Supersaurus

Skeletal reconstruction in the Museum of Ancient Life, Thanksgiving Point

• Colorado and Wyoming, USA ( Morrison Formation )

• Supersaurus vivianae Jensen, 1985

Supersaurus is a genus of sauropod dinosaur from the family of Diplodocidae. With a body length of approximately 35 meters there is a very large members of this family.

Was first described in 1985 by James Jensen Supersaurus based on fragmentary remains from Colorado ( USA); a second, more complete skeleton from Wyoming was described in 2007. Both skeletons combined constitute from 45 to 50 % of the total skeleton.

The skeletons are from the Morrison Formation and can be dated to the Upper Jurassic ( Tithonian early ). Thus Supersaurus shared its habitat with the closely related, well-studied diplodocids Apatosaurus, Diplodocus and Barosaurus. The only known species is Supersaurus vivianae.

The name Supersaurus is a Latin- Ancient Greek mixed word and means " About lizard" (Latin: super - " on", gr sauros - " lizard" ), which is to draw attention to the large size of the type specimen, a shoulder girdle ( Scapulocoracoid ), who erected has a height of 2.44 meters. The second part of the species name, vivianae honors Vivian Jones, a Amateurpaläontologin that many important sites discovered along with her husband in Colorado, including the famous Dry Mesa Quarry, which harbored the first skeleton of Supersaurus.

Features

Supersaurus was a large, four-legged herbivore with a barrel-shaped body, pillar-like legs, a very long neck and a very long and whip-like tail. The Diplodocidae family can be divided into two subfamilies - the Apatosaurinae and Diplodocinae, the Apatosaurinae are built heavier than the more delicate Diplodocinae. Supersaurus follows the blueprint of Apatosaurinae: So the ribs with a length of up to 3.05 meters were very long, which has a deep and massive hull. The leg bones were also built relatively robust.

Supersaurus is one of the largest known dinosaurs, whose fossils are surviving complete enough to allow reliable size estimates. David Lovelace and colleagues ( 2007) estimate the body length of 33 to 34 meters, assuming that Supersaurus in his body proportions the better-known Apatosaurus resembled. Gregory S. Paul ( 2010) came up to 35 meters.

Using the estimated body volume, which was determined using a 3D live model, as well as the presumed average tissue density of the body weight was estimated to be 35 to 40 tons. The specimen discovered in Colorado was slightly larger than the second, discovered in Wyoming copy.

From related genera is Supersaurus differs mainly by the construction of the vertebrae. The cervical vertebrae were extremely extended: each discovered, complete vertebral body is longer than 1 meter, the longest vertebral body found measures 1.38 meters. While the vertebrae of the cervical spine in other diplodocids large lateral openings ( Pleurocoele ) showed, these openings were greatly reduced in Supersaurus and not more than 3 to 8 inches in diameter. Unique were the vertebral bodies of the rear portion of the back spine, ophisthocoel, that is, on the front convex and concave on the rear side, were - for all other diplodocids these vertebrae were amphiplat, that is flattened at both ends.

System

Supersaurus was closely related to the genus Apatosaurus to well known and contemporary. The exact relationships of both genera are still controversial: To classify Lovelace and colleagues ( 2007) Supersaurus as a representative of the Apatosaurinae, along with Apatosaurus and Suuwassea; the Apatosaurinae are doing the opposite Diplodocinae ( and Diplodocus Barosaurus ). John Whitlock (2011) contradicts and argues that several common features between Apatosaurus and Supersaurus plesiomorphies are so original features that have been adopted by the precursors of Diplodocidae and are lost in the further evolution of this group. Thus Apatosaurus and Supersaurus would not form a natural group, but stood as the most primitive representatives of Diplodocidae at the base of the family tree of the group, while Diplodocus and Barosaurus would be the most advanced representatives.

Cladogram simplified after Lovelace and colleagues, 2007:

Suuwassea

Supersaurus

Apatosaurus

Barosaurus

Diplodocus

Diplodocus hallorum ( " Seismosaurus " )

Cladogram simplified after Whitlock, 2011:

Apatosaurus

Supersaurus

Dinheirosaurus

Tornieria

Barosaurus

Diplodocus

History of research and findings

The first skeleton was salvaged 1972-1979 by James Jensen in the Dry Mesa Quarry, an important reference in Mesa County west of Delta, Colorado. The bones were located when they were discovered not in skeletal composite, and were mixed with various other Sauropodenknochen why their correct allocation has long been unclear. Jensen ( 1985) arranged these fossils initially three new sauropod genera to - Supersaurus, Ultrasaurus (later renamed Ultrasauros ) and Dystylosaurus. Supersaurus was based on a shoulder belt ( Scapulocoracoide ), the additional seat leg, an isolated caudal vertebrae and a series were attributed from 12 caudal vertebrae. Later it turned out that the fossils described as Ultrasaurus actually belonged to two different sauropods - a Scapulocoracoid could Brachiosaurus be attributed, while it turned out, the remaining fossils, including the type material of Ultrasauros than other parts of the Supersaurus skeleton - so Ultrasauros is now as a junior synonym of Supersaurus. Dystylosaurus Meanwhile, based only on a single vertebra, which could be also attributed to the Supersaurus skeleton, even this genus thus was invalid.

2007 second, obtained about 30% Supersaurus skeleton described. Only this second skeletal finds from the Dry Mesa Quarry were re-evaluated and assignments to Supersaurus be confirmed. This skeleton ( copy number WDC DMJ -021 ) comes from the Jimbo Quarry near Douglas, Wyoming, and includes portions of the neck, back, and tail spine, fragments of the sacrum, pelvis, femur and complete tibia and fibula with a. In contrast to the Dry Mesa Quarry no other Sauropodenfossilien were discovered in the Jimbo Quarry, but the skeleton of a small theropod maniraptoren. Probably the Supersaurus and the theropod have been buried by a mudslide in place ( in situ).