Eleutherornis

Eleutherornis cotei is an extinct flightless predatory cariamiform bird which lived during the Middle Eocene of France and Switzerland. Since the early 20th century, researchers have initially described the fossils of Eleutherornis as separate taxa, some remains as a species of Gastornis and others as an ancient ratite related to modern ostriches. However, subsequent analyses have questioned the original interpretations, and a thorough reexamination in 2013 indicated that all of these described remains represent the same species.

It is estimated that Eleutherornis is a relatively tall bird that could grow up to in total height. Paleontologists now agree that Eleutherornis certainly belongs to the order Cariamiformes, which includes the modern seriemas and the extinct Phorusrhacidae, a group of flightless predatory birds mainly known from the Americas. This makes Eleutherornis a relative of the phorusrhacids, with some researchers even suggesting that Eleutherornis is a European member of this group, though this claim has been disputed by others and additional material may be required for confirmation.