 The type species of the genus is the Ascension frigatebird (Fregata aquila). For many years, the consensus was to recognise only two species of frigatebird, with larger birds as F. aquila and smaller as F. ariel. In 1914 the Australian ornithologist Gregory Mathews delineated five species, which remain valid. Analysis of ribosomal and mitochondrial DNA indicated that the five species had diverged from a common ancestor only recently — as little as 1.5 million years ago. There are two species pairs, the great and Christmas Island frigatebirds, and the magnificent and Ascension frigatebirds, while the fifth species, the lesser frigatebird, is an early offshoot of the common ancestor of the other four species. Three subspecies of the lesser and five subspecies of the great frigatebird are recognised.
