Dicraeosauridae

Dicraeosaurids Temporal range: Middle Jurassic - Early Cretaceous, 166–122 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Amargasaurus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	†Sauropodomorpha
Clade:	†Sauropoda
Superfamily:	†Diplodocoidea
Clade:	†Flagellicaudata
Family:	†Dicraeosauridae Janensch, 1929
Genera
†Amargasaurus †Amargatitanis †Bajadasaurus †Brachytrachelopan †Dicraeosaurus †Dyslocosaurus †Lingwulong †Pilmatueia †Smitanosaurus †Suuwassea †Tharosaurus

Dicraeosauridae is a family of diplodocoid sauropods who are the sister group to Diplodocidae. Dicraeosaurids 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, Asia, Africa, and South America.^[1] In 2023, a dicraeosaurid fossil was discovered in India for the first time.^[2] Their temporal range is from the Early or Middle Jurassic to the Early Cretaceous.^[3][4][5] Few dicraeosaurids survived into the Cretaceous, the youngest of which was Amargasaurus.^[6]

The group was first described by German paleontologist Werner Janensch in 1914 with the discovery of Dicraeosaurus in Tanzania.^[7] Dicraeosauridae are distinct from other sauropods because of their relatively short neck size and small body size.^[3]

The clade is monophyletic and well-supported phylogenetically with thirteen unambiguous synapomorphies uniting it.^[6] They 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.^[6] However, there is some disagreement among paleontologists on the phylogenetic placement of Suuwassea, the only genus 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.^[6][8] The placement of Suuwassea within Dicraeosauridae or Diplodocidae has substantial biogeographic implications for the evolution of Dicraeosauridae.^[9]