How big was the Archbishop?
June 2, 2021
Various Internet rumours have suggested that the Archbishop is a super-giant sauropod one third larger than the mounted Giraffatitan specimen MB.R.2181 (formerly HMN SII). This is incorrect.

Migeod’s assessment of the size of the animal was based on the vertebrae: “The [neck] vertebrae found give a 20-foot [6.10 m] length […] The length of the back including the sacral region was about 15 feet [4.57 m]. The eight or nine caudal vertebrae cover about 6 feet [1.83 m]” (Migeod 1931a:90). This gives the total preserved length of the skeleton as 41 feet (12.50 m). By comparison, Janensch (1950b:102) gives lengths of portions of the mounted skeleton of MB.R.2181 as 8.78m (neck), 3.92m (torso) and 1.07m (sacrum) for a torso-plus-sacrum length of 4.99m. On this basis, the preserved neck of NHMUK PV R5937 is only 69% as long as that of MB.R.2181, but since the first four vertebrae were missing and omitted from Migeod’s measurement, this factor cannot be taken at face value. More informative is the torso-plus-sacrum length, which in NHMUK PV R5937 is 92% the length of MB.R.2181.
This is consonant with measurements of individual elements, which compare as follows:
Table 4. Comparative measurements of Archbishop and Giraffatitan elements
Element | Measurement (cm) | Archbishop | Giraffatitan | Ratio |
---|---|---|---|---|
Torso plus sacrum | total length | 457 | 499 | 0.916 |
C10 (mC4) | centrum length | 99 | 100 | 0.990 |
C11 (mC3) | centrum length | 104 | 100[1] | 1.040 |
D4 (mD3) | centrum length | 27 | 36 | 0.750 |
Longest rib | length over curve | 235 | 263 | 0.894 |
Left scapulocoracoid | length over curve | 221 | 238[2] | 0.929 |
Right humerus | length | 146 | 213 | 0.685 |
Right humerus | width | 51 | 59 | 0.864 |
Right ilium | length | 98 | 123[3] | 0.797 |
Right ilium | height | 79 | 96[4] | 0.823 |
Femur | length | 122 | 196[5] | 0.622 |
Average | 0.846 |
Archbishop measurements taken from Migeod (1931a) and converted from imperial; Giraffatitan measurements are for MB.R.2181 except where noted, and are taken from Janensch (1950a:44) and Janensch (1961).
Notes.
[1] Janensch (1950a) did not report a total centrum length for C11, as its condyle had not been removed from the cotyle of C10; but since the length of its centrum omitting the condyle was, at 87 cm, identical to that of C10, it is reasonable to estimate its total length as also equal to that of C10.
[2] Janensch (1961:181) did not include measurements for the right scapula of MB.R.2181, which is incorporated into the mounted skeleton, but does give the proximodistal length of its right coracoid as 45 cm. Using the 193 cm length given for the similarly sized scapula Sa 9, we can deduce a reasonable total estimate of 238 cm for the scapulocoracoid.
[3] Estimated by Janensch (1950b:99) based on cross-scaling from the fibula and ilium of Find J from the Upper Saurian Marl.
[4] This is the measurement provided by Janensch (1961:199) for the ilium Ma 2, which is incorporated into the mounted skeleton, and which Janensch (1950b:99) considered to match MB.R.2181 very precisely.
[5] Based on a restoration of the midshaft which Janench (1950b:99) calcuated based on other finds.
Individual lines of this table should each be treated with caution: Migeod’s measurements may have been unreliable, and in any case are underspecified: for example, we do not know whether, when he gave a vertebra’s length, he included overhanging prezygapophyses or the condyle. Similarly, we know that Migeod (1931:96) wrote that a rib “was as much as 92.5 inches long”, but we do not know for certain that, like Janensch, he measured the length over the curve rather than the straight-line distance between the ends. And when Migeod says that the ilium “measured 38.5 by 31 inches” we do not know that the height was measured “at the public process”, as Janensch (1961:199) specified.
With those caveats in place, nevertheless, a picture emerges of a sauropod somewhat smaller than MB.R.2181, though by no means negligible. On average, the measurements come out about 15% smaller than those of Giraffatitan.
But this average conceals a great deal of variation. The cervical vertebrae are comparable in length to those of MB.R.2181 (The total of 203 cm for C10 and C11 in the Archbishop, only 1.5% longer than 200 cm for MB.R.2181, is a difference well within the margin of measurement error). The Archbishop’s scapulocoracoid may have been 93% as long as in MB.R.2181. But the limb bones are signficantly shorter (87% for the humerus and a scarcely credible 62% for the femur), and the humeri at least bseem to be have been proportionally more robust in the Archbishop: only 2.86 times as long as wide, whereas the ratio is 3.61 in MB.R.2181. If Migeod’s measurements can be trusted, we have here an animal whose neck is as long as that of Giraffatitan, but whose limbs are noticably shorter. These proportions corroborate the hypothesis that the Archbishop is not a specimen of Giraffatitan.
Accidental anaglyphs
October 16, 2020
Everyone knows that the very first thing you should do to improve your specimen photography is to use a tripod: it eliminates hand-shake and gives you much crisper photos. In most respects, my photographs have got much, much better since I’ve been habitually using a tripod.
But it has meant I’ve not been able to benefit from happy accidents like the one that gave me this 3D anaglyph of the Archbishop‘s Cervical S in dorsal view:
(Do you have red-cyan glasses? Yes? Good! You will be able to appreciate all the delicious morphological information in this photo. No? Go and order some right now — they cost literally a dollar.)
The reason I was able to make this very useful image is because back in the old pre-tripod days I would sometimes accidentally move a little bit between taking two more-or-less identical photographs. Here are the two images that I was able to composite into the anaglyph above:
Each of them is pretty uninformative alone: who can tell one nondescript area of brown bone from another? But when combined, they are extraordinarily more informative. If you don’t have 3D glasses then (A) get some! and (B) you can get some idea of how helpful the 3D information is from the crude wigglegram below, which simply switches back and forth between the two images.
And I can’t overstate how enormously helpful I have found these accidentally sourced anaglyphs as I write the descriptive part of the Archbishop manuscript. Even at this level of crudity, they have shown me several important points of morphology that I would certainly have missed if I’d been working only from my orthogonal-view photos, and saved me from more than one misinterpretation.
The moral is twofold:
- When taking specimen photographs, use a tripod — but deliberately get some pairs of shots where the camera is moved to the side by about 7 cm (the distance between the pupils in an average human).
- If you don’t have any red-cyan glasses, get some!
Hey, Mike! Why haven’t you been blogging much lately?
October 14, 2020
Well, one reason is the utterly rancid “block editor” that WordPress has started imposing with increasing insistence on its poor users. If there is one thing that world really doesn’t need, it’s a completely new way of writing text. Seriously, WordPress, that was a solved problem in 1984. As Henry Spencer very nearly said back in the eighties, “thy creativity is better used in solving problems than in creating beautiful new impediments to productivity“.
But enough pointless whining: instead, check out this bad boy:

Taylor (in prep. for 2020: Figure V). NHMUK PV R5937, “The Archbishop”, cervical vertebra V (most anterior preserved cervical vertebra, probably C6), left side still encased in plaster. A. Reconstruction of right lateral view with neural spine, prezygapophysis, diapophysis, condyle, cotyle and cervical rib restored. The prezygapophysis from the succeeding vertebra that has adhered to this element is shown in red. B. Dorsal view with anterior to the right. C. Posterior view. D. Right lateral view. E. Anterior view. F. Ventral view with anterior to the right. Scale bar 20 cm.
Yes, it’s your friend and mine, The Archbishop! It’s a big titanosauriform sauropod excavated by F. W. H. Migeod for the British Museum (Natural History) back in 1930, from the same Tendaguru Formation that yielded the awesome Giraffatitan specimens in the Museum für Naturkunde Berlin.
Yes, I admit I have been working on the Archbishop for more than sixteen years, and that I gave a talk about it at SVPCA 2005, and that I failed utterly to get it done as part of the Paleo Project Challenge 2010, and that as early as 2011 I was in despair about ever finishing it, and that I promised to do it by SVPCA 2016 but didn’t.
But in 2018 I did something significant, which was to actually start writing the paper in public. Now anyone can follow the progress of the project — and it’s progressing. The manuscript currently runs to about fifty printed pages, although that length is inflated by twenty-odd beautiful illustrations — of which the “Cervical V” image above is just one. (Do click through to see it in all its glory.)
So, yeah. That’s the main reason I am not blogging much. Because I am writing the paper. Finally.
Just write the Archbishop description already!
September 3, 2015
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:
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.
Photography and illustration talk, Part 7: Manipulating photographs
February 21, 2014
Photography and illustration talk, Part 2: Taking good photographs
February 8, 2014
Specimen photos with desaturated backgrounds
April 25, 2013
Generally when we present specimen photos in papers, we cut out the backgrounds so that only the bone is visible — as in this photo of dorsal vertebrae A and B of NHM R5937 “The Archbishop”, an as-yet indeterminate Tendaguru brachiosaur, in right lateral view:
But for some bones that can be rather misleading: they may be mounted in such a way that part of the bone is obscured by structure. For example — and this is a very minor case — the ventral margins of the centra in the photo above are probably slightly deeper than they appear, because the centra are slightly sunk within the plinth that holds the vertebrae upright.
So I’ve been toying with a different idea: instead of cutting the background out completely, leaving it in place but toning it down. Then the supporting structure is visible, but clearly distinct from the actual bone. (For a more extreme case, see the “Apatosaurus” minimus sacrum.)
Here’s how the image above looks if I desaturate the background:
I’m not sure what to make of this. It looks a bit strange to me, but that might only be the strangeness of unfamiliarity.
And it might not work so well (or indeed it might work better) for photos taken against a busier background.
What do you think?