Well, that didn’t take long. Earlier today, my subterranean hacker collective released thousands of emails exchanged by Mike Taylor and Brian Engh, which touched on numerous issues of national and global security. Of most interest to SV-POW! readers will be this correspondence from just a few hours ago:

– – – – – – – – – – – – – – – – – – – – – – – –

Mike: Artwork attached. [Scroll down to see Mike’s submission.–MJW]

Brian: NAILED IT.

I haven’t been responding here to entrants but i feel pretty safe calling this one the winner already. Thank you for submitting. We can now sit back and laugh as all the other feeble entrants squabble knowing that you’ve already got this one in the bag.

Mike: Thanks, Brian. I hesitated before submitting this, thinking it might not be fair to up-and-coming artists who need the win more than I do; but in the end, I decided that was patronising. If they’re going to win the prize, they have to beat me on merit. You never know: it could happen.

– – – – – – – – – – – – – – – – – – – – – – – –

So, it looks like Brian has made his decision and the contest is effectively over. Although Mike says that someone else winning the contest “could happen”, Brian’s already signaled his intention to “laugh as all the other feeble entrants squabble”, which hardly sounds like he’s going to be giving anyone else a fair shake.

In Brian’s defense, the art that Mike submitted is glorious:

So complex and subtle is this work, so playful in its blending of traditional and cutting-edge thinking, so packed with detail, life history, and sheer emotion, that I feel certain that it will usher in a new era of paleoart as the dominant aesthetic expression on this planet.

Still, I don’t see how #TheSummonENGH2018 is going to survive the inevitable scandal of having a winner secretly chosen on the second day of the contest. I’m torn between towering admiration for my friends and colleagues, and fear for the rifts this may cause in the paleoart community.

I’ve reached out to representatives of both Mike and Brian for comment, and I’ll keep you updated on this developing story as more information becomes available.

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Someone on Facebook asked whether sauropods had subcutaneous fat, and by the time my answer hit five paragraphs I thought, “The merciful thing to do here is blog this and link to it.” So here are some things to keep in mind regarding the integumentary systems of sauropods.

Emu dissection at UC Santa Cruz back in 2004. Note the fat pad on the chest and how it abruptly comes to an end.

Sauropods may have had some subcutaneous fat – we can’t rule it out – but it probably wasn’t broadly distributed as it is in mammals. In the interaction of their air sac systems with connective tissue, sauropods were probably a lot like birds. Most birds don’t have subcutaneous fat all over their bodies. Instead, they have subcutaneous air sacs (or pneumatic diverticula) over parts or all of their bodies – in pelicans these are like bubble wrap under the skin, presumably for impact padding and insulation (Richardson 1939, 1943). The diverticula go everywhere and most places they go, they replace adipose tissue, even the harmless bits of fat between muscles that are basically the body’s packing peanuts (broiler chickens don’t count here, they’ve been artificially selected to be radically unhealthy). We suspect that sauropods had subcutaneous diverticula because so many other aspects of their pneumatic systems correspond to those of living birds (see the discussion in Wedel and Taylor 2013b for more on that).

Contrast the narrow line of adipose tissue down the ventral midline with the almost-completely-lean hindlimb.

That’s not to say that birds don’t have subcutaneous fat, just that it tends to be highly localized. Back in grad school I got to help dissect an emu (link) and a rhea (one, two), and in both cases the fat was concentrated in two places: huge paired fat pads over the pelvis, like big lozenges, and a concentration over the sternum with extensions along the ventral midline from the base of the neck to the cloaca. It was weird, the fat would be present and then it would just stop, like somebody flipped a switch. We pulled 18 lbs of fat off a 102-lb emu, so it wasn’t a trivial part of the body composition. IME, even relatively fatty birds like ducks tend to have the fat start and stop abruptly, and again, the fat deposits tend to be concentrated on the breast and tummy and over the hips.

Fat-tailed gecko, borrowed from here.

A lot of lizards and crocs and even some turtles carry fat deposits in their tails, and that is one aspect of sauropod anatomy that is definitely un-bird-like. So some sauropods might have had fat tails.

We can be pretty sure that at least some sauropods had thick skin. Osteoderms (armor plates) from Madagascar show that the bits that were embedded in the skin could be up to 7cm thick, so the surrounding skin was at least that thick and possibly even thicker (Dodson et al. 1998). And that was most likely on Rapetosaurus, which was not a huge sauropod. So giant sauropods might have had even thicker skin. Maybe. Remember that big-ass-ness (here arbitrarily defined as 40+ metric tons) evolved independently in:

They probably didn’t all get there looking the same way, beyond sharing the basic sauropod bauplan.

I’m too lazy to write about the fossil evidence for scaly skin and keratinous spines in sauropods – see this post and the references therein.

One final thing to think about is scar tissue. The scar tissue on the chest of a male elephant seal can be up to 5cm thick. Some sauropods might have had calluses or patches of scar tissue in predictable places, from combat, or habitually pushing down trees with their chests or tails, or doing whatever weird things real animals do when we’re not looking.

So in the toolbox of things to play with in reconstructing the integument of sauropods, we have thick skin, keratinous spines, osteoderms, fat pads (possibly concentrated over the hips and shoulders or on the tail), subcutaneous diverticula, calluses, and scar tissue. And that’s just the stuff we have found or reasonably inferred so far, barely 150 years into our exploration of animals we know mostly from bits and bobs, whose size means they mostly got buried in big sediment-dumping events that would not preserve delicate integumentary structures. Give us a millennium of Yixian Formations and Mahajanga Basins and Howe Quarries and the picture will probably change, and the arrow of history dictates that it will change for the weirder.

Likely? Probably not. But roll the evolutionary dice for 160 million years and you’ll get stranger things than this. Recycled from this post.

Finally, and related to my observation about big-ass-ness: sauropods were a globally-distributed radiation of animals from horse-sized to whale-sized that existed from the Late Triassic to the end of the Cretaceous. The chances that all of them had the same integumentary specializations, for display or combat or insulation or camouflage or whatever, are pretty darned low. Support weird sauropods – and vanilla ones, too.

Almost immediate update: I’ve just been reminded about Mark Witton’s excellent post on dinosaur fat from a couple of years ago. Go read that, and the rest of his blog. I’m sure I missed other relevant posts at other excellent blogs – feel free to remind me in the comments.

References

When I was nine, a copy of Don Glut’s The New Dinosaur Dictionary turned up in my local Waldenbooks. It wasn’t my first dinosaur book, by far – I’d been a dinosaurophile since the age of three. But The New Dinosaur Dictionary was different.

Up to that point, I had subsisted on a heavy diet of kids’ dino books and the occasional article in National Geographic and Ranger Rick. The kids’ books were aimed at kids and the magazine articles were pitched at an engagingly popular level. I didn’t understand every word, but they were clearly written for curious layfolk, not specialists.

A typical spread from The New Dinosaur Dictionary (Glut, 1982). The armored sauropod blew my young mind.

The New Dinosaur Dictionary was something else entirely. It had photos of actual dinosaur bones and illustrations of skeletons with cryptic captions like, “Skeleton of Daspletosaurus torosus. (After Russell)”. Okay, clearly this Russell cove was out there drawing dinosaur skeletons and this book had reproduced some of them. But nobody I knew talked like that, and the books I had access to up to that point held no comparable language.

The New Dinosaur Dictionary (Glut, 1982: p. 271)

Then there was stuff like this: “The so-called Von Hughenden sauropod restored as a brachiosaurid by Mark Hallett”. A chain of fascinating and pleasurable ideas detonated in my brain. “The so-called” – say what now? Nobody even knew what to call this thing? Somehow I had inadvertently sailed right to the edge of human knowledge of dinosaurs, and was peering out into taxa incognita. “Restored as a brachiosaurid” – so this was just one of several possible ways that the animal might have looked. Even the scientists weren’t sure. This was a far cry from the bland assurances and blithely patronizing tones of all my previous dinosaur books.

“By Mark Hallett.” I didn’t know who this Hallett guy was, but his art was all over the book, along with William Stout and some guy named Robert T. Bakker and a host of others who were exploding my conception of what paleo art could even be. Anyway, this Mark Hallett was someone to watch, not only because he got mentioned by name a lot, but because his art had a crisp quality that teetered on some hypercanny ridge between photorealism and scribbling. His sketches looked like they might just walk off the page.

In case that line about scribbling sounds dismissive: I have always preferred sketches by my favorite artists to their finished products. The polished works are frequently inhumanly good. They seem to have descended in a state of completed perfection from some divine realm, unattainable by mere mortals. Whereas sketches give us a look under the hood, and show how a good artist can conjure light, shadow, form, weight, and texture from a few pencil strokes. Put it this way: I am anatomist by temperament first, and by training and occupation second. Of course I want to see how things are put together.

The New Dinosaur Dictionary (Glut, 1982: p. 75)

Anyway, The New Dinosaur Dictionary was something completely new in my experience. It wasn’t aimed at kids and written as if by kids, like lots of kids’ books. It wasn’t even written by adults talking down (deliberately or inadvertently) to kids, or trying to reach a wide audience that might include kids. It was written by an adult, aiming at other adults. And it was admitting in plain language that we didn’t know everything yet, that there were lots of animals trembling on the outer threshold of scientific knowledge. I didn’t understand half of it – I was down in an ontogenetic trench, looking up as these packets of information exploded like fireworks over my head.

In Seeing In the Dark, the best book about why you should go out stargazing for yourself, Timothy Ferris writes about growing up on Florida’s Space Coast in the early 1960s, and watching the first generation of artificial satellites pass overhead:

I felt like an ancient lungfish contemplating the land from the sea. We could get up there.

That’s precisely the effect that The New Dinosaur Dictionary had on me: I could get up there. Maybe not immediately. But there were steps, bodies of knowledge that could be mastered piecemeal, and most of all, mysteries to be resolved. The book itself was like a sketch, showing how from isolated and broken bones and incomplete skeletons, scientists and artists reconstructed the world of the past, one hypothesis at a time. Now I take it for granted, because I’ve been behind the curtain for a couple of decades. But to my 9-year-old self, it was revolutionary.

This has all come roaring back because of something that came in the mail this week. Or rather, something that had been waiting in the mailroom for a while, that I finally picked up this week: a package from Mark Hallett, enclosing a copy of his 2018 dinosaur calendar. And also this:

 

An original sketch, which he gave to me as a Christmas present. The published version appears on one of the final pages of our book, where we discuss the boundaries between the known – the emerging synthesis of sauropod biology that we hoped to bring to a broader audience by writing the book in the first place – and the unknown – the enduring mysteries that Mark and I think will drive research in sauropod paleobiology for the next few decades. Presented without a caption or commentary, the sketch embodies sauropods as we see them: emerging from uncertainty and ignorance one hard-won line at a time, with ever-increasing solidity.

Thank you, Mark, sincerely. That sketch, what it evokes, both for me now and for my inner 9-year-old – you couldn’t have chosen a better gift. And I couldn’t be happier. Except perhaps to someday learn that our book exploded in the mind of a curious kid the way that The New Dinosaur Dictionary did for me 34 years ago, a time that now seems as distant and romantic as the primeval forests of the Mesozoic.

This post started out as a comment on this thread, kicked off by Dale McInnes, in which Mike Habib got into a discussion with Mike Taylor about the max size of sauropods. Stand by for some arm-waving. All the photos of outdoor models were taken at Dino-Park Münchehagen back in late 2008.

I think it’s all too easy to confuse how big things do get from how big they could get, assuming different selection pressures and ecological opportunities. I’m sure someone could write a very compelling paper about how elephants are as big as they could possibly be, or Komodo dragons, if we didn’t have indricotheres and Megalania to show that the upper limit is elsewhere. This is basically what Economos (1981) did for indricotheres, either forgetting about sauropods or assuming they were all aquatic.

Truly, a mammal of excellence and distinction. With Mike and some dumb rhino for scale.

In fact, I’ll go further: a lot of pop discussions of sauropod size assume that sauropods got big because of external factors (oxygen levels, etc.) but were ultimately limited by internal factors, like bone and cartilage strength or cardiovascular issues. I think the opposite is more likely: sauropods got big because of a happy, never-repeated confluence of internal factors (the Sander/et al. [2008, 2011, 2013] hypothesis, which I think is extremely robust), and their size was limited by external, ecological factors.

Take a full-size Argentinosaurus or Bruhathkayosaurus – even modest estimates put them at around 10x the mass of the largest contemporary predators. Full-grown adults were probably truly predator-immune, barring disease or senescence. So any resources devoted to pushing the size disparity higher, instead of invested in making more eggs, would basically be wasted.

If there was reproductive competition among the super-giants, could the 100-tonners have been out-reproduced by the 70-tonners, which put those extra 30 tonnes into making babies? Or would the 100-tonners make so many more eggs than the 70-tonners (over some span of years) that they’d still come out on top? I admit, I don’t know enough reproductive biology to answer that. (If you do, speak up in the comments!) But if – if – 70-tonners could out-reproduce 100-tonners, that by itself might have been enough to put a cap on the size of the largest sauropods.

Another possibility is that max-size adult sauropods were neither common nor the target of selection. In most populations most of the time, the largest individuals might have been reproductively active but skeletally-immature and still-growing subadults (keep in mind that category would encompass most mounted sauropod skeletons, including the mounted brachiosaurs in Chicago and Berlin). If such individuals were the primary targets of selection, and they were selected for a balance of reproductive output and growth, then the few max-size adults might represent the relatively rare instances in which the developmental program “overshot” the selection target.

Dave Hone and Andy Farke and I mentioned this briefly in our 2016 paper, and it’s come up here on the blog several times before, but I still have a hard time wrapping my head around what that would mean. Maybe the max-size adults don’t represent the selective optimum, but rather beneficial traits carried to extreme ends by runaway development. It seems at least conceivable that the bodies of such animals might have been heavily loaded with morphological excrescences – like 15- to 17-meter necks – that were well past the selective optimum. As long as those features weren’t inherently fatal, they could possibly have been pretty darned inefficient, riding around on big predator-immune platforms that could walk for hundreds of kilometers and survive on garbage.

What does that swerve into weird-but-by-now-well-trod ground have to do with the limits on sauropod size? This: if max-size adults were not heavy selection targets, either because the focus of selection was on younger, reproductively-active subadults, or because they’d gotten so big that the only selection pressure that could really affect them was a continent-wide famine – or both – then they might not have gotten as big as they could have (i.e., never hit any internally-imposed, anatomical or biomechanical limits) because nothing external was pushing them to get any bigger than they already were.

Or maybe that’s just a big pile of arm-wavy BS. Let’s try tearing it down, and find out. The comment thread is open.

References

In writing the recent preprint “Xenoposeidon is the earliest known rebbachisaurid sauropod dinosaur” (Taylor 2017), it was invaluable to have a 3D model of the Xenoposeidon vertebra available. Here’s a short clip of viewing the model in the free MeshLab program. (It’s well worth full-screening to get the full impact.)

As I pan around, I look first at the upper margin of the posterior articular facet of the centrum, showing how the posterior margin of the neural arch shades into it — something that is not really apparent from photos, but needs the shifting perspectives that 3D offers to eliminate the interpretation that this contiguous border is due to damage.

Then I zoom in on the complex of laminae at the top of the left side of the neural arch, and explore the shapes of the intersections (ACPL with lateral CPRL, and PCDL with CPOL).

Finally I look at the distinctive sets of laminae on the anterior face of the vertebra which enclose the big, teardrop shaped centroparapophyseal fossa: lateral CPOL coming in from the lateral face of the arch, medial CPOL emerging from the pedicels, and the additional arched laminae that bound the space.

It’s just great to be able to do this. Time and again as I was preparing that manuscript, I went back to the model to check some detail — much as, twenty years earlier, Matt kept driving into the OMNH late at night to look at the Sauroposeidon holotype, to check out some idea he’d had as he worked on the description. The difference is, I didn’t need to drive into Norman, Oklahoma — or even London, England. The idea now of going back to trying to understand fossils from photos seems ridiculous.

A few years back, Matt wrote:

The idea of superseding photographs with 3D photogrammetric models is not original. I got religion last week while I was having beers with Martin Sander and he was showing me some of the models he’s made. He said that going forward, he was going to forbid his students to illustrate their specimens only with photographs; as far as he was concerned, now that 3D models could be cheaply and easily produced by just about everyone, they should be the new standard.

I’m totally on board with that, and said as much in the concluding paragraph of the new preprint.

The last thing I want to say here is to acknowledge the enormous amount of help I’ve had from Heinrich Mallison, digitizer extraordinaire at the Museum für Naturkunde Berlin. He’s invested many, many hours building models for me from my photos, pointing me to programs that I can use to view them, and helping me get started on making my own models. The greatest regret of my palaeontological life is that, when I happened to be in Berlin on 19th November 2008 and Heinrich invited me to come and watch the Germany-England friendly at his place, I couldn’t do it, and missed out on a pretty unique chance to see England beat Germany, in Germany, with a German. I doubt that chance will come up again any time soon.

I leave you with EmperorDinobot‘s life restoration of Xenoposeidon, which I stumbled across a few days ago. Obviously it’s wildly speculative, but I’m cool with that.

References

  • Taylor, Michael P. 2017. Xenoposeidon is the earliest known rebbachisaurid sauropod dinosaur. PeerJ PrePrints 5:e3415. doi: 10.7287/peerj.preprints.3415 [PDF] [PeerJ page]

 

I floated this idea on Fist Full of Podcasts, and Andrew Stuck gave it a shout-out in the comments, so I’m promoting it to a post.

The idea, briefly, is that sauropods grew fast and had enormous energy demands and even though horsetails and pine needles are surprisingly nutritious (Hummel et al. 2008), they probably suck to eat all the time. Extant herbivores are notoriously carnivorous when no-one is looking, and it’s silly to assume that extinct ones were any different. It seems likely that a big, hungry sauropod, gifted by natural selection with more selfish opportunism than compassion, would probably have viewed a turtle as a quick shot of protein and calcium, and a welcome hors d’oeuvre before stripping yet another conifer or tree fern. Furthermore, said sauropod would have been well-equipped to render the unfortunate chelonian into bite-size chunks, as shown above. The first time might even have been accidental. (Yeah, sure, Shunosaurus, I believe you. [rolls eyes])

Given that sauropods and turtles coexisted over most of the globe for most of the Mesozoic, I’ll bet this happened all the time. I don’t know how to falsify that,* but how could it not have? You’d have to assume that sauropods didn’t run into turtles, or that their mercy outweighed their curiosity and hunger. That’s even more bonkers than turtle nachos.** As Sherlock Holmes almost said, “When you have eliminated the impossible, whatever remains – no matter how stupid/awesome – was probably done by sauropods.”

* “Oh, you found a boatload of turtle shell pieces at your fossil site? How tantalizingly unprecedented – please tell me more!” said no-one ever. Seriously, everyone who works on stuff younger than the Early Jurassic seems to bitch about all of the turtle frags they find, whether they’re looking for Apatosaurus or Australopithecus.

** Not to be all navel-gazey, but that is conservatively the greatest sentence I have ever written.

In conclusion, sauropods stomped on turtles and ate them, because duh. Fight me.

Further Reading

For more sauropods stomping, see:

And for sauropods not eating, but gettin’ et:

Reference

Hummel, J., Gee, C. T., Südekum, K. H., Sander, P. M., Nogge, G., & Clauss, M. (2008). In vitro digestibility of fern and gymnosperm foliage: implications for sauropod feeding ecology and diet selection. Proceedings of the Royal Society of London B: Biological Sciences, 275(1638), 1015-1021.

 

 

Cryptic Aquilops, by Brian Engh. Available as a poster print – see below.

One of the many nice things about getting to help name new taxa is that once you let them out into the world, other people can unleash their considerable talents on ‘your’ critters. Which means that every now and then, something cool pops up that you have a deep personal connection to. Things have been fairly quiet on the Aquilops front for a while, and all of a sudden I have news.

I’m still waiting for a plush Aquilops – c’mon, Homo sapiens, how has this not happened already? – but if you’d like a life-size Aquilops in bronze, sculptor James Herrmann has you covered. James got in touch with me last fall when the project was just in the planning stages. His timing was excellent – I’d just seen the presentation on camouflage in Psittacosaurus at SVPCA, and the paper by Vinther et al. was out a week or two later. I sent James some papers and photos of dead animals, he sent back photos of the work in progress, and now his Aquilops is done.

About the sculpture, James writes:

I am offering the sculpture for sale as a limited edition of 25.  The sculpture is life sized, it is approximately 60 lbs and is 33″L x 14”H x 11”W.  The price I am asking for it is $4500.  I am getting a slab of green soapstone for the base although it does display well without the stone so it will be bolted on from below and not epoxied. […] The gingko leaves and log part of the sculpture were made from molds taken from plants growing locally.

I dig it. If you’re interested in getting one, please visit his website, HerrmannStudio.com.

Aquilops ’14. I was there, man. It was crazy. A Brian Engh joint.

Next item: back in 2014, Brian Engh created the public face of Aquilops with the wonderful graphic art he did for the paper and the press release. Now he’s gone back to the well and reimagined Aquilops, based in part on what we know of its paleoecology – that’s the image at the top of the post. He explains his new view of Aquilops in a thoughtful and wide-ranging video on his paleoart YouTube channel. (If you miss his rap videos set in the Daikaijucene, he also has a YouTube channel for music and monsters. And a blog. And a Patreon page. You get the picture.) You should also check out the two-part interview with Brian at the PLOS Paleo Community blog (part 1, part 2).

Here’s the aforementioned video:

Poster prints of Aquilops Classic and Next Gen can be purchased through Brian’s website, DontMessWithDinosaurs.com.

Finally, a couple of older Aquilops-themed art things that I didn’t cover when they happened. Lead author Andy Farke is also an award-winning homebrewer and he concocted his Eagle Face Oatmeal Stout in honor of our little buddy. He has lots more beer-and-dinosaur crossover goodness on his brewing blog – check it out.

Last fall artist Natalie Metzger did a bunch of drawings of extant animals wearing the skulls of extinct animals for Inktober. In the very first batch was this awesome squirrel looking unexpectedly badass in an Aquilops skull. I don’t know what it means, but I would totally play that D&D campaign. Natalie has a bunch more cool stuff on her blog and Patreon page, and she’ll be at the Rose City Comic Con in Portland this September, so go say hi and buy her art.

Really finally, I am not on Twitter – trust me, I don’t need less of a filter between my occasional stupidity and the world – but for all the rest of you, keep an eye on #Aquilops and, if you’re a heartless jerk, #Aquilopsburrito.

Have more Aquilops stuff I haven’t covered but should? The comment field is open.

References