January 25, 2010
In my not-long-quite-so-recent-any-more paper on Brachiosaurus and Giraffatitan, I gave as one of the autapomorphies of Brachiosaurus proper that the glenoid articular surface of its coracoid is laterally deflected. Although we’ve discussed this a little in comments on SV-POW!, it’s not yet made it into one of our actual articles. I hestitated to feature it here since it’s so darned appendicular, but in the end I concluded that it was too interesting and potentially important to overlook.
So here it is!
The deflected surface is most apparent in the posterior view at the right of the fiigure, in which it appears deflected about 55 degrees from the horizontal. That’s misleading, though — partly because the shape is more complex in three dimensions than can be easily visualised from these orthogonal shots, and partly because of course the coracoid was not held perfectly vertical in life. In fact, the orientation of the coracoid in sauropods, and of the entire shoulder girdle, remains rather controversial. It’s not an area I’ve got involved in so far, but this Mystery Coracoid Of Weirdness (hereafter MCOW) might just be my gateway into the wacky world of pectoral girdles.
The ventral view at the bottom of the figure is also informative: as you can see from that angle, the articular surface extends a long way laterally (i.e. towards the top of the figure in this orientation). Once you’ve got your eye in with those images, it’s easy to see the facet in the lateral-view photo, despite the less than ideal saturated lighting: it’s shaped like a raindrop falling towards bottom left. (Well, not really: raindrops are actually vertically flattened spheroids rather then raindrop-shaped, but that’s not the point.)
Observations and interpretations on this oddity will be very welcome.
Finally, here is your regularly scheduled sauropod vertebra:
December 29, 2009
Yes, you too can have your very own brachiosaurid cervical! Specifically, “Cervical P” of the as-yet unnamed brachiosaur NHM R5937, informally known as “The Archbishop”. Here is is!
(All images of the vertebra are copyright the NHM.)
All you need is scissors, glue, and this handy cut-out-and-keep schematic. You’ll want to click through to the full-resolution version (which if I say it myself is a thing of some beauty.)
Print this out, then cut around the black lines to make the template:
Then fold downwards along all the grey lines:
Now, just glue the tabs, fold the lines at right angles, and stick the box together.
The very last tab you glue will be the most difficult to get right, because you won’t be able to press the two parts together once the box is closed. So make sure that you glue the long side of the blank base last, as it doesn’t matter so much if that’s not don’t cleanly.
And there is the final result, this time in the opposite view:
And that’s all there is to it!
December 22, 2009
Ever since we started working on Sauroposeidon, Rich Cifelli and I dreamed of seeing the reconstructed neck on display. That vision has come to fruition.
The Oklahoma Museum of Natural History opened a totally new building in 2000. Coincidentally, the opening ceremony for the new digs was held the same week that the paper naming Sauroposeidon came out in JVP. The exhibits in the new building were pretty cool right out of the gate, but the exhibit people have not been idle, and if you haven’t been there in a year or three you will find many things that you have not seen before.
My favorite upgrade is the new orientation gallery, which introduces museum visitors to the functions of the museum and the kinds of work that go on in the research wing, including most of the traditional -ologies. The reconstructed neck and head of Sauroposeidon hang from the ceiling, spanning most of the length of the gallery and extending out into the museum’s great hall.
The beast was reconstructed by Research Casting International. I got to visit their workshop in Ontario, Canada, a little over a year ago to see how things were coming along. The people there were extremely serious about getting things right (how refreshing!). We spent quite a while talking about how Sauroposeidon was different from Giraffatitan (RCI remounted the Humbolt dinos) and sketching out what the missing bits might have looked like, especially the skull.
Of course we don’t have any skull material from Sauroposeidon, but we do have skulls and partial skulls from several other basal titanosauriforms. Together with one of the people working on the Sauroposeidon project, I filled up a couple of pieces of paper with sketches showing what a slender mid-Cretaceous brachiosaur might have looked like. In particular, and in keeping with the gracility of the cervical vertebrae, we narrowed the skull a bit to get rid of the dreaded Giraffatitan Toilet-Bowl Head.
The completed neck and head were already mounted in the OMNH when I visited last Christmas, but the gallery wasn’t open yet so all I got–and all I could pass on to you–was this teaser. The new orientation gallery opened in the middle of this spring, so Sauroposeidon has been hanging out there for a while. This is just the first chance I’ve gotten to go see my baby.
What a fine present. Merry Christmas from the SV-POW!sketeers!
Update from Mike
Here is my Christmas card to you all.
December 2, 2009
It’s a strange thing, but no-one seems to bother properly figuring their sauropods’ cervical ribs — that is, the long, thin, posteriorly directed ribs of the neck vertebrae. I’ll be bucking that trend when the Archbishop paper comes out, but to get your mouth watering ahead of time, here is the head of the cervical rib that I have arbitrarily designated X1, the largest of those preserved in the Archbishop:
The top image shows the rib in anterior view, with dorsal pointing to the left; the middle row shows the rib with anterior pointing upwards, in (from left to right), lateral, dorsal, medial and ventral views; the bottom row shows posterior view, again with dorsal to the left. Click through the image to see the full glory of the high-resolution version. Remember folks: you only get this sort of high-resolution image published in PLoS journals!
As I mentioned, sauropod cervical ribs have been pretty comprehensively ignored in the literature. I can’t offhand think of a single paper about them (unless you count Martin et al.’s (1998) proposal that they functioned in ventral compression-bracing of sauropods’ necks, and let’s not even start on that), and I am really struggling to think of paper that figures them. Even the usually super-reliable Osborn and Mook (1921) dropped the ball here, with a single illustration (out of 127 figures) and single short paragraph of text (out of 141 pages). Here it is:
Janensch (1950) did discuss the cervical ribs of Giraffatitan in some detail, but his figures are not very informative. If anyone knows of better treatments of sauropod cervical ribs in the literature, then please mention it in the comments!
Because of this poor coverage in the published record, it’s hard for me to compare the Archbishop cervical ribs with those of other taxa. For example, the medial view of X1 (in the middle of the “cross” in the image above) shows that the internal face of the cervical rib loop, where the cervical rib reaches up to articulate with the diapophysis of its vertebra, has two parallel struts of bone extending vertically with a narrow groove between them. Is that unusual? I have no idea.
(I do have photos of some other Tendaguru cervical ribs, referred to Giraffatitan — although if I’m right that the Archbishop is not Giraffatitan, so that there are multiple brachiosaurs in the Tendaguru Formation, then who knows whether that referral is correct?)
Finally, we come to the matter of your cervical ribs. I would have liked to do this post as one in the Your Noun Is Adjective series, but the brutal truth is, you don’t even have any cervical ribs — unless you are one of the lucky 0.2% that, according to the Wikipedia article, have a supernumary rib which is frankly just an additional dorsal rib (uh, thoracic rib I guess) that’s growing out of your last cervical vertebra by mistake. (Wikipedia’s horrible humanist bias is apparent here, in that the article doesn’t even mention the fact that plenty of other animals have cervical ribs and love them.)
Anyway, here’s how human cervical ribs look, stolen from Do You Really Need Back Surgery? A Surgeon’s Guide to Neck and Back Pain and How to Choose Your Treatment:
- Janensch, Werner. 1950. Die Wirbelsaule von Brachiosaurus brancai. Palaeontographica (Suppl. 7) 3:27-93.
- Martin, John, Valérie Martin-Rolland, and Eberhard (Dino) Frey. 1998. Not cranes or masts, but beams: the biomechanics of sauropod necks. Oryctos 1:113-120.
- Osborn, Henry Fairfield, and Charles C. Mook. 1921. Camarasaurus, Amphicoelias and other sauropods of Cope. Memoirs of the American Museum of Natural History, n.s. 3:247-387, and plates LX-LXXXV.
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.)
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:
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:
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:
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:
Because the scanner spits out X-rays in all directions, it’s controlled from a separate room, behind lead-impregnated glass:
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:
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.
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.
November 6, 2009
I’m following up immediately on my last post because I am having so much fun with my wallaby carcass. As you’ll recall, I was lucky enough to score a subadult male wallaby from a local farm park. Today, we’re going to look at its feet.
Wallabies are macropods; together with their close relatives the kangaroos and Wallaroos, they make up the genus Macropus, literally “bigfoot”. So wallabies got there long before cryptic North American anthropoids. And indeed their feet are big. Here are those feet, in dorsal view, from before I started doing unspeakable things to my specimen:
From here they look pretty weird, but it’s only when we go round the back that we really see how odd they are. Same feet in ventral view:
There are (at least) three things to notice here: first just that the feet are very long; second, the thick, scaly pad that runs all the way up to the heel; and third, the bizarre arrangement of toes. At first glance, it seems that there is one main toe and a smaller one each side, but if you look more closely you’ll see that the medial “toe” is really two tiny toes closely appressed, so that they function as a single toe. This condition is known as syndactyly, Darren tells me. Also from Darren: it’s digit I that is missing in macropods, so the tiny-toe pair are digits II and III, the main toe is IV and the lateral one is V.
(By the way, seeing my patio in these photos reminds me of something I forgot to mention in the previous post: it’s surprisingly difficult to wash wallaby blood off paving slabs. Remember that, kids, it’ll be on the test.)
Regular readers will remember from last time that I planned to prepare the skull and left fore- and hindlimbs by simmering and dissection, and let nature deal with the rest of the elements. You’ve already seen the skull, so here goes with that foot.
After an initial simmer, I was able to skin the left pes, so here it is at that stage, in medial view:
From this angle, you can clearly see the absurdly thin second metatarsal (MT II) that supports the innermost of those two tiny digits. MT III is just as long and thin, but is fused proximally to the much larger MT IV, as we shall see below. The simmering has resulted in the more distal phalanges breaking away from their more proximal brethren, and being pulled downwards and beneath them. This is most apparent with the tiny digits, whose supporting phalanges are clearly visible poking out above the claws. So the large lump of what looks like cartilage at top right is actually phalanx IV-I, with IV-II and IV-III (the ungual) beneath it. Also note the significant amount of resilient tissue below the metatarsals. I’ve cut most of it away, but you can get a good idea from the bits that are still attached distally.
Here is the metatarsus in ventral view after I had removed the phalanges:
Here you can clearly see the syndactyly (in those two closely appressed thin metatarsals II and III at the top of the picture) and the very sculpted distal ends of the larger metatarsals IV and V.
Now let’s skip straight to to the completed stripped-down pes, now in dorsal view:
It’s interesting that the phalangeal formula is so uniform: 0-3-3-3-3. That is, all four digits have two normal phalanges and an ungual. But the differences in proportions between them are quite something.
This is our first look at the tarsals — those seven bones on the left of the picture, before we get to the metatarsals. The three big ones fit together very nicely. At the back you see the calcaneum, where the achilles tendon attaches; next is the astragalus, which sits on top of the calcaneum and where the distal end of the tibia articulates. Next up is a bone whose name I don’t know, being pretty darned ignorant of ankles — might it be the cuboid? Anyway, even after cleaning and cartilage-removal , this articulates very nicely indeed with both the calcaneum and MT IV.
Medial to these (i.e. below them in the picture) are four much smaller tarsal bones whose identity I can’t even guess at. It’s not clear to me how they articulate with the big tarsals — they were all pretty solidly embedded in cartilage and gloop and I fear that they’re not going to fit neatly whatever I do. Hints will be welcome.
One big surprise was the small bones between the metatarsals and their corresponding phalanges: one each at the ends of MT II and MT III, and two each at the ends of MT IV and MT V. Because the proximal phalanges articulate so nicely with their metatarsals, it’s clear that these small bones were not positioned between them in life, but rather floated above them — rather as your kneecap, or patella, floats above your femur-tibia joint. They are sesamoids. Does anyone know whether this sesamoid formula of 0-1-1-2-2 is common? Seems a bit weird to me.
Finally, I leave you with the entire left hindlimb: foot as in the previous picture, surmounted by the tibia and fibula, then by the femur, all in anterior view. Just to the left of the femur-tibia joint is a small bone which I assume is the patella.
Special bonus wallaby limb: over there on the right is the left forelimb. As you can see, I’ve done the easy part (scapula, humerus, ulna and radius) but I still have to dissect out the bones from the wrist and hand — a picky, tedious job that to be frank I am not looking forward to. The feet are much more exciting than the hands.
That’s all for today. On Sunday evening I am off to London to spend a whole week in the company of the Archbishop. The plan is to spend Monday to Wednesday taking final publication-quality photos (I finally have a proper tripod) and digging out field photos and suchlike from the museum archives, then take Cervical U to be CT-scanned at the Royal Veterinary College, courtesy of theropod hindlimb mechanics guru John Hutchinson. Friday is emergency backup in case something crops up to delay the scanning, and also gives me a chance to retake any photos that didn’t come out as required. The plan is that this visit should give me everything I need (pictures, measurements, observations, historical documents) to finish up the long-overdue Archbishop description. Fingers crossed.
I leave you with a puzzle. This is the jacket that I have designated “Lump Z”:
Can anyone offer a guess as to what this is, and which way up it should be? It’s a jacket that was opened years ago — before I was involved with the specimen — but never fully prepared. Matt and I have discussed it a little, but I don’t want to prejudice anyone with our guesswork, so I leave the floor open. What is it?
SV-POW! Dollars are at stake!
After a completely barren 2008, this year is turning out to be a good one for me in terms of publications. Today sees the publication of Taylor (2009b), entitled Electronic publication of nomenclatural acts is inevitable, and will be accepted by the taxonomic community with or without the endorsement of the code — one of those papers where, if you’ve read the title, you can skip the rest of the paper. (Although on that score, my effort is knocked into a cocked hat by Hulke 1880.)
The message of the paper will be familiar to anyone who’s been following the Shiny Digital Future thread on this site; as indeed will parts of the text, as the paper is basically a more carefully worked and cohesive form of an argument that I’d previously spread across half a dozen blog posts, a similar number of emails on the ICZN mailing list and any number of comments on other people’s blogs. The sequence of section headings in the paper tells its own story:
And that conclusion reads as follows:
While we were looking the other way, the digital revolution has happened: everyone but the ICZN now accepts electronic publication. The Code is aﬀorded legitimacy by workers and journals only because it serves them; if we allow it to become anachronistic then they will desert it – or, at best, pick and choose, following only those provisions of the Code that suit them. Facing this reality, the Code has no realistic option but to change – to recognise electronic publishing as valid.
I have no detailed recommendations to make regarding the recently proposed amendments to the Code (ICZN, 2008). Instead I ask only this simple question: will the Code step up to the plate and regulate electronic publications as well as printed publications? Because this is the only question that remains open. Simply rejecting electronic publication is no longer a valid option.
Which I’m sure is familiar rhetoric to long-time SDF advocates, but which I hope will rattle a few cages in the more conservative ranks of specialist taxonomists. I think it’s a very promising sign that BZN, the official journal of the ICZN, is prepared to publish this kind of advocacy — they didn’t even ask me to tone down the language. I hope it indicates that in high places, they are sensing which way the wind is blowing.
Here’s a reminder of why electronic publishing is so desirable: figure 3 from Sereno et al.’s (2007) paper on the bizarre skull of the rebbachisaurid Nigersaurus:
Let me remind you that this was a paper about skulls — vertebrae were not even on the agenda. Yet click through the image (go on, you have to) and you will see them each presented in glorious high-resolution detail. That paper was of course published in the PLoS ONE — a journal that, because it is online only, can provide this quality of figure reproduction, which shames even the very best of printed journals. To see printed-on-paper figures this detailed and informative, you have to right back to Osborn and Mook (1921).
Which is why I recently decided to put my open-access money where my electronic-only mouth is, and submit the forthcoming Archbishop description to a PLoS journal. In response to a challenge from Andy Farke, I rather precipitately made a public commitment to do my level best to get that paper submitted this calendar year; and while that may not actually happen, having that goal out there can only help. Seeing that gorgeous quarry photo of Spinophorosaurus was what tipped me over the edge into wanting to use PLoS. My plan is to describe the living crap out of that bad boy, photograph every element from every direction and put the whole lot in the paper — make the paper as close as possible as a surrogate for the specimen itself. Only PLoS (to my knowledge) can do this.
(Of course, once you start wanting to include other kinds of information in your publications — videos, 3d models, etc. — then an electronic-only venue is literally your only option.)
I leave you with two photos of “Cervical P” of the Archbishop; commentary by Matt. These images are copyright the NHM since it’s their specimen.
- Hulke, J. W. 1880. Iguanodon Prestwichii, a new species from the Kimmeridge Clay, distinguished from I. Mantelli of the Wealden Formation in the S.E. of England and Isle of Wight by differences in the shape of the vertebral centra, by fewer than five sacral vertebrae, by the simpler character of its tooth-serrature, &c., founded on numerous fossil remains lately discovered at Cumnor, near Oxford. Quarterly Journal of the Geological Society 36:433-456. doi:10.1144/GSL.JGS.1880.036.01-04.36
- International Commission on Zoological Nomenclature. 2008. Proposed amendment of the International Code of Zoological Nomenclature to expand and refine methods of publication. Zootaxa 1908: 57-67, Bulletin of Zoological Nomenclature 65(4): 265-275 and various other places.
- Osborn, H. F. and C. C. Mook. 1921. Camarasaurus, Amphicoelias and other sauropods of Cope. Memoirs of the American Museum of Natural History, n.s. 3: 247-387, and plates LX-LXXXV. [HUGE download, but totally worth it.]
- Sereno, Paul C., Jeffrey A. Wilson, Lawrence M. Witmer, John A. Whitlock, Abdoulaye Maga, Oumarou Ide and Timothy A. Rowe. 2007. Structural Extremes in a Cretaceous Dinosaur. PLoS ONE 2 (11): e1230 (9 pages). doi:10.1371/journal.pone.0001230
- Taylor, Michael P. 2009. Electronic publication of nomenclatural acts is inevitable, and will be accepted by the taxonomic community with or without the endorsement of the Code. Bulletin of Zoological Nomenclature 66(3):205-214.
March 29, 2009
As Matt frequently reminds me, it’s now nearly five years since I started to work on “The Archbishop”, more formally known as BMNH R5973, the Natural History Museum’s long-neglected Tendaguru brachiosaur. This is, or at least once was, one of the most complete brachiosaurid specimens ever discovered — although quite a bit of the material has gone missing or remains unprepared. It’s true that I owe the world a proper description, especially since I spoke about the specimen as long ago as the 2005 SVPCA (Symposium of Vertebrate Palaeontology and Comparative Anatomy) and have been sitting on it ever since. So: you have my apologies, along with a promise to get into gear RSN.
But what I want to know is this: since this specimen is radioactive, and I’ve been working with it for five years now, surely according to all the rules of literature, I should by now have developed brachiosaurid superpowers? At the very least, the ability to have a neck way long compared with my body:
Better still would be the ability to crush my enemies to dust beneath my Mighty Forefeet of Justice. And yet, so far, nothing. It doesn’t seem fair somehow.
Since we’re talking about the Archbishop, let’s take a look at Cervical U, the best preserved of the five cervicals that are available for study:
When it was found in 1930, in an expedition to Tendaguru, Tanzania, led by F. W. H. Migeod, the Archbishop consisted of an articulated vertebral column all the way from cervical 5 through to caudal 8 or so — by far the best vertebral sequence of any brachiosaur — along with cervical and dorsal ribs, a scapula, both humeri, pelvic elements and a partial femur. At least, if you believe Migeod; but the material that made it back to London, survived the Second World War and has been prepared is a fraction of that: five cervicals in various states of repair, some cervical ribs, two excellent dorsals (featured previously, though not in a big way), two further dorsal centra and a dorsal neural spine, an indeterminate long-bone fragment and a smushed proximal pubis. Migeod measurements make it seem unlikely that all the material really belongs to a single animal — for example, the humeri seem much too short — but the articulation of the vertebrae makes their associated pretty rock solid. And that is plenty enough to make this an awesome specimen.
Here is Migeod’s quarry map:
I don’t want to say too much more about the Archbishop for fear of stealing my own thunder, but it’s no secret that I don’t think it’s Brachiosaurus brancai. For those who want to know more, the slides from my 2005 SVPCA talk are available. Enjoy!
- Migeod, F. W. H. 1931. British Museum East Africa Expedition: Account of the work done in 1930. Natural History Magazine 3(19): 87-103.
- Taylor, Michael P. 2005. Sweet seventy-five and never been kissed: the Natural History Museum’s Tendaguru brachiosaur. p. 25 in Paul M. Barrett (ed.), Abstracts volume for 53rd Symposium of Vertebrae Palaeontology and Comparative Anatomy, The Natural History Museum, London, 7th-9th September 2005. 41 pp.
November 22, 2008
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.
November 6, 2008
Today, we bring you the long-overdue third installment in everyone’s favourite Mystery Sauropod Dorsals serial, our trawl through the NHM’s collection of mostly isolated elements from the Wealden Supergroup.
Many of these elements are too bashed up to be diagnostic (with the Xenoposeidon holotype R2095 being an honourable exception). But there are one or two that are much better preserved, and arguably the best of these are the pair of elements BMNH R88/R89, which in some sense belong to “Eucamerotus” (read on). These are difficult to photograph well, because they are in a glass case in the public gallery, but fortunately Hulke (1880: plate IV) illustrated the more anterior and better preserved of the two:
Like far too many British sauropod specimens, this one is mired in a taxonomic hell-hole. It was described by Hulke as belonging to Ornithopsis, a genus based on a horribly non-diagnostic type specimen, and it is this name that appears on the exhibit label (along with the incorrect specimen numbers R89/90 … oh well, One Out Of Two Ain’t Bad.)
Here is my least bad photo of R88 and R89, in left lateral view, with R88 on the left:
Blows (1995) referred this pair of dorsals, and a bunch of other specimens, to another ancient British name, Eucamerotus — in fact, he nominated them as paratypes — but didn’t give any reason for doing so. (He also referred to the R88/R89 pair jointly as R90, thus further muddling the specimen numbering.) Blows’s reassignment to Eucamerotus is puzzling, because while the Eucamerotus type specimen is also pretty undiagnostic, consisting only of a partial neural arch, it does have one obvious apomophy, which is huge robust parapophyses supported on what I like the call The Prezygaparapophyseal Laminae Of Doom. (Remind me to show you this specimen some time.) That feature, of course, R88 and R89 completely lack.
So what are they? I don’t think they can be referred with any confidence whatsoever to either Ornithopsis or Eucamerotus, two questionable genera of which at least the first is invalid. So perhaps the right thing to do would be to torpedo those names and raise R88/89 as the type specimen of a new taxon? There’s more work to do before taking such a step, not least an exhaustive trawl through the historical literature, but I think that might eventually prove the way to go.
Based on general proportions and overall “gestalt”, these vertebrae appear to be brachiosaurid — but I put them in a cladistic analysis a while back (so far unpublished) and they didn’t clade unambiguously with Brachiosaurus, so we’ll have to see how that develops when I finally get around to adding my thirty-odd new characters of the dorsals. Don’t hold your breath. At least, these elements are much more convincingly brachiosaurid than anything else I’ve seen from the Wealden. So do they consitute Britain’s best brachiosaur?
Well, maybe. Not if you count The Archbishop, Migeod’s Tendaguru brachiosaur, which I’ve been working on for waaay too long now, but really, really will describe Real Soon Now. (Amazingly, this specimen has yet to appear on SV-POW!, unless you count my T-shirt in one of the photos of our Oxford Museum visit.) But since this specimen is from the Tendaguru Formation of Tanzania, it should probably be discounted from the BBB competition.
In fact, Britain’s Best Brachiosaur is probably the “Barnes High Sauropod” from the Isle of Wight. But that’s in private hands and the ownership/availability situation is complex. For that reason, no-one has yet published on it, and in fact I have never seen any of the material except what’s embedded in a wall-mount at Dinosaur Isle. I’m not sure what’s happening with this specimen (I don’t think anyone is) but if I ever get a chance to find out, I will!
- Blows, William T. 1995. The Early Cretaceous brachiosaurid
dinosaurs Ornithopsis and Eucamerotus from the Isle of
Wight, England. Palaeontology 38 (1): 187-197.
- Hulke, J. W. 1880. Supplementary Note on the Vertebræ of Ornithopsis, Seeley, = Eucamerotous, Hulke. Quarterly Journal of the Geological Society 36: 31-35. doi:10.1144/GSL.JGS.1880.036.01-04.06