today the idea of the sauropod trunk is not taken seriously anymore, for good reason. No reptile group ever had the facial musculature required for such an organ and various details of the skull anatomy also speak against it.

Fig. 9

Nonetheless, researcher John Martin proposed a variation if it in 1996 with this 3D model of Diplodocus with prehensile lips. This never went anywhere and the exact reasoning and methods behind it remain obscure, though as Darren Naish noted, the position of the nostrils in this model is somewhat prophetic.

Fig. 10

For in 2001, Lawrence Witmer released an influential study, wherein he compared the fleshy nostril positions of various living reptiles and came to the conclusion that the position of it in sauropods and other dinosaurs was much more forward on the skull, close to the snout-tip, as in most other terrestrial vertebrates. In this view, the bony nostrils were just the base for an elaborate flesh-and-cartilage structure, not too dissimilar from what is seen in the noses of modern monitor lizards. This probably could have served a variety of functions, like sound production, thermoregulation and/or maybe housing a rete mirable, the same type of organ giraffes use to soften blood pressure when lowering their heads.

Fig. 11

Witmer’s hypothesis has become widely accepted among modern paleontologists and has now become a standard in paleoart. It should be mentioned, however, that not everyone has been on-board with this. Though open to the fleshy nose reconstructions, Hallett & Wedel (2016) still prefer the classic placement, for a rather succinct reason. Many of the giant, erect-necked sauropods would have had to bow their neck and head down to drink water at such an angle that, if the nostrils were truly at the front of the snout, they would have been submerged in the water, while if they were atop the head, the animal could have breathed more easily. In some ways this seems to go full circle to the old blowhole-interpretation, though it seems like a valid point to consider. The idea that retracted nostrils also made bulk-feeding on thorny trees easier could also still hold some water.

The Neck Wars

Fig. 12

A more well-known issue that arose in the 90s is the question of neck-posture. As a counter-movement to the increasingly more giraffe-like interpretation of sauropod lifestyle, paleontologists such as John Martin (1998) or Kent Stevens (1999) used computer model studies to argue that the sauropod neck was quite stiff and predominantly held in the osteologically neutral posture, meaning horizontally straight forward and largely unable to raise the head above shoulder-level, with the musculature actually being better adapted towards bending the neck down. In this view, sauropods such as Diplodocus were actually low-browsers, who evolved their necks to more easily forage the ground like living vacuum cleaners or giant geese without having to move much. This interpretation was famously immortalized by documentaries such as Walking with Dinosaurs.

 

Fig. 13

Although quite popular throughout the 90s and 2000s and still repeated in some popular sources here and there, this idea has come under quite a lot of criticism. Not only is the vertical lifestyle blatantly obvious in the skeleton of sauropods such as Giraffatitan, but almost all living tetrapods do not hold their necks in the osteologically neutral posture. Instead, muscles, ligaments and especially cartilage give a great deal more flexibility than would be expected from just the bones, with the neck more often than not being actually held diagonal curving upward when neutral (Taylor et al. 2009). A horizontally held, stiff neck would have also been a prime unprotected target for various predatory dinosaurs (Hallett & Wedel 2016). Even independently of the low-browsing hypothesis, the idea that sauropods evolved their long necks so they could just feed a lot without having to walk (as still repeated in recent popular media like Brusatte’s The Rise and Fall of the Dinosaurs) makes little sense, for no living large animal functions by this strategy (Hallett & Wedel 2016). The energy expended by walking up to a close food source is trivial, especially for large animals, as their larger steps alone mean they need to walk less, they actually use fewer calories relative to their size and need less food per kilogram than smaller animals (Hallett & Wedel 2016). So, if you feed from the ground, simply using your legs will always stay the more viable option rather than evolving a new hyperspecialized organ, which makes it far more likely that the sauropod neck instead evolved to reach hard-to-access food sources, such as tree canopies. Of course, one might point to ostriches, being long-necked grass-eaters, but their neck length evolved to compensate for their long legs, which they need to run away from predators (Bakker 1986), something which sauropods did not do.

Fig. 14

A perhaps final blow was dealt to the beam-necked sauropod idea with the 2020 computer-model study done by Vidal et al. on Spinophorosaurus. This study showed that the vertebrae of the pelvic area of this sauropod articulated into a concave wedge, which naturally lifted the spinal column of the animal diagonally upward and also meant the front limb girdle sat lower than usually reconstructed. This means that even in the osteologically neutral posture proposed by Stevens and others, the head and neck would have been pointing upward, quite ideal for high-browsing. That the musculature of the neck was adapted more for bending down makes even more sense in this light, as the ligaments and bones were already doing a great job holding it upright, meaning the animal only needed to exert muscular force when needing to bow down to drink. This has some rather far-reaching consequences, as Spinophorosaurus is generally classified as a basal eusauropod or at least a close relative of that group and the authors reason that this skeletal configuration would have applied to most if not all members of that clade. Since Eusauropoda comprises the Mamenchisauridae, the Diplodocoids (such as Diplodocus or Brontosaurus) and the Macronaria (Brachiosaurids and titanosaurs), this would mean that we have been reconstructing the majority of sauropod postures not diagonal enough (though some are already on their way to correct that).

Fig. 15

In general, it has therefore become popular again to depict Diplodocus and relatives (the animal depicted here seems to be a brontosaur) as high browsers. Sometimes by even using the double-beam chevron bones in their tails that Dippy derives its name from to prop themselves up onto their hindlegs in order to reach even higher into the treetops. This is by far not a new idea, though if this is something they did only occasionally or were specialized for doing regularly has in itself become a minor debate (see Foster 2020).

A final hurdle for the high-browsing camp is the question of how these giant animals handled their blood pressure, which is already a challenge for the much smaller giraffes. Most studies conclude that, in order to pump enough blood into the head of an erect-necked sauropod such as Diplodocus or Giraffatitan, the animals would have required gigantic hearts rivalling those of the largest cetaceans, which seems unlikely. This is today used as the main argument by beam-neck-supporters against sauropods raising their necks vertically. However, to paraphrase Naish (2021), it would be naïve to use this to discount every other evidence in favour of erect-neck postures without first assuming that these remarkable animals did not find solutions to these problems. Instead of having one giant heart, one proposal has been that sauropods may have had multiple pseudohearts along the neck which helped a more reasonably sized main heart with pumping, though such structures are virtually unknown in modern vertebrates, making it seem unlikely (Ganse et al. 2011). More likely, sauropods employed a wide array of smaller soft tissue adaptations, similar to what is seen in giraffes, to collectively lower the need for a large heart and deal with other blood pressure problems, like edema in the extremities. These adaptations were likely a combination of a rete mirabile, muscular venuous pumps, precapillary vasoconstriction, thicker blood vessel walls, extremely strong connective tissues, blood-cushions in the feet (as seen in horses), as well as blood with a much higher oxygen transport capacity (Ganse et al. 2011). That we will ever find evidence for any of this seems unfortunately unlikely, as such organs rarely fossilize. In the best case scenario, a baby sauropod maybe died and got preserved in a high-quality lagerstätte to the same degree as was the Scipionyx holotype and is now waiting to be uncovered.

The Headless Sauropod?

In terms of classification, a lot has also changed in the world of Diplodocus. First described in 1991, Seismosaurus hallorum soon became Diplodocus hallorum in the early 2000s, being a species even larger and longer than the famous D. carnegii, though suspected by some to be synonymous with the original D. longus. The problem with this is that D. longus has itself become a dubious taxon, on account of its original remains being too fragmentary. An attempt was therefore made in 2016 to strip D. longus off its status as the type species for the genus and instead grant D. carnegii the honour, but the proposal was rejected by the ICZN.

A more distressing revelation was made in 2015 by Tschopp et al., in the same study which also resurrected Brontosaurus as a valid genus. Analysing nearly all known remains referred to Diplodocus, they found that, due to the circumstances in which they were found and assigned, none of the skulls thought to belong to Diplodocus could be conclusively linked to the taxon or the species therein. All former Diplodocus skulls were either actually remains of the genus Galeamopus (as is the case with the original head of Dippy, USNM 2673) or could not be identified further than indeterminate Diplodocines, as is the case with USNM 2672, the skull you saw in Part 1 that was retroactively assigned by Marsh to the D. longus holotype. While there is a good chance that the latter ones do indeed come from Diplodocus (Tschopp et al. 2015), we cannot actually be sure until we find a new one firmly attached to a skeleton that is decisively Diplodocus.

In short, for now we do not know for certain what Diplodocus’ skull really looked like (though it likely did not differ too much from that of other diplodocids), which makes all the earlier nitty gritty debates about soft tissue placements rather funny in hindsight. It goes to show that even taxa we thought we knew well for a long time can still end up surprising us, sometimes even becoming more mysterious with time.

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References:

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Image sources:

  • Fig. 1: Holland 1924
  • Fig. 2: Gilmore 1932.
  • Fig. 3: Lescaze 2017.
  • Fig. 4 & 5: Augusta 1956.
  • Fig. 6: Bakker 1968.
  • Fig. 7 & 8: Bakker 1986.
  • Fig. 9: Junk in the trunk by Tetrapod Zoology.
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  • Fig. 13: Taylor et al. 2009.
  • Fig. 14: Vidal et al. 2020.
  • Fig. 15: Hallet & Wedel, p. 146.