This order comprises the following four families:
Genus-level phylogeny of extant Bucerotiformes based on Gonzalez et al. (2013) and Tamashiro et al. (2019). The distribution of each family is indicated by the colour-code used throughout this website (see Distribution code).
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. (pdf)
Tamashiro RA, White NE, Braun MJ, Faircloth BC, Braun EL, and Kimball RE (2019), What are the roles of taxon sampling and model fit in tests of cyto-nuclear discordance using avian mitogenomic data?, Mol. Phylogenet. Evol. 130, 132-144. (abstract, open manuscript)
Writhed Hornbill, (Rhabdotorrhinus leucocephalus),
Rufous Hornbill (Buceros hydrocorax)