Garudimimidae

Deinocheiridae is an extinct family of ornithomimosaurian dinosaurs, living in Asia and North America from the Aptian until the Maastrichtian, with a possible Late Jurassic record in Europe. The family was originally named by Halszka Osmólska and Roniewicz in 1970, including only the type genus ''Deinocheirus''. In a 2014 study by Yuong-Nam Lee and colleagues and published in the journal ''Nature'', it was found that Deinocheiridae was a valid family. Lee ''et al.'' found that based on a new phylogenetic analysis including the recently discovered complete skeletons of ''Deinocheirus'', the type genus, as well as ''Garudimimus'' and ''Beishanlong'', could be placed as a successive group, with ''Beishanlong'' as the most primitive and ''Deinocheirus'' as most derived. The family Garudimimidae, named in 1981 by Rinchen Barsbold, is now a junior synonym of Deinocheiridae as the latter family includes the type genus of the former. The group existed from 115 to 69 million years ago, with ''Beishanlong'' living from 115 to 100 mya, ''Garudimimus'' living from 98 to 83 mya, and ''Deinocheirus'' living from 71 to 69 mya. Other genera included are ''Paraxenisaurus'', and possibly ''Harpymimus'' and ''Hexing''.

Classification

When originally named, Halszka Osmólska and Ewa Roniewicz, found that ''Deinocheirus'' was a carnosaurian, and because of its extremely unusual arms, named the monotypic family Deinocheiridae for it. Osmólska and Roniewicz found that Deinocheiridae could be placed within the superfamily Megalosauroidea, within the infraorder Carnosauria (Carnosauria at the time was a paraphyletic group of all large theropods). Previously, the only carnosaurian from that time and place in Asia was the tyrannosaurid ''Tarbosaurus''.

Osmólska and Roniewicz diagnosed Deinocheiridae, based on the only genus of the time in the family, ''Deinocheirus''. Their diagnosis was "Gigantic carnivorous dinosaurs with long, slender scapula and long fore limbs; manus with three, uniformly developed fingers, ending in strong, large claws". Based on ''Deinocheirus'' again, the temporal range and distribution for the family was found limited to the Upper Cretaceous of the Upper Nemegt Formation of the Gobi Desert, Mongolia. Osmólska and Roniewicz noted, however, that the features of this family were very similar to those of ''Ornithomimus'', but kept them separate on the possibility of convergence.

Rinchen Barsbold used this family as potentially valid, and in 1976, named the infraorder Deinocheirosauria for it. Within the infraorder he placed Deinocheiridae and Therizinosauridae, finding reason for the families to be united. In 1983, Barsbold elaborated, mentioning features uniting deinocheirids and therizinosaurids, mainly in the region of the hand and forelimb. He hypothesized that deinocheirosaurs would have had moderately-sized skull even though they were gigantic in size. ''Deinocheirus'' was mentioned and diagnosed as the only deinocheirid, while ''Therizinosaurus'' was mentioned to be the only therizinosaurid.

Jacques Gauthier, in 1986, found that Deinocheiridae was synonymous with Ornithomimidae. He used Ornithomimidae as a similar group to Ornithomimosauria, including ''Elaphrosaurus'' (a non-coelurosaurian), ''Ajancingenia'' (then ''Ingenia''; an oviraptorid), ''Ornithomimus'', ''Struthiomimus'', ''Archaeornithomimus'', ''Gallimimus'', ''Dromiceiomimus'', ''Garudimimus'' and ''Deinocheirus''.

In a 2014 study by Yuong-Nam Lee and his colleagues, describing new specimens of ''Deinocheirus'', it was found that the genus was indeed a close relative of ''Ornithomimus'', and that the family Deinocheiridae was valid and not monotypic. Lee ''et al.'' analysed the new specimens, which showed very distinct features, and found that the genera ''Garudimimus'' and ''Beishanlong'', previously classified as close relatives of, although more primitive than, Ornithomimidae, could be grouped together in Deinocheiridae. As ''Garudimimus'' was strongly supported to be in the family as the closest relative of ''Deinocheirus'', the family Garudimimidae, named in 1981 by Barsbold, one of the coauthors of the Lee ''et al.'' paper, is now a junior synonym of Deinocheiridae. Lee ''et al.'' gave Deinocheiridae it first and only definition: "''Deinocheirus mirificus'' and all taxa sharing a more recent common ancestor with it than ''Ornithomimus velox''". The cladogram published by Lee ''et al.'' and including the new material of ''Deinocheirus'', is shown below in a simplified form.

In the 2019 description of ''Hesperornithoides'', ''Deinocheirus'' was recovered as more basal than ''Garudimimus'' in a clade with ''Hexing'' and a Deinocheirid placement for ''Garudimimus'' was considered unlikely, requiring 14 more steps.

References

{{Taxonbar, from=Q3021317

Ornithomimosauria
Dinosaur families
Cretaceous dinosaurs