The genus was first recognized by [[John Gould]] in 1846. Field researchResearch by Karl-L. Schuchmann published in 2016, however, found notable differences between some populations traditionally assigned to ''O. underwoodii'', and recommended that three [[allopatric]] [[subspecies]] groups, ''addae'', ''annae'' and ''peruanus'', should be raised to species level.<ref>{{cite journal | title=Biogeography and taxonomy of racket-tail hummingbirds (Aves: Trochilidae: Ocreatus): Evidence for species delimitation from morphology and display behavior | journal=Zootaxa | volume=4200 | issue=1 | pages=83 | doi= 10.11646/zootaxa.4200.1.3 | pmid=27988640 | url= https://www.researchgate.net/publication/311004563| year=2016 | last1=Schuchmann | first1=Karl-L. | last2=Weller | first2=André-A. | last3=Jürgens | first3=Dietmar }}</ref> The research results have been mostly accepted by the [[International Ornithological Union]], with more data required for the species status of Anna's racket-tail (''annae''), which they instead regard as a subspecies of ''O. addae''.<ref>{{cite web | url=http://www.worldbirdnames.org/updates/proposed-splits/ | title=Proposed Splits/Lumps « IOC World Bird List}}</ref> The [[American Ornithological Society]] has yet to recognize the split.
