Suuwassea
| Suuwassea | ||||||||||
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Reconstructed skeleton, exhibited in Paris |
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| Temporal occurrence | ||||||||||
| Upper Jurassic (possibly Tithonium ) | ||||||||||
| 152.1 to 145 million years | ||||||||||
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| Scientific name | ||||||||||
| Suuwassea | ||||||||||
| Harris & Dodson , 2004 | ||||||||||
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Suuwassea is a genus of sauropod dinosaur from the group of Diplodocoidea , which lived in the Upper Jurassic (probably Tithonium ) of North America. Like all sauropods, Suuwassea was a large, quadruped (four-footed) herbivore with a long neck and tail. So far, only a partial skeleton is known, which was collected in 1999 and 2000 and first described by Harris and Dodson in 2004. The only species is Suuwassea emilieae .
features
Suuwassea reached a length of 14 to 15 meters. Although Suuwassea showed some characteristics of both the Dicraeosauridae and the Diplodocidae ; however, because of some primitive features, the genus is classified outside of these families . Suuwassea differs from the Dicraeosauride, for example, in that the frontal bones are not fused together; from the Diplodocidae by the arrangement of the bones around the foramen magnum .
Systematics and paleobiogeography
Suuwassea is classified outside of the Dicraeosauridae and Diplodocidae, but is considered more derived than the third Diplodocoid family, the Rebbachisauridae . The find sheds new light on the origins of the Dicraeosauridae and the Diplodocidae; it shows that many features that were previously considered unique to the Diplodocidae or the Dicraeosauridae could actually be plesiomorphies that arose earlier. The first authors put up a new group, the Fragellicaudata, which should include the youngest common ancestor of Dicraeosaurus and Diplodocus and all descendants; Suuwassea is included in this group .
Suuwassea also raises questions as to whether the Fragellicaudata originated in Laurasia , the northern land masses, or Gondwana , the southern land masses. Currently, dicraeosaurids are only known from Gondwana (Africa and South America), while Diplodocidae occurred on Gondwana and Laurasia. The primitive features of Suuwassea could indicate that this group originated in Laurasia and then migrated to Gondwana. This could also mean that dicraeosaurids existed in Laurasia before the migration. Alternatively, basal Fragellicaudata could have been distributed worldwide, with the dicraeosaurids developing on Gondwana after the supercontinent Pangea broke up. The question of why dicraeosaurids, unlike diplodocids, were restricted to Gondwana, however, remains a mystery.
| Diplodocoidea |
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Find and naming
The fossils were discovered in Southern Carbon County , Montana, and geologically belong to the Morrison Formation . The salvaged partial skeleton (holotype ANS 21122) consists of some cranial bones ( premaxillary , partial upper jaw , quadratum , complete neurocranium ), some vertebrae ( atlas , cervical, dorsal and caudal vertebrae), the right shoulder blade , croacoid, some leg bones ( humerus , right shin , right fibula , heel bone ) and some foot bones.
The name Suuwassea is derived from suuwassa , a term from the Absarokee language , and means something like "the first thunder in spring". The Crow are an Indian tribe on whose settlement area the bones were found. If you take the roots of the words, "suu" means something like "thunder" and "wassa" means "former", analogous to the common name "thunder lizards" for sauropods, as is the case with Brontosaurus . The Artepitheth emilieae honors the sponsor of the expedition that found the bones.
supporting documents
Web links
literature
- Jerald D. Harris, Peter Dodson : A new diplodocoid sauropod dinosaur from the Upper Jurassic Morrison Formation of Montana, USA. In: Acta Palaeontologica Polonica. Vol. 49, No. 2, 2011, ISSN 0567-7920 , pp. 197-210, online .
Individual evidence
- ^ John A. Whitlock: Inferences of Diplodocoid (Sauropoda: Dinosauria) Feeding Behavior from Snout Shape and Microwear Analyzes. In: PLoS ONE . Vol. 6, No. 4, 2011, e18304, doi : 10.1371 / journal.pone.0018304 .