| Eopteranodon | |
|---|---|
 | |
| Holotype ofEopteranodon lii | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | †Pterosauria |
| Suborder: | †Pterodactyloidea |
| Clade: | †Azhdarchoidea |
| Family: | †Tapejaridae |
| Subfamily: | †Sinopterinae |
| Genus: | †Eopteranodon Lü & Zhang, 2005 |
| Type species | |
| †Eopteranodon lii Lü & Zhang, 2005 | |
| Other species | |
| |
Eopteranodon (meaning "dawnPteranodon (toothless wing)") is agenus oftapejaridpterosaur from theAptian-ageLower CretaceousYixian Formation ofBeipiao City,Liaoning, China. The genus was named in 2005 by paleontologistsLü Junchang andZhang Xingliao. Thetype species isEopteranodon lii. A second species,E. yixianensis, was named in 2023, but its validity has been questioned.[2]
Eopteranodon is based on thetype specimen orholotype BPV-078, an incomplete skeleton and skull. Its skull, including a large crest, was toothless and similar to that ofPteranodon. The skull lacks the point of the snout but it was in life less than 200 millimeters long (7.9 inches), and the animal had awingspan of about 1.1 meters (3.6 feet). A second specimen, D2526, described in 2006, had a larger wingspan.[3]
Despite its similarities toPteranodon,Eopteranodon was not placed into afamily by its describers, who put it into thecladePteranodontia asincertae sedis (uncertain position).[3] Shortly thereafter, aphylogenetic study of all known Yixian pterosaurs by the same scientists found it to be close to the azhdarchoids, noted for the crested generaTapejara andTupuxuara, and the giant, long-neckedQuetzalcoatlus.[4] A further analysis of other recently discovered forms, in 2006 still considered basal to (having split off earlier than) azhdarchoids, helped the original authors, along withDavid Unwin, to place these species together withEopteranodon in a new cladeChaoyangopteridae, the possible sister group of theAzhdarchidae.[5]
However, in 2014, in an analysis by Brian Andres and colleagues,Eopteranodon was recovered as a basal member of the cladeTapejaromorpha, closely related to the species "Sinopterus"gui andNemicolopterus crypticus. Their cladogram is shown on the left.[6] Later, in 2017, in another phylogenetic analysis,Eopteranodon was considered a member of the familyTapejaridae based on proportions of the crest on the lower jaw and the limbs.[7] This concept has been followed by several studies in 2019, including the one by Borja Holgado and colleagues,[8] and the one byAlexander Kellner and colleagues. The cladogram on the right is based on the topology made by Kellner and colleagues.[9]
Topology 1: Andreset al. (2014). | Topology 2: Kellneret al. (2019).
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