Editing Pteranodon (section)

===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]]
                                 }} }} }} }} }} }} }} }} }} }}