This order (formerly considered a subset of Pelecaniformes) comprises four families:
Mixed species-level and genus-level timetree of extant Suliformes based on Patterson et al. (2011), Kennedy & Spencer (2014), Kennedy et al. (2018), Kennedy et al. (2019), and Kennedy et al. (2023). The distribution of each taxon is indicated by the colour-code used throughout this website (Distribution code). Note, however, that the divergence times among species of the genus Fregata have not been studied yet.
References
Baiao PC, and P.G. Parker (2012), Evolution of the melanocortin-1 receptor (MCIR) in Boobies and Gannets (Aves: Suliformes), J. Hered. 103, 322-329. (pdf)
Gibb GC, Kennedy M, and Penny D (2013), Beyond phylogeny: pelecaniform and ciconiiform birds, and long-term niche stability, Mol. Phylogenet. Evol. 68, 229-238. (abstract)
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)
Hughes J, Kennedy M, Johnson KP, Palma RL, and Page RDM (2007), Multiple cophylogenetic analyses reveal frequent cospeciation between pelecaniform birds and Pectinopygus lice, Syst. Biol. 56, 232-251. (free pdf)
Kennedy M, and Spencer HG (2004), Phylogenies of the Frigatebirds (Fregatidae) and Tropicbirds (Phaethontidae), two divergent groups of the traditional order Pelecaniformes, inferred from mitochondrial DNA sequences, Mol. Phylogenet. Evol. 31, 31-38. (abstract)
Kennedy M, and Spencer HG (2014), Classification of the cormorants of the world, Mol. Phylogenet. Evol. 79, 249-257. (abstract)
Kennedy M, Seneviratne SS, Rawlence NJ, Ratnajake S, and Spencer HG (2019), The phylogenetic placement of the enigmatic Indian Cormorant, Phalacrocorax fuscicollis (Phalacrocoracidae), Mol. Phylogenet. Evol. 130, 227-232. (abstract)
Kennedy M, Seneviratne SS, Mendis UK, and Spencer HG (2019), Sorting out the Snakebirds: the species status, phylogeny and biogeography of the Darters (Aves: Anhingidae), J. Zool. Syst. Evol. Res. 57, 892-899. (abstract)
Kennedy M, Salis AT, Seneviratne SS, Rathnayake D, Nupen LJ, Ryan PG, Volponi S, Lubbe P, Rawlence NJ, and Spencer HG (2023), Phylogeny of the microcormorants, with description of a new genus, Zool. J. Linn. Soc. 199, 310-317. (free pdf)
Kuhl H, Frankl-Vilches C, Bakker A, Mayr G, Nikolaus G, Boerno ST, Klages S, Timmermann B, and Gahr M (2021), An unbiased molecular approach using 3'UTRs resolves the avian family-level tree of life, Mol. Biol. Evol. 38, 108-127. (free pdf)
Patterson SA, Morris-Pocock JA, and Friesen VL (2011), A multilocus phylogeny of the Sulidae (Aves: Pelecaniformes), Mol. Phylogenet. Evol. 58, 181-191. (abstract)
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, 569-57. (abstract)