Brachiosaurus altithorax, last four dorsals

October 11, 2007

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


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

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

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

25 Responses to “Brachiosaurus altithorax, last four dorsals”

  1. Mike from Ottawa Says:

    Hmmm, “oblique left anterodorsolateral aspect” sure is a long way of saying “11 O’Clock high”.

  2. Mike from Ottawa Says:

    With more seriousness, but still trying to pretend to more knowledge than I have, why is the distal anterodorsal surface of the neural spines on those vertabrae so rugose? It is regular enough and similar enough on the several vertebrae that it doesn’t look like an artifact of preservation or prepearation.

    Now to wait and find out how badly I’ve messed up those terms. But it is a weird lookin bit of bone, even allowing for the fact it’s a bit of bone on a bone that looks like nothing so much as a spaceship out of Star Wars.

  3. Mike from Ottawa Says:

    Oh, hang on, is that just crap in there, filling up a notch in the divided neural spine?

  4. Mike Taylor Says:

    Oh, dude, if only you knew how many times I have observed that individual sauropod vertebrae would make awesome spaceships. I once made a semi-serious effort to persuade Matt’s friend Jarrod, who works in special effects, to base on off a cervical. No dice so far, but it’s bound to happen sooner or later.

    Your’re right that “oblique left anterodorsolateral aspect” is verbose; unfortunately, sometimes verbosity is the price of precision. (Sometimes it’s not: sometimes it’s just showing off. But not this time.)

    Regarding the rugosity on the dorsal part of the anterior face of all the neural spines (and, yes, you slightly badgered up the terminology :-), you’re right that this is significant. What the photo doesn’t show (but if you stay tuned long enough you’ll probably see one that does) is that the posterior faces of the neural spines have very similar rugosities. In life, these would have been the anchor points for epaxial muscles and ligaments. In Brachiosaurus altithorax (but not B. brancai) these have a distinctive inverted-triangle shape. In the most posterior pair of B. brancai dorsals, which are co-ossified, the ligament joining their neural spines is itself ossified. Picture to follow some time, I guess :-)

  5. Mike Taylor Says:

    No, it’s not crap!

  6. David Marjanović Says:

    Your’re right that “oblique left anterodorsolateral aspect” is verbose; unfortunately, sometimes verbosity is the price of precision.

    “Oblique” was redundant, though. It’s contained in “anterodorsolateral”. :->

    Which in turn should be “craniodorsolateral” <duck & cover>

  7. asier Says:

    Which differences are form theese dorsals to Ultrasauros dorsal???


  8. Mike Taylor Says:

    Oh, gosh, lots of differences. This was addressed very comprehensively by Curtice et al. in 1996:

    Curtice, Brian D., Kenneth L. Stadtman and Linda J. Curtice. 1996. A reassessment of Ultrasauros Macintoshi (Jensen, 1985). The continental Jurassic M. Morales (Ed.) Museum of Northern Arizona Bulletin. 60:87-95.

    For a short time only, you can download a copy from:

    Click to access CurticeEtAl1996-ultrasauros.pdf

  9. asier Says:

    Oh thank you very much for the PDF

  10. asier Says:

    I was in a Doubt, because in a lot of webs say that ultrasuros may exits or may not. That the are doubts in paleontology world about this dinosaur… I thoutgh that some Paleontologist defends the ultrasauros dorsal as a brachiosaurid.

    PD:Sorry my english

  11. Mike Taylor Says:

    Sorry, asier, there is no doubt about “Ultrasauros” any more — at least, not among palaeontologists. No-one has published a challenge to the conclusions of Curtice et al. (1996) and I can tell you that Matt and I both find it wholly convincing. “Ultrasaurus” was a nice idea (no-one likes the idea of super-giant brachiosaurids more than I do!) but not based on anything solid.

  12. Matt Wedel Says:

    We should point out that “Ultrasauros” was based on a big dorsal vertebra and a big scapulocoracoid. The big dorsal turned out to be Supersaurus, and it was the holotype, so “Ultrasauros” is now a junior synonym of Supersaurus, the same way that Brontosaurus is a junior synonym of Apatosaurus.

    The scapulocoracoid was not part of the type, it was a referred specimen. And it does belong to a brachiosaurid, and since the only known brachiosaurid in the quarry is Brachiosaurus, Curtice et al. referred it to Brachiosaurus. So there was a super-giant brachiosaurid roaming around the western US in the Late Jurassic–Brachiosaurus itself. What’s more, there are pieces of equally large individuals of Brachiosaurus brancai from Tanzania. These elements indicate animals about 15% larger in linear terms than the mounted skeleton in Berlin. An animal that is 15% larger linearly will weigh half again as much (1.15×1.15×1.15=1.52). If an average Brachiosaurus weighed 30 tons, those big guys would have weighed 45 tons or more. Argentinosaurus might have weighed twice that, and there’s always Amphicoelias, but still, 45 tons is nothing to sneeze at.

  13. asier Says:

    Thank you so much ;-)

  14. Mike Taylor Says:

    … or not. As Curtice et al. (1996: table 1) showed, the coracoid of the Dry Mesa “Ultrasauros” scapulocoracoid is smaller in both length and breadth than that of the Brachiosaurus altithorax holotype FMNH P25107 (Riggs 1904:241), so the obvious conclusion would be that it came from a smaller animal than that holotype. And there are many good reasons for thinking that FMNH P25107 is almost exactly the same size as the Brachiosaurus brancai type HMN SII, so the Dry Mesa brachiosaur was probably smaller than the only North American brachiosaur specimen known from half-decent remains. (No offence to Sauroposeidon intended :-) )

  15. asier Says:

    Yeah, Jensen use to say that the “Ultrasauros” scapulocoracoid was of 270 mm. But finally was 250 mm.
    Why he lied?

    thanks again!

  16. Mike Taylor Says:

    I think that “lied” is an unnecessarily harsh interpretation. It’s easy to be mistaken when measuring fossils. Sometimes, it’s not even clear what so seemingly simple a word as “length” means. For example, should scapulocoracoid length be measured along the outside curve (as Jensen may have done) or as the shortest straight line between the most anterior and posterior points (as Curtice may have done)? Frustratingly, there are no standards for these things: the best we can do is be explicit about precisely what measurements we’ve made.

  17. asier Says:

    Ok, thanks!
    I have another question (if I´m making too many question tell me). Is Brachiosaurus altithorax more heavily built than Braciosaurus brnacai (Giraffatitan)?, I mean,the two dinosaurs with the same lenght and heigh… B.altithorax will weight some tons more??.
    Did brachiosaurus althitorax have a crest on the top of the head like in brancai???.

    Thank you!!!

  18. Mike Taylor Says:

    Yes, B. altithorax seems to be a little more heavily built than B. brancai, based on limb proportions.

    We won’t know anything about the skull of B. altithorax until we find a skull associated with postcranial elements from that species, which so far no-one has. There’s a paper describing a possible B. altithorax skull, but the association is speculative.

    Carpenter, K., Tidwell, V. (1998). Preliminary description of a Brachiosaurus skull from Felch Quarry 1, Garden Park, Colorado. Modern Geology. 23: 69-84.

  19. asier Says:

    Good Morning!!!

    another question…. jejeje

    Is true that Brachiosaurus nougaredi sacrum is about 1.3 meters in lenght???, thats implies a third longer than brachiosaurus althiorax or giraffatitan…
    With the same corporal proportions, Brachiosaurus nougaredi would weight around 100 tons!!!


  20. Mike Taylor Says:

    Wow. I’d not registered that before. Yes, according to Lapparent (1960: 40), “Such as could be removed and reconstructed, this sauropod sacrum presents an exceptional size: total length = 130 cm; diameter = 80 cm.”, whereas the sacrum of the B. altithorax holotype FMNH P25107 is “only” 95 cm. long (Riggs 1904:236). Taken at face value, that means that Lapparent’s specimen is 130/95 = 1.37 times as long in linear dimension, and so 1.37^3 = 2.56 times as heavy, which would be about 90 tonnes if as seems reasonable B. altithorax massed about 35 tonnes: probably heavier than Argentinosaurus, the best estimate for which is the 73 tonnes of Mazzetta et al. (2004).

    Alas, all is not as it seems. First, the “B“. nougaredi sacrum is narrower than that of B. altithorax — 80 cm. compared with 98 cm. That’s weird. Then, the tibia of “B“. nougaredi is a mere 85 cm long (Lapparent 1960:41) compared with 95, 107 and 112 cm for three B. brancai individuals listed by Janensch (1961:211). So what’s going on? One possibility is that this animal was proportionally very strange. Another is that the type material is a chimera, and that the sacrum belonged to a very large brachiosaurid and the tibia to a smaller individual. Most likely, I think, both these things may be true. The sacrum proportions taken alone suggest something quite different from Brachiosaurus, and there is no strong reason to think that the tibia, found 880 m(!) away from the sacrum, belonged to the same animal.

    What does seem clear is that this material is well overdue for restudy. I think that some (most? all?) of it is reasonably accessible, in the Paris NHM, so hopefully someone will get around to in the next few years. Thanks for bringing it to our attention!


    Janensch, Werner, 1961, Die Gliedmaszen und Gliedmaszengurtel der Sauropoden der Tendaguru-Schichten: Palaeontographica, 7 (1), teil 3, lief. 4, pp. 177-235.

    Lapparent, Albert F. de, 1960, Les dinosauriens du “Continental Intercalaire” du Sahara Central: Memoires de la Societe Geologique de France (Nouvelle Serie), 88A, 56 pages.

    Mazzetta, Gerardo V., Per Christiansen and Richard A. Farina. 2004. Giants and Bizarres: Body Size of Some Southern South American Cretaceous Dinosaurs. Historical Biology, 2004, 1-13.

    Riggs, Elmer S., 1904, Structure and relationships of opisthocoelian dinosaurs. Part II, the Brachiosauridae: Field Columbian Museum, Geological Series 2, 6, pp. 229-247, plus plates LXXI-LXXV.

  21. asier Says:

    Oh, thanks for you very complete answer…
    Another thing that I would like talk about is about Brachiosaurus weight… I check the information that finally you get 35 tons for brachiosaurus extrapolating the weight of an elephant. First of all I don´t think a 4 meters high elephant couldn´t weight so much. I think 10 tons is more likely. That elephant that you talking about, has never been weighted, Its mass had gotten extrapolating smaller elephants mass… (I think…).

    Another thing is that, that explication tells a 18 feet shoulder heigh.
    The man is standing near Brachiosaurus leg (I think is you, no???), has his hand up, from the flor to the hand I calculate almost 7 feet, + another 7 fett of humerus = 14. And I think that there are much more than 4 feet, from the humerus to the top of the back (nearly 6 feet).
    total height = 20 feet.
    extrapolating the weight of the 13 tons elephant, we get a more than 50 tons Braciosaurus. if the elphant weight 10 tons, 40 tons Brachiosaurus.

    The Giraffatitan of the berlin museum, is more than 20 feet height at the shoulder, no??????


    PD: If 13 feet, high elephant weights 13 tons. The Mammuthus Sungari would weight more than 25 tons, nearly the weight of Brachiosaurus that Matt says…

  22. Mike Taylor Says:

    Hi, asier. The “measurement” of brachiosaur weight by pretending it’s a big elephant is of course very, very approximate and unreliable. It’s interesting principally because it provides some verification for the more rigorously derived mass estimates in the literature. We discussed those estimates in some length in Xenoposeidon week, day 4: the question everyone is asking … how big was it? which I think you will find interesting.

    The bottom line is that estimating mass of extinct animals is a very black art and that none of our numbers can be trusted.

    (And, no the Berlin brachiosaur is not larger than the Chicago mount.)

  23. Asier Says:


    How tall are the pair of BMNH R 5937 dorsals???
    I think that the berlin brachiosaurus brancai dorsals are bit over 100 cm.


  24. Mike Taylor Says:

    Hi, Asier. I am going to answer that question over on the Aegyptosaurus article, since I just mentioned R5937 in a comment on that article, and that’s where it will be seen by most people.

  25. […] The more retentive among you SV-POW! veterans might remember way back in the very first month of this blog when I showed you what I said were the last four presacral vertebrae of the Brachiosaurus altithorax holotype FMNH P25107.  Actually, I don’t know what I was thinking — they were presacrals 4-7, not 1-4, but that’s not the point.  The point is that Mike From Ottawa (whatever happened to him?) asked about the very rugose anterior surfaces of the neural spines, and I replied: […]

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