The hylocitrea (Hylocitrea bonensis), also known as the yellow-flanked whistler or olive-flanked whistler, is a species of bird that is endemic to montane forests on the Indonesian island of Sulawesi.[3] It is monotypic within the genus Hylocitrea, and has traditionally been considered a member of the family Pachycephalidae, but recent genetic evidence suggests it should be placed in a monotypic subfamily of the family Bombycillidae,[4] or even its own family, Hylocitreidae.[1] A 2019 study[5] found it to be a sister group to a clade containing the hypocolius (Hypocoliidae) and the extinct Hawaiian honeyeaters (Mohoidae), with the clade containing all three being a sister group to the silky-flycatchers (Ptiliogonatidae). The divergences forming these families occurred in the early Miocene, about 20-23 million years ago.[5][6]
^ abGill, F; D Donsker, eds. (2011). "Waxwings to Swallows". IOC World Bird Names (version 2.9). Archived from the original on July 24, 2011. Retrieved 17 August 2011.