Two species are known and have been named Songzia heidangkouensis[1] and Songzia acutunguis.[2] The genus and family names for the type species were originally first published in a newsletter, and only subsequently in a scientific journal to fulfill the ICZN's requirements valid new scientific names. As such, they were considered nomina nuda until the journal article was published for validation of the taxonomic acts.[2] An additional fossil found in the Driftwood siteavifauna of the Eocene Okanagan Highlands was tentatively referred the to family,[3] as has a fossil from the PaleoceneMenat Formation[4]
^ abWang, M.; Mayr, G.; Zhang, J.; Zhou, Z. (2012). "Two New Skeletons of the Enigmatic, Rail-like Avian Taxon Songzia Hou, 1990 (Songziidae) from the Early Eocene of China". Alcheringa. 36 (4): 487–499. doi:10.1080/03115518.2012.673302. S2CID83880203.
^Mayr, G.; Archibald, S.B.; Kaiser, G.W.; Mathewes, R.W. (2019). "Early Eocene (Ypresian) birds from the Okanagan Highlands, British Columbia (Canada) and Washington State (USA)". Canadian Journal of Earth Sciences. 56 (8): 803–813. Bibcode:2019CaJES..56..803M. doi:10.1139/cjes-2018-0267. S2CID135271937.