Neognathae is an infraclass of birds, called neognaths, within the class Aves of the clade Archosauria. Neognathae includes the majority of living birds; the exceptions being the tinamous and the flightless ratites, which belong instead to the sister taxon Palaeognathae. There are nearly 10,000 living species of neognaths.
The Phaethontiformes are an order of birds. They contain one extant family, the tropicbirds (Phaethontidae), and one extinct family Prophaethontidae from the early Cenozoic. Several fossil genera have been described, with well-preserved fossils known as early as the Paleocene. The group's origins may lie even earlier if the enigmatic waterbird Novacaesareala from the latest Cretaceous or earliest Paleocene of New Jersey is considered a tropicbird.
Neoaves is a clade that consists of all modern birds with the exception of Palaeognathae and Galloanserae. This group is defined in the PhyloCode by George Sangster and colleagues in 2022 as "the most inclusive crown clade containing Passer domesticus, but not Gallus gallus". Almost 95% of the roughly 10,000 known species of extant birds belong to the Neoaves.
Mirandornithes is a clade that consists of flamingos and grebes. Many scholars use the term Phoenicopterimorphae for the superorder containing flamingoes and grebes.
Aequornithes, or core water birds, are defined in the PhyloCode as "the least inclusive crown clade containing Pelecanus onocrotalus and Gavia immer".
Psittacopasseres is a taxon of birds consisting of the Passeriformes and Psittaciformes (parrots). Per Ericson and colleagues, in analysing genomic DNA, revealed a lineage comprising passerines, psittacines and Falconiformes. The group was proposed following an alignment of nuclear intron sequences by Shannon Hackett et al. in 2008. It was formally named as Psittacopasserae in a 2011 Nature Communications article by Alexander Suh and other authors working with Jürgen Schmitz's group, based on genetic analysis of the insertion of retroposons into the genomes of key avian lineages over the course of evolution during the Mesozoic Era. This clade was defined in the PhyloCode by George Sangster and colleagues in 2022 as the least inclusive crown clade containing Psittacus erithacus and Passer domesticus.
Australaves is a clade of birds, defined in 2012, consisting of the Eufalconimorphae as well as the Cariamiformes. They appear to be the sister group of Afroaves. This clade was defined in the PhyloCode by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing Cariama cristata and Passer domesticus".
Afroaves is a clade of birds, consisting of the kingfishers and kin (Coraciiformes), woodpeckers and kin (Piciformes), hornbills and kin (Bucerotiformes), trogons (Trogoniformes), cuckoo roller (Leptosomiformes), mousebirds (Coliiformes), owls (Strigiformes), raptors (Accipitriformes) and New World vultures (Cathartiformes). The most basal clades are predatory, suggesting the last common ancestor of Afroaves was also a predatory bird. This group was defined in the PhyloCode by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing Accipiter nisus, Colius colius, and Picus viridis, but not Passer domesticus".
Telluraves is a recently defined clade of birds defined by their arboreality. Based on most recent genetic studies, the clade unites a variety of bird groups, including the australavians as well as the afroavians. This grouping was defined in the PhyloCode by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing Accipiter nisus and Passer domesticus". They appear to be the sister group of the Phaethoquornithes.
Otidimorphae is a clade of birds that contains the orders Cuculiformes (cuckoos), Musophagiformes (turacos), and Otidiformes (bustards) identified in 2014 by genome analysis. George Sangster and colleagues in 2022 named the clade uniting turacos and bustards as Musophagotides, defining it in the PhyloCode as "the least inclusive crown clade containing Otis tarda and Musophaga violacea, but not Grus grus or Mesitornis variegatus".
Phaethoquornithes is a clade of birds that contains Eurypygimorphae and Aequornithes, which was first recovered by genome analysis in 2014. Members of Eurypygimorphae were originally classified in the obsolete group Metaves, and Aequornithes were classified as the sister taxon to Musophagiformes or Gruiformes.
Coraciimorphae is a clade of birds that contains the order Coliiformes (mousebirds) and the clade Cavitaves. The name however was coined in the 1990s by Sibley and Ahlquist based on their DNA-DNA hybridization studies conducted in the late 1970s and throughout the 1980s. However their Coraciimorphae only contains Trogoniformes and Coraciiformes. Coraciimorphae was defined in the PhyloCode by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing Colius colius and Picus viridis, but not Accipiter nisus or Passer domesticus".
Eucavitaves is a clade that contains the order Trogoniformes (trogons) and the clade Picocoraciae. The group was defined in the PhyloCode by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing Trogon viridis and Picus viridis". The name refers to the fact that the majority of them nest in cavities.
Cavitaves is a clade that contains the order Leptosomiformes and the clade Eucavitaves. This group was defined in the PhyloCode by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing Leptosomus discolor and Picus viridis". The name refers to the fact that the majority of them nest in cavities.
Picocoraciae is a clade that contains the order Bucerotiformes and the clade Picodynastornithes supported by various genetic analysis and morphological studies. While these studies supported a sister grouping of Coraciiformes and Piciformes, a large scale, sparse supermatrix has suggested alternative sister relationship between Bucerotiformes and Piciformes instead. This group was defined in the PhyloCode by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing Buceros rhinoceros, Coracias garrulus, and Picus viridis".
Columbimorphae is a clade/superorder discovered by genome analysis that includes birds of the orders Columbiformes, Pterocliformes (sandgrouse), and Mesitornithiformes (mesites). This group was defined in the PhyloCode by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing Columba oenas, Mesitornis variegatus, and Pterocles alchata". Previous analyses had also recovered this grouping, although the exact relationships differed. Some studies indicated a sister relationship between sandgrouse and pigeons while other studies favored a sister grouping of mesites and sandgrouse instead. This sister relationship of the sandgrouses and mesites was named by George Sangster and colleagues in 2022 as the clade Pteroclimesites and defined in the PhyloCode as "the least inclusive crown clade containing Mesitornis variegatus and Pterocles alchata".
Picodynastornithes is a clade that contains the orders Coraciiformes and Piciformes. This grouping also has current and historical support from molecular and morphological studies. This group was defined in the PhyloCode by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing Coracias garrulus, Alcedo atthis, and Picus viridis".
Notopalaeognathae is a clade that contains the order Rheiformes (rheas), the clade Novaeratitae, and the clade Dinocrypturi. Notopalaeognathae was named by Yuri et al. (2013) and defined in the PhyloCode by Sangster et al. (2022) as "the least inclusive crown clade containing Rhea americana, Tinamus major, and Apteryx australis". The exact relationships of this group, including its recently extinct members, have only recently been uncovered. The two lineages endemic to New Zealand, the kiwis and the extinct moas, are not each other's closest relatives: the moas are most closely related to the Neotropical tinamous, and the kiwis are sister to the extinct elephant birds of Madagascar, with kiwis and elephant birds together sister to the cassowaries and emu of New Guinea and Australia. The South American rheas are either sister to all other notopalaeognaths or sister to Novaeratitae. The sister group to Notopalaeognathae is Struthionidae.
Novaeratitae is a proposed clade that was originally defined to contain the recent common ancestors of the orders Casuariiformes and Apterygiformes (kiwis). This clade was named by Yuri et al. (2013) and phylogenetically defined in the PhyloCode by Sangster et al. (2022) as "the least inclusive crown clade containing Apteryx australis and Casuarius casuarius". Recently it has been determined that the elephant birds of the extinct order Aepyornithiformes were the closest relatives of the kiwis, and therefore are part of this group. The implication is that ratites had lost flight independently in each group, as the elephant birds are the only novaeratites found outside Oceania. This clade has been contested by other studies, which find the relationships between the four main clades of non-ostrich palaeognaths to be an unresolved polytomy, with only slightly more genetic support for Novaeritiae over alternative proposals.
Pelecanimorphae is a clade of aequornithean birds that comprises the orders Ciconiiformes, Suliformes and Pelecaniformes. In the past the name has been used as a homonym for Pelecaniformes. Pelecanimorphae is defined in the PhyloCode by George Sangster and colleagues in 2022 as "the least inclusive clade containing Pelecanus onocrotalus, Sula leucogaster, and Ciconia ciconia". The less inclusive clade Pelecanes was named by Sangster et al, 2022 to unite Pelecaniformes and Suliformes and defined in the PhyloCode as the "least inclusive crown clade containing Pelecanus onocrotalus and Sula leucogaster".
