Euhelopodidae is a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their bo ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s of disputed membership and affinities, which contains ''

Euhelopus ''Euhelopus'' is a genus of sauropod dinosaur that lived between 145 and 133 million years ago during the Berriasian and Valanginian stages of the Early Cretaceous in what is now Shandong Province in China. It was a large quadrupedal herbivore. U ...

'' and its close relatives. Most proposed euhelopodids are from East Asia. Euhelopodidae was first recognized by Carl Wiman in 1929, under the name Helopodidae, as ''Euhelopus'' was originally named ''Helopus''. However, the name had already been proposed for a bird, so in 1956

Alfred Sherwood Romer Alfred Sherwood Romer (December 28, 1894 – November 5, 1973) was an American paleontologist and biologist and a specialist in vertebrate evolution. Biography Alfred Romer was born in White Plains, New York, the son of Harry Houston Romer an ...

proposed the name ''Euhelopus'' and Euhelopodinae as replacements; Romer classified Euhelopodinae as a subfamily of Brachiosauridae, in which he also included Camarasaurinae and Cetiosaurinae, rather than as a family of its own. In addition to ''Euhelopus'' itself, Romer included ''Chiayusaurus'', ''Omeisaurus'', and ''Tienshanosaurus'' in Euhelopodinae. The taxonomic content of Euhelopodidae is uncertain, as a result of the unstable position of ''Euhelopus'' itself. Some studies have concluded that ''Euhelopus'' is a non-neosauropod closely related to ''Mamenchisaurus'', which would make Euhelopodidae equivalent to

Mamenchisauridae Mamenchisauridae is a family of sauropod dinosaurs belonging to Eusauropoda known from the Jurassic and Early Cretaceous of Asia and Africa. Some members of the group reached gigantic sizes, amongst the largest of all sauropods. Classification T ...

. Other studies have interpreted ''Euhelopus'' as neosauropod united with titanosaurs in Somphospondyli. A joint study by Jeffrey Wilson and Paul Upchurch, who had previously taken opposite sides in the debate, concluded that ''Euhelopus'' was closely related to titanosaurs. However, the lack of research on ''Mamenchisaurus''-like taxa has hindered proper testing of this hypothesis, and there are several similarities between ''Euhelopus'' and ''Mamenchisaurus''-like taxa that have not been taken into account in most analyses. Michael D'Emic (2012) formulated the first phylogenetic definition of Euhelopodidae, defining it as the clade containing " neosauropods more closely related to ''Euhelopus zdanskyi'' than to '' Neuquensaurus australis''". Below is a cladogram presenting the cladistic hypothesis of Euhelopodidae proposed by D'Emic.

References

Macronarians Jurassic first appearances Prehistoric dinosaur families {{sauropodomorph-stub