Yixianopterus
Yixianopterus | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Order: | †Pterosauria |
Suborder: | †Pterodactyloidea |
Clade: | † Istiodactyliformes
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Genus: | †Yixianopterus Lü et al., 2006 |
Type species | |
†Yixianopterus jingangshanensis Lü et al., 2006
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Yixianopterus is a
Classification
Lü et al. (2006) assigned Yixianopterus to the Lophocratian family Lonchodectidae based on dental characters, and ratio comparisons between wing phalanx I and II, metacarpal IV, and ulna. This specimen was classified it as the first Asian representative of Lonchodectidae[3]. Martill (2011) considered it potentially related to his new taxon Unwindia[4], and Witton (2013) assigned it to the family Ornithocheiridae[5].
A reappraisal of the holotype specimen and phylogenetic analysis by Jiang et al. (2020) recovered Yixianopterus as a basal member of the clade
Lanceodontia
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Holotype JZMP-V-12
Holotype JZMP-V-12 was discovered within the Jinggangshan bedding, the uppermost layer of the Yixian Formation[2]. Many Jehol Biota associated with the Jinggangshan bedding are fish, ephemerid, and plant fragments. The holotype found contained fragmented segments leading to its classification as a new genus and species of flying reptile from the Early Cretaceous. Preserved segments include the right forelimb, a foot, and teeth[1].
The recovered right forelimb segment contained two broad, thin plates each measuring 35 cm x 35 cm x 2 cm. The conditions under which the holotype was preserved crushed the ends of the right humerus, but what remains is 101.6 mm long
The foot of holotype JZMP-V-12 was found in a well-preserved condition. Metatarsal III is 28.19mm long while what was preserved of the tibia is 102.63 mm in length. Kellner et al. (2019) identified the ratio as less than 27.5%, a typical characteristic of the clade Ornithocheiroidea[1].
Lü et al. (2006) identified the ratios between wing phalanx I and II, wing phalanx I and metacarpal IV, and metacarpal IV and ulna, as being unique to Yixianopterus[3].
Lü et al. (2006) noted that the teeth of the specimen were subequal with diastema increasing posteriorly[3]. Kellner et al. (2019) identified the triangular and labiolingually compressed teeth as a characteristic of Pteranodontoidea. The front two incisors are particularly more slender and longer than the rest[1].
An outline of the head preserved within the sediment showed a dorsal inclination[1]. This would indicate that the shape of the skull is rather narrow where the mouth opening is, with the majority of the skull surrounding the brain.
References
- ^ a b c d e f Shun-Xing, Jiang; Xin-Jun, Zhang; Xin, Cheng; Xiao-Lin, Wang. "A new pteranodontoid pterosaur forelimb from upper Yixian Formation, with a revision of Yixianopterus jingangshanesis". Vertebrata PalAsistica. 59 (2): 81–94.
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- ^ a b c Lü, J; Ji, S; Yuan, C; Gao, Y; Sun, Z; Ji, Q (2006). "New pterodactyloid pterosaur from the Lower Cretaceous Yixian Formation of Western Liaoning". Papers from the 2005 Heyuan International Dinosaur Symposium. Beijing: Geological Publishing House: 195–203.
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- ^ Witton, Mark P (2013). Pterosaurs: Natural History, Evolution, Anatomy. Princeton, NJ: Princeton University Press.