page_title: Supersaurus
section_title: Ultrasauros
hierarchical_section_title: Supersaurus / History / Ultrasauros
caption_attribution_description: English: Image of James A. Jensen in his preparation lab at BYU, standing by forefoot of ultrasaurus. Dr. Jensen did not copyright his images, which he gave to me, his elder son, in his will. He died in 1998 at which point I received all of his images and paleo materials. I have not added copyright so this image does not have and has never had a copyright. Doctorjrj 05:40, 25 February 2007 (UTC)
context_page_description: Supersaurus is a genus of diplodocid sauropod dinosaur that lived in North America during the Late Jurassic period. The type species, S. vivianae, was first discovered by Vivian Jones of Delta, Colorado, in the middle Morrison Formation of Colorado in 1972. The fossil remains came from the Brushy Basin Member of the formation, dating to about 153 million years ago. A potential second species, S. lourinhanensis, is known from Portugal and has been dated to a similar time.
context_section_description: Jensen, who described the original Supersaurus specimen, simultaneously reported the discovery of another gigantic sauropod, which would later be named "Ultrasaurus" macintoshi (later renamed Ultrasauros macintoshi). The type specimen (the specimen used to define a new species) of Ultrasauros, being a backbone (dorsal vertebra, labelled BYU 9044), was later found to have come from Supersaurus. In fact, it probably belonged to the original Supersaurus specimen, which was discovered in the same quarry in 1972. Therefore, Ultrasauros became a junior objective synonym of Supersaurus, which had been named first and thus retains priority, and the name Ultrasauros was abandoned.
  Other bones that were found at the same location and originally thought to belong to Ultrasauros, like a shoulder girdle (scapulocoracoid, BYU 9462), actually belonged to Brachiosaurus, possibly a large specimen of Brachiosaurus altithorax. The Brachiosaurus bones indicate a large, but not record-breaking individual, a little larger than the "Brachiosaurus" brancai (Giraffatitan brancai) mount in the Berlin's Natural History Museum. Larger specimens of Brachiosaurus are known from the Tendaguru beds of Tanzania, in east Africa.
  Originally, these Supersaurus and Brachiosaurus bones were believed to represent a single dinosaur that was estimated to reach about 25 to 30 meters (80 to 100 ft) long, 8 meters (25 ft) high at the shoulder, 15 meters (50 ft) in total height, and weighing maybe 70 metric tons (75 short tons). At the time, mass estimates ranged up to 180 tons, which placed it in the same category as the blue whale and the equally problematic Bruhathkayosaurus.
  The naming of the chimeric Ultrasauros has a similarly complicated history. Ultrasaurus (with the final "u") was the original choice, and was widely used by the media after the discovery in 1979. However, the name of a new species must be published with a description to become official.
  Before Jim Jensen published his discovery in 1985, another paleontologist, Kim Haang Mook, used the name Ultrasaurus in a 1983 publication to describe what he believed was a giant dinosaur in South Korea. This was a different, much smaller dinosaur than Jensen's find, but Kim thought it represented a similarly gigantic animal because he confused a humerus for an ulna. While the logic of naming was incorrect, the Ultrasaurus from Kim's find fulfilled the requirements for naming and became regarded as a legitimate, if dubious genus. Thus, because Jensen did not publish his own "Ultrasaurus" find until 1985, Kim's use retained its official priority of name, and Jensen was forced to choose a new name (in technical terms, his original choice was "preoccupied" by Kim's sauropod). In 1991, at his suggestion, George Olshevsky changed one letter, and renamed Jensen's sauropod Ultrasauros, with the final "o".
  When it was later discovered that the new name referred to bones from two separate, and already known species, the name Ultrasauros became a junior synonym for Supersaurus. Since the bones from the Brachiosaurus were only used as a secondary reference for the new species, Ultrasauros is not a junior synonym for Brachiosaurus. Since Supersaurus was named slightly earlier, the name Ultrasauros has been discarded in favor of Supersaurus.
caption: James A. Jensen with the reconstructed front leg of Ultrasauros
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