I know, I know — you never believed this day would come. And who could blame you? Nearly thirteen years after my 2005 SVPCA talkSweet Seventy-Five and Never Been Kissed, I am finally kicking the Archbishop descriptive work into gear. And I’m doing it in the open!

In the past, I’ve written my academic works in LibreOffice, submitted them for peer-review, and only allowed the world to see them after they’ve been revised, accepted and published. More recently, I’ve been using preprints to make my submitted drafts public before peer review. But there’s no compelling reason not to go more open than that, so I’ll be writing this paper out in the open, in a public GitHub repository than anyone can access. That also means anyone can file issues if they thing there’s something wrong or missing, and anyone can submit pull-requests if they have a correction to contribute.

I’ll be writing this paper in GitHub Flavoured Markdown so that it displays correctly right in the browser, and so that patches can be supported. That will make tables a bit more cumbersome, but it should be manageable.

Anyway, feel free to follow progress at https://github.com/MikeTaylor/palaeo-archbishop

The very very skeletal manuscript is at https://github.com/MikeTaylor/palaeo-archbishop/blob/master/archbishop-manuscript.md

Here I am at SVPCA in 2015. I am haunted by the fact that ten years ago at SVPCA 2005, I gave a talk about the NHM’s Tendaguru brachiosaurid, NHMUK R5937. And the description is still not done and submitted a full decade later. Even though it’s objectively one of the most beautiful specimens in the world:

dorsals-ab-composite

So here is my pledge to the world:

By this time next year (i.e. the start of SVPCA 2016 in Liverpool), I will have written and submitted this description. If I fail, I give you all permission — no, I beg you — to mock me mercilessly. Leave mocking comments on this blog, yes; but more than that, those of you at SVPCA are invited to spend the week pointing contemptuously at me and saying “Ha!”

Let’s hope it doesn’t come to that.

Update (6 September): see also.

A few months ago, prosauropod supremo Adam Yates blogged about the Aardonyx cake that the BPI honours class baked in his honour.  In the comments, I mentioned that my wife Fiona once made me a BMNH R5937:D9 cake (i.e. a cake in the form of the more posterior of the pair of nicely preserved dorsal vertebrae of The Archbishop, in right lateral view). At the time, I couldn’t find the photo that I knew had been taken, and Adam asked me to post it when it turned up.

Voila!

And here, once more, is the real thing for comparison:

(Note that the topology of the lateral lamination is spot on, with a single infradiapophyseal lamina which forks into anterior and posterior branches only some way ventral to the diapophysis.  That’s what you look for in a cake.)

Update (21 April)

Silly me, of course what I should have shown is the cake and the vertebra side by side.  Here they are — together at last!

This post is nearly three weeks late — it’s based on a piece of artwork that appeared on 25 September, and which I wanted to write about immediately.  But it got washed away in the flood of camel necks (which by the way is not over yet), and then in the festival of articular cartilage, then by the whole “Amphicoelias brontodiplodocus” thing and the subsequent discussion of amateurs in palaeo, and then by what was already an overdue announcement of my sauropod history paper and the attendant copyright nonsense.  So it’s been a stupidly busy time here at SV-POW! Towers, but now the air has cleared a little, and it’s time to look at this beauty:

 

Life restoration of NHM R5937 "The Archbishop" (Brachiosauridae incertae sedis), by Nima.

 

This would be a beautiful piece of art by any standards — the world can always use brachiosaur art! — but what makes this extra special for me is that it is the first ever life restoration of my very own brachiosaur, BHM R5937, the Tendaguru specimen known as The Archbishop.  It’s by SV-POW! regular Nima, and I am absolutely delighted to see it.  It’s very Greg Paul-like, and I mean that in the most positive sense.  (I may not be a fan of Greg’s taxonomic vicissitudes, but his art is just beautiful.)

Over on his blog, Nima has described in detail how he created this piece, and shows four progressively refined versions (of which the one above is the last) — I urge you to check it out if you’re interested in art, brachiosaurs or both.

Nima’s blog-post also includes a brief history of the Archbishop, mostly taken from my 2005 SVPCA talk.  It’s a good summary, but I do have a few comments to make.  (I typed a lot of this in as a comment to the original post, but Blogger ate my comments as usual.)

  • The specimen is not known as M23, and has never been — that is in fact the designation of the Tendaguru quarry from which is was excavated.  Paul (1988) mistakenly conflated the quarry name with a specimen number, and referred to this specimen as BMNH M23, and Glut’s (1977) encyclopaedia perpetuated the error, but it’s always been R5937.
  • “The giant Brachiosaurus finds of the Germans” are now, of course, Giraffatitan.
  • “Controversy lingered” — well, no, not really.  The problem was worse than that: no-one paid a blind bit of notice to the specimen before 2004.
  • “It turns out the double spine claim was totally bogus and unscientific” — well, we don’t really know that yet.  It’s certainly true that none of the prepared vertebrae (five cervicals, two complete dorsals and an additional dorsal spine) have bifid spines; but Migeod reported these from the anterior dorsals, and it’s not clear that we have those.  A fair bit of material remains in jackets, and more has probably been lost or destroyed.  So it is possible, if unlikely, that one day we’ll open one of those jackets and find good evidence for bifid spines.
  • “Close-up of the Archbishop vertebrae (doesn’t look much like the mitre of an archbishop to me, but who knows” — well, the name The Archbishop is not based on any resemblance of the bones to a mitre.  (Nor is it based on anything else.  It’s completely arbitrary.)

Last 0f all, what about the actual picture?  Well, the long, thin, snakelike neck is beautiful art, but I don’t think it’s great science.  The height of the cervicals that we have for this animal show that the neck would have had to be quite a bit dorsoventrally taller than shown here.  And because there were only 13 cervical vertebrae — 12 if you omit the atlas, which is really a whole nother kettle of badgers, a neck bent into a strongly sigmoid pose like this would exhibit noticable kinks at some of the intervertebral joints — as you can see in giraffes when they twist their necks.

That aside, though, this is great.  Again, I am really delighted that it’s out there.  Congratulations to Nima!

CT-Scanning the Archbishop

November 18, 2009

Last week, for the first time ever, I spent the entire working week on palaeo.  I took a week away from my job, and spent it staying in London, working on the Archbishop at the Natural History Museum.  (For those of you who have not been paying attention, the Archbishop is the informal name of the specimen NHM R5937, a brachiosaurid sauropod from the same Tendaguru area that produced Giraffatitan brancai, and which has been generally assumed to represent that species.)

DSCN7528

Brachiosauridae incertae sedis NHM R5937, "The Archbishop", Cervical U in right lateral view. Photo copyright the NHM since it's their specimen.

My main goal was to take final publication-quality photographs that I can use in the description (which I have committed to try really, really hard to get submitted by the end of 2009).  There’s quite a bit of material (more than for Xenoposeidon, anyway!) — six cervicals in various states of preservation/preparation, cervical ribs, two complete dorsals, two more dorsal centra and a dorsal spine, some scap scraps, a partial ?pubis, a long-bone fragment and “Lump Z“, whatever that is.  What you see above is my best lateral-view photograph of what I’ve designated “Cervical U”.  One of these days, I’m going to do a post on how to photograph large fossils — something it’s taken me five years to get the hang of — but for today, I want to tell you about an exciting adventure with Cervical U.  [Update: I wrote the How To post a few months later.]

Because my other big goal on this trip was to get it CT-scanned.  Thanks to the generosity of John Hutchinson of the Royal Veterinary College, and to the help of the NHM people in arranging a loan, everything was set up for my host Vince Bickers and me to ferry the specimen up to the RVC, scan it and return it.

But first it had to be packed:

The Archbishop, Cervical U, packed and ready for transportation. Behind, Lorna Steel and Sandra Chapman of the NHM, who did the work.

Lorna and Sandra spent a long time looking for a crate big enough to pack the bone in, but came up empty — there was one that was long enough but not wide enough, one that was tall enough but not long enough, and so on.  In the end we sat the bone, on its very solid plaster base, on a plastic pallet, and wrapped it in pillows, bubble-wrap and that blue stuff whose name I don’t know.

As it happened, the scan had to be delayed for a day due to lack of personnel at RVC, but Vince and I took the vertebra up on the Thursday anyway; he had to return to work on the Friday, but I took public transport to RVC for the big day.  Before we went into the scanning room, John showed me his freezer room:

Just a couple of the freezers at RVC

I found it amusing that they have enough Segments Of Awesome that they have to label the various elephant-part freezers differently.  And further down the aisle:

John Hutchinson proudly shows off his dead baby rhino.

Then it was off to the scanning facility, where we found that we had to unpack the vertebra: it was small enough to go through the machine, but there was no way the pallet was going through.  Once we’d unpacked it and removed it, it fit pretty nicely:

The Archbishop's Cervical U all lined up and ready to go through the scanner, courtesy of John and radiographer Victoria Watts.

Because the scanner spits out X-rays in all directions, it’s controlled from a separate room, behind lead-impregnated glass:

Inside the control room

We ran three scans before we got the settings right — we needed more voltage to get through the bone and matrix than we’d first realised, and a filter was causing unhelpful moire patterns.  The third scan was definitely the best, and the one I expect to be working with.

[Boring technical side-note: I plan to use 3D Slicer for visualisation thanks to Andy Farke’s series of tutorials. But, frustratingly, I wasn’t able to load the DICOM files from the scan into that program: it crashes when trying to load them (segmentation fault) even though it works fine on the ankylosaur skull that Andy walked us through in the tutorials.  I fixed this by gluing the 300-odd files together into a single stack file that 3D Slicer was able to read.  For the benefit of anyone else who needs to do this, the command (on a Ubuntu Linux box) was: medcon  -f  *.dcm  -c  dicom  -stack3d  -n  -qc]

Here is an example slice, showing part of the condyle in posterior view:

CT slice through the condyle of The Archbishop's Cervical U, in posterior view. Dorsal is to the left.

The grey blobs at the bottom of the image are the plaster jacket that supports the vertebra; the white is bone, and the light grey inside it is matrix that fills the pneumatic spaces.  I’m showing the condyle here because its cavities are clearly visible: further back in the vertebra, they are harder to pick out, perhaps in part because of the iron bars scattering the X-rays.  It’s notable that this vertebra is less pneumatic than would be expected for a brachiosaurid — by eye, it looks like like the condyle is only 20-30% air, and this slice is not unrepresentative.  Most neosauropods would be at least twice this pneumatic, so we may have an Archbishop autapomorphy here.

I’ve not yet persuaded 3D Slicer to build a 3D model for me, but I’m pleased to say that before I left RVC, John mocked up a quick-and-dirty render of the bone using only density threshholding, and I can at least show you that.

The Archbishop, Cervical U, CT scan 3d model in left ventrolateral view

Here we see the bone from the left side, previously obscured by solid plaster.  From a single static image, it’s not easy to make out details, but we can at least see that there is a solid ventral floor to the centrum … and that those two crossed iron bars obscure much that we would like to see.  You will get more of an idea from the rotating video that this is screencapped from.

Looking at this and comparing it with the right-lateral photo at the top of the post, it’s apparent that the density threshhold was set too high when making this model: all the bone along the lower right margin of the middle part of the centrum is good, but it’s been omitted from the model.  In other words, the vertebra is more complete than this proof-of-concept model suggests.  Hopefully I will shortly be able to show you a better model.

If you’ve been following SV-POW! closely – perhaps a little too closely – you will know of BMNH R5937, a Tendaguru sauropod collected in 1930 on one of the British Museum (Natural History) expeditions, and reported in 1931 by Frederick Migeod (pronounced ‘mee-zhou’). Discovered in the ‘M23’ quarry at Tendaguru, the specimen was assumed by Migeod and all subsequent authors to be another specimen of Brachiosaurus brancai, but what’s notable is that Migeod mentioned several features in the vertebrae of the specimen that really sounded quite un-Brachiosaurus-like. Despite the size and quality of the specimen however, nobody ever got round to studying it properly – until Mike did exactly this. An abstract and talk slides on the specimen can be found here. For whatever reason, the specimen has become known as The Archbishop.

While Migeod wrote about The Archbishop, he never published any illustrations of it (with the exception of a quarry map). I don’t think I’m betraying any secrets by letting on that Mike is working on a full technical desciption of the specimen, wherein it will of course be illustrated properly. Little known however is that The Archbishop has appeared in the literature before, but (unsurprisingly, and in keeping with tradition) has been misidentified as Brachiosaurus. After all, it’s a big sauropod and it comes from Tendaguru, so it must be Brachiosaurus, right? Here’s the proof: it’s p. 94 of David Lambert’s Ultimate Dinosaur Book, published by Dorling Kindersley in 1993. The Archbishop photo is, of course, up there at top right, masquareding as the dorsal vertebrae of Brachiosaurus brancai.

It’s time to revisit everyone’s favourite trio of apocryphal super-sized sauropods! (Yes, we’ve talked about this before, but only very briefly, and that was nearly eleven years ago. Things have moved on since then.)

John Sibbick’s classic artwork showing three giant sauropods, including two of Jensen’s three. On the left is Seismosaurus Gillette 1991, which is not directly relevant to today’s post. In the middle is the brachiosaur Ultrasaurus, and on the right the diplodocid Supersaurus. Poor, unloved Dystylosaurus doesn’t get a look-in — perhaps because this was drawn before that name had been announced?

Here’s the story so far …

1. Jensen’s discoveries

In a series of expeditions beginning in April 1972, following a tip from uranium prospectors Eddie and Vivian Jones, Jim Jensen found numerous massive sauropod fossils in the Dry Mesa quarry, southwest Colorado. The Supersaurus pelvis at least was still in the ground as late as August 1972 (George 1973b:51–52) and the excavations continued into 1982 (Jensen 1985:697).

Eschewing such pedestrian venues as Science, Nature or indeed the Journal of Vertebrate Paleontology, Jensen first told the world about these finds in the popular press. The oldest widely circulated work that mentions them is Jean George’s (1973b) piece in Reader’s Digest, condensed from the same author’s piece in the Denver Post’s Empire Magazine earlier that year (George 1973a).

“‘Supersaurus,’ as we shall call him, now awaits an official name and taxonomic classification”, wrote George (1973b:53) — but the piece does not mention the names “Ultrasaurus” or “Dystylosaurus” and I’ve not been able to determine when those informal names became known to the world. (Can anyone help?) We do know that Jensen was informally using the name “Ultrasaurus” as early as 1979 (Curtice et al. 1996:87).

Anyway, for reasons that have never been very clear, Jensen concluded that the remains represented not one, not two, but three gigantic new genera: a diplodocid, which he named “Supersaurus”; a brachiosaurid, which he named “Ultrasaurus”; and an unidentifiable which he named “Dystylosaurus”. All these names were informal at this point, like “Angloposeidon” and “The Archbishop”.

2. Kim’s accidental Ultrasaurus

After Jensen had been using these names informally for some years, Kim (1983) named an indeterminate Korean sauropod as Ultrasaurus tabriensis. Based on the abstract (the only part of the paper in English, apart from the figure captions), Kim was aware of Jensen’s dinosaurs: “Judging by the large size of the ulna the animal may belong to the sauropod dinosaur, which is much bigger than Supersaurus. A new name Ultrasaurus tabriensis is proposed for the convenience of the further study.” While this does not quite go so far as to say that Kim considered the ulna to belong to the same genus as Jensen’s brachiosaur, it seems unlikely that he was aware of Supersaurus but not of Ultrasaurus, and landed independently on the latter name by coincidence. In fact, the “ulna” is a humerus, as shown by Lee et al. (1997).

Either way, in naming his species, Kim inadvertently preoccupied Jensen’s chosen genus name, with conseqences that we shall see below. By all accounts, the material the Kim described is in any case indeterminate, and the genus is generally considered a nomen nudum (e.g. Olshevsky 1991:139, Glut 1997:1001).

Kim 1983, plate 1, parts 1-3, illustrating the proximal portion of the huge “ulna” that the name Ultrasaurus tabriensis was founded on. As is apparent, this is actually the proximal end of a humerus, meaning that the animal is rather less large than Kim supposed — although the 42 cm width across the proximal end is still nothing to be sniffed at. It is about 71% the width of the 59 cm-wide humerus of the Giraffatitan brancai paralectotype MB.R.2181 (previously HMN SII).

Two years after this, and presumably unaware of Kim’s paper or incorrectly assuming his informal use of the name “Ultrasaurus” gave him priority, Jensen published a formal account of his finds, naming them (Jensen 1985). Unfortunately, while the paper does contain formal nomenclatural acts that are valid according to the rules of the ICZN, Jensen did not explain his reasoning for the creation of the new genera, and his selection of type material was problematic, as we shall see below. Also, the specimen numbers that he used have been superseded — I do not know why, but my guess would be that he re-used numbers that were already in use for other specimens, so his own material had to be given new numbers.

3. Jensen’s three sauropods

The following three genera (with their type species) were named, in this order:

1. Supersaurus vivianae, based on the holotype BYU 9025 (BYU 5500 of his usage), a scapulocoracoid measuring 2.44 m in length. To this, he referred an even larger scapulocoracoid whose length he gives as 2.70 m (though Curtice and Stadtman 2001:39 found that this length to be due to optimistic reconstruction); an ischium; either one or two mid-caudal vertebrae (his paper contradicts itself on this); and a sequence of 12 articulated caudal vertebrae. Unfortunately, Jensen’s use of specimen numbers for most of these referred elements is inconsistent, but he is at least consistent in referring to the second scapulocoracoid as BYU 5501.

Supersaurus vivianae referred scapulocoracoid BYU 12962, photographed at the North American Museum of Natural Life. The exhibit text reads: “Supersaurus scapula and coracoid. This is the actual Supersaurus bone that the world saw when the announcement was made of the new animal’s discovery in 1972. The scapula lay in the ground for five more years, waiting for the collection of other fossils that lay in the path of excavation. The flatness of the bone presented a challenge to “Dinosaur Jim” Jensen, who had to figure out a way to get the bone safely out of the ground. He finally accomplished this by cutting the scapula into three pieces. In 1988, Cliff Miles, Brian Versey and Clark Miles prepared the bone for study. It is still one of the largest dinosaur bones known in the world. Specimen on loan from Brigham Young University’s Earth Science Museum. Late Jurassic/Early Cretaceous (about 144 million years ago)

2. Ultrasaurus macintoshi, based on the holotype BYU 9044 (BYU 5000 of his usage), a dorsal vertebra measuring 1.33 m in height. To this, he referred BYU 9462 (BYU 5001 of his usage), a scapulocoracoid measuring 2.7 m in length; BYU 9024 (BYU 5003 of his usage), a huge cervical vertebra; and an anterior caudal vertebra.

Ultrasaurus macintoshi holotype dorsal vertebra BYU 9044, photographed at the North American Museum of Natural Life. (It’s incredibly hard to photograph well because it’s behind reflective glass.)

3. Dystylosaurus edwini, based on the holotype BYU 4503 (BYU 5750 of his usage), a dorsal vertebra. He did not refer any other material to this taxon, and considered it “Family indeterminate” commenting that it “no doubt represents a new sauropod family”. Poor Dystylosaurus has always been the unloved member of this group, and pretty much ignored in the literature aside from the Curtice & Stadtman (2001) synonymisation paper discussed below.

Dystylosaurus edwini holotype BYU 4503, a diplodocoid anterior dorsal vertebra.

In a subsequent paper, Jensen (1987:600–602) removed the big cervical BYU 9024 (BYU 5003 of his usage) from Ultrasauros and reassigned it to Diplodocidae. The text of this paper never refers it to Supersaurus vivianae in particular, but it is illustrated and captioned as belonging to that taxon (Jensen 1987:figures 7A-B, 8C), and this assignment is generally assumed to have been meant.

When Jensen became aware of Kim’s (1983) preoccupation of the name Ultrasaurus, he recognised that his own genus needed a new name. At his suggestion, Olshevsky (1991) erected the replacement name Ultrasauros (with a single-letter spelling difference) for Jensen’s taxon based on the dorsal vertebra BYU 9044. We will use this revised spelling hereon, and the taxon Ultrasaurus Kim 1983 is of no further interest to this story.

The relevant extract from Olshevsky (1991:139).

4. Curtice’s synonymies

This was how things stood, with Jensen’s assignment of the material to his three new genera standing unchallenged, until Brian Curtice came on the scene in the mid 1990s. In a series of three publications (two papers, one abstract), he first synonymised Ultrasauros with Supersaurus, then Dystylosaurus also with Supersaurus, and finally (tentatively) Supersaurus itself with Barosarus. If Curtice’s suggestions were all correct, then there were no new sauropods from Jensen’s work in the the Dry Mesa quarry, just a lot of Barosaurus material.

Was he right? We’ll now consider each of the three publications in turn.

First, Ultrasauros. Jensen had always considered this genus to be a brachiosaurid due to the morphology of the scapulocoracoid BYU 9462 — and indeed this element does seem to be brachiosaurid. Unfortunately, he did not found the taxon on this element, but on the dorsal vertebra BYU 9044. Curtice et al. (1996) re-examined this element, and argued convincingly that it was not an anterior dorsal from a brachiosaurid, as Jensen had thought, but a posterior dorsal from a diplodocid. Since its neural spine morphology matches that of the first preserved sacral spine (S2) of the Supersaurus sacrum, and since it was found between the two Supersaurus scapulocoracoids, Curtice et al. (1996:94) considered BYU 9044 to be a vertebra of Supersaurus (belonging to the holotype individual), and therefore concluded that Ultrasauros was a junior subjective synonym of Supersaurus. They inferred that the referred Ultrasauros scapulocoracoid BYU 9462 therefore did not belong to the same species as the type, since it was brachiosaurid, and referred it to Brachiosaurus sp.

We consider all of Curtice et al.’s (1996) arguments well-founded and convincing, and agree with their conclusions. As a result, both spellings of Jensen’s brachiosaurid genus are now discarded: Ultrasaurus as a nomen dubium, and Ultrasauros as a junior synonym.

Curtice et al. (1996:figure 2). “Uncrushed” Supersaurus vivianae caudal dorsal, BYU 9044, right lateral view.

A few years later, Curtice and Stadtman (2001) took aim at Dystylosaurus. Jensen had argued that it was unique because of the paired centroprezygapophyseal laminae that supported each prezygapophysis from below — and it was from this feature than the genus took its name. But Curtice and Stadtman pointed out that this supposedly unique feature is in fact almost ubiquitous in diplodocids. Because it, too, was found between the two Supersaurus scapulae (close to the Ultrasaurus dorsal), Curtice and Stadtman referred it, too, to Supersaurus, thereby collapsing all three of Jensen’s taxa into one. This argument, too, is well supported and has been generally accepted.

Finally, in a sole-authored abstract, Curtice (2003) hedged about whether he considered Supersaurus to be Barosaurus. I will quote directly, as the line of reasoning is vague and difficult to summarise:

The question of is Supersaurus truly a distinct genus from Barosaurus is now testable. The former Dystylosaurus dorsal vertebra provides an autapomorphy for Supersaurus, that being a strongly reduced bifid neural spine on dorsal four. This loss of bifidity is important for in all other diplodocids the neural spine is still deeply bifurcated on dorsal four. Only Barosaurus has a reduction in cleft depth that far forward in the dorsal column. Supersaurus has all but lost the cleft, more closely resembling the sixth dorsal vertebra of Barosaurus than the fourth.

It is disappointing that this abstract never became a more rigorously argued paper, because the conclusion here is highly equivocal. Curtice appears to be saying that Supersaurus is distinct from Barosaurus — but only on the basis of bifidity reducing two vertebrae more anteriorly in Supersaurus. In other words, he seems to be suggesting that the two taxa are indisinguishable aside from this rather minor difference.

At any rate, this speculation in a conference abstract has generally been ignored, and Supersaurus considered a valid and distinct genus.

5. Jimbo the WDC Supersaurus

In 2008, Lovelace et al. (2008, duh) described WDC DMJ-021, a new specimen of Supersaurus vivianae at the Wyoming Dinosaur Center that is known informally as “Jimbo”. (Confusingly, they refer to the Supersaurus holotype scapulocoracoid by yet a third specimen number, BYU 12962; but this is the revised specimen number of the referred scapulocoracoid, not the holotype.)

Lovelace et al. (2008) did not justify in detail their referral of Jimbo to Supersaurus. The closest they come is this brief passage on page 529–530:

While a scapula is not known for WDC DMJ-021, other elements are identical to axial elements referred to the type individual of Supersaurus. Referral of all material is supported by relative position within their respective quarries (Curtice and Stadtman 2001; Lovelace 2006), size of the skeletal elements, and congruence of phylogenetically significant diplodocid characters between the scapula and referred material.

All of this is kind of weaselly. What it amounts to is this: vertebrae are “identical” to those referred to the BYU Supersaurus (but not really, as we’ll see), and the elements are really big, and the Supersaurus holoype scap comes out in about the same place as Jimbo in a phylogenetic analysis if you code them up separately. This is weak sauce, and I would really have liked to see a much more explicit “Jimbo shares synapomorphies X, Y and Z with BYU Supersaurus” section.

Among the ways in which the justification for this assignment disappoints is that the presacrals that are described as “identical” to the BYU elements are not at all well preserved (Lovelace et al. 2008:figures 3D–E, 4A, 5A): in particular C13, presumably the best preserved cervicals as it is the only one illustrated, is missing the condyle, prezygapophyses and neural spine. It’s not possible to be sure in light of the small monochrome illustrations in the paper, but it does not seem likely that these elements can be reliably assessed as identical to the BYU cervical.

Lovelace et al. (2008:figure 3). Lateral views of cervical vertebrae from A, Diplodocus carnegii (Hatcher 1901); B, Barosaurus lentus (Lull 1919); C, Apatosaurus louisae (Gilmore 1936); D and E, Supersaurus vivianae; demonstrating pneumatic modifications of centra. Supersaurus has the least amount of modification with minimal size for pneumatopores. Internal structure is similar to that seen in other diplodocids (Janensch, 1947). Left lateral view of Cv.13 (D, missing the condyle, prezygapophyses and neural spine; length of incomplete centra 94cm). E, cross section through Cv.11, 5cm posterior of the diapophysis.

The big surprise in the Jimbo paper is that in the phylogenetic analysis (Lovelace et al. 2008:figure 14), the compound BYU+WDC Supersaurus is recovered as an apatosaurine, the sister taxon to Apatosaurus, rather than as a diplodocine as had been assumed in previous studies due to its resemblance to the diplodocine Barosaurus.

The huge specimen-level phylogenetic analysis of diplodocoids by Tschopp et al. (2015) corroborated Lovelace et al’s (2008) referral of the WDC specimen to Supersaurus vivianae, as the two species were sister groups in all most parsimonious trees, with quite strong character support (Tschopp et al. 2015:187). But it placed the Supersaurus clade at the base of Diplodocinae, not within Apatosaurinae as Lovelace et al. (2008) had found.

This, then, was the state of play when Matt and I started to work on Supersaurus during the 2016 Sauropocalypse: Ultrasauros and Dystylosaurus had both been sunk into Supersaurus, and the WDC specimen had been referred to the same species.

Next time, we’ll look what Matt and I found in Utah, and what we think it means for Supersaurus and its friends.

 

References

  • Curtice, Brian D. 2003. Two genera down, one to go? The potential synonomy [sic] of Supersaurus with Barosaurus. Southwest Paleontological Symposium 2003, Guide to Presentations. Mesa Southwest Museum, January 25 2003. Unpaginated.
  • Curtice, Brian D. and Kenneth L. Stadtman. 2001. The demise of Dystylosaurus edwini and a revision of Supersaurus vivianae. Western Association of Vertebrate Paleontologists and Mesa Southwest Museum and Southwest Paleontologists Symposium, Bulletin 8:33-40.
  • Curtice, Brian D., Kenneth L. Stadtman and Linda J. Curtice. 1996. A reassessment of Ultrasauros macintoshi (Jensen, 1985). M. Morales (ed.), “The continental Jurassic”. Museum of Northern Arizona Bulletin 60:87–95.
  • George, Jean. 1973a. Supersaurus, giant of the giants. Denver Post,
    Empire Magazine. May 13, 1973, pp 14ff.
  • George, Jean. 1973b. Supersaurus, the biggest brute ever. Reader’s Digest (June 1973):51–56.
  • Glut, Donald F. 1997. Dinosaurs: the Encyclopedia. McFarland & Company Inc., Jefferson. 1076 pp.
  • Jensen, James A. 1985. Three new sauropod dinosaurs from the Upper Jurassic of Colorado. Great Basin Naturalist 45(4):697–709.
  • Jensen, James A. 1987. New brachiosaur material from the Late Jurassic of Utah and Colorado. Great Basin Naturalist 47(4):592–608.
  • Kim, Haang Mook. 1983. Cretaceous dinosaurs from South Korea. Journal of the Geological Society of Korea 19(3):115–126.
  • Lee, Yuong-Nam., S. Y. Yang and E. J. Park. 1997. Sauropod dinosaur remains from the Gyeongsang Supergroup, Korea; pp. 103–114 in S. Y. Yang, M. Huh, Y.-N. Lee and M. G. Lockley (eds.), International Dinosaur Symposium for Uhangri Dinosaur Center and Theme Park in Korea. Journal of Paleontological Society of Korea, Special Publication 2.
  • Lovelace, David M., Scott A. Hartman and William R. Wahl. 2008. Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. Arquivos do Museu Nacional, Rio de Janeiro 65(4):527–544.
  • Olshevsky, George. 1991. A revision of the parainfraclass Archosauria Cope, 1869, excluding the advanced Crocodylia. Mesozoic Meanderings 2:1–196.
  • Tschopp, Emanuel, Octávio Mateus and Roger B. J. Benson. 2015. A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda). PeerJ 2:e857. doi:10.7717/peerj.857

 

2018 at SV-POW!

December 31, 2018

Last year about this time I vowed to return SV-POW! to its nominal roots: a new post at least once a week for all of 2018. It had been a while since the blog had lived up to the letter of its name, and I thought it would be a fun challenge to see if blogging to a schedule again would be inspiring or oppressive.

Then I went and had probably the busiest year of my professional career: 12 invited talks in 5 different states, 12 visits to museum collections or research labs, plus another 3 visits to museum public galleries for fun, 4 trips for fieldwork, 3 conference presentations, and more CT scanning than I have done since the last millennium. Happily, I am not the sole proprietor here and Mike and I can take turns driving when the other is occupied.

So how’d we do?

In January I blogged about weird neural canals, part of an obsession that would occupy most of my mental bandwidth this year, and also about the impact of Don Glut’s New Dinosaur Dictionary when I was a kid. A post on sauropod gigantism sparked a very active discussion that ran to 47 comments, which is a rarity these days.

Gonzalez Riga et al. (2018: figure 6). Mendozasaurus neguyelap cervical vertebra (IANIGLA-PV 076/1) in (A) anterior, (B) left lateral, (C) posterior, (D) right lateral, (E) ventral and (F) dorsal views. Scale bar = 150 mm. Sorry it’s monochrome, but that’s how it appears in the paper.

February was mostly run-of-the-mill posts on vertebral morphology and open access. The standouts were Mike’s post on weird cervical vertebrae and my unexpectedly popular off-topic post on the durability of tungsten. I see that my teaser post on a trip to see elephant seals has not yet been followed up. There’s a lot of that around here–we’re often too busy with the next thing to finish up the last thing. I’ve given up feeling bad about that, and accepted that it’s just how we roll.

Mike ruled March with a flurry of posts, including a couple worth revisiting on how grant funding is awarded and on the state of play vis-a-vis Big Publishing. Also (and uncharacteristically) Mike posted on appendicular bones of birds, both skinny and fat. It was left to me to represent for sauropods, with posts on the cervical vertebrae of Alamosaurus and Suuwassea and some noodling about sauropod skin.

I flew solo in April, with some posts derived from my spring travels. A very long post on the suitability of dinosaur femora as clubs was good, goofy fun, but an arresting video of a rhino going ass-over-teakettle and getting up unhurt, and the humility that should inspire in us, is the clear standout for the month.

In May I started CT scanning sauropod vertebrae again and went to Utah for the first of several stints of fieldwork this year. Mike started work on the Archbishop (allegedly), and blogged about Argentinosaurus poop. My series on bird neural canals, represented by these posts (two links) is still incomplete, and has now been superseded by the Haplocanthosaurus presentation at the 1st Palaeontological Virtual Congress.

June was comparative anatomy month here at SV-POW!, with Mike posting on the dead things in his woodshed, and me writing about exploded turtles and the amazing collection of anatomical preparations in Peter Dodson’s office. I also managed two posts about field adventures in the Oklahoma panhandle.

Figure 4. Centra and neural arches of posterior dorsal vertebrae from two rebbachisaurid sauropods (not to scale), highlighting the distinctive “M” shape formed by laminae on the lateral face of the neural arch. A. NHMUK PV R2095, the holotype and only vertebra of Xenoposeidon proneneukos. B. MNHN MRS 1958, a posterior dorsal vertebra from the holotype specimen of Rebbachisaurus garasbae.

In July Mike and I returned to our regular dance partners. For Mike, that meant serious and whimsical posts about Xenoposeidon, which for a few months held the title of the oldest known rebbachisaur. I had Haplocanthosaurus caudals on the brain, both old and new. Posts on fieldwork in Oklahoma and Utah bookended the month.

My fascination with Haplocanthosaurus extended into August, and I CT scanned a Diplodocus caudal and attended a pterosaur conference. Mike kicked off a discussion about vertebral orientation with a pair of posts that would eventually lead to our presentation on the topic at the 1st Palaeo Virtual Congress. And I see that I still owe the world a “down in flames” perspective on my own career.

In September the vertebral orientation discussion expanded to take in the Brachiosaurus holotype and Komodo dragons, and Mike blogged about imposter syndrome. The most personally satisfying event in September was that Jessie Atterholt and I started to get the word out about some of the collaborative research we’ve been doing in the past year, with her very well-received talk at SVPCA and the archiving of our abstract and slideshow on PeerJ Preprints.

October saw the return of #MikeTaylorAwesomeDinoArt, and the 2018 TetZooCon, and #MikeTaylorAwesomeDinoArt at TetZooCon. I also had a return to form, with a series of posts about pneumaticity, and a batch of new paleo-memes. The biggest actual news was the enigmatic Amphicoelias fragillimus dethroning Xenoposeidon as the new world’s oldest rebbachisaur.

November was entirely representative of SV-POW!, with an eclectic grab-bag of posts on a museum mount, neck flexibility, a historical illustration, bird vertebrae, academic publishing, and what is probably our real favorite dinosaur (no matter what we might say when asked in interviews or in person): the insanely overbuilt Apatosaurus.

This month we’re closing out the year with posts on dissecting a pig head, our presentations at the 1st Palaeo Virtual Congress, the open birth of the vertebral orientation paper, a long overdue post on cleaning bird vertebrae, and this, our first yearly retrospective.

The Salutary Effects of Blogging

This blog started as a joke, and we thought we’d see if we could keep up the gag for a whole year. But it very rapidly evolved into something much more serious, in a way that none of us expected. SV-POW! doesn’t just give us a forum to interact with you, our colleagues. It also forces us to talk to each other, regularly, about subjects that we care about. I love reading Mike’s posts, because after all this time, I still often have no idea what he’s going to say. After 18 years of friendship, 14 joint conference presentations, 11 years of blogging together, and 7 coauthored papers, we still regularly surprise each other with unexpected observations and provocative questions. Not only do we not always agree, we very often disagree, but we disagree constructively. Neither of us is willing to let a subject drop until we’ve gotten to the root of the disagreement, and that process sharpens us both.

Bottom line, we both need SV-POW! Not only as a forum for discussion, although that’s rewarding, or as a soapbox, although that’s sometimes useful, or a generator of occasionally publishable ideas, although that’s an unexpected bonus. We need to blog here because it forces us to keep learning what we think and what we know, both individually and as a team. If you enjoy the output or find it interesting or infuriating or worth thinking about, we’re happy — honored, in fact. But at this point I think we would keep blogging if there was no audience at all. It is a whetstone for our minds.

Let’s see what 2019 will bring. Happy New Year, everyone! We’ll see you in the future.

I’m delighted to announce the publication today of my new paperXenoposeidon is the earliest known rebbachisaurid sauropod dinosaur”. This is the peer-reviewed version, in my favourite journal PeerJ, of the manuscript that became available as a preprint eight months ago — which was in turn a formalisation of a blog-post from 2015.

Taylor (2018: Figure 3). Autapomorphies of Xenoposeidon proneneukos NHMUK PV R2095, mid-posterior dorsal vertebra, highlighted in red. A. anterior view. B. left lateral view. Numbers pertain to the numbering of autapomorphies in the text. 1a, neural arch covers whole of centrum, and 1b is contiguous with posterior articular facet. 2, neural arch is inclined forward by 30–35 degrees relative to the vertical. 3a, inclined ridge-like lamina marks ventral margin of 3b broad featureless area of bone. 4, large teardrop-shaped anterior fossa. 5a, vaulted laminae bound this fossa, but are not the medial CPRLs (5b, drawn in finer lines), which continue up to the presumed location of the prezygapophyses.

In a sense, then, this paper is old news. It doesn’t contain any startling new insights that readers of this blog wouldn’t already have been aware of. But it’s become more rigorous, better argued and justified, better illustrated (the image above is one of two new figures), and generally toughened in the forge of peer-review. It’s also now, of course, officially part of the scientific record.

I’m delighted about this paper for several reasons. First, of course, because Xenoposeidon is a beautiful specimen and now turns out to be rather more important than I’d previously realised. Second, because I hope this paper’s inclusion of the high-resolution full-colour 3D model as a supplementary file will help to establish this as common practice. But also third, because it’s my first paper in ages.

In fact, if you were being harsh, you could say it’s my first real paper since the annus mirabilis of 2013 when Matt and I had four good, solid papers come out in a single year. My CV lists five papers between then and now, but a case can be made that none of them really count:

  • Taylor 2014 is essentially an addendum to my and Matt’s PLOS ONE paper the year before.
  • Upchurch et al. 2105 is a significant and substantial piece of work, but almost all the credit on that one is due to Paul and Phil.
  • Taylor 2016 is more of an advocacy piece than a scholarly paper.
  • Ansolabehere et al. 2016 is merely a report summarising a multi-day discussion, and I am in any case only one of nine(!) co-authors.
  • Taylor 2017 is just a short comment on someone else’s ICZN petition. (In fact that one is so feeble I should just remove it from my CV.)

Putting it all together, it’s been the best part of five years since I made a significant contribution to the scientific record, and to be honest I was starting to wonder whether I could still do it. (My deep thanks go to Paul Upchurch and Phil Mannion for keeping my publication record on life-support with that Haestasaurus paper!)

The challenge for me now is, having got back on the horse, to ride it hard. In particular:

That’s not even mentioning other long-in-the-works projects like the descriptions of Apatosaurusminimus and “Biconcavoposeidon”. Sheesh. I’m so lazy. Nearly as bad as Darren.

References

 

I can’t even count how many sauropod vertebra pictures we’ve posted here across the last ten years, but I am confident that the total comes to at least a lot. Here’s a picture from each year of the blog’s existence so far — let’s vote on which is the best!

November 15, 2007: Xenoposeidon week, day 1: Introducing Xeno

The stark beauty of the Xenoposeidon proneneukos holotype NHMUK R2095, a mid-to-posterior partial dorsal vertebra in left and right lateral views.

February 1, 2008: Your neck is pathetic

Sauroposeidon proteles holotype OMNH 53062, 8th cervical vertebra in left lateral view (1400 mm total length). Entire human neck for scale.

January 7, 2009: The sauropods of Star Wars: Special Edition

Our old friend Giraffatitan brancai MB.R.2181 once more, this time with Matt for scale.

February 12, 2010: Tutorial 8: how to photograph big bones

The Archbishop in all its glory. The much-loved dorsals 8 and 9, in right lateral view, of the Tendaguru brachiosaurid NHMUK R5937.

May 16, 2011: Why the long necks? Probably not sexual selection

Taylor et al. (2011), fig. 1: Sauropod necks, showing relationships for a selection of species, and the range of necks lengths and morphologies that they encompass. Phylogeny based on that of Upchurch et al. (2004: fig. 13.18). Mamenchisaurus hochuanensis (neck 9.5 m long) modified from Young & Zhao (1972: fig. 4); Dicraeosaurus hansemanni (2.7 m) modified from Janensch (1936: plate XVI); Diplodocus carnegii (6.5 m) modified from Hatcher (1903: plate VI); Apatosaurus louisae (6 m) modified from Lovelace, Hartman & Wahl (2008: fig. 7); Camarasaurus supremus (5.25 m) modified from Osborn & Mook (1921: plate 84); Giraffatitan brancai (8.75 m) modified from Janensch (1950: plate VIII); giraffe (1.8 m) modified from Lydekker (1894:332). Alternating grey and white vertical bars mark 1 m increments.

April 15, 2012: Neural spine bifurcation in sauropods, Part 6: more reasons why Haplocanthosaurus is not a juvenile of a known diplodocid

Wedel 2009: Fig. 6. Pneumatization of the presacral vertebrae in Haplocanthosaurus. (A) X-ray image of a posterior cervical vertebra of CM 879 in right lateral view. (B) A CT slice through the same vertebra. (C) X-ray image of an anterior dorsal vertebra of CM 572 in left lateral view. (D) X-ray image of the same vertebra in anterior view.

January 16, 2013: Plateosaurus is pathetic

Our old friend C8 of the Giraffatitan brancai paralectotype MB.R.2181 in left dorsolateral view, with a comparable cervical of the prosauropod Plateosaurus for scale.

February 12, 2014: Can PeerJ really be only a year old?

Barosaurus lentus holotype YPM 429, Vertebra Q (C?13). Top row: left ventrolateral view. Middle row, from left to right: anterior view, with ventral to the right; ventral view; posterior view, with ventral to the left. Bottom row: right lateral view, inverted. Inset shows diapophyseal facet on right side of vertebra, indicating that the cervical ribs were unfused in this individual despite its great size. Note the broad, flat prezygapophyseal facet visible in anterior view. (Taylor and Wedel 2013b: figure 6)

September 14, 2015: So what were apatosaurs doing with their crazy necks?

A slide from our 295 SVPCA talk, illustrating key points in apatosaurine neck morphology that led us to the BRONTOSMASH hypothesis.

May 18, 2016: Thank you to all our Sauropocalypse hosts!

Mike compares Jensen’s sculpture of the big Supersaurus cervical BYU 9024 with the actual fossil.

August 15, 2017: “Biconcavoposeidon”

AMNH FARB 291, five consecutive posterior dorsal vertebrae of a probably brachiosaurid sauropod which we informally designate “Biconcavoposeidon”, in right lateral view.

(Yes, there are eleven pictures: we’ve been running for ten years, but that includes both the end of 2007 and the start of 2017.)

So, which is the picture of the decade? Vote here (and let us know in the comments if we missed your favourite).