User:JurassicClassic767/sandbox
Pteranodon | |
---|---|
Mounted replica skeleton of an adult male P. longiceps at the American Museum of Natural History | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Order: | †Pterosauria |
Suborder: | †Pterodactyloidea |
Family: | †Pteranodontidae |
Subfamily: | †Pteranodontinae Williston, 1892 |
Genus: | †Pteranodon Marsh, 1876 |
Type species | |
†Pteranodon longiceps Marsh, 1876
| |
Other species | |
| |
Synonyms | |
Genus synonymy Species synonymy
|
Pteranodon (
Similar to other pterosaurs of its family, Pteranodon is mostly known for its elongated
When Pteranodon was unearthed in 1870, it was, back then, the largest known pterosaur, with wingspan estimates of about 6.25 meters (20.5 ft). Larger wingspan estimates have been done in the past however, and some have reached an impressive 7.25 meters (23.8 ft) based on specimens that were proportionally larger than any other known Pteranodon specimens. Throughout the history of Pteranodon, many species were also formerly assigned to it, e.g.
History of discovery
Earliest finds
The first fossil remains of Pteranodon were uncovered in an 1870 expedition led by American
Later, in 1872, Marsh had realized that the name he had chosen, "P. oweni", had already been used for a pterosaur species described by British paleontologist
In the same year, 1872, Marsh's rival, paleontologist
Naming
In 1874, Marsh had hired many fossil collectors to work in the exposures of the Niobrara Formation. More fossil material was collected in the next 6 years, among these include specimen YPM 1177, which was discovered in 1876. YPM 1177 is a well-preserved and nearly complete skull, this specimen revealed that the pterosaur species from the Niobrara Formation were different from every other pterosaur species that were then known, this is because it possessed features such as toothless jaws and a
Other discoveries
In the same paper publishing P. longiceps, Marsh named another species, Pteranodon gracilis, based on a
Revising species
In 1892, Samuel Williston examined the classification of Pteranodon by Marsh, and he noticed that back in 1871, Seeley had mentioned the existence of a partial set of toothless pterosaur jaws from the Cambridge Greensand of England, which he named "Ornithostoma",[12] and because the primary characteristic Marsh had used to separate Pteranodon from other pterosaurs was its lack of teeth, Williston concluded that "Ornithostoma" must be considered the senior synonym of Pteranodon, and he reassigned the species P. ingens as Ornithostoma ingens due to this conclusion.[13][5] Interestingly, he also reassigned Cope's Ornithochirus harpyia into Ornithostoma, creating the new combination Ornithostoma harpyia.[5] In 1901 however, German paleontologist Felix Plieninger pointed out that "Ornithostoma" had never been scientifically described or even assigned to a species name until Williston's work, and therefore had been a nomen nudum and could not beat out Pteranodon for naming priority.[14][3] Williston accepted this conclusion and went back to calling the genus Pteranodon. Both Williston and Plieninger however, were incorrect, because unnoticed by both of them was the fact that back in 1891, Seeley himself had finally described and properly named Ornithostoma, assigning it to the species named as O. sedgwicki.[5][15] In the 2010s, more research on the identity of Ornithostoma showed that it was probably not Pteranodon or even a close relative, but may in fact have been an
Williston was also the first scientist to critically evaluate all of the Pteranodon species classified by Cope and Marsh. He did agree with most of Marsh's classifications, but a few exceptions were made.[3] First, he did not believe that P. ingens and P. umbrosus could be considered synonyms, which even Cope had come to believe. Williston considered both P. velox and P. longiceps to be dubious; the first (P. velox) was based on non-diagnostic fragments, and the second (P. longiceps), though known from a complete skull, probably was a synonym of one of the other previously named species.[5] In 1903, Williston revisited the question of Pteranodon classification, and revised his earlier conclusion, in which he stated that there were only three species of Pteranodon, instead of seven. He also considered both P. comptus and P. nanus to be specimens of Nyctosaurus, and divided the others into small (P. velox), medium (P. occidentalis), and large species (P. ingens) primarily based on the shape of their upper arm bones.[16] He also followed his first conclusion of P. longiceps being a synonym of either P. velox or P. occidentalis based on its size, but he did not specify to which of the two species would be synonymized.[16] Later that year, paleontologist George Francis Eaton became the first scientist to publish a more detailed description of the entire Pteranodon skeleton. He used his findings to revise the classification of this genus, once again based on a better understanding of the differences in pteranodontid anatomy.[5] Eaton found that most of the differences in bone shapes could be easily explained by the pressures of fossilization, and concluded that none of the Pteranodon skeletons had any significant differences from each other besides their size. Therefore, Eaton was left to decide his classification scheme based on differences in the skulls alone. He assigned the different sized skulls into different species according to their size, but in the end, Eaton only recognized three valid species: P. occidentalis, P. ingens, and P. longiceps.[17][18] In 1910, Eaton assigned specimen YPM 1164 as the type species of P. occidentalis, and stated that back then, Marsh had observed the form of the jaws of P. occidentalis in a fragmentary skull of specimen YPM 1179, and from his notes it is evident to also consider this specimen as the type, thus assigning it as the "type skull" of P. occidentalis.[19] This was incorrect however, because the remains found of YPM 1179 were not collected until after the initial publication of P. occidentalis in 1871 by Marsh, which was published under the preoccupied name "Pterodactylus" oweni.[19]
In the same year as the assignments of YPM 1164 and YPM 1179, Eaton had given credit to Williston's conclusions after he had criticized them back in 1903, this was due to the incompleteness and uncertainty of the specimens. Eaton also limited his discussions of the skeletons of Pteranodon afterwards.[20] In doing so, he noticed one issue: he couldn't trace a fibula in the preserved specimens, which was stated by Williston back then. Williston then mentioned that he found distinct remains of the fibula fused with the tibia, and therefore, he conducted experiments in 1912 using clay models of bones to help determine the effects of crushing and flattening on the shapes of the arm bones that Eaton had used in his own classifications.[20][21] In 1920, paleontologist Carl Wiman had noted that in his description of the specimens purchased by fossil collector Charles Hazelius Sternberg, a tibia of which he figured to belong to Pteranodon included a remnant of a fibula, this meant that at least several specimens had this state of preservation.[20]
In 1952, paleontologist
Later revisions
In 1975, paleontologist
Description
Size
Pteranodon specimens are extremely well represented in the fossil record, with at least 1,200 identified, which is more than any other pterosaur. Detailed descriptions of their anatomy and analysis of their life history have been debated since, and even with the amount of specimens found, more than half still lack completeness, so paleontologists base upon the better known specimens to extract data.[5][11]
Marsh initially estimated the wingspan of Pteranodon around 7.6 meters (25 ft) following his publication of the genus, this made Pteranodon the largest known pterosaur back then, and no other wingspan estimates could challenge it. This was later downsized by Eaton in 1910 however, giving a lower estimate of about 6.8 meters (22 ft). In 1910, Eaton concluded that factoring flexions to the wing bones would give a more realistic wingspan estimate, instead of just adding the length of both wing bones snd shoulder width.
Average wingspan estimates for Pteranodon had since decreased, adult males are estimated to have had a wingspan of only about 5.6 meters (18 ft), and adult females were yet smaller, and according to several analyses, their wingspans only measured about 3.8 meters (12 ft).
Several methods have been used to estimate the mass of large male specimens, which have also been considered notoriously unreliable, producing a wide range of estimates from as low as 20 kilograms (44 lb), to as high as 93 kilograms (205 lb). Published in 2010, a review of pterosaur size estimates concluded by researchers
Skull and beak
When Pteranodon was discovered, the skull was yet to be known, and therefore paleontologists based upon other pterosaur genera (most notably Pterodactylus) to make early reconstructions of the animal, in which Pteranodon had teeth, and lacked the cranial crest. When the first skull of Pteranodon was unearthed and then analyzed, paleontologists had understood more about the skull anatomy of Pteranodon, and concluded that it was unique compared to European pterosaurs such as Rhamphorhynchus.
Unlike earlier pterosaurs such as Rhamphorhynchus and Pterodactylus, Pteranodon had a toothless beak that was made of solid, bony margins that projected from the base of the jaws, similar to modern-day birds. The beaks also had subparallel dorsal and ventral margins, as well as slender and thin, but sharp points. The maxilla was found to be longer than the mandible, and was curved upward, this was more exaggerated in males than in females.[37] One specimen in particular (UALVP 24238) has been found to possess a distinctive curvature than in other specimens, which likely corresponded with the beak widening towards the tip. While the tip of the beak is not known in this distinct specimen, the level of curvature suggests it would have been extremely long. The unique form of this specimen's beak led to a genus reassigning in 2010 by Brazilian paleontologist Alexander Kellner, in which the genus would be called Dawndraco.[27] A recorded skull length of Pteranodon based on several skull fragments was about 1.3 meters (4.3 ft), this was concluded by Marsh with his publication of P. longiceps back in 1876.[3]
Shoulder girdle
The
In YPM 1175, the scapula and coracoid were united, and were defective behind and below the
Wings
Pteranodon had wings very similar in build to the modern-day
The structure of the wings also suggest that Pteranodon flew very long distances without flapping constantly, similar to the related
Forelimbs
Pteranodon had unusually long forelimbs compared to other pterosaur genera, this may be, yet again, another indication that Pteranodon was more advanced, or at least more derived.
Vertebral anatomy
Pteranodon had nine cervical vertebrae, counting the atlas and the axis as the first two units of the vertebral column. All of the Pteranodon specimens had the atlas and axis co-ossified, but in specimens YPM 1175 and YPM 1177, it is not possible to trace readily the limits of the theoretical elements that composed the fused vertebrae. The third, fourth, fifth, sixth and seventh cervicals are similar in appearance in terms of general form, their only slight difference is seen in their lengths. The natural sequence of the cervicals of Pteranodon can also be seen without any doubt. Measurements of the cervical centra of YPM 1175 have been done by Eaton in 1910; following him, the third cervical centrum measured 61 millimeters (2.4 in), the fourth 67 millimeters (2.6 in), the fifth 88 millimeters (3.5 in), the sixth 76 millimeters (3.0 in), and the seventh 65 millimeters (2.6 in). With these measurements of the cervical centra in mind, it would appear that the third cervical was the shortest of the five vertebrae, then the fourth and fifth successively increasing in length, but afterwards, the sixth and seventh were decreasing, and the size of the seventh cervical was reduced comparably to the fourth. While this sequence is present in YPM 1175, it is also substaintiated in part by YPM 2594, where the third cervical is anything but greater in size than the united atlas and axis, which is where it is remained attached. Pneumatic canals have found to lighten the cervical vertebrae to where they enter the centra.[31][47][32]
Nearly all the dorsal vertebrae of Pteranodon are involved in one or two heavily fused girder-like structures called the
Tail and caudal
The last few vertebrae were fused into a long rod that extended until the beginning of the animal's tail. The tail of Pteranodon was relatively short compared to earlier genera such Rhamphorhynchus, which led to the idea that the later genera such as Pteranodon used their tail less often. The entire length of the tail was about 3.5 percent the size of the wingspan, and was up to 25 centimeters (9.8 in) in the largest males, which is not that impressively large in terms of tail-to-wingspan ratio.
Hindlimbs
In contrast to the forelimbs of Pteranodon, its hindlimbs were relatively short compared to the overall size of the body. Pteranodon, and its relative Nyctosaurus, had the shortest hindlimbs of any pterosaur genera, in terms of hindlimb-to-body ratio, only about 20 percent the size of the wing.[41]
Some remains of the feet of Pteranodon were also found, and are enough for paleontologists to determine how their size were. Contrary to the small feet seen in earlier pterosaurs such as
Classification
Evolution and timespan
Fossils of Pteranodon are primarily known from the Niobrara Formation of the central United States. Broadly defined, Pteranodon existed for more than 4 million years, from the late Coniacian to the early Campanian stages of the Late Cretaceous period.[5] 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 the fossils in this formation, demonstrating that the species P. sternbergi, now considered to belong to the separate genus Geosternbergia, existed in the formation from 88 to 85 million years ago, while the type, and potentially only species, P. longiceps, existed between 86 and 84.5 million years ago.[42]
In the early 1990s, Bennett noted that the two major
Phylogeny
Studies on Pteranodon specimens have suggested that it was a distant relative of the ornithocheirids such as Ornithocheirus due to the similar diet, as well as the flight techniques and features. A genus called Anhanguera for example, had broad caudal vertebrae that was similar to that of Pteranodon.[37][52][53]
|
Topology 2: Longrich and colleagues (2018).[54]
|
Paleobiology
Flight and aerodynamics
The flight ability of Pteranodon was intensively more than pterosaurs, and the flight techniques that Pteranodon used were similar to those of modern-day albatrosses, which consisted in long distance flights and rarely flapping.
Later, in 1974,
Another flight analysis of the species P. ingens was conducted by Ross Stein in 1975. In the analysis, Stein considered that Pteranodon would have been better suited for soaring or gliding rather than a flapping flight, as concluded in previous analysis. He also concluded that the minimum flight velocity of P. ingens was calculated to have been about 4.5 meters (15 ft) per second, while the maximum was around 15 meters (49 ft) per second. Along with this, the wing-beat cycle of Pteranodon would have been about 1 stroke per second, and therefore it would have allowed an unassisted takeoff.[60][58]
Terrestrial locomotion
Respiration
Studying and analyzing the
Skeletal pneumatization
Diet and feeding
References
- ISBN 9780813724270.
- S2CID 131057784.
- ^ S2CID 128801077.
- ^ a b Everhart 2017, p. 275.
- ^ a b c d e f g h i j k l m n o p q r s t u v Bennett, S.C. (1994). "Taxonomy and systematics of the Late Cretaceous pterosaur Pteranodon (Pterosauria, Pterodactyloidea)" (PDF). Occasional Papers of the Natural History Museum, University of Kansas. 169: 1–70.
- ^ Everhart 2017, p. 276.
- ^ Everhart 2017, pp. 276–277.
- ^ Everhart 2017, p. 278.
- ^ "Pteranodon". Lexico.
- ^ "longiceps". EngYes.
- ^ a b c d e Bennett, S.C. (2000). "Inferring stratigraphic position of fossil vertebrates from the Niobrara Chalk of western Kansas" (PDF). Current Research in Earth Sciences: Kansas Geological Survey Bulletin. 244: 26.
- .
- ^ S2CID 67809186.
- ^ Plieninger F., 1901. Beiträge zur kenntnis der Flugsaurier. Palaeontolographica, 53, 209–213.
- .
- ^ a b c Williston, S. W. (1903). "On the osteology of Nyctosaurus (Nyctodactylus), with notes on American pterosaurs" (PDF). Field Columbian Museum. 2 (3): 125–163.
- .
- .
- ^ a b c d e f g Schoch, R.M. (1984). "Notes on the type specimens of Pteranodon and Nyctosaurus (Pterosauria, Pteranodontidae) in the Yale Peabody Museum collections" (PDF). Postilla. 194. Peabody Museum of Natural History Yale University: 1–23.
- ^ a b c Everhart 2017, p. 289.
- doi:10.1086/621967.
- JSTOR 3626742.
- ^ a b Harksen, J. C. (1966). "Pteranodon sternbergi, a new fossil pterodactyl from the Niobrara Cretaceous of Kansas" (PDF). Proceedings South Dakota Academy of Science. 45: 74–77.
- ^ JSTOR 3627663.
- JSTOR 3627664.
- S2CID 132670322.
- ^ PMID 21152777.
- ^ Everhart 2017, p. 293.
- ^ a b Bennett, S.C. (1994). "The Pterosaurs of the Niobrara Chalk". The Earth Scientist. 11 (1): 22–25.
- ^ Everhart 2017, p. 294.
- ^ a b c d e f g Eaton, G.F. (1910). "Osteology of Pteranodon". Memoirs of the Connecticut Academy of Arts and Sciences. 2: 1–38.
- ^ S2CID 90380603.
- S2CID 90893067.
- ^ PMID 21085624.
- ^ Cite error: The named reference
marsh1876a
was invoked but never defined (see the help page). - ^ Cite error: The named reference
Bennett1992
was invoked but never defined (see the help page). - ^ a b c d Witton 2013, p. 177.
- ^ a b Williston, S.W. (1897). "Restoration of Ornithostoma (Pteranodon)". Kansas University Quarterly. 6: 35–51.
- .
- ^ S2CID 129846497.
- ^ a b c d e f g h Witton 2013, p. 179.
- ^ ISBN 978-1-4020-1443-7.
- ^ )
- ^ "Clipping the Wings of Giant Pterosaurs: Comments on Wingspan Estimations and Diversity". Acta Geoscientica Sinica. 31: 79–81. 2010.
{{cite journal}}
: Cite uses deprecated parameter|authors=
(help) - doi:10.1086/621914.
- ^ Everhart 2017, p. 292.
- ^ doi:10.1098/rstb.1974.0007.)
{{cite journal}}
: CS1 maint: multiple names: authors list (link - ^ Benton 2014, p. 237.
- ^ )
- ^ a b Bennett, S. C. (1987). "New evidence on the tail of the pterosaur Pteranodon (Archosauria: Pterosauria)." Pp. 18–23 in Currie, P. J. and E. H. Koster (eds.), Fourth Symposium on Mesozoic Terrestrial Ecosystems, Short Papers. Occasional Papers of the Tyrrell Museum of Paleontology, #3.
- ^ Witton 2013, p. 195.
- PMID 21437387.
- ^ "Description of a new species of Anhangueridae (Pterodactyloidea) with comments on the pterosaur fauna from the Santana Formation (Aptian–Albian), northeastern Brazil". National Science Museum Monographs. 17: 1–135. 2000.
{{cite journal}}
: Cite uses deprecated parameter|authors=
(help) - ^ PMID 29534059.)
{{cite journal}}
: CS1 maint: unflagged free DOI (link - PMID 31784545.
- doi:10.26879/1015.
- S2CID 84617119.
- ^ a b Everhart 2017, pp. 293–294.
- ^ "Aerodynamic characters of the cranial crest in Pteranodon" (PDF). Hone, D.W.E. And Buffetaut, e. (Eds) Flugsaurier: Pterosaur Papers in Honour of Peter Wellnhofer. Zitteliana B. 28: 167–174. 2008.
{{cite journal}}
: Cite uses deprecated parameter|authors=
(help) - S2CID 130404646.
- ^ S2CID 155090508.
- PMID 31652295.
- .
- S2CID 135332458.
Further reading
- Everhart, Michael (2017). Oceans of Kansas, Second Edition: A Natural History of the Western Interior Sea. Indiana University Press. ISBN 978-0-253-02715-3.
- Witton, Mark (2013). Pterosaurs: Natural History, Evolution, Anatomy. Princeton University Press. ISBN 978-0691150611.
- Buffetaut, Eric; Mazin, Jean-Michel (2003). Evolution and Paleobiology of Pterosaurs. Geological Society of London. ISBN 978-0691150611.
- Benton, Michael (2014). Vertebrate Palaeontology. ISBN 978-1-118-40755-4.