Euenantiornithes

Euenantiornithes is a superorder of Cretaceous birds. They are considered to contain the more advanced taxa of the Enantiornithes, the dominant group of birds during the late Mesozoic. Other, more plesiomorphic Enantiornithes such as Iberomesornis romerali or Noguerornis gonzalezi, are not considered to belong herein, but altogether, the Euenantiornithes appear to contain the bulk of the Enantiornithes.

Despite being in accordance with phylogenetic nomenclature, the Euenantiornithes have come under severe criticism by proponents of that taxonomical system, such as Paul Sereno, who called them "'a [sic] ill-defined clade [...] a good example of a poor choice in a phylogenetic definition'" As they are technically validly described as a clade but might be a phenetic evolutionary grade instead, they could be considered a test case for how the proposed PhyloCode would deal with nomina dubia.

Systematics and taxonomy
Several taxa have been established at order rank in this group. Many contain only the type species and most are incertae sedis regarding their interrelationships. They are consequently dismissed by many authorities. Apart from that, the placement of the following taxa is even less resolved:

Basal Euenantiornithes Euenantiornithes incertae sedis Family Kuszholiidae (disputed) Order Aberratiodontuiformes (disputed) Order "Cathayornithiformes" (disputed) Order Alexornithiformes (disputed) Order Gobipterygiformes (disputed) Order Enantiornithiformes
 * Eoalulavis (Early Cretaceous)
 * Boluochia (Early Cretaceous) - cathayornithid?
 * Concornis (Early Cretaceous) - cathayornithid? enantiornithiform?
 * Cuspirostrisornis (Early Cretaceous)
 * Enantiornithes gen. et sp. indet. CAGS-IG-04-CM-007 (Xiagou Early Cretaceous of Mazongshan, PRC)
 * Eoenantiornis (Early Cretaceous)
 * Largirostrornis (Early Cretaceous)
 * Longchengornis (Early Cretaceous)
 * Longirostravis (Early Cretaceous)
 * Hebeiornis (Early Cretaceous) - possibly a nomen nudum; if valid, includes Vescornis
 * Enantiornithes gen. et sp. indet. RBCM.EH2005.003.0002 (Northumberland Late Cretaceous of Hornby Island, Canada)
 * Gurilynia (Late Cretaceous) - enantiornithiform?
 * Halimornis (Late Cretaceous)
 * Lectavis (Late Cretaceous) - enantiornithiform?
 * Lenesornis (Late Cretaceous)
 * Neuquenornis (Late Cretaceous) - cathayornithid? avisaurid?
 * Yungavolucris (Late Cretaceous) - enantiornithiform?
 * Kuszholia (Late Cretaceous)
 * Family Aberratiodontuidae
 * Aberratiodontus (Early Cretaceous)
 * Family "Cathyornithidae"
 * Sinornis/Cathayornis (Early Cretaceous) - which name is correct is disputed
 * Eocathayornis (Early Cretaceous)
 * Family Alexornithidae
 * Alexornis (Late Cretaceous)
 * Kizylkumavis (Late Cretaceous)
 * Sazavis (Late Cretaceous)
 * Family Gobipterygidae
 * Gobipteryx (Late Cretaceous)
 * Family Enantiornithidae (disputed)
 * Enantiornis (Late Cretaceous)
 * Family Avisauridae
 * Avisaurus (Late Cretaceous)
 * Soroavisaurus (Late Cretaceous)

Doubtful Euenantiornithes

It is not clear whether these taxa are Euenantiornithes:
 * Enantiornithes gen. et sp. indet. MZ unnumbered (Adamantina Late Cretaceous of Presidente Prudente, Brazil) - enantiornithiform?
 * Enantiornithes gen. et sp. indet. Patrick Mechin collection 606 (Late Cretaceous of Bastide-Neuve, France) - alexornithid?

For these birds, it is not even fully resolved that they were Enantiornithes, but they show some characters usually found in Euenantiornithes: "Jibeinia" (Early Cretaceous) is a nomen dubium.
 * Longipteryx (Early Cretaceous) - own order?
 * Nanantius (Early -? Late Cretaceous) - enantiornithiform?
 * Abavornis (Late Cretaceous)
 * Explorornis (Late Cretaceous)
 * Horezmavis (Late Cretaceous of Kyzyl Kum, Uzbekistan) - gobipterygiform?
 * Incolornis (Late Cretaceous)
 * Family Zhyraornithidae - enantiornithiform?
 * Zhyraornis (Late Cretaceous)