P. recurvirostra is known from a partial wing (KUVP 10105) found in the Colton Formation, from the Late PaleocenetoEarly Eocene sediments of the Wasatch Plateau near Ephraim, Utah.[2]P. isoni, much larger than P. pervetus, is known from the Late PaleoceneAquia FormationinMaryland, based on the partial humerus (USNM 294116) and partial fingerbone (USNM 294117) that were initially described, as well as a complete humerus (SMM P96.9.2).[11][2] Three humeri that were initially believed to be from Headonornis are suggested to belong to P. isoni, and the holotype coracoidofHeadonornis may also be assigned to as P. isoni, though these claims require additional material for confirmation.[12][3] However, Headonornis is now referred to as a stem group representative of the Phoenicopteriformes.[13]
The holotype and paratypes of "P." mongoliensis are known from the Early EoceneofMongolia,[4] but these fragmentary specimens are poorly preserved and they likely belong to a stem Phoenicopterimorphae, not a presbyornithid.[9] Undescribed fossils are also known from the Paleocene of Utah.[3]Wunketru howardae, previously thought to be a species of Telmabates or a junior synonym of P. pervetus, is now considered a distinct anseriform.[14]
Along with Teviornis, Presbyornis was one of the earliest stem anseriforms.[3] Because of its long legs and neck, Presbyornis could stand up to 1 metre (3.3 ft) tall and was initially mistaken for a flamingo, but it was reclassified as an anseriform when the duck-like anatomy of its skull and bill was found.[15] Later, it was believed to represent a transitional stage between the anseriforms and the shorebirds, but it is now considered a member of an extinct group of anseriforms which was most closely related to modern screamers. Judging from numerous fossil findings, Presbyornis is presumed to have lived in colonies around shallow lakes.[2] Its broad, flat bill was used to filter food (small plants and animals) from the water, in the manner of today's dabbling ducks.[15]
^This species was first described as Coltonia recurvirostra by John William Hardy in 1959.[1] Ericson (2000) reclassified it as a species of Presbyornis by the name P. recurvirostrus,[2] and this species was also referred to as P. recurvirostris by Kurochkin, Dyke & Karhu (2002)[3] and Kurochkin & Dyke (2010).[4] However, since recurvirostra is a noun in apposition, combining the Latinrecurvus meaning 'bent' or 'curved backwards' with rostrum meaning 'bill',[5] the original spelling is to be maintained regardless of the change in generic gender, as noted by ICZN Article 31.2.1.[6] Thus, P. recurvirostra is the correct spelling, as used by De Pietri et al. (2016)[7] and Worthy et al. (2023).[8]
^ abKurochkin, Evgeney N.; Dyke, Gareth J. (2010). "A Large Collection of Presbyornis (Aves, Anseriformes, Presbyornithidae) from the Late Paleocene and Early Eocene of Mongolia". Geological Journal. 45 (4): 375–387. Bibcode:2010GeolJ..45..375K. doi:10.1002/gj.1177. S2CID140588679.
^Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 331. ISBN978-1-4081-2501-4.
^"Article 31. Species-group names". Retrieved May 29, 2024. A species-group name that is a simple or compound noun (or noun phrase) in apposition need not agree in gender with the generic name with which it is combined (the original spelling is to be retained, with gender ending unchanged; see Article 34.2.1).
^Olson, S. (1994). "A giant Presbyornis (Aves: Anseriformes) and other birds from the Paleocene Aquia Formation of Maryland and Virginia". Proceedings of the Biological Society of Washington. 107: 429–435. hdl:10088/6493.
^ abPalmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 181. ISBN1-84028-152-9.
Dyke, Gareth J. (2001): The Fossil Waterfowl (Aves: Anseriformes) from the Eocene of England. American Museum Novitates3354: 1–15. PDF fulltext
Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 181. ISBN1-84028-152-9.
Wetmore, Alexander (1926): Fossil birds from the Green River Deposits of Eastern Utah. Annals of the Carnegie Museum16: 391–402.
