The taxon comprises the following clades:

Family-level timetree of extant Aequornithes after Stiller et al. (2024), with the distribution of each family being indicated by the colour-code used throughout this website (Distribution code).

Family-level classification of extant Aequornithes.

References

Hackett SJ, Kimball RT, Reddy S, Bowie RCK, Braun EL, Braun MJ, Chojnowski JL, Cox WA, Han KL, Harshman J, Huddleston CJ, Marks BD, Miglia KJ, Moore WS, Sheldon FH, Steadman DW, Witt CC, and Yuri T (2008), A phylogenetic study of birds reveals their evolutionary history, Science 320, 1763-67. (abstract)

Jarvis ED et al. (2014), Whole-genome analysis resolve early branches in the tree of life of modern birds, Science 346, 1320-31. (pdf)

Kuhl H, Frankl-Vilches C, Bakker A, Mayr G, Nikolaus G, Boerne ST, Klages S, Timmermann B, and Gahr N (2021), An unbiased molecular approach using 3'UTRs resolves the avian family-tree of life. Mol. Biol. Evol. 38, 108-127. (free pdf)

Kuramoto T, Nishihara H, Watanabe M, and Okada N (2015) Determining the position of storks on the phylogenetic tree of waterbirds by retroposon insertion analysis, Genome Biol. Evol. 7, 3180-89. (pdf)

Prum RO, Berv JS, Dornburg A, Field DJ, Townsend JP, Lemmon EM, and Lemmon AR (2015), A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing, Nature 526, 569-573. (abstract)

Sangster G, and Mayr G (2021), Feraequornithes: a name for the clade formed by Procellariiformes, Sphenisciformes, Ciconiiformes, Suliformes, and Pelecaniformes (Aves), Vertebr. Zool. 71, 49-53. (pdf)

Stiller J, Feng S, Chowdhury AA, Rivas-González I, Duchêne DA, Fang Q, Deng Y, Kozlov A, Stamatakis A, Claramunt S, Nguyen JMT, Ho SYW, Faircloth BC, Haag J, Houde P, Cracraft J, Balaban M, Mai U, Chen G, Gao R, Zhou C, Xie Y, Huang Z, Cao Z, Yan Z, Ogilvie HA, Nakhleh L, Lindow B, Morel B, Fjeldså J, Hosner PA, da Fonseca RR, Petersen B, Tobias JA, Székely T, Kennedy JD, Reeve AH, Liker A, Stervander M, Antunes A, Tietze DT, Bertelsen M, Lei F, Rahbek C, Graves GR, Schierup MH, Warnow T, Braun EL, Gilbert MTP, Jarvis ED, Mirarab S, and Zhang G (2024), Complexity of avian evolution revealed by family-level genomes, Nature 629, 851-860. (pdf) 

Suh A, Smeds L, and Ellegren H (2015), The dynamics of incomplete lineage sorting across the ancient adaptive radiation of Neoavian birds, PLoS Biology 13: e:1002224. (pdf)

Wu S, Rheindt FE, Zhang J, Wang J, Zhang L, Quan C, Li Z, Wang M, Wu F, Qu Y, Edwards SV, Zhou Z, and Liu L (2024), Genomes, fossils, and the concurrent rise of modern birds and flowering plants in the Late Cretaceous, Proc. Natl. Acad. Sci. 121. (pdf)