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Arambourgiania philadelphiae (Arambourg, 1959) Inabtanin alarabia Rosenbach, Goodvin, Albshysh, Azzam, Smadi, Mustafa, Zalmout & Mantilla, 2024 |
ABSTRACT
Pterosaurs were the earliest and largest vertebrates to evolve powered flight, but they are the only major volant group that has gone extinct. Attempts to understand pterosaur flight mechanics have relied on aerodynamic principles and analogy with extant birds and bats. Both lines of inquiry rely on the size, three-dimensional shape, and internal structure of flight bones, which in pterosaurs are surprisingly rare. Remarkably, two new large-bodied pterosaur individuals with three-dimensionally preserved wing elements were recently recovered from Upper Cretaceous (Maastrichtian) horizons of Jordan. Both specimens represent azhdarchoid pterosaurs; one is referrable to the giant species Arambourgiania philadelphiae (ca. 10 m wingspan) and the second to a new, smaller species Inabtanin alarabia gen. et sp. nov. (ca. 5 m wingspan). In this study, we describe these new specimens and use high-resolution micro-computed tomography scans to reconstruct and compare the internal osteology of the humeri of these two differently sized species to that of extant birds, for which internal bone structure can be correlated with flight behavior. The humerus of Arambourgiania exhibits a series of helical ridges formed along the cortical bone, whereas Inabtanin exhibits a denser pattern of hollow struts. Variation in internal structure for these individuals likely reflects responses to mechanical forces applied on the wings of pterosaurs. Results indicate that Inabtanin has internal bone morphology similar to that of flapping birds, whereas the internal morphology of Arambourgiania is most similar to that of soaring birds.
PTEROSAURIA Kaup, Citation1834
PTERODACTYLOIDEA Plieninger, Citation1901
AZHDARCHOIDEA Nesov, Citation1984
INABTANIN ALARABIA, gen. et sp. nov.
Etymology—Inabtanin is named for the geomorphological structure near the locality where the specimen was collected, which is called Tal Inab (“grape hill”) owing to its prominent coloration. The generic name combines the Arabic words inab, for grape, and tanin for dragon. Allusions to dragons are common in pterosaur etymology and so tanin was chosen to reflect the Arabic language of Jordan, and because of its similarity to the English word tannin, derived from the French tanin which relates to coloration. The generic name translates to both grape-dragon and grape-colored. The specific name alarabia was chosen in reference to the Arabian Peninsula.
Kierstin L. Rosenbach, Danielle M. Goodvin, Mohammed G. Albshysh, Hassan A. Azzam, Ahmad A. Smadi, Hakam A. Mustafa, Iyad S. A. Zalmout and Jeffrey A. Wilson Mantilla. 2024. New Pterosaur remains from the Late Cretaceous of Afro-Arabia provide insight into Flight Capacity of large Pterosaurs. Journal of Vertebrate Paleontology. e2385068 DOI: doi.org/10.1080/02724634.2024.2385068
