This mentioned taxonomy is an attempt to make an conclusive assignment from the different classifications of various scientists. Because the taxonomy may change due to the latest investigative methods and other findings, our map is a guide only.
G. Mayr, 2018 - First record of a tarsometatarsus of Tonsala hildegardae (Plotopteridae) and other avian remains from the late Eocene/early Oligocene of Washington State (USA) - Geobios (51), 51-59 (journal article, English)
G. Mayr, 2016 - New Late Eocene and Oligocene Remains of the Flightless, Penguin-Like Plotopterids (Aves, Plotopteridae) from Western Washington State, U.S.A. - Journal of Vertebrate Paleontology (36), e1163- (journal article, English)
G. Kaiser, 2015 - A new member of the family Plotopteridae (Aves) from the late Oligocene of British Columbia, Canada - Palaeontologia Electronica (18), 1-18 (journal article, English)
G. J. Dyke, 2011 - Fossil Plotopterid Seabirds from the Eo-Oligocene of the Olympic Peninsula (Washington State, USA): Descriptions and Functional Morphology - PLoS One (6), - (journal article, English)
K. Sakurai, 2008 - New penguin-like bird (Pelecaniformes; Plotopteridae) from the Late Oligocene Tokoro Formation, northeastern Hokkaido - Oryctos (7), 83-94 (journal article, English)
S. L. Olson, 1996 - A new genus and two new species of gigantic Plotopteridae from Japan (Aves: Pelecaniformes) - Journal of Vertebrate Paleontology (16), 742-751 (journal article, English)
S. L. Olson, 1980 - A new genus of penguin-like pelecaniform bird from the Oligocene of Washington (Pelecaniformes: Plotopteridae) - Natural History Museum of Los Angeles County, Contributions in Science (330), 51-57 (book/book chapter, English)