Eastern striated pardalote, Pardalotus striatus ornatus. Their molecular and morphological plesiomorphy has long misled researchers about the pardalotes' affiliations.
The Sibley-Ahlquist taxonomy controversially redefines the families Acanthizidae (spinebills) and Dasyornithidae (bristlebirds) as subfamilies within the larger family Pardalotidae (pardalotes). However, later work indicated that the Pardalotidae are more closely related to the Meliphagidae (honeyeaters) and could be considered a subfamily within them. The Acanthizidae have also been traditionally considered aberrant honeyeaters, and could also be considered a subfamily of Meliphagidae; however, they seem to be very ancient members of Meliphagoidea and if the pardalotes are separated as a distinct family apart from Meliphagidae, the spinebills might be split off too. But some ornithologists maintain that separating the spinebills and pardalotes into separate families would mean creating two monotypic families with a mere six species in total, and so keeping the spinebills within the Meliphagidae and possibly merging the pardalotes therein as well seems to be a more sensible course of action.[3]
The Sibley-Ahlquist taxonomy also placed the Petroicidae (Australasian "robins") in the Meliphagoidea. This is now no longer favoured; as more recent work show that they form a distinct lineage of uncertain relationships; all that can be said at present with reasonable certainty is that the Petroicidae are neither Passerida ("advanced" songbirds) nor a very ancient songbird group.[3]
References
^Barker, F. Keith; Barrowclough, George F. & Groth, Jeff G. (2002): A phylogenetic hypothesis for passerine birds: taxonomic and biogeographic implications of an analysis of nuclear DNA sequence data. Proceedings of the Royal Society B269 (1488): 295–308. doi:10.1098/rspb.2001.1883PDF fulltext
Ford, H.A. (2001). "Family Meliphagidae honeyeaters and Australian chats"(PDF). In Higgins, Peter J.; Peter, Jeffrey M.; Steele, W.K. (eds.). Handbook of Australian, New Zealand and Antarctic Birds. Volume 5: Tyrant-flycatchers to Chats. Melbourne: Oxford University Press. pp. 457–461. ISBN0-19-553258-9.