Supersaurus vivianae

Supersaurus vivianae

Etymology: Vivian's Super-lizard (Vivian was Jim Jensen's wife).

Family: Diplodocidae (possibly basal Apatosaurinae)
Time: Late Jurassic, Kimmeridgian-Tithonian epochs, ~153-150 mya
Location: Morrison Formation, Brushy Basin member (Utah, Colorado and Wyoming)
Estimated mass: ~40 tons (Adult holotype scapulacoracoid BYU 9025/ referred scapulacoracoid BYU 12962, and referred BYU specimens of similar size).
                          The WDC specimen "Jimbo" was approximately 32 tons.

Finally, a Paleo-King diplodocid!

Supersaurus, the only one of Jim Jensen's giant sauropods to retain its original name and classification, has been restored several times before, but this is the most detailed and fossil-based restoration to date. It turned out to be a bit shorter in length (both the BYU and WDC material) than typically estimated.

This is also probably my favorite diplodocid species, apart from Apatosaurus ajax. I find macronarians much more interesting, but a few diplodocids like these are less "vanilla" than we've been led to believe.

The BYU material from Dry Mesa Quarry originally consisted of two scapulacoracoids, of which the left (the holotype) is far more heavily eroded, a huge cervical vertebra (which is still the largest dinosaur cervical on record), three dorsals (the anteriormost of which was once labeled "Dystylosaurus edwini" and the next of which was once the erroneously assigned holotype of "Ultrasauros" until Jensen realized this bone was diplodocid and did not match his 9-foot brachiosaur shoulder blade), a very tall and worn anterior caudal, and a few distal caudals. More caudals were later referred from Dry Mesa, as well as a pelvis from Thanksgiving Point in Utah. The referred ulna BYU 13744 is 20% larger than expected for the holotype, and may belong to an unusually large specimen of Supersaurus or to another species entirely (Lovelace, et. al., 2007 supports the latter conclusion). I simply scaled it down to the holotype as a referable Supersaurus part until it can be proven conclusively to be something else.

The more complete specimen WDC DMJ-021 "Jimbo" found near Douglas, Wyoming is slightly smaller than the BYU specimens, and its cervical and rib material helps better restore the animal's proportions. 

*Note: For those of you that are wondering, the diplodocine Seismosaurus was indeed of a similar length to these Supersaurus specimens, though slimmer and lighter, and with a more conservative neck/tail ratio as is typical of most diplodocids. Estimates of 130 ft.+ lengths for any of these animals are simply excessive (until a bigger specimen turns up at least). And no, it was not D. longus. There are significant differences.


DISCLAIMER: My Honor is called Loyalty, and my Art is Honorable – therefore I do not take credit for any other artist's skeletal or schematic references used as reference for this image. Nor do I claim them as my own.

This image refers 's skeletal/schematic: www.deviantart.com/art/Somethi… as a VERY general basis. The majority of the bones are drawn based on the published material in Jensen (1985) and Lovelace, et. al. (2007) with some morph de-crushing applied.

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REFERENCES:

Curtice, B., Stadtman, K., and Curtice, L. (1996) "A re-assessment of Ultrasauros macintoshi (Jensen, 1985)." Pp. 87-95 in M. Morales (ed.), The Continental Jurassic: Transactions of the Continental Jurassic Symposium, Museum of Northern Arizona Bulletin number 60.

Curtice, B.; Stadtman, K. (2001). "The demise of Dystylosaurus edwini and a revision of Supersaurus vivianae". In McCord, R.D.; Boaz, D. Western Association of Vertebrate Paleontologists and Southwest Paleontological Symposium - Proceedings 2001. Mesa Southwest Museum Bulletin. 8. pp. 33–40.

Foster, J. (2007). "Appendix." Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press. pp. 327-329.

Jensen, James A. (1985). "Three new sauropod dinosaurs from the Upper Jurassic of Colorado." Great Basin Naturalist, 45: 697-709.

Lovelace, David M.; Hartman, Scott A.; Wahl, William R. (2007). "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. 65 (4): 527–544.