Some authorities have advocated a complete merger of the genus Ixos with Hypsipetes – and even the entire "Hypsipetes group" of bulbuls, which also includes Hemixos, Iole and Tricholestes. Being the oldest genus name, Ixos would apply to all of them, rather than Hypsipetes as is often believed.[3] This re-classification seems hardly appropriate however, since Alophoixus and Setornis cannot be excluded from the "Hypsipetes group", and an all-out merge would turn the resultant "genus" Ixos into an ill-defined "wastebin taxon". The erroneous inclusion of I. virescens in Hypsipetes has caused the Nicobar bulbul to be listed under its invalid junior synonymH. nicobariensis rather than the valid names H. virescens or I. nicobariensis.[3]
Extant species
There are five extant species in the genus Ixos:[4]
^Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 209. ISBN978-1-4081-2501-4.
^ abGregory (2000), Pasquet et al. (2001), Moyle & Marks (2006)
^ abGill, Frank; Donsker, David; Rasmussen, Pamela, eds. (August 2024). "Bulbuls". IOC World Bird List Version 14.2. International Ornithologists' Union. Retrieved 5 September 2024.
Gregory, Steven M. (2000): Nomenclature of the Hypsipetes Bulbuls (Pycnonotidae). Forktail16: 164–166. PDF fulltext
Moyle, Robert G. & Marks, Ben D. (2006): Phylogenetic relationships of the bulbuls (Aves: Pycnonotidae) based on mitochondrial and nuclear DNA sequence data. Mol. Phylogenet. Evol.40(3): 687–695. doi:10.1016/j.ympev.2006.04.015 (HTML abstract)
Pasquet, Éric; Han, Lian-Xian; Khobkhet, Obhas & Cibois, Alice (2001): Towards a molecular systematics of the genus Criniger, and a preliminary phylogeny of the bulbuls (Aves, Passeriformes, Pycnonotidae). Zoosystema23(4): 857–863. PDF fulltext