Awesome!!!
[...] Apsaraviformes was proposed by Livezey and Zusi (2007), so should have priority over Palintropiformes. Ambiortus shares an absent capital groove with Apsaravis, and if related would mean the order should be called Ambiortiformes (Kurochkin, 1982) instead.
As Jaime points out, priority does not exist in the ICZN above the family group of ranks.
Kurochkin, 1982. Novyy otryad ptits iz nizhnego mela Mongolii.
"A new order of birds from the Early Cretaceous of Mongolia."
Doklandy
Doklady. "Reports", "laid-down ones".