Gastornis

Gastornis Temporal range: Paleocene – mid Eocene, Selandian–Lutetian PreꞒ Ꞓ O S D C P T J K Pg N
Mounted skeleton of Gastornis giganteus, sometimes referred to as Diatryma gigantea
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	†Gastornithiformes
Family:	†Gastornithidae Fürbringer, 1888
Genus:	†Gastornis Hébert, 1855 (vide Prévost, 1855)
Type species
†Gastornis parisiensis Hébert, 1855
Other species
†G.? giganteus (Cope, 1876) †G.? sarasini Schaub, 1929 †G.? geiselensis Fischer, 1978 †G. russelli Martin, 1992 †G.? xichuanensis (Hou, 1980) †G. laurenti Mourer-Chauviré & Bourdon, 2020
Synonyms
Diatryma? Cope, 1876 Barornis? Marsh, 1894 Omorhamphus? Sinclair, 1928 Zhongyuanus? Hou, 1980

Gastornis is an extinct genus of large, flightless birds that lived during the mid-Paleocene to mid-Eocene epochs of the Paleogene period. Most fossils have been found in Europe, and some species typically referred to the genus are known from North America and Asia. Several genera, including the well-studied genus Diatryma, have historically been considered junior synonyms of Gastornis. However, this interpretation has been challenged recently, and some researchers currently consider Diatryma to be a valid genus.

Gastornis species were very large birds that were traditionally thought to have been predators of various smaller mammals, such as ancient, diminutive equids. However, several lines of evidence, including the lack of hooked claws (in known Gastornis footprints), studies of their beak structure and isotopic signatures of their bones, have caused scientists to now consider that these birds were probably herbivorous, feeding on tough plant material and seeds. Gastornis is, generally, agreed to be related to the Galloanserae, the group containing waterfowl and gamebirds.