P. recurvirostra is known from a partial wing (KUVP 10105) found in theColton Formation, from theLate Paleocene toEarly Eocene sediments of theWasatch Plateau near Ephraim,Utah.[2]P. isoni, much larger thanP. pervetus, is known from the LatePaleoceneAquia Formation inMaryland, 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 fromHeadonornis are suggested to belong toP. isoni, and the holotypecoracoid ofHeadonornis may also be assigned to asP. isoni, though these claims require additional material for confirmation.[12][3] However,Headonornis is now referred to as a stem group representative of thePhoenicopteriformes.[13]
The holotype and paratypes of "P."mongoliensis are known from theEarly Eocene ofMongolia,[4] but these fragmentary specimens are poorly preserved and they likely belong to a stemPhoenicopterimorphae, not a presbyornithid.[9] Undescribed fossils are also known from the Paleocene ofUtah.[3]Wunketru howardae, previously thought to be a species ofTelmabates or a junior synonym ofP. pervetus, is now considered a distinctanseriform.[14]
Along withTeviornis,Presbyornis was one of the earlieststem 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 aflamingo, but it was reclassified as an anseriform when theduck-like anatomy of itsskull andbill was found.[15] Later, it was believed to represent a transitional stage between the anseriforms and theshorebirds, but it is now considered a member of anextinct group of anseriforms which was most closely related to modernscreamers. Judging from numerousfossil 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'sdabbling ducks.[15]
^This species was first described asColtonia recurvirostra by John William Hardy in 1959.[1] Ericson (2000) reclassified it as a species ofPresbyornis by the nameP. recurvirostrus,[2] and this species was also referred to asP. recurvirostris by Kurochkin, Dyke & Karhu (2002)[3] and Kurochkin & Dyke (2010).[4] However, sincerecurvirostra is a noun in apposition, combining theLatinrecurvus meaning 'bent' or 'curved backwards' withrostrum 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 ofPresbyornis (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". RetrievedMay 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 giantPresbyornis (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.
