What is "cypselomorphae"

Cypselomorphae is a clade of birds. It includes the living families and orders Caprimulgidae (nightjars, nighthawks and allies), Nyctibiidae (potoos), Apodiformes (swifts and hummingbirds), as well as the Aegotheliformes (owlet-nightjars) whose distinctness was only recently realized. The Apodiformes (which include the " Trochiliformes" of the Sibley-Ahlquist taxonomy) and the Aegotheliformes form the Daedalornithes.