Struthionidae is a
family of flightless
ratite birds which first appeared during the
Eocene epoch. It is today represented by the sole living genus
Struthio, but also contains several extinct genera. Traditionally the order
Struthioniformes contain the world's ratites, but recent genetic analysis has found that the group is not monophletyic, as it paraphyletic in respect to the
tinamous.