Itardiornis is an extinct genus of the family Messelornithidae from late Eocene and early Oligocene. Only one species is described, Itardiornis hessae, from Quercy fissure fillings.Mourer-Chaviré C. (1995) The Messelornithidae (Aves: Gruiformes) from the Paleogene of France. - Cour. Forsch.-Inst. Senckenberg, 181: 95-105
References
Further reading Mayr, G. Paleogene Fossil Birds. Springer, 2009. p. 93