What is "struthionidae"

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 contained the world's ratites, but recent genetic analysis has found that the group is not monophletyic, as it paraphyletic in respect to the tinamous.