Editing Quetzalcoatlus (section)

=== Other referred and reclassified material ===
[[File:Aff Quetzalcoatlus - Longrich et al 2018.PNG|left|thumb|FSAC-OB 14, a vertebra assigned to aff. ''Quetzalcoatlus'']]
Though most pterosaur remains from Big Bend have been referred to ''Quetzalcoatlus'', some other material exists. Most prominent amongst these is a specimen discovered around {{convert|380|m|ft}} north of the Pterodactyl Ridge localities, designated as TMM 42489-2 and compromising a partial skull and jaws as well as five articulated neck vertebrae. It was immediately noted for its distinct shorted-jawed anatomy compared to what had come to be expected from ''Q. lawsoni'' specimens.<ref name=brown2021/><ref name=andres2021/> Despite this distinctiveness, it was referred to as a separate ''Quetzalcoatlus sp.'' in a 1991 book by Langston. As early as 1996, however, this was revised with recognition it was certainly a new genus informally known as the "short-faced pterosaur". It was formally named in the 2021 paper alongside ''Q. lawsoni'', as the genus ''[[Wellnhopterus]]''. In addition to this specimen, several indeterminate azhdarchid remains and some remains too fragmentary to assign beyond [[Pterosauria]] are known from Big Bend. Some of these represent smaller animals than the uniformly sized ''Q. lawsoni'' remains. Whether any of these remains represented separate animals from ''Quetzalcoatlus'' cannot be determined.<ref name=andres2021/>
[[File:Cryodrakon_holotype_cervical_IV,_humerus,_pteroid,_and_tibia..jpg|thumb|Specimens of ''[[Cryodrakon]]'', once considered to represent ''Quetzalcoatlus'']]
Several specimens from across Late Cretaceous North America were historically referred to ''Quetzalcoatlus''.<ref name=thomas2025/> In 1982 a femur from the [[Campanian]] aged [[Dinosaur Park Formation]] of [[Alberta]], [[Canada]] was referred to the genus by [[Philip J. Currie]] and [[Dale Russell]].<ref name="Currie1982">{{cite journal |last1=Currie |first1=Philip J. |last2=Russell |first2=Dale A. |date=1982 |title=A giant pterosaur (Reptilia: Archosauria) from the Judith River (Oldman) Formation of Alberta |journal=Canadian Journal of Earth Sciences |volume=19 |issue=4 |pages=894–897 |bibcode=1982CaJES..19..894C |doi=10.1139/e82-074}}</ref><ref name=Currie2005>{{Cite book |last1=Currie |first1=Philip J. |author-link1=Philip J. Currie |url=https://archive.org/details/dinosaurprovinci0000unse/ |title=Dinosaur Provincial Park : a spectacular ancient ecosystem revealed |last2=Godfrey |first2=Stephen J. |date=2005 |publisher=Bloomington : Indiana University Press |isbn=978-0-253-34595-0 |editor-last=Currie |editor-first=Philip J. |chapter=Pterosaurs |editor-last2=Koppelhaus |editor-first2=Eva B.}}</ref><ref name=Hone2019>{{Cite journal |last1=Hone |first1=D. |last2=Habib |first2=M. |last3=Therrien |first3=F. |date=September 2019 |title=''Cryodrakon boreas'', gen. et sp. nov., a Late Cretaceous Canadian azhdarchid pterosaur |url=https://qmro.qmul.ac.uk/xmlui/handle/123456789/60704 |journal=Journal of Vertebrate Paleontology |volume=39 |issue=3 |pages=e1649681 |bibcode=2019JVPal..39E9681H |doi=10.1080/02724634.2019.1649681 |s2cid=203406859}}</ref> Currie later described further remains from Dinosaur Park in a 2005 book, noting their morphological similarity to ''Quetzalcoatlus'' but expressing caution against referral to the genus.<ref name=Currie2005/> In 2019, however, all azhdarchid remains from the formation were revised as distinct from ''Quetzalcoatlus'' and named as the new genus ''[[Cryodrakon]]''.<ref name=Hone2019/> A humerus from the [[Two Medicine Formation]] in [[Montana]] was also provisionally referred to the genus;<ref name=padian1992>{{cite journal | url=https://www.tandfonline.com/doi/abs/10.1080/02724634.1992.10011433 | title=New light on Late Cretaceous pterosaur material from Montana | journal=Journal of Vertebrate Paleontology | last1=Padian | first1=Kevin | last2=Smith | first2=Matt | year=1992 | volume=12 | issue=1 | pages=87–92 | doi=10.1080/02724634.1992.10011433}}</ref> it was considered an indeterminate azhdarchid or a specimen of ''[[Montanazhdarcho]]'' by subsequent studies.<ref>{{cite journal | author = Alexander Averianov | year = 2014 | title = Review of taxonomy, geographic distribution, and paleoenvironments of Azhdarchidae (Pterosauria) | doi = 10.3897/zookeys.432.7913 | journal =ZooKeys | issue = 432 | pages = 1–107 | pmid=25152671 | pmc=4141157| doi-access = free | bibcode = 2014ZooK..432....1A }}</ref><ref>{{Cite journal |last1=Starkey |first1=Rebecca |last2=Habib |first2=Michael |last3=Persons |first3=W. Scott |date=June 1, 2024 |title=A pteranodontid wing with traces of extensive invertebrate scavenging from the Pierre Shale (Sharon Springs Member, Campanian–Maastrichtian), east central Wyoming (Niobrara County) |url=https://www.sciencedirect.com/science/article/pii/S0195667124000107 |journal=Cretaceous Research |volume=158 |pages=105837 |doi=10.1016/j.cretres.2024.105837 |bibcode=2024CrRes.15805837S |issn=0195-6671}}</ref> A neck vertebra from the [[Hell Creek Formation]], also from Montana but dating to the [[Maastrichtian]], was discovered in 2002 and initially referred in 2006 to ''Quetzalcoatlus''.<ref name="henderson&peterson2006">{{cite journal|last1=Henderson|first1=Michael D.|last2=Peterson|first2=Joseph E.|title=An azhdarchid pterosaur cervical vertebra from the Hell Creek Formation (Maastrichtian) of southeastern Montana|journal=Journal of Vertebrate Paleontology|year=2006|volume=26|issue=1|pages=192–195|doi=10.1671/0272-4634(2006)26[192:AAPCVF]2.0.CO;2|s2cid=130751879|url=http://doc.rero.ch/record/15687/files/PAL_E2073.pdf}}</ref> The 2021 paper merely considered it an [[azhdarchoidea|azhdarchiform]] specimen of uncertain affinities, but the 2025 study named it as the holotype of a distinct genus ''[[Infernodrakon]]''.<ref name=andres2021/><ref name=thomas2025>{{Cite journal |last=Thomas |first=Henry N. |last2=Hone |first2=David W. E. |last3=Gomes |first3=Timothy |last4=Peterson |first4=Joseph E. |title=Infernodrakon hastacollis gen. et sp. nov., a new azhdarchid pterosaur from the Hell Creek Formation of Montana, and the pterosaur diversity of Maastrichtian North America |url=https://www.tandfonline.com/doi/full/10.1080/02724634.2024.2442476 |journal=Journal of Vertebrate Paleontology | year=2025 |volume=0 |issue=0 |pages=e2442476 |doi=10.1080/02724634.2024.2442476 |issn=0272-4634}}</ref>

Another neck vertebra, discovered in the similarly aged [[Lance Formation]] in [[Wyoming]] and first described in 1964, was later referred to ''Quetzalcoatlus'' by Brent H. Breithaupt in 1982; later studies referred it to ''[[Azhdarcho]]'' or as an indeterminate azhdarchid or azhdarchiform.<ref name=andres2021/><ref name=Breithaupt1982>{{cite journal | url=https://pubs.geoscienceworld.org/uwyo/rmg/article-abstract/21/2/123/110696/Paleontology-and-paleoecology-of-the-Lance | title=Paleontology and paleoecology of the Lance Formation (Maastrichtian), east flank of Rock Springs Uplift, Sweetwater County, Wyoming | journal=Rocky Mountain Geology | last1=Breithaupt | first1=Brent H. | year=1982 | volume=21 | issue=2 | pages=123–151}}</ref><ref name=thomas2025/> The 2025 ''Infernodrakon'' study found it to be distinguishable from taxon, but anatomically compatible with ''Q. lawsoni''; when tested in a phylogenetic analysis, they found it to form a [[polytomy]] with ''Q. lawsoni'', ''Q. northropi'', and a Moroccan specimen. Therefore, they considered it plausible it belonged to a small ''Q. lawsoni'' individually, but decided to merely make a tentative referral to ''Quetzalcoatlus'' at the genus level due to the incomplete nature of the specimen.<ref name=thomas2025/> The Moroccan specimen, from the [[Ouled Abdoun Basin]] (Maastrichtian), is designated as [[Hassan II University of Casablanca|FSAC]]-OB 14 and was referred to aff. ''Quetzalcoatlus'' by a 2018 study. This indicates it is considered unlikely to belong to the genus but bears extreme anatomical similarity to it.<ref name="longrich2018">{{cite journal|last1=Longrich|first1=Nicholas R.|last2=Martill|first2=David M.|last3=Andres|first3=Brian|last4=Penny|first4=David|title=Late Maastrichtian pterosaurs from North Africa and mass extinction of Pterosauria at the Cretaceous-Paleogene boundary|journal=PLOS Biology|year=2018|volume=16|issue=3|pages=e2001663|doi=10.1371/journal.pbio.2001663|pmid=29534059|pmc=5849296|doi-access=free}}</ref>