Opisthodactylus

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: ParaHoxozoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Cladus: Olfactores
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Cladus: Sauropsida
Cladus: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Neodiapsida
Cladus: Sauria
Cladus: Archelosauria
Cladus: Archosauromorpha
Cladus: Crocopoda
Cladus: Archosauriformes
Cladus: Eucrocopoda
Cladus: Archosauria
Cladus: Avemetatarsalia
Cladus: Ornithodira
Cladus: Dinosauromorpha
Cladus: Dinosauriformes
Cladus: Dracohors
Cladus: Dinosauria
Cladus: Saurischia
Cladus: Theropoda
Cladus: Neotheropoda
Cladus: Averostra
Cladus: Tetanurae
Cladus: Avetheropoda
Cladus: Coelurosauria
Cladus: Tyrannoraptora
Cladus: Maniraptoromorpha
Cladus: Maniraptoriformes
Cladus: Maniraptora
Cladus: Pennaraptora
Cladus: Paraves
Cladus: Eumaniraptora
Cladus: Avialae
Subclassis: Aves
Cladus: Avebrevicauda
Cladus: Pygostylia
Cladus: Ornithothoraces
Cladus: Ornithuromorpha
Cladus: Carinatae
Subclassis/Parvclassis: Neornithes
Infraclassis/Cohors: Palaeognathae
Ordo: Rheiformes

Familia: †Opistodactylidae
Genus: †Opisthodactylus
Species: †O. horacioperezi – †O. kirchneri – †O. patagonicus
Name

Opisthodactylus Ameghino, 1891: 453
References
Primary references

Ameghino, F. 1891. Enumeración de las aves fósiles de la República Argentina. Revista Argentina Historia Natural 1: 441–453. BHL Reference page.

Opisthodactylus is an extinct genus of rhea from the Early to Middle Miocene Santa Cruz and Chichinales Formations and the Late Miocene (Montehermosan) Andalhuala Formation of Argentina. Three species are described: the type species, O. patagonicus, O. kirchneri and O. horacioperezi. The species O. kirchneri was described in 2017 by Noriega et al.[1] Fossils of O. horacioperezi were found together with fossils of Patagorhacos terrificus.[2]
References

Opisthodactylus at Fossilworks.org

Federico L. Agnolin and Pablo Chafrat (2015). "New fossil bird remains from the Chichinales Formation (Early Miocene) of northern Patagonia, Argentina". Annales de Paléontologie. 101 (2): 87–94. Bibcode:2015AnPal.101...87A. doi:10.1016/j.annpal.2015.02.001.