Hope you had a good Christmas – I did! Here’s an old article from Tet Zoo ver 1, apologies if you recall it from its first airing in 2006. The article is now a bit dated – sorry about that (I’ve added one or two new bits).
Even if you’re not an expert on dinosaurs, it’s likely that you’ve heard – firstly – that some sauropods were rily, rily big and – secondly – that these biggest of the big included such whoppers as Seismosaurus, Supersaurus and Argentinosaurus. It’s always helpful that their names are easy to remember. Recent work has not only resulted in the publication of reasonably accurate size estimates for these dinosaurs, it has also clarified their taxonomy and phylogenetic positions.
Supersaurus vivianae from the Morrison Formation of Colorado is, despite its name, a valid taxon – specifically it’s a diplodocid diplodocoid, and apparently an apatosaurine (the image at the top of page shows a new skeletal mount of this taxon). Recent estimates put its total length at 33 m. The most oft-figured bit of Supersaurus is its enormous scapulocoracoid: it’s usually depicted with the late Jim Jensen, its discoverer and describer, lying alongside it. For a change, here (at left) is a curious new take on the theme (borrowed from here). Oh, and if you’re wondering about Ultrasauros (originally informally named Ultrasaurus: note the spelling difference), it’s no longer regarded as a valid taxon as the type material – a posterior dorsal vertebra – was shown by Brian Curtice and colleagues (Curtice et al. 1996) to belong to Supersaurus (come back Brian, all is forgiven!). The famous Ultrasauros scapulocoracoid doesn’t belong together with the vertebra, and has mostly been regarded as belonging to Brachiosaurus (either to Brachiosaurus sp. or to Brachiosaurus altithorax. In the most recent appraisal of the specimen, Taylor (2009) supported the latter referral). Below, you can see dead fish expert Graeme Elliott standing alongside the Ultrasauros scapulocoracoid (go here for hilarious caption, sorry Graeme).
Moving on, Seismosaurus hallorum (originally described as S. halli), from the Morrison Formation of New Mexico, is also a diplodocid diplodocoid, but recent work indicates that it is not generically distinct from Diplodocus and should thus be renamed Diplodocus hallorum. Originally claimed to be over 40 m long, new estimates put it between 30 and 35 m. Supersaurus and Diplodocus hallorum, being relatively gracile diplodocids, probably weighed between 25 and 50 tons (Paul 1994a, b, 1997).
A few more super-sauropods have been added to the list in recent years. Most are titanosaurs, the predominantly Cretaceous sauropod clade originally thought to be late-surviving relatives of diplodocoids but now known to be close kin of the short-skulled brachiosaurs. Argentinosaurus huinculensis, named in 1993, is a huge titanosaur from the Upper Cretaceous Río Limay Formation of Argentina: it was perhaps 30 m long. Paralititan stromeri is another massive titanosaur, this time from the Upper Cretaceous of Egypt. Estimated by its describers as having been around 30 m long, it has more recently been down-sized to a mere 26 m (the image below is Todd Marshall’s painting of Paralititan, taken from here). Puertasaurus reuili, named in 2005 and from the Upper Cretaceous Pari Aike Formation of Argentina, was similar in size to these forms. Finally, Turiasaurus riodevensis is a gigantic Spanish form, and it’s not a titanosaur, belonging instead to a hitherto unrecognised clade termed Turiasauria. It was described at the end of 2006 (go here for more) and is one of the biggest sauropods known, with an estimated length of 36-39 m.
Exactly how heavy these mega-sauropods were is mildly controversial. Accurate mass estimates generally agree that they were on the order of 80-90 tons, but Royo-Torres et al. (2006), the describers of Turiasaurus, put this animal at half this. However, they used a notoriously unreliable method of estimating weight.
While you might have heard of Supersaurus, Seimosaurus or Argentinosaurus – and perhaps even Turiasaurus and Paralititan – have you heard of… Amphicoelias fragillimus? Well, ok, if you’re a dinosaur ubernerd then the answer will be yes, but not if you’re a normal person. Though described as long ago as 1878, this sauropod has remained decidedly obscure and hardly heard of until pretty recently. I’ve done my part for the cause, having mentioned it at every opportunity: in both Dinosaurs of the Isle of Wight, and Walking With Dinosaurs: The Evidence, it’s discussed and touted as, possibly, the biggest sauropod of them all. Naish & Martill (2001), for example, stated ‘What has recently been claimed as the biggest of all sauropods and, indeed, the biggest of all land animals, is actually a specimen discovered in 1878. Based only on a single enormous vertebra, now lost, Amphicoelias fragillimus has been estimated to have reached a length of 60 m and may have attained a weight of 150 tons!’ (p. 230). If these estimates are valid, then this animal was twice as long as Supersaurus and Diplodocus, and perhaps over four times heavier. Err, gosh.
Amphicoelias fragillimus, giant of giants
In August 1878 the famous and prolific scientist* Edward Drinker Cope (1840-1897), shown here, described a new super-sauropod, Amphicoelias fragillimus, from the Garden Park quarries of the Morrison Formation of Colorado. It was represented only by an incomplete dorsal vertebra and the distal end of a femur (contra Naish & Martill above: whoops!). A good drawing of the vertebra was provided (Cope 1878), showing that this sauropod was clearly a diplodocoid: a member of the same sauropod clade as Diplodocus, Apatosaurus and their relatives (the name Diplodocimorpha is also sometimes used for these animals: see Taylor & Naish 2005: free pdf). The big deal is how, err, big these remains were. The partial vertebra had a preserved height of 1.5 m and, when reconstructed on the basis of comparison with complete diplodocoid vertebrae, has a total height of 2.7 m. Again… gosh (or words to that effect) [Amphicoelias fragillimus compared to a person below, from wikipedia].
* Though usually described (by palaeontologists) as a palaeontologist, Cope was also an accomplished herpetologist and ichthyologist, which explains the name of the journal Copeia.
If history were fair, we would all have grown up familiar with Cope’s hyper-enormous Amphicoelias fragillimus, and we would be less impressed by Brachiosaurus and Balaenoptera, let alone with paltry little 20-m long sauropods like ‘Angloposeidon’ (go here). But it was not to be, and it was to sink into the morass of obscurity. In a major 1921 review of Cope’s sauropods, Henry Fairfield Osborn and Charles Mook noted that they were unable to locate the immense vertebra in Cope’s sauropod collection (Osborn & Mook 1921), today at the American Museum of Natural History (New York). It was lost.
And… I’ll have to stop there. The rest of the story will come in part II. It concentrates on those recent studies that have looked at this species, and one of the most-asked questions about this remarkable dinosaur: was it a hoax? Stay tuned, all will be revealed.
For previous Tet Zoo posts on sauropods see…
- Gigantoraptor, Eocursor and… baby Toni
- The world’s most amazing sauropod
- The horror that is LOLSAUROPODS
- The hands of sauropods: horseshoes, spiky columns, stumps and banana shapes
- Junk in the trunk: why sauropod dinosaurs did not possess trunks
- Sauropod dinosaurs held their necks in high, raised postures
- Thunder-Lizards: the Sauropodomorph Dinosaurs (a book review)
And – if you’re serious about sauropods – you really should be spending more time at SV-POW!
Refs – -
Cope, E. D. 1878. A new species of Amphicoelias. American Naturalist 12, 563-565.
Curtice, B. D., Stadtman, K. L. & Curtice, L. J. 1996. A reassessment of Ultrasauros macintoshi (Jensen, 1985). In Morales, M. (ed) The Continental Jurassic. Museum of Northern Arizona Bulletin 60, 87-95.
Davidson, J. P. 2002. Bonehead mistakes: the backround in scientific literature and illustrations for Edward Drinker Cope’s first restoration of Elasmosaurus platyurus. Proceedings of the Academy of Natural Sciences of Philadelphia 152, 215-240.
McIntosh, J. S. 1998. New information about the Cope collection of sauropods from Garden Park, Colorado. Modern Geology 23, 481-506.
Naish, D. & Martill, D. M. 2001. Saurischian dinosaurs 1: Sauropods. In Martill, D. M. & Naish, D. (eds) Dinosaurs of the Isle of Wight. The Palaeontological Association (London), pp. 185-241.
Osborn, H. F. & Mook, C. C. 1921. Camarasaurus, Amphicoelias and other sauropods of Cope. Memoirs of the American Museum of Natural History, n.s. 3, 247-287.
Paul, G. S. 1994a. Is Garden Park home to the world’s largest known land animal? Tracks in Time 4 (5), 1.
- . 1994b. Big sauropods – really, really big sauropods. The Dinosaur Report Fall 1994, 12-13.
- . 1997. Dinosaur models: the good, the bad, and using them to estimate the mass of dinosaurs. In Wolberg, D. L., Stump, E. & Rosenberg, G. D. (eds) Dinofest International: Proceedings of a Symposium Sponsored by Arizona State University. Academy of Natural Sciences (Philadelphia), pp. 129-154.
Royo-Torres, R., Cobos, A. & Alcalá, L. 2006. A giant European dinosaur and a new sauropod clade. Science 314, 1925-1927.
Taylor, M. P. 2009. A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914). Journal of Vertebrate Paleontology 29, 787-806.