Neoavesis acladethat consists of all modernbirds(Neornithes or Aves) with the exception ofPalaeognathae(ratites and kin) andGalloanserae(ducks, chickens and kin).[4]This group is defined in thePhyloCodeby George Sangster and colleagues in 2022 as "the most inclusive crown clade containingPasser domesticus,but notGallus gallus".[5]Almost 95% of the roughly 10,000 known species of extant birds belong to the Neoaves.[6]
The early diversification of the various neoavian groups occurred very rapidly around theCretaceous–Paleogene extinction event,[7][8]and attempts to resolve their relationships with each other have resulted initially in much controversy.[9][10]
The early diversification of the various neoavian groups occurred very rapidly around theCretaceous–Paleogene extinction event.[11]As a result of the rapid radiation, attempts to resolve their relationships have produced conflicting results, some quite controversial, especially in the earlier studies.[12][13][14]Nevertheless, some recent large phylogenomic studies of Neoaves have led to much progress on defining orders and supraordinal groups within Neoaves. Still, the studies have failed to produce to a consensus on an overall high order topology of these groups.[15][16][17][14]A genomic study of 48 taxa by Jarviset al.(2014) divided Neoaves into two main clades,ColumbeaandPasserea,but an analysis of 198 taxa by Prumet al.(2015) recovered different groupings for the earliest split in Neoaves.[15][16]A reanalysis with an extended dataset by Reddyet al.(2017) suggested this was due to the type of sequence data, with coding sequences favouring the Prum topology.[17]The disagreement on topology even with large phylogenomic studies led Suh (2016) to propose ahard polytomyof nine clades as the base of Neoaves.[18]An analysis by Houdeet al.(2019) recovered Columbea and a reduced hard polytomy of six clades within Passerea.[19]
Despite other disagreements, these studies do agree on a number of supraorderal groups, which Reddyet al.(2017) dubbed the "magnificent seven", which together with three "orphaned orders" make up Neoaves.[17]Significantly, they both include a large waterbird clade (Aequornithes) and a large landbird clade (Telluraves). The groups defined by Reddyet al.(2017) are as follows:
^abBraun, Edward L.; Cracraft, Joel; Houde, Peter (2019). "Resolving the Avian Tree of Life from Top to Bottom: The Promise and Potential Boundaries of the Phylogenomic Era".Avian Genomics in Ecology and Evolution.pp. 151–210.doi:10.1007/978-3-030-16477-5_6.ISBN978-3-030-16476-8.S2CID198399272.