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'' 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 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. 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 Neosauropoda is a clade within Dinosauria, coined in 1986 by Argentine paleontologist José Bonaparte and currently described as ''Saltasaurus loricatus'', ''Diplodocus longus'', and all animals directly descended from their most recent common an ...

more closely related to ''Euhelopus zdanskyi'' than to ''

Neuquensaurus australis ''Neuquensaurus'' (meaning "Neuquén lizard") is a genus of saltasaurid sauropod dinosaur that lived in the Late Cretaceous, about 80 million years ago in Argentina and Uruguay in South America. Its fossils were recovered from outcrops of the Ana ...

''". Below is a cladogram presenting the cladistic hypothesis of Euhelopodidae proposed by D'Emic.

References

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