Haplocanthosaurus

Skeletal reconstruction of Haplocanthosaurus delfsi

• North America ( Morrison Formation )

• Haplocanthosaurus priscus
• Haplocanthosaurus delfsi

Haplocanthosaurus ( " einstachelige lizard" ) is a genus of sauropod dinosaur from the Upper Jurassic of North America. The type species is H. priscus ( synonym: H. utterbacki ). Haplocanthosaurus is one of the most primitive sauropods, which were found in North America.

Description

Haplocanthosaurus, like all sauropods, a four-legged herbivores. H. priscus reached a length of up to a maximum of 13 meters and an estimated weight of about 5 tonnes. H. delfsi was up to 21.5 meters long by 35 to 50 percent and could have weighed about 25 tons. The skeletal structure is primitive, this is especially true for the vertebrae, the spinous processes are massive, so do not branch out, as is the case with many other sauropods. In this feature, the scientific name of the genus refers. Haplocanthosaurus agrees in many characteristics with Cetiosaurus. He had a very long neck, made ​​up of 14 vertebrae.

Discovery history

1901, the well-preserved partial skeletons of two individuals in the vicinity of Canyon City were discovered in the U.S. state of Colorado, which, however, is absent in sauropods as very often, the skull and thus valuable diagnostic information. John Bell Hatcher chose the larger of the two specimens as the holotype for his 1903 published scientific description and named the new genus and species from the late Kimmeridgian Haplocanthus priscus. But since this name was already in use for a genus of fossil fishes, they could not be maintained.

In the same region, but at a higher stratigraphic level (middle Tithonian ), an excavation team found behalf of the Cleveland Museum of Natural History in 1954 a third, less complete specimen, the only recognized in 1988 by JS McIntosh and ME Williams as a separate species H. delfsi been. The epithet of species name refers to the leader of the group, students Edwin R. Delfs. All skeletons discovered so far are from the well-known for their abundance of vertebrate fossils Morrison Formation.