Phaethoquornithes

Phaethoquornithes is a clade of birds that contains Eurypygimorphae and Aequornithes,^[4] which was first recovered by genome analysis in 2014.^[5] Members of Eurypygimorphae were originally classified in the obsolete group Metaves,^{[clarification needed]} and Aequornithes were classified as the sister taxon to Musophagiformes or Gruiformes.^[6][7]

Phaethoquornithes Temporal range: Early Paleocene–Holocene 62–0 Ma[1] PreꞒ Ꞓ O S D C P T J K Pg N Possible an early origin based on molecular clock[2]
Juvenile red-throated loon (Gavia stellata)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Clade:	Neoaves
Clade:	Phaethoquornithes Sangster et al., 2022[3]
Subgroups
Phaethontimorphae Aequornithes
Synonyms
Ardeae

This group has also been informally called Ardeae.^[8] Older classifications have used Ardeae in a different sense, as a suborder of Ciconiiformes containing herons and related species.^[9] George Sangster and colleagues in 2022 named and defined this clade in the PhyloCode as the least inclusive crown clade containing Phaethon aethereus and Pelecanus onocrotalus, but not Apus apus, Charadrius hiaticula, Musophaga violacea, or Passer domesticus.^[4]

Phaethoquornithes	Eurypygimorphae Phaethontiformes (tropicbirds) Eurypygiformes (sunbittern and kagu) Aequornithes Gaviiformes (loons/divers) Feraequornithes Austrodyptornithes Procellariiformes (albatrosses, shearwaters, and petrels) Sphenisciformes (penguins) Pelecanimorphae Ciconiiformes (storks) Pelecanes Suliformes (frigatebirds, gannets, cormorants, and darters) Pelecaniformes (pelicans, herons and ibises)

Cladogram based on Kuhl et al. (2020) and Stiller et al. (2024),^[2][10] with clade names following Sangster et al (2022).^[4]