Dicraeosaurid
| Dicraeosauridae Temporal range: Late Jurassic - Early Cretaceous |
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| Amargasaurus | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Superorder: | Dinosauria |
| Suborder: | †Sauropodomorpha |
| Superfamily: | †Diplodocoidea |
| Family: |
†Dicraeosauridae Janensch, 1929 |
| Genera | |
Dicraeosauridae is a family of diplodocoid sauropods who are the sister group to Diplodocidae. Dicraesaurids are a part of the Flagellicaudata, along with Diplodocidae. Dicraeosauridae includes genera such as Amargasaurus, Suuwassea, Dicraeosaurus, and Brachytrachelopan. Specimens of this family have been found in North America, Africa, and South America. Their temporal range is from the Late Jurassic to the Middle Cretaceous. The only known Cretaceous survivor of the dicraeosaurids is Amargasaurus.
The group was first described by German paleontologist Werner Janensch in 1914 with the discovery of Dicraeosaurus in Tanzania. Dicraeosauridae are distinct from other sauropods because of their relatively short neck size and small body size.
The clade is monophyletic and well-supported phylogenetically with thirteen unambiguous synapomorphies uniting it. They likely diverged from Diplodocidae in the Mid-Jurassic, as evidenced by the diversity of dicraeosaurids in both South America and East Africa when Gondwana was still united by land. However, there is some disagreement among paleontologists on the phylogenetic placement of Suuwassea, the only genera of the Dicraeosauridae to be found in North America. It has been characterized as a basal dicraeosaurid by some and a member of the Diplodocidae by others. The placement of Suuwassea within Dicraeosauridae or Diplodocidae has substantial biogeographic implications for the evolution of Dicraeosauridae.
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Wikipedia