Supersaurus
| Supersaurus | ||||||||||||
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Skeleton reconstruction at the Museum of Ancient Life in Lehi , Utah |
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| Temporal occurrence | ||||||||||||
| Upper Jurassic (Lower Tithonian ) | ||||||||||||
| 152.1 to 147.7 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Supersaurus | ||||||||||||
| Jensen , 1985 | ||||||||||||
| Art | ||||||||||||
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Supersaurus is a genus of sauropod dinosaur from the family of Diplodocidae . With a body length of approximately 35 meters, it is a very large member of this family.
Supersaurus was first described in 1985 by James A. Jensen based on fragmentary remains from Colorado ( USA ); a second, more complete Wyoming skeleton was described in 2007. Both skeletons combined form 45 to 50% of the entire skeleton.
The skeletons come from the Morrison Formation and can be dated to the Upper Jurassic (early Tithonian ). 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 "over-lizard" (Latin super - "over", Greek sauros - "lizard"), which should indicate the considerable size of the type specimen. For example, the shoulder girdle (scapulocoracoid) found has an erect height of 2.44 meters. The second part of the species name, vivianae , honors Vivian Jones, an amateur paleontologist who, together with her husband, discovered numerous important sites in Colorado, including the famous Dry Mesa Quarry , which contained the first skeleton of Supersaurus .
features
Supersaurus was a large, four-legged herbivore with a barrel-shaped body, columnar legs, a very long neck, and a very long and whip-like tail. The family of the Diplodocidae can be divided into two subfamilies - the Apatosaurinae and the Diplodocinae, whereby the Apatosaurinae are more heavily built than the more delicate Diplodocinae. Supersaurus follows the blueprint of the Apatosaurinae: the ribs were very long with a length of up to 3.05 meters, which indicates a deep and massive body. The leg bones were also built to be relatively robust.
Supersaurus is one of the largest known dinosaurs, the fossil record of which is complete enough to allow reliable size estimates to be made. David Lovelace and colleagues (2007) estimate the body length to be 33 to 34 meters, assuming that Supersaurus resembled the better-known Apatosaurus in its body proportions . Gregory S. Paul (2010) came up to 35 meters.
With the help of the estimated body volume, which was determined with the aid of a 3D living model, and the assumed average tissue density, the body weight could be estimated at 35 to 40 tons. The specimen discovered in Colorado was slightly larger than the second specimen discovered in Wyoming.
Supersaurus differs from related genera primarily in the structure of the vertebrae. The cervical vertebrae were extremely elongated: each discovered, complete vertebral body is longer than 1 meter, the longest vertebral body found measures 1.38 meters. While the vertebral bodies of the cervical spine in other Diplodocidae had large lateral openings (pleurocoele), these openings in Supersaurus were greatly reduced and no larger than 3 to 8 centimeters in diameter. The vertebral bodies of the posterior section of the vertebral column were also unique; they were ophisthocoel , that is, convex on the front and concave on the rear - in all other Diplodocidae these vertebral bodies were amphiplat , that is, flattened at both ends.
Systematics
Supersaurus was closely related to the well-known and contemporary Apatosaurus genus . The exact relationship between the two genera is still controversial: Lovelace and colleagues (2007) classify Supersaurus as a representative of the Apatosaurinae, together with Apatosaurus and Suuwassea ; the Apatosaurinae stand opposite the Diplodocinae ( Barosaurus and Diplodocus ). John Whitlock (2011) contradicts and argues that various common features between Apatosaurus and Supersaurus are plesiomorphies , i.e. original features that were adopted from the predecessors of the Diplodocidae and have been lost in the further evolution of this group. Thus Apatosaurus and Supersaurus would not form a natural group, but as the most original representatives of the Diplodocidae would be at the base of the family tree of the group, while Diplodocus and Barosaurus would be the most advanced representatives.
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Cladogram, simplified from Lovelace and colleagues, 2007:
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Cladogram, simplified from Whitlock, 2011:
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Research history and finds
The first skeleton was recovered between 1972 and 1979 by James A. Jensen in the Dry Mesa Quarry , a major find in Mesa County west of Delta in Colorado. When they were discovered, the bones were not part of the skeletal system and were mixed with various other sauropod bones, which is why their correct assignment was unclear for a long time. Jensen (1985) initially assigned these fossils to three new genera of sauropods - Supersaurus , Ultrasaurus (later renamed Ultrasauros ) and Dystylosaurus . Supersaurus was based on a shoulder girdle (scapulocoracoide) to which an ischium , an isolated caudal vertebra and a series of 12 caudal vertebrae were also assigned. Later it turned out that the fossils described as Ultrasaurus actually belonged to two different sauropods - a scapulocoracoid could be attributed to Brachiosaurus , while the remaining fossils, including the type material of Ultrasauros , turned out to be further parts of the Supersaurus skeleton - so Ultrasauros is today as a younger synonym of Supersaurus . Dystylosaurus, meanwhile, was based only on a single dorsal vertebra, which could also be assigned to the Supersaurus skeleton, which also made this genus invalid.
In 2007 a second Supersaurus skeleton, about 30% intact, was described. Only with this second skeleton could the finds from the Dry Mesa Quarry be reassessed and assignments to Supersaurus confirmed. This skeleton (copy number WDC DMJ-021) comes from the Jimbo Quarry near Douglas in Wyoming and includes parts of the cervical, back, and caudal spine, fragments of the sacrum , pelvis, femur, and entire tibia and fibula . In contrast to the dry mesa quarry, no other sauropod fossils were discovered in the jimbo quarry, but the skeleton of a small maniraptor theropod . Presumably the Supersaurus and the Theropod were buried on the spot ( in situ ) by a debris flow .
literature
- James A. Jensen: Three new sauropod dinosaurs from the Upper Jurassic of Colorado. In: Western North American Naturalist. Vol. 45, No. 4, 1985, ISSN 1527-0904 , pp. 697-709, online .
- David M. Lovelace, Scott A. Hartman, William R. Wahl: Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. In: Arquivos do Museu Nacional. Vol. 65, No. 4, 2007, pp. 527-544, digitized version (PDF; 1.9 MB) .
Individual evidence
- ↑ a b c Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 191, online .
- ↑ Ben Creisler: Dinosauria Translation and Pronunciation Guide. Archived from the original on July 10, 2011 ; accessed on August 21, 2014 .
- ↑ a b James A. Jensen: Three new sauropod dinosaurs from the Upper Jurassic of Colorado. In: Western North American Naturalist. Vol. 45, No. 4, 1985, pp. 697-709, here pp. 701-704: Supersaurus vivianae, n. Gen, n. Sp.
- ^ A b D. M. Lovelace, SA Hartman, WR Wahl: Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. In: Arquivos do Museu Nacional. Vol. 65, No. 4, 2007, pp. 527-544, here pp. 530-537: Description of the material.
- ^ DM Lovelace, SA Hartman, WR Wahl: Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. In: Arquivos do Museu Nacional. Vol. 65, No. 4, 2007, pp. 527-544, here pp. 541-542: Conclusions.
- ^ DM Lovelace, SA Hartman, WR Wahl: Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. In: Arquivos do Museu Nacional. Vol. 65, No. 4, 2007, pp. 527-544, here p. 541: Size of the largest diplodocids.
- ^ DM Lovelace, SA Hartman, WR Wahl: Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. In: Arquivos do Museu Nacional. Vol. 65, No. 4, 2007, pp. 527-544, here p. 538: Phylogenetic Analysis.
- ^ A b John A. Whitlock: A phylogenetic analysis of Diplodocoidea (Saurischia: Sauropoda). In: Zoological Journal of the Linnean Society. Vol. 161, No. 4, 2011, ISSN 0024-4082 , pp. 872-915, here pp. 87-88 and 96, doi : 10.1111 / j.1096-3642.2010.00665.x .
- ^ DM Lovelace, SA Hartman, WR Wahl: Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. In: Arquivos do Museu Nacional. Vol. 65, No. 4, 2007, pp. 527-544, here p. 540.
- ↑ a b c James A. Jensen: Three new sauropod dinosaurs from the Upper Jurassic of Colorado. In: Western North American Naturalist. Vol. 45, No. 4, 1985, pp. 697-709.
- ^ Brian D. Curtice, Kenneth L. Stadtman, Linda J. Curtice: A reassessment of Ultrasauros macintoshi (Jensen, 1985). In: Michael Morales (Ed.): The continental Jurassic. Transactions of the Continental Jurassic Symposium, October 21-23, 1996, Museum of Northern Arizona, Flagstaff, Arizona (= Museum of Northern Arizona. Bulletin Series. Vol. 60). Museum of Northern Arizona, Flagstaff AZ 1996, ISBN 0-89734-119-8 , pp. 87-95, digitized version (PDF; 378.55) .
- ^ A b D. M. Lovelace, SA Hartman, WR Wahl: Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. In: Arquivos do Museu Nacional. Vol. 65, No. 4, 2007, pp. 527-544, here pp. 527-528: Introduction.
- ↑ David M. Lovelace: An Upper Jurassic Morrison Formation fire-induced debris flow: Taphonomy and paleoenvironment of a sauropod (Sauropoda: Supersaurus vivianae) locality, East-Central Wyoming. In: John R. Foster, Spencer G. Lucas (eds.): Paleontology and geology of the Upper Jurassic Morrison formation (= New Mexico Museum of Natural History & Science. Bulletin. 36, ISSN 1524-4156 ). New Mexico Museum of Natural History & Science, Albuquerque NM 2006, pp. 47-56, online .
