Suuwassea
Reconstructed skeleton, exhibited in Paris
- Montana, United States ( Morrison Formation )
- Suuwassea emilieae
Suuwassea is a genus of sauropod dinosaur from the group of Diplodocoidea, in the Upper Jurassic ( Tithonian presumably ) lived in North America. Like all sauropods had Suuwassea a large, quadrupeder ( four-footed ) herbivore with a long neck and tail. Previously, a partial skeleton is only known that was collected in 1999 and 2000 and first described by Harris and Dodson 2004. The only way 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; because of some primitive features of the genus is classified outside of these families. From the Dicraeosauride to Suuwassea distinguishes, for example by the non- fused frontal bones; of the Diplodocidae by the arrangement of the bones around the foramen magnum.
Systematics and paleobiogeography
Suuwassea classified outside the Dicraeosauridae and Diplodocidae, but is considered to be derived as the third Diplodocoiden family which Rebbachisauridae. The discovery sheds new light on the origins of Dicraeosauridae and Diplodocidae; he shows that many features that were previously on the Diplodocidae or for Dicraeosauridae as unique, indeed could be plesiomorphies that arose earlier. The first author presented to a new group Fragellicaudata, which should include the most recent common ancestor of Dicraeosaurus and Diplodocus and all descendants; to this group also Suuwassea is counted.
Suuwassea also raises questions about whether the Fragellicaudata in Laurasia, the northern land masses, or in Gondwana, the southern land masses had their origin. Currently Dicraeosauriden only from Gondwana (Africa and South America ) are known, while diplodocids occurred on Gondwana and Laurasia on. The primitive features of Suuwassea could indicate that this group originated in Laurasia, and then migrated after Gondwana. This could also mean that there was Dicraeosauriden before migration in Laurasia. Alternatively basal Fragellicaudata could have been spread throughout the world, could have evolved with the Dicraeosauriden after the breakup of the supercontinent Pangaea Gondwana. The question of why Dicraeosauriden were different than diplodocids restricted to Gondwana, however, remains enigmatic.
Suuwassea
Dicraeosauridae
Diplodocidae
Rebbachisauridae
Fund 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 skull bones ( premaxilla, partial maxilla, quadrate, complete neurocranium ), some vertebrae ( atlas, cervical, dorsal, and caudal vertebrae ), the right shoulder blade, Croacoid, some leg bones ( humerus, right tibia, right fibula, calcaneus ) and some foot bones.
The name is derived from Suuwassea suuwassa, a term from the language of Absarokee, and means something like "the first thunder in the spring." The Crow are a tribe of Indians, on the settlement area the bones were found. Taking the roots of words, means " suu " as much as "thunder" and " wassa " " former ", analogous to the common name " thunder lizards " of sauropods, as in Brontosaurus. The Artepitheth emilieae honors the sponsor of the expedition, which found the bones.