| Euhelopodids | |
|---|---|
 | |
| Life restoration of aEuhelopus zdanskyi | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Clade: | †Macronaria |
| Clade: | †Somphospondyli |
| Family: | †Euhelopodidae Romer, 1956 |
| Type species | |
| †Euhelopus zdanskyi Wiman, 1929 | |
| Genera | |
| Synonyms | |
| |
Euhelopodidae is afamily ofsauropoddinosaurs of disputed membership and affinities, which containsEuhelopus and its close relatives. Most proposed euhelopodids are from East Asia.
Euhelopodidae was first recognized by Carl Wiman in 1929, under the name Helopodidae, asEuhelopus was originally namedHelopus.[1] However, the name had already been proposed for a bird, so in 1956Alfred Sherwood Romer proposed the nameEuhelopus 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 toEuhelopus itself, Romer includedChiayusaurus,Omeisaurus, andTienshanosaurus in Euhelopodinae.[2]
The taxonomic content of Euhelopodidae is uncertain, as a result of the unstable position ofEuhelopus itself.[3] Some studies have concluded thatEuhelopus is a non-neosauropod closely related toMamenchisaurus, which would make Euhelopodidae equivalent toMamenchisauridae. Other studies have interpretedEuhelopus 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 thatEuhelopus was closely related to titanosaurs.[4] However, the lack of research onMamenchisaurus-like taxa has hindered proper testing of this hypothesis, and there are several similarities betweenEuhelopus andMamenchisaurus-like taxa that have not been taken into account in most analyses.[5]
Michael D'Emic (2012) formulated the first phylogenetic definition of Euhelopodidae, defining it as the clade containing "neosauropods more closely related toEuhelopus zdanskyi than toNeuquensaurus australis". Below is a cladogram presenting the cladistic hypothesis of Euhelopodidae proposed by D'Emic.
In their 2021description ofSilutitan, Wanget al. recovered it as a derived euhelopodid, as the sister taxon toEuhelopus. The results of theirphylogenetic analysis, which included several other euhelopodid taxa, are shown in thecladogram below:[6]
