After P.A.S.T president Gilles Danis commented on our post about the Chicago airport Brachiosaurus mount, I got into an interesting email conversation with him. Here, posted with his kind permission and only lightly edited, are his thoughts on the Brachiosaurus mount.

Brachiosaurus mount at Chicago O'Hare Airport, terminal one. Pelvis in ventral view, anterior to the left.

Brachiosaurus mount at Chicago O’Hare Airport, terminal one. Pelvis in ventral view, anterior to the left.

Gilles writes:

The story of this mount (s) is chequered. The casts of real material include the sacrum, the caudal, a number of dorsals, some rib fragments, one femur, a very badly eroded humerus and a coracoid. [Update: also the right ilium, as Gilles subsequently confirmed by email.]

On the mount that was in the museum and later was moved to the airport, we had a peculiar situation to deal with. Because museums like to have people walking under the rib cage of high sauropods, this becomes a safety hazard for two reasons. The first is that it cannot be allowed to fall on the people (obviously) and even though the cast was of light plastic, the engineers insisted in overbuilding the support (namely the legs and arms). Also because while in the Field Museum, it stood in the path of a fire exit, we had to have a certain amount of distance between the front and hind limbs (I forget the exact measurement). The only way that we could achieve that was to add two vertebrae for a total of 12 dorsals. We chose to duplicate two of real vertebrae at the lower end of the dorsal section.

The Brachiosaurus mount in its original position in the main hall of the Field Museum. I can't find a higher resolution version of this photo -- can anyone help?

The Brachiosaurus mount in its original position in the main hall of the Field Museum. I can’t find a higher resolution version of this photo — can anyone help?

The funny thing is only one person figured that one out and that was Bill Simpson the collections manager. Also to support this structure, we were asked to used way oversized steel in the limbs which meant that we had to “inflate” the real humerus and femur to accommodate the material. This is why the cast is so bad; it is half stuffing.

It is interested to see how a lie perpetuates itself. The following year, the Hayashibara museum ordered a mount of the same skeleton and they were very interested in getting the distance between the feet and manus. So we, again, had to make a Brachiosaurus limoensis.

Not satisfied with this silly situation, Disney came to us in 1996 and ordered that very same skeleton again with the stretch limo factor for another dinosaur that you walk under for the Wild Animal Kingdom park in Orlando. Up to that point, only Bill Simpson had realized the error. But I had just had it up to there with these stretch dinosaurs and revealed the problem. After that, in 1999, we replaced the skeleton in Stanley Field Hall with one on the terrace to make room for Sue the T. rex. On this Brachiosaurus, we have the normal 10 dorsals. The last Brachiosaurus we mounted is in the North American Museum of Ancient Life (N.A.M.A.L.) at Thanksgiving Point, Lehi, Utah, again a normal skeleton.

If this was not enough we restored Seismosaurus halli (now Diplodocus hallorum). This project was sponsored by a Japanese company who was to get the first mount. They took Gillette’s publication and read that the skeleton would have been 150′ long or 50 meters. We soon realized that there was a mistake, that the tail was not missing a huge section but had simply drifted away from the sacrum and the skeleton would not be even close to the predicted length. The Japanese would have none of it. After months of negotiations, we arrived at a compromise and we made the skeleton 40 meters long, 133’+ by adding some whiplash vertebrae until it was that long. By then I had had enough and threw in the towel but not before mounting another Seismosaurus for the museum is Albuquerque which is correct.

As for the Berlin brachiosaur: I spent some time in Berlin measuring, photographing and drawing (Donna Sloan did the drawing) the original material there, but they would not allow us to mould it. What I found interesting is that in 1992 when I was there, most of the skeleton of the mount was not original but it was not cast either. It was sculpted wood.

I have many more tails (pun, ha,ha) about sauropods. I should write them down sometime.

Many thanks to Gilles for allowing us to reproduce this important information.

Gilles’ list of real material that was cast for the mount includes very nearly all of the holotype FMNH P25107 — assuming that “a number of dorsals” means seven, the number that Riggs excavated and had prepared. The only fossil elements not apparently appearing are the fragmentary first caudal and the right ilium. But it seems to me from some of my photos of the airport mount (see the image at the top) that a cast of the right ilium was used. [Update: yes, Gilles confirmed by email that the right ilium was indeed cast from real material.]

Regarding the number of dorsal vertebrae: it may have been circumstances that forced P.A.S.T to give the mount 12 dorsals, but Migeod’s pre-description of the NHM’s Tendaguru brachiosaur gives good reason to think this is likely the correct count.

Similarly, although the torso was therefore longer than Gilles had intended, it might have ended up correct, as careful comparison of the lengths of the Brachiosaurus and Giraffatitan dorsals suggests that the torso of the former was about 23% longer.

To my shame, I’d not realised that the Brachiosaurus at the airport has two more dorsals than the one in the Field Museum picnic area, despite Matt having posted a ventral-view photo of the airport mount that clearly shows the twelve dorsals and a lateral-view photo of the museum mount that clearly shows ten.

When Gilles says “most of the skeleton of the [Berlin] mount was not original but it was not cast either”, I assume he’s referring to the presacral vertebrae, which as Janensch explained in his 1950 paper about that mount were too heavy and fragile to mount. The sculptures in Janensch’s mount were not particularly good, but they have been replaced by much better ones in the remount.

 

Today sees the publication of the new Journal of Vertebrate Paleontology, and with it my paper on the two best-known brachiosaurs and why they’re not congeneric (Taylor 2009).  This of course is why I have been coyly referring to “Brachiosaurus” brancai in the last few months … I couldn’t bear to make the leap straight to saying Giraffatitan, a name that is going to take me a while to get used to.

But before we go lunging into the details, here is my skeletal reconstruction of Brachiosaurus proper, taken from the paper:

Taylor-SVP-Brachiosaurus-fig7-reconstruction-R3-480px

Skeletal reconstruction of Brachiosaurus altithorax, with Homo sapiens and Canis familiaris for scale, from Taylor (2009:fig. 7). White bones represent the elements of the holotype FMNH P 25107. Light grey bones represent material referred to B. altithorax: the Felch Quarry skull USNM 5730, the cervical vertebrae BYU 12866 (C?5) and BYU 12867 (C?10), the “Ultrasauros” scapulocoracoid BYU 9462, the Potter Creek left humerus USNM 21903, left radius and right metacarpal III BYU 4744, and the left metacarpal II OMNH 01138. Dark grey bones modified from Paul’s (1988) reconstruction of Giraffatitan brancai. Scale bar equals 2 m.

Those of you familiar with Greg Paul’s classic reconstruction of Giraffatitan brancai will immediately recognise that Real Brachiosaurus is rather differently proportioned, especially in having a longer torso and tail.

This paper has been in the works for some time, and while it was in review and then in press at JVP, it led a double life as Chapter 2 of my dissertation.  (For most of its gestation period, the paper’s title was just “Brachiosaurus brancai is not Brachiosaurus“, and the folder where I keep all the project files is still called “bb-is-not-b”).  In the end, I chickened out and went for a longer, more formal, title.

So why are the two species not congeneric?  Well, it’s a long story, and you can read about the detail in the paper, but the bottom line is that virtually every bone that is known from both species differs in significant respects between them.

Of course, I am not the first to suggest that the African brachiosaurid that we know and love isn’t exactly Brachiosaurus.  Credit for that goes to Greg Paul, who more than twenty years ago executed a then-new skeletal reconstruction of that species (the very same reconstruction that is now considered the classic), and in doing so noticed some differences between the American type species Brachiosaurus altithorax and the African referred species “Brachiosaurus” brancai (Paul 1988).  Paul hedged his bets, though: rather than erect a new genus for the African animal, he proposed a subgenus Brachiosaurus (Giraffatitan), so that the full name of the species would become Brachiosaurus (Giraffatitan) brancai; and that of the type species would become Brachiosaurus (Brachiosaurus) altithorax.  Unsurprisingly, this cumbersome nomenclatural scheme did not catch on, and I have not been able to locate a single subsequent reference to these subgenera in the literature.

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Second caudal vertebrae of Brachiosaurus altithorax and Brachiosaurus brancai, equally scaled, from Taylor (2009:fig. 3). A, B, B. altithorax holotype FMNH P 25107; C-G, B. brancai referred specimen HMN Aa. A, C, posterior; B, D, F, right lateral; E, G, anterior. A-B modified from Riggs (1904:pl. LXXV); C-E modified from Janensch (1950a:pl. 2), F-G modified from Janensch (1929:fig. 15). Scale bar equals 50 cm.

That didn’t mean the idea was dead, though: three years later, George Olshevsky’s self-published mega-revision of dinosaur taxonomy proposed raising the name Giraffatitan to genus level (Olshevsky 1991).  Although this genus became popular on the Internet (it cropped up, for example, in Mike Keesey’s much-lamented Dinosauricon web-site), it was almost completely ignored in the technical literature, and even Greg Paul himself subsequently seems to have reverted to using the name Brachiosaurus brancai (e.g. Paul 1994:246).

Why was the new name overlooked?  Partly, I suspect, just because it’s so butt ugly — everyone knows and loves Brachiosaurus brancai, and the name itself has a definite poetry to it that Giraffatitan sorely lacks.  But mostly it’s because Paul didn’t really make a case for the separation that he proposed — wrongly stating, for example, that “the caudals, scapula, coracoid, humerus, ilium, and femur of B. altithorax and B. brancai are very similar” (Paul 1988:7).

That’s how things stood a few years back when I started to take a serious interest in Migeod’s Tendaguru brachiosaurid, which lives in the basement of the Natural History Museum in London.  It quickly started to seem to me that it wasn’t the same thing as what everyone means by Brachiosaurus, but to make sense of it all, I needed first to figure out what the Brachiosaurus actually does mean.  That meant visiting the type material of both species, in Chicago and Berlin, and really looking closely.

Well, I don’t want to go on all day — apart from anything, England play Croatia in a World Cup qualifier in just over an hour — so I’ll just show you some of the the differences between the dorsal vertebrae of the two species.  (You’ll have seen the caudals up above — I just threw them in to break up all that text).

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Dorsal vertebrae of Brachiosaurus altithorax and Brachiosaurus brancai in posterior and lateral views, equally scaled, from Taylor (2009:fig. 1). A, B, E, F, I, J, M, N, B. altithorax holotype FMNH P 25107, modified from Riggs (1904:pl. LXXII); C, D, G, H, K, L, O, P, B. brancai lectotype HMN SII, modified from Janensch (1950a:figs. 53, 54, 56, 60-62, 64) except H, photograph by author. Neural arch and spine of K sheared to correct for distortion. A, D, E, H, I, L, M, P, posterior; B, F, G, J, N, right lateral; C, K, O, left lateral reflected. A, B, dorsal 6; C, D, dorsal 4; E-H, dorsal 8; I-L, dorsal 10; M, N, P, dorsal 12; O, dorsals 11 and 12. Corresponding vertebrae from each specimen are shown together except that dorsal 4 is not known from B. altithorax so dorsal 6, the most anterior known vertebra, is instead shown next to dorsal 4 of B. brancai. Scale bar equals 50 cm.

Lots and lots of differences here — I will quote from the Systematic Paleontology section on the type species: “Postspinal lamina absent from dorsal vertebrae (character 130); distal ends of transverse processes of dorsal vertebrae transition smoothly onto dorsal surfaces of transverse processes (character 142); spinodiapophyseal and spinopostzygapophyseal laminae on middle and posterior dorsal vertebrae contact each other (character 146); posterior dorsal centra subcircular in cross-section (character 151); posterior dorsal neural spines progressively expand mediolaterally through most of their length (“petal” or “paddle” shaped) (character 155); mid-dorsals about one third longer than posterior dorsals (see Paul, 1988:7); middorsals only about 20% taller than posterior dorsals (see Paul, 1988:8); dorsal centra long (Janensch, 1950a:72) so that dorsal column is over twice humerus length (Paul, 1988:8); transverse processes of dorsal vertebrae oriented horizontally (Paul, 1988:8); dorsal neural spines oriented close to vertical in lateral view; dorsal neural spines triangular in lateral view, diminishing smoothly in anteroposterior width from wide base upwards; deep inverted triangular ligament rugosities on anterior and posterior faces of neural spines” …. *gasp*

So anyway: the upshot of all this is that “Brachiosaurus” brancai differs from Brachiosaurus altithorax more than, say, Barosaurus does from Diplodocus; and so it must be placed in its own genus … and that genus has to be Giraffatitan, because of the ICZN’s principle of priority.  And THAT is why the very end of the paper — the last sentence of the Acknowledgements — reads:

Finally, I beg forgiveness from all brachiosaur lovers, that so beautiful an animal as “Brachiosaurus” brancai now has to be known by so inelegant a name as Giraffatitan.

Anyway, go and read the paper; full-resolution figures are freely available if you want to look more closely than the JVP’s PDF allows.

References

(And, yes, Randy, I know what your comment is going to say; go ahead and say it anyway, it’ll give me a chance to explain why your approach is wrong :-))

Considering how much time I’ve spent playing around mounted sauropod skeletons, I cannot believe it never occurred to me to do this:

This is the mounted Brachiosaurus skeleton in the United terminal at Chicago O’Hare. It used to be in the main hall of the Field Museum, but they booted it out to make room for some vulgar overstudied theropod (ht to Paul Barrett for that supremely useful phrase). The indoor version was moved to O’Hare, and they made a second, weatherproof cast which is now mounted outside the northwest corner of the Field Museum.

We spend so much time looking at drawings or photos of bones or entire skeletons in lateral view. It is nice to get a kick-in-the-brainpan reminder that sauropods existed in 3D. And it is always rewarding to see something familiar from a new angle.

Lots of good stuff here. Anterior is toward the bottom of the photo; you can see the scapulae arcing back over the anterior ribs, the coracoids sternal plates converging and disappearing out of the bottom of the image, and the humeri angling out to either side. The thing does not really sprawl as much as it might seem from this picture–keep in mind that there is a lot of vertical foreshortening going on. Speaking of, you can see the neck zooming off into space at the bottom center. At the top of the image you can see the sacrum and the preacetabular blades of the ilia flaring out to either side.

The seven posterior dorsals are cast from the holotype of Brachiosaurus altithorax, as are the sacrum, the first couple of caudals, one humerus, one ilium, and one femur. The rest of the mounted skeleton is either mirrored from available elements or subbed in from Brachiosaurus brancai.

I’m posting this because (a) it’s a really cool photo, and (b) it illustrates something peculiar, which is that the dorsal vertebrae of Brachiosaurus are oddly–one might even say freakishly–slender. This is true of both the B. altithorax and B. brancai dorsals. I was recently standing under yet another copy of this skeleton and someone I was with asked if those were even the right vertebrae, because even to non-specialists they look too small.

I WILL have more to say about that one of these days, but for now just dig the austere beauty.

Photo (c) Tristan Savatier – www.loupiote.com – Used by permission.

In the last post, Matt promised you non-brachiosaurs, sacrals and caudals. And so I bring you the gift of … brachiosaur dorsals! Feast your eyes, gloat your soul, on the last four presacral vertebrapresacral vertebrae 4-7 of the Brachiosaurus altithorax holotype FMNH P25107.  [My mistake — for some reason, I called these the last four when I originally wrote this post.  Now fixed — Mike, 11 September 2009.]

boba-dorsals-500px.jpeg

These bones form part of the first brachiosaurid sauropod ever described. It was initially reported by Elmer S. Riggs in 1901, described and named by him in 1903, and described in more detail, again by Riggs, in 1904.

It’s still one of the best brachiosaurid specimens, consisting of the last seven dorsal vertebrae, sacrum, first two caudals, left coracoid (NOT right as stated by Riggs), right humerus, ilium and femur, and ribs. Sadly no skull elements or cervicals, though.

Here we see the bones in an oblique left anterodorsolateral aspect, with your humble chronicler in the background, measuring something so quickly that motion blur hides his craggy, manly features. That I am in the photo means that Matt must have taken it. It’s one of 122 photos that we took of these dorsals, in a single long, crazy day that, apart from brachiosaur dorsals, was also filled with brachiosaur humeri, giraffe cervicals and Godzilla rolls (sushi). Ah, happy days!

Things to Make and Do

January 31, 2010

We like to keep you busy with arts-and-crafts projects :)

For some reason, these posts always make the think of a fictional book entitled Things a Boy Can Do that crops up in one of Richmal Crompton’ Just William stories.

Picture is unrelated. Seriously. I’m just allergic to posts with no visuals. Stand by for more random brachiosaurs.

Here’s something I’ve been meaning to post for a while, about my changing ideas about scholarly publishing. On one hand, it’s hard to believe now that the Academic Spring was almost a decade ago. On the other, it’s hard for me to accept that PeerJ will be only 8 years old next week–it has loomed so large in my thinking that it feels like it has been around much longer. The very first PeerJ Preprints went up on April 4, 2013, just about a month and a half after the first papers in PeerJ. At that time it felt like things were moving very quickly, and that the landscape of scholarly publishing might be totally different in just a few years. Looking back now, it’s disappointing how little has changed. Oh, sure, there are more OA options now — even more kinds of OA options, and things like PCI Paleo and Qeios feel genuinely envelope-pushing — but the big barrier-based publishers are still dug in like ticks, and very few journals have fled from those publishers to re-establish themselves elsewhere. APCs are ubiquitous now, and mostly unjustified and ruinously expensive. Honestly, the biggest changes in my practice are that I use preprint servers to make my conference talks available, and I use SciHub instead of interlibrary loan.

But I didn’t sit down to write this post so I could grumble about the system like an old hippie. I’ve learned some things in the past few years, about what actually works in scholarly publishing (at least for me), and about my preferences in some areas, which turn out to be not what I expected. I’ll focus on just two areas today, peer review, and preprints.

How I Stopped Worrying and Learned to Love Peer Review

Surprise #1: I’m not totally against peer review. I realize that the way it is implemented in many places is deeply flawed, and that it’s no guarantee of the quality of a paper, but I also recognize its value. This is not where I was 8 years ago; at the time, I was pretty much in agreement with Mike’s post from November, 2012, “Well, that about wraps it up for peer-review”. But then in 2014 I became an academic editor at PeerJ. And as I gained first-hand experience from the other side of the editorial desk, I realized a few things:

  • Editors have broad remits in terms of subject areas, and without the benefit of peer reviews by people who specialize in areas other than my own, I’m not fit to handle papers on topics other than Early Cretaceous North American sauropods, skeletal pneumaticity, and human lower extremity anatomy.
  • Even at PeerJ, which only judges papers based on scientific soundness, not on perceived importance, it can be hard to tell where the boundary is. I’ve had to reject a few manuscripts at PeerJ, and I would not have felt confident about doing that without the advice of peer reviewers. Even with no perceived importance criterion, there is definitely a lower bound on what counts as a publishable observation. If you find a mammoth toe bone in Nebraska, or a tyrannosaur tooth in Montana, there should probably be something more interesting to say about it, beyond the bare fact of its existence, if it’s going to be the subject of a whole paper.
  • In contentious fields, it can be valuable to get a diversity of opinions. And sometimes, frankly, I need to figure out if the author is a loony, or if it’s actually Reviewer #2 that’s off the rails. Although I think PeerJ generally attracts fairly serious authors, a handful of things that get submitted are just garbage. From what I hear, that’s the case at almost every journal. But it’s not always obvious what’s garbage, what’s unexciting but methodologically sound, and what’s seemingly daring but also methodologically sound. Feedback from reviewers helps me make those calls. Bottom line, I do think the community benefits from having pre-publication filters in place.
  • Finally, I think editors have a responsibility to help authors improve their work, and reviewers catch a lot of stuff that I would miss. And occasionally I catch something that the reviewers missed. We are collectively smarter and more helpful than any of us would be in isolation, and it’s hard to see that as anything other than a good thing.

The moral here probably boils down to, “white guy stops bloviating about Topic X when he gains actual experience”, which doesn’t look super-flattering for me, but that’s okay.

You may have noticed that my pro-peer-review comments are rather navel-gaze-ly focused on the needs of editors. But who needs editors? Why not chuck the whole system? Set up an outlet called Just Publish Everything, and let fly? My answer is that my time in the editorial trenches has convinced me that such a system will silt up with garbage papers, and as a researcher I already have a hard enough time keeping up with all of the emerging science that I need to. From both perspectives, I want there to be some kind of net to keep out the trash. It doesn’t have to be a tall net, or strung very tight, but I’d rather have something than nothing.

What would I change about peer review? Since it launched, PeerJ has let reviewers either review anonymously, or sign their reviews, and it has let authors decide whether or not to publish the reviews alongside the paper. Those were both pretty daring steps at the time, but if I could I’d turn both of those into mandates rather than options. Sunlight is the best disinfectant, and I think almost all of the abuses of the peer review system would evaporate if reviewers had to sign their reviews, and all reviews were published alongside the papers. There will always be a-holes in the world, and some of them are so pathological that they can’t rein in their bad behavior, but if the system forced them to do the bad stuff in the open, we’d all know who they are and we could avoid them.

Femur of Apatosaurus and right humerus Brachiosaurus altithorax holotype on wooden pedestal (exhibit) with labels and 6 foot ruler for scale, Geology specimen, Field Columbian Museum, 1905. (Photo by Charles Carpenter/Field Museum Library/Getty Images)

Quo Vadis, Preprints?

Maybe the advent of preprints was more drawn out than I know, but to me it felt like preprints went from being Not a Thing, Really, in 2012, to being ubiquitous in 2013. And, I thought at the time, possibly transformative. They felt like something genuinely new, and when Mike and I posted our Barosaurus preprint and got substantive, unsolicited review comments in just a day or two, that was pretty awesome. Which is why I did not expect…

Surprise #2: I don’t have much use for preprints, at least as they were originally intended. When I first confessed this to Mike, in a Gchat, he wrote, “You don’t have a distaste for preprints. You love them.” And if you just looked at the number of preprints I’ve created, you might get that impression. But the vast majority of my preprints are conference talks, and using a preprint server was just the simplest way to the get the abstract and the slide deck up where people could find them. In terms of preprints as early versions of papers that I expect to submit soon, only two really count, neither more recent than 2015. (I’m not counting Mike’s preprint of our vertebral orientation paper from 2019; he’s first author, and I didn’t mind that he posted a preprint, but neither is it something I’d have done if the manuscript was mine alone.)

My thoughts here are almost entirely shaped by what happened with our Barosaurus preprint. We put it up on PeerJ Preprints back in 2013, we got some useful feedback right away, and…we did nothing for a long time. Finally in 2016 we revised the manuscript and got it formally submitted. I think we both expected that since the preprint had already been “reviewed” by commenters, and we’d revised it accordingly, that formal peer review would be very smooth. It was not. And the upshot is that only now, in 2021, are we finally talking about dealing with those reviews and getting the manuscript resubmitted. We haven’t actually done this, mind, we’re just talking about planning to make a start on it. (Non-committal enough for ya?)

Why has it taken us so long to deal with this one paper? We’re certainly capable — the two of us got four papers out in 2013, each of them on a different topic and each of them substantial. So why can’t we climb Mount Barosaurus? I think a big part of it is that we know the world is not waiting for our results, because our results are already out in the world. We’re the only ones being hurt by our inaction — we’re denying ourselves the credit and the respect that go along with having a paper finally and formally published in a peer-reviewed journal. But we can comfort ourselves with the thought that if someone needs our observations to make progress on their own project, we’re not holding them up. Just having the preprint out there has stolen some of our motivation to the get the paper done and out, apparently enough to keep us from doing it at all.

Mike pointed out that according to Google Scholar, our Barosaurus preprint has been cited five times to date, once in its original version and four times in its revised version. But to me, the fact that the Baro manuscript has been cited five times is a fail. Because all of my peer-reviewed papers from 2014-2016, which have been out for less long, have been cited more. So I read that as people not wanting to cite it. And who can blame them? Even I thought it would be supplanted by the formally-published, peer-reviewed paper within a few weeks or months.

Mike then pointed me to his 2015 post, “Four different reasons to post preprints”, and asked how many of those arguments still worked for me now. Number 2 is good, posting material that would otherwise never see the light of day — it’s basically what I did when I put my dissertation on arXiv. Ditto for 4, which is posting conference presentations. I’m not moved by either 1 or 3. Number 3 is getting something out to the community as quickly as possible, just because you want to, and number 1 is getting feedback as quickly as possible. The reason that neither of those move me is that they’re solved to my satisfaction by existing peer-reviewed outlets. I don’t know of any journals that let reviewers take 2-4 months to review a paper anymore. I don’t know how much credit for the acceleration should go to PeerJ, which asks for reviews in 10 to 14 days, but surely some. And I don’t usually have a high enough opinion of my own work to think that the community will suffer if it takes a few months for a paper to come out through the traditional process.

(If it seems like I’m painting Mike as relentlessly pro-preprint, it’s not my intent. Rather, I’d dropped a surprising piece of news on him, and he was strategically probing to determine the contours of my new and unexpected stance. Then I left the conversation to come write this post while the ideas were all fresh in my head. I hope to find out what he thinks about this stuff in the comments, or ideally in a follow-up post.)

Back to task: at least for me, a preprint of a manuscript I’m going to submit anyway is a mechanism to get extra reviews I don’t want*, and to lull myself into feeling like the work is done when it’s not. I don’t anticipate that I will ever again put up a preprint for one of my own manuscripts if there’s a plausible path to traditional publication.

* That sounds awful. To people who have left helpful comments on my preprints: I’m grateful, sincerely. But not so grateful that I want to do the peer review process a second time for zero credit. I didn’t know that when I used to file preprints of manuscripts, but I know it now, and the easiest way for me to not make more work for both of us is to not file preprints of things I’m planning to submit somewhere anyway.

So much for my preprints; what about those of other people? Time for another not-super-flattering confession: I don’t read other people’s preprints. Heck, I don’t have time to keep up with the peer-reviewed literature, and I have always been convinced by Mike’s dictum, “The real value of peer-review is not as a mark of correctness, but of seriousness” (from this 2014 post). If other people want me to part with my precious time to engage with their work, they can darn well get it through peer review. And — boomerang thought — that attitude degrades my respect for my own preprint manuscripts. I wouldn’t pay attention to them if someone else had written them, so I don’t really expect anyone else to pay attention to the ones that I’ve posted. In fact, it’s extremely flattering that they get read and cited at all, because by my own criteria, they don’t deserve it.

I have to stress how surprising I find this conclusion, that I regard my own preprints as useless at best, and simultaneously extra-work-making and motivation-eroding at worst, for me, and insufficiently serious to be worthy of other people’s time, for everyone else. It’s certainly not where I expected to end up in the heady days of 2013. But back then I had opinions, and now I have experience, and that has made all the difference.

The comment thread is open. What do you think? Better still, what’s your experience?

Here’s one of my most prized possessions: a cannon bone from a giraffe. I got it last fall from Necromance, a cool natural history store in LA. Originally they had a matched pair on display in the front window. Jessie Atterholt got one of them last summer, and I got the other a few months later.

The cannon bones of hoofed mammals consist of fused metacarpals (in the forelimbs) or metatarsals (in the hindlimbs). In this case, the giraffe cannon bone in the top photo is the one from the right forelimb, consisting of the fused 3rd and 4th metacarpals, which correspond to the bones in the human hand leading to the middle and ring fingers. Only my third metacarpal is traced in the top photo. For maximum homology goodness I should have traced MC4, too, but I’m lazy.

I didn’t know that this was a right forelimb cannon bone when I got it. In fact, I only figured that out this afternoon, thanks to the figures and text descriptions in Rios et al. (2016), which I got free through Palaeontologia Electronica (you can too). The weirdly large and perfectly circular holes at the ends of my cannon bone were clearly drilled out by somone, I guess maybe for mounting purposes? At first I thought it might have been to help the marrow cook out of the shaft of the bone during simmering and degreasing, but none of the drilled holes intersect the main marrow cavity, they’re just in the sponge of trabecular bone at the ends of the element.

This post is a sequel to one from last year, “Brachiosaurus and human metacarpals compared“, which featured metacarpal 3 from BYU 4744, the partial skeleton of Brachiosaurus from Potter Creek, Colorado. I know what everyone’s thinking: can we make these two high-browsing giants throw hands?

Yes, yes we can. The giraffe cannon bone is 75.5cm long, and the brachiosaur metacarpal is 57cm long, or 75.5% the length of the giraffe element. I scaled the two bones correctly in the above image. My hands aren’t the same size because they’re at different distances from the camera, illustrating the age-old dictum that scale bars are not to be trusted.

The Potter Creek brachiosaur is one of the largest in the world–here’s me with a cast of its humerus–but ‘my’ giraffe is not. World-record giraffes are about 19 feet tall (5.8m), and doing some quick-and-dirty cross-scaling using the skeleton photo above suggests that the metacarpal cannon bone in a world-record giraffe should be pushing 90cm. So the giraffe my cannon bone is from was probably between 15.5 and 16 feet tall (4.7-4.9m), which is still nothing to sniff at.

I don’t know how this bone came to be at Necromance. I assume from an estate sale or something. I only visited for the first time last year, and at that time they had three real bones from giraffes out in the showroom: the two cannon bones and a cervical vertebra. They might have put out more stuff since–it’s been about six months since I’ve been there–but all of the giraffe bones they had at that point have been snapped up by WesternU anatomists. Jessie and I got the cannon bones, and Thierra Nalley got the cervical vertebra, which is fair since she works on the evolution of necks (mostly in primates–see her Google Scholar page here). I don’t know if there are any photos of Thierra’s cervical online, but Jessie did an Instagram post on her cannon bone, which is nearly as long as her whole damn leg.

There will be more anatomy coming along soon, and probably some noodling about sauropods. Stay tuned!

Reference

Ríos M, Danowitz M, Solounias N. 2016. First comprehensive morphological analysis on the metapodials of Giraffidae. Palaeontologia Electronica 19(3):1–39.

 

 

On today’s episode of the I Know Dino postcast, Garret interviews Brian and me about our new Brachiosaurus bones and how we got them out of the field. You should listen to the whole thing, but we’re on from 10:10 to 48:15. Here’s the link, go have fun. Many thanks to the I Know Dino crew for their interest, and to Garret for being such a patient and accommodating host. Amazingly, there is a much longer version of the interview available for I Know Dino Patreon supporters, so check that out for more Brachiosaurus yap than you are probably prepared for.

The photo is an overhead shot of me, Casey Cordes, and Yara Haridy smoothing down a plaster wrap around the middle of humerus. The 2x4s aren’t on yet, and the sun is low, so this must have been in the late afternoon on our first day in the quarry in October. Photo by Brian Engh, who perched up on top of the boulder next to the bone to get this shot.

For the context of the Brach-straction, see Part 1 of Jurassic Reimagined on Brian’s paleoart YouTube channel, and stay tuned for more.

Arm lizard

December 16, 2019

Reconstructed right forelimb of Brachiosaurus at Dinosaur Journey in Fruita, Colorado, with me for scale, photo by Yara Haridy. The humerus is a cast of the element from the holotype skeleton, FMNH P25107, the coracoid looks like a sculpt to match the coracoid from the holotype (which is a left), and the other elements are either cast or sculpted from Giraffatitan. But it’s all approximately correct. The actual humerus is 204cm long, but the distal end is eroded and it was probably 10-12cm longer in life. I don’t know how big this cast is, but I know that casts are inherently untrustworthy so I suspect it’s a few cm shorter than it oughta be. For reference, I’m 188cm, but I’m standing a bit forward of the mount so I’m an imperfect scale bar (like all scale bars!). For another view of the same mount from five years ago, see this post.

So I guess the moral is that even thought this reconstructed forelimb looks impressive, the humerus was several inches longer, even before we account for any shrinkage in the molding and casting process, and the gaps between the bones for joint cartilage should probably be much wider, so the actual shoulder height of this individual might have been something like a foot taller than this mount. A mount, by the way, that is about as good as it could practically be, and which I love — I’m including all the caveats and such partly because I’m an arch-pedant, and partly because it’s genuinely useful to know all the ways in which a museum mount might be subtly warping the truth, especially if you’re interested in the biggest of the big.

All of which is a long walk to the conclusion that brachiosaurs are pretty awesome. More on that real soon now. Stay tuned.

 

I had an interesting opportunity when I was in Utah and Colorado a couple of weeks ago. At Dinosaur Journey in Fruita, Colorado, I went looking for a cast of the Potter Creek Brachiosaurus humerus. I found it — more on that another time — and I also found a cast of BYU 4503, the holotype dorsal vertebra of Dystylosaurus (now almost universally regarded as Supersaurus [but then…]), lurking with it in a corner of the collections room.

Dystylosaurus cast, posterior view.

Somehow I had overlooked the Dystylosaurus cast on all of my previous visits to DJ, which is a shame, because the cast is easy to pick up, flip over, and manipulate. Very much unlike the actual fossil, which combines the charming attributes, shared with many other sauropod vertebrae, of weighing hundreds of pounds but still being awfully fragile.

Dystylosaurus cast, anterior view.

So, hey ya, I had a chance to photograph and measure both sides of the vertebra. You’re not supposed to take measurements from casts, but I figured what the heck, no-one was going to lock me up for it, and I could compare the measurements from the cast to the measurements of the real thing when I visited BYU later in the trip. And that’s exactly what I did. It was easy to make sure I took the second set of measurements the same way I had done the first set, because I took them just a few days apart.

The real deal at BYU.

Here’s what I got. For each measurement, the actual value measured from the real fossil at BYU comes first, followed by the same measurement from the cast at Dinosaur Journey, followed by the difference as a percentage of the first (true) measurement.

  • Total Height (as preserved): 1050mm / 1022mm / -2.6%
  • Max Width (as preserved): 905mm / 889mm / -1.8%
  • Anterior Centrum Height: 400mm / 394mm / -1.5%
  • Anterior Centrum Width: 470mm / 454mm / -3.4%
  • Posterior Centrum Height: 365mm / 352mm / -3.5%
  • Posterior Centrum Width: 480mm / 473mm / -1.5%

They’re not the same! On average, the measurements of the cast are 2.4% smaller than the same measurements taken from the actual bone. (Incidentally, you may be wondering how I measured the posterior centrum faces of the BYU vertebra without flipping it. I used a couple of wooden blocks as orthogonators and measured between them, and I did it at several points to make sure they were truly parallel. In essence, I made giant redneck calipers, a method that Mike and I have had to employ many times when measuring huge, weirdly-shaped fossils. Remind me to show you John Foster’s giant caliper setup sometime.)

Dinosaur Journey cast in right lateral view, big doofus for scale.

Anyway, the discrepancy in the measurements should not be surprising. It is a known phenomenon that when an object is molded and cast, there is a little bit of shrinkage. You can see it bedevil Adam Savage in his quest for the ultimate Maltese Falcon replica in this charming video:

So, on one hand, no outright disasters here; all of the cast measurements are within a few percent of the real measurements, so if all you had was a cast, you could get a pretty good sense of the size of the real thing. But precision counts, even among giant sauropods. In a world where the largest vertebra of Argentinosaurus is only 1cm bigger in diameter than the largest vertebra of Patagotitan, differences like I got with Dystylosaurus would be enough to scramble the order of giant vertebrae. So if you’re ever stuck measuring something from a cast, be forthright and say as much, so that no-one mistakes the cast measurements for the real thing.

Here are some more measurements from BYU 4503, the real thing, for you completists. Note that the vertebra is sheared a bit from right postero-ventral to left antero-dorsal, so figuring out how to take the centrum length is not straightforward. I ended up doing it twice, once orthogonal to the posterior centrum face, and once following the slant of the centrum, both at the mid-height of the centrum, as shown in the little diagram from my notebook (above).

  • Centrum Length, left side, orthogonal: 295mm
  • Centrum Length, left side, on the slant: 310mm
  • Centrum Length, right side, orthogonal: 280mm
  • Centrum Length, right side, on the slant: 305mm
  • Max Width across prezygs: 305mm
  • Min gap between prezygs: 19mm
  • Max Width across parapophyses: 620mm
  • Max antero-posterior length of prezyg articular surfaces: 55mm
  • Max antero-posterior depth of hypantrum: 95mm
  • Max antero-posterior depth of fossa between spino-prezyg laminae (SPRLs): 80mm
  • Neural spine cavity, max antero-posterior extent: 40mm
  • Neural spine cavity, max medio-lateral extent: 70mm

Finally, a huge thanks to Julia McHugh at Dinosaur Journey and Brooks Britt and Rod Scheetz at BYU for letting me come play with their huge toys er, hugely important scientific specimens. Rod was particularly helpful, shifting giant things about with a forklift, helping me measure bones that are longer than I am tall, and boxing up loan specimens for me. Mike and I have had really good luck with pro-science curators and collections managers, but the folks at DJ and BYU have always been standouts, and I can’t thank them enough.

Back into the Corner of Shame, artificially tiny Dystylosaurus!