Editing Pteranodon (section)

==Classification==

===Timespan and evolution===
[[File:Pteranodon longiceps launch.jpg|thumb|Skeleton of ''P. longiceps'', in launch pose, [[Telus World of Science, Vancouver]]]]
''Pteranodon'' fossils are known primarily from the [[Niobrara Formation]] of the central United States. Broadly defined, ''Pteranodon'' existed for more than four million years, during the [[Santonian]] stage of the [[Cretaceous]] period.<ref name=bennett1994>{{Cite journal | author = Bennett, S.C. | year = 1994 | title = Taxonomy and systematics of the Late Cretaceous pterosaur ''Pteranodon'' (Pterosauria, Pterodactyloida) | journal = Occasional Papers of the Natural History Museum, University of Kansas | volume = 169 | pages = 1–70}}</ref> The genus is present in most layers of the Niobrara Formation except for the upper two; in 2003, [[Kenneth Carpenter]] surveyed the distribution and dating of fossils in this formation, demonstrating that ''Pteranodon sternbergi'' existed there from 88 to 85 million years ago, while ''P. longiceps'' existed between 86 and 84.5 million years ago. A possible third species, which Kellner named ''[[Geosternbergia|Geosternbergia maiseyi]]'' in 2010, is known from the Sharon Springs member of the [[Pierre Shale Formation]] in Kansas, [[Wyoming]], and [[South Dakota]], dating to between 81.5 and 80.5 million years ago.<ref name=carpenter2003>{{cite journal | last1 = Carpenter | first1 = K | year = 2003 | title = Vertebrate Biostratigraphy of the Smoky Hill Chalk (Niobrara Formation) and the Sharon Springs Member (Pierre Shale) | journal = High-Resolution Approaches in Stratigraphic Paleontology | volume = 21 | pages = 421–437 | doi = 10.1007/978-1-4020-9053-0 | series = Topics in Geobiology | isbn = 978-1-4020-1443-7}}</ref>

In the early 1990s, Bennett noted that the two major [[Polymorphism (biology)|morphs]] of pteranodont present in the Niobrara Formation were precisely separated in time with little, if any, overlap. Due to this, and to their gross overall similarity, he suggested that they probably represent [[chronospecies]] within a single evolutionary lineage lasting about 4 million years. In other words, only one species of ''Pteranodon'' would have been present at any one time, and ''P. sternbergi'' (or ''Geosternbergia'') in all likelihood was the direct ancestor species of ''P. longiceps''.<ref name=bennett1994niobrara/>

===Valid species===
Many researchers consider there to be at least two species of ''Pteranodon''. However, aside from the differences between males and females described above, the post-cranial skeletons of ''Pteranodon'' show little to no variation between species or specimens, and the bodies and wings of all pteranodonts were essentially identical.<ref name=bennett1994/>

Two species of ''Pteranodon'' are traditionally recognized as valid: ''Pteranodon longiceps'', the [[type species]], and ''Pteranodon sternbergi''. The species differ only in the shape of the crest in adult males (described above), and possibly in the angle of certain skull bones.<ref name=bennett1994/> Because well-preserved ''Pteranodon'' skull fossils are extremely rare, researchers use stratigraphy (i.e. which rock layer of the geologic formation a fossil is found in) to determine species identity in most cases.

''Pteranodon sternbergi'' is the only known species of ''Pteranodon'' with an upright crest. The lower jaw of ''P. sternbergi'' was {{convert|1.25|m|ft|sp=us}} long.<ref name="BTD">Zimmerman, H., Preiss, B., and Sovak, J. (2001). ''Beyond the Dinosaurs!: sky dragons, sea monsters, mega-mammals, and other prehistoric beasts'', Simon and Schuster. {{ISBN|0-689-84113-2}}.</ref> It was collected by [[George F. Sternberg]] in 1952 and described by John Christian Harksen in 1966, from the lower portion of the Niobrara Formation. It was older than ''P. longiceps'' and is considered by Bennett to be the direct ancestor of the later species.<ref name=bennett1994/>

Because fossils identifiable as ''P. sternbergi'' are found exclusively in the lower layers of the Niobrara Formation, and ''P. longiceps'' fossils exclusively in the upper layers, a fossil lacking the skull can be identified based on its position in the geologic column (though for many early fossil finds, precise data about its location was not recorded, rendering many fossils unidentifiable).<ref name=kellner2010/>
[[Image:Pteranodonts.png|thumb|350px|Variation in cranial anatomy and classification of specimens assigned to ''Pteranodon'' (drawn to scale, unpreserved portions shown in gray)]]
Below is a [[cladogram]] showing the phylogenetic placement of this genus within Pteranodontia from Andres and Myers (2013).<ref name=LoneStarPterosaurs>{{Cite journal | last1 = Andres | first1 = B. | last2 = Myers | first2 = T. S. | doi = 10.1017/S1755691013000303 | title = Lone Star Pterosaurs | journal = Earth and Environmental Science Transactions of the Royal Society of Edinburgh | pages = 383–398 | year = 2013 | volume=103 | issue = 3–4| s2cid = 84617119 }}</ref>
{{clade| style=font-size:85%;line-height:85%
|label1=[[Pteranodontia]]
|1={{clade
         |label1=[[Nyctosauridae]]
         |1={{clade
            |1=''[[Muzquizopteryx coahuilensis]]''
            |2=''[[Nyctosaurus lamegoi|"Nyctosaurus" lamegoi]]''
            |3=''[[Nyctosaurus gracilis]]''}}
         |2={{clade
            |1=''[[Alamodactylus byrdi]]''
            |label2=[[Pteranodontoidea]]
            |2={{clade
               |1={{clade
                  |1='''''Pteranodon longiceps'''''
                  |2=''[[Pteranodon sternbergi]]''}}
               |2={{clade
                  |label1=[[Istiodactylidae]]
                  |1={{clade
                     |1=''[[Longchengpterus zhaoi]]''
                     |2={{clade
                        |1=''[[Nurhachius ignaciobritoi]]''
                        |2={{clade
                           |1=''[[Liaoxipterus brachyognathus]]''
                           |2={{clade
                              |1=''[[Istiodactylus latidens]]''
                              |2=''[[Istiodactylus sinensis]]''}} }} }} }}
                  |2={{clade
                     |1=''[[Lonchodectes compressirostris]]''
                     |2={{clade
                        |1=''[[Aetodactylus halli]]''
                        |2={{clade
                           |1=''[[Cearadactylus atrox]]''
                           |2={{clade
                              |1=''[[Brasileodactylus araripensis]]''
                              |2={{clade
                                 |1=''[[Ludodactylus sibbicki]]''
                                 |2=[[Ornithocheirae]]
                                 }} }} }} }} }} }} }} }} }} }}
===Alternative classifications===
[[File:Old Pteranodon mount.jpg|thumb|left|''P. occidentalis'' mount wherein arms, shoulder girdle, and fingers are actual bones, and the rest has been drawn from other specimens.]]
Due to the subtle variations between specimens of pteranodontid from the Niobrara Formation, most researchers have assigned all of them to the single genus ''Pteranodon'', in at least two species (''P. longiceps'' and ''P. sternbergi'') distinguished mainly by the shape of the crest. However, the classification of these two forms has varied from researcher to researcher. In 1972, Halsey Wilkinson Miller published a paper arguing that the various forms of ''Pteranodon'' were different enough to be placed in distinct subgenera. He named these ''Pteranodon (Occidentalia) occidentalis'' (for the now-disused species ''P. occidentalis'') and ''Pteranodon (Sternbergia) sternbergi''. However, the name ''Sternbergia'' was preoccupied, and in 1978 Miller re-named the species ''Pteranodon (Geosternbergia) sternbergi'', and named a third subgenus/species combination for ''P. longiceps'', as ''Pteranodon (Longicepia) longiceps''. Most prominent pterosaur researchers of the late 20th century however, including S. Christopher Bennett and [[Peter Wellnhofer]], did not adopt these subgeneric names, and continued to place all pteranodont species into the single genus ''Pteranodon''.

In 2010, pterosaur researcher [[Alexander Kellner]] revisited H.W. Miller's classification. Kellner followed Miller's opinion that the differences between the ''Pteranodon'' species were great enough to place them into different genera. He placed ''P. sternbergi'' into the genus named by Miller, ''Geosternbergia'', along with the Pierre Shale skull specimen which Bennett had previously considered to be a large male ''P. longiceps''. Kellner argued that this specimen's crest, though incompletely preserved, was most similar to ''Geosternbergia''. Because the specimen was millions of years younger than any known ''Geosternbergia'', he assigned it to the new species ''[[Pteranodon sternbergi|Geosternbergia maiseyi]]''. Numerous other pteranodont specimens are known from the same formation and time period, and Kellner suggested they may belong to the same species as ''[[Pteranodon sternbergi|G. maiseyi]]'', but because they lack skulls, he could not confidently identify them.<ref name=kellner2010/> However, both species previously referred to ''Geosternbergia'' were separately included as those of ''Pteranodon'' (''P. sternbergi'' and ''P. maiseyi'') based on phylogenetic analysis in 2024.<ref>{{Cite journal |last1=Pêgas |first1=Rodrigo V. |date=2024-06-10 |title=A taxonomic note on the tapejarid pterosaurs from the Pterosaur Graveyard site (Caiuá Group, ?Early Cretaceous of Southern Brazil): evidence for the presence of two species |journal=[[Historical Biology]] |language=en |pages=1–22 |url=https://www.researchgate.net/publication/381306918 |doi=10.1080/08912963.2024.2355664 |issn=0891-2963}}</ref>

===Disused species===
[[File:Williston Pteranodon.jpg|thumb|left|S.W. Williston's reconstruction of ''Ornithostoma ingens'', a synonym of ''P. longiceps'']]

A number of additional species of ''Pteranodon'' have been named since the 1870s, although most now are considered to be junior synonyms of two or three valid species. The best-supported is the [[type species]], ''P. longiceps'', based on the well-preserved specimen including the first-known skull found by S. W. Williston. This individual had a wingspan of {{convert|7|m|ft|sp=us}}.<ref name=PW96>{{cite book |last=Wellnhofer |first=Peter |title=The Illustrated Encyclopedia of Pterosaurs |orig-year=1991 |year=1996 |publisher=Barnes and Noble Books |location=New York |isbn=978-0-7607-0154-6 |pages=139}}</ref> Other valid species include the possibly larger ''P. sternbergi'', with a wingspan originally estimated at {{convert|9|m|ft|0|abbr=on}}.<ref name=PW96/> ''P. oweni'' (''P. occidentalis''), ''P. velox'', ''P. umbrosus'', ''P. harpyia'', and ''P. comptus'' are considered to be ''nomina dubia'' by Bennett (1994) and others who question their validity. All probably are synonymous with the more well-known species.

Because the key distinguishing characteristic Marsh noted for ''Pteranodon'' was its lack of teeth, any toothless pterosaur jaw fragment, wherever it was found in the world, tended to be attributed to ''Pteranodon'' during the late nineteenth and early twentieth centuries. This resulted in a plethora of species and a great deal of confusion. The name became a [[wastebasket taxon]], rather like the dinosaur ''[[Megalosaurus]]'', to label any pterosaur remains that could not be distinguished other than by the absence of teeth. Species (often dubious ones now known to be based on sexual variation or juvenile characters) have been reclassified a number of times, and several [[Genus|subgenera]] have in the 1970s been erected by Halsey Wilkinson Miller to hold them in various combinations, further confusing the taxonomy (subgenera include ''Longicepia'', ''Occidentalia'', and ''Geosternbergia''). Notable authors who have discussed the various aspects of ''Pteranodon'' include Bennett, Padian, Unwin, Kellner, and Wellnhofer. Two species, ''P. oregonensis'' and ''P. orientalis'', are not pteranodontids and have been renamed ''[[Bennettazhia]] oregonensis'' and ''[[Bogolubovia]] orientalis'' respectively.

===List of species and synonyms===
Status of names listed below follow a survey by Bennett, 1994 unless otherwise noted.<ref name=bennett1994/>
{| class="wikitable sortable"
|-
! Name
! Author
! Year
! Status
! class="unsortable" | Notes
|-
| ''[[Pterodactylus]] oweni''
| Marsh
|[[1871 in paleontology|1871]]
|''[[Nomen dubium]]''
|Renamed ''Pterodactylus occidentalis'' Marsh 1872 on grounds of ''oweni'' being preoccupied by "Pterodactylus oweni" Seeley 1864 (''nomen nudum'' for ''Ornithocheirus oweni'' Seeley 1870)
|-
| ''[[Pterodactylus]] ingens''
| Marsh
|[[1872 in paleontology|1872]]
|Reclassified as ''Pteranodon ingens''
|
|-
| ''[[Pterodactylus]] occidentalis''
| Marsh
|[[1872 in paleontology|1872]]
|Junior objective synonym of ''Pterodactylus oweni''
|Reclassified from ''Pterodactylus oweni'' Marsh 1871 on grounds of ''P. oweni'' being preoccupied by "Pterodactylus oweni" Seeley 1864 (''nomen nudum'' for ''Ornithocheirus oweni'' Seeley 1870)
|-
| ''[[Pterodactylus]] velox''
| Marsh
|[[1872 in paleontology|1872]]
|''[[Nomen dubium]]''
|Reclassified as ''Pteranodon velox''
|-
| ''Ornithochirus umbrosus''
| Cope
|[[1872 in paleontology|1872]]
|''Nomen dubium''
|
|-
| ''Ornithochirus harpyia''
| Cope
|[[1872 in paleontology|1872]]
|''Nomen dubium''
|
|-
| ''Pterodactylus umbrosus''
| (Cope) Cope
|([[1872 in paleontology|1872]]) [[1874 in paleontology|1874]]
|Reclassification of ''Ornithochirus umbrosus''
|
|-
| ''Pteranodon longiceps''
| Marsh
|[[1876 in paleontology|1876]]
|Valid
|Type species
|-
| ''Pteranodon ingens''
| (Marsh) Williston
|([[1872 in paleontology|1872]]) [[1876 in paleontology|1876]]
|''Nomen dubium''
|Reclassified from ''Pterodactylus ingens''
|-
| ''Pteranodon occidentalis''
| Marsh
|([[1872 in paleontology|1872]]) [[1876 in paleontology|1876]]
|Junior objective synonym of ''Pterodactylus oweni''
|Reclassified from ''Pterodactylus occidentalis''
|-
| ''Pteranodon velox''
| Marsh
|([[1872 in paleontology|1872]]) [[1876 in paleontology|1876]]
|''Nomen dubium''
|Reclassified from ''Pterodactylus velox'', based on a juvenile specimen
|-
| ''Pteranodon gracilis''
| Marsh
|[[1876 in paleontology|1876]]
|Reclassified as ''[[Nyctosaurus|Nyctosaurus gracilis]]''
|
|-
| ''Pteranodon comptus''
| Marsh
|[[1876 in paleontology|1876]]
|''Nomen dubium''
|
|-
| ''Pteranodon nanus''
| Marsh
|[[1876 in paleontology|1876]]
|Reclassified as ''[[Nyctosaurus|Nyctosaurus nanus]]''
|
|-
| ''[[Ornithocheirus]] umbrosus''
| (Cope) Newton
|([[1872 in paleontology|1872]]) [[1888 in paleontology|1888]]
|Reclassified as ''Pteranodon umbrosus''
|Spelling correction of ''Ornithochirus umbrosus''
|-
| ''[[Ornithocheirus]] harpyia''
| (Cope) Newton
|([[1872 in paleontology|1872]]) [[1888 in paleontology|1888]]
|Reclassified as ''Pteranodon harpyia''
|Spelling correction of ''Ornithochirus harpyia''
|-
| ''Pteranodon umbrosus''
| (Cope) Williston
|([[1872 in paleontology|1872]]) [[1892 in paleontology|1892]]
|''Nomen dubium''
|Reclassification of ''Ornithochirus umbrosus''
|-
| ''[[Ornithostoma]] ingens''
| (Marsh) Williston
|([[1872 in paleontology|1872]]) [[1893 in paleontology|1893]]
|Synonym of ''Pteranodon ingens''
|Reclassified from ''Pteranodon ingens''
|-
| ''[[Ornithostoma]] umbrosum''
| (Cope) Williston
|([[1872 in paleontology|1872]]) [[1897 in paleontology|1897]]
|Synonym of ''Pteranodon umbrosus''
|Reclassified from ''Pteranodon umbrosus''
|-
| ''Pteranodon oregonensis''
| [[Charles W. Gilmore|Gilmore]]
|[[1928 in paleontology|1928]]
|Reclassified as ''[[Bennettazhia|Bennettazhia oregonensis]]''
|
|-
| ''Pteranodon sternbergi''
| Harksen
|[[1966 in paleontology|1966]]
|Valid
|
|-
| ''Pteranodon marshi''
| Miller
|[[1972 in paleontology|1972]]
|Synonym of ''Pteranodon longiceps''
|
|-
| ''Pteranodon bonneri''
| Miller
|[[1972 in paleontology|1972]]
|Reclassified as ''[[Nyctosaurus|Nyctosaurus bonneri]]''
|
|-
| ''Pteranodon walkeri''
| Miller
|[[1972 in paleontology|1972]]
|Synonym of ''Pteranodon longiceps''
|
|-
| ''Pteranodon (Occidentalia) eatoni''
| (Miller) Miller
|([[1972 in paleontology|1972]]) [[1972 in paleontology|1972]]
|Synonym of ''Pteranodon sternbergi''
|
|-
| ''Pteranodon eatoni''
| (Miller) Miller
|([[1972 in paleontology|1972]]) [[1972 in paleontology|1972]]
|Synonym of ''Pteranodon sternbergi''
|Reclassified from ''Pteranodon (Occidentalia) eatoni''
|-
| ''Pteranodon (Longicepia) longicps'' {{sic}}
| (Marsh) Miller
|([[1872 in paleontology|1872]]) [[1972 in paleontology|1972]]
|Synonym of ''Pteranodon longiceps''
|Reclassified from ''Pteranodon longiceps''
|-
| ''Pteranodon (Longicepia) marshi''
| (Miller) Miller
|([[1972 in paleontology|1972]]) [[1972 in paleontology|1972]]
|Synonym of ''Pteranodon longiceps''
|Reclassified from ''Pteranodon marshi''
|-
| ''Pteranodon (Sternbergia) sternbergi''
| (Harksen) Miller
|([[1966 in paleontology|1966]]) [[1972 in paleontology|1972]]
|Reclassified as ''Pteranodon (Geosternbergia) sternbergi''
|Reclassified from ''Pteranodon sternbergi''
|-
| ''Pteranodon (Sternbergia) walkeri''
| (Miller) Miller
|([[1972 in paleontology|1972]]) [[1972 in paleontology|1972]]
|Reclassified as ''Pteranodon (Geosternbergia) walkeri''
|Reclassified from ''Pteranodon walkeri''
|-
| ''Pteranodon (Pteranodon) marshi''
| (Miller) Miller
|([[1972 in paleontology|1972]]) [[1973 in paleontology|1973]]
|Synonym of ''Pteranodon longiceps''
|Reclassified from ''Pteranodon marshi''
|-
| ''Pteranodon (Occidentalia) occidentalis''
| (Marsh) Olshevsky
|([[1872 in paleontology|1872]]) [[1978 in paleontology|1978]]
|Synonym of ''Pteranodon occidentalis''
|Reclassified from ''Pteranodon occidentalis''
|-
| ''Pteranodon (Longicepia) ingens''
| (Marsh) Olshevsky
|([[1872 in paleontology|1872]]) [[1978 in paleontology|1978]]
|Synonym of ''Pteranodon ingens''
|Reclassified from ''Pteranodon ingens''
|-
| ''Pteranodon (Pteranodon) ingens''
| (Marsh) Olshevsky
|([[1872 in paleontology|1872]]) [[1978 in paleontology|1978]]
|Synonym of ''Pteranodon ingens''
|Reclassified from ''Pteranodon ingens''
|-
| ''Pteranodon (Geosternbergia) walkeri''
| (Miller) Miller
|([[1972 in paleontology|1972]]) [[1978 in paleontology|1978]]
|Synonym of ''Pteranodon longiceps''
|Reclassified from ''Pteranodon walkeri''
|-
| ''Pteranodon (Geosternbergia) sternbergi''
| (Harksen) Miller
|([[1966 in paleontology|1966]]) [[1978 in paleontology|1978]]
|Synonym of ''Pteranodon sternbergi''
|Reclassified from ''Pteranodon (Sternbergia) sternbergi''
|-
| ''Pteranodon orientalis''
| (Bogolubov) Nesov & Yarkov
|([[1914 in paleontology|1914]]) [[1989 in paleontology|1989]]
|Reclassified as ''[[Bogolubovia|Bogolubovia orientalis]]''
|Reclassified from ''[[Ornithostoma|Ornithostoma orientalis]]''
|-
| ''Geosternbergia walkeri''
| (Miller) Olshevsky
|([[1972 in paleontology|1972]]) [[1991 in paleontology|1991]]
|Synonym of ''Pteranodon sternbergi''
|Reclassified from ''Pteranodon (Sternbergia) walkeri''
|-
| ''Geosternbergia sternbergi''
| (Harksen) Olshevsky
|([[1966 in paleontology|1966]]) [[1991 in paleontology|1991]]
|Synonym of ''Pteranodon sternbergi''
|Reclassified from ''Pteranodon (Geosternbergia) sternbergi''
|-
|}