Nipponopterus is the first formally described pterosaur from Japan. It lived during the Late Cretaceous, about 90 million years ago, on the island of Kyushu. Nipponopterus belonged to the family of pterosaurs Azhdarchidae, specifically the subfamily Quetzalcoatlinae, which includes the largest pterosaurs.
The name of this extinct azhdarchid genus, Nipponopterus mifunensis, means “Nippon wing” from Mifune. In 2000, researchers first reported the discovery of an unidentified azhdarchid. At the time, there was insufficient information about the family to provide an accurate interpretation of the find. A detailed analysis now reveals that the discovered element is the rear portion of a partial sixth cervical vertebra.
In 2024, Zhou et al. described a new genus, Nipponopterus, based on these fossil remains, which includes a single species, N. mifunensis.
The specimen, MDM 349, originates from the middle part of the Upper Formation of the Mifune Group, located near the Amagimi Dam in Mifune Town, Kumamoto Prefecture, on the island of Kyushu, Japan. The lens-shaped, coarse-grained sandstone layer, situated between two layers of tuff, facilitated the dating of the find.
This new species exhibits numerous traits characteristic of the Quetzalcoatlinae and is quite similar to the unnamed fragmentary Burkhant azhdarchid from the Turonian–Coniacian of Mongolia. The wingspan of both species was approximately 3–3.5 meters.
Since pterosaur skeletons were highly lightweight, with pneumatic and thin-walled bones, they were very fragile and do not preserve well in the fossil record. In most locations, researchers typically recover only fragmentary specimens.
This formation yielded a first wing phalanx and a mid-cervical vertebra from indeterminate azhdarchid pterosaurs, but researchers have not assigned these finds to Nipponopterus. Additionally, they discovered an indeterminate wing metacarpal there. Pterosaur tracks, Pteraichnus nipponensis, are known from the Tetori Group.
The first pterosaur specimen discovered in Japan, which remains undescribed, consists of a partial femur, metatarsal, pedal phalanx, and caudal vertebra. It originates from the Yezo Group (Santonian–Lower Campanian) on Hokkaido and represents an indeterminate pteranodontid.
Pterosaurs were the first flying vertebrates on Earth, living from the Late Triassic to the Late Cretaceous. These successful flying reptiles achieved wingspans exceeding 10 meters and grew as tall as modern giraffes, making them the largest flying animals of all time. Over their existence, they evolved significant morphological diversity, giving rise to many strange and unusual species.
The family Azhdarchidae, to which Nipponopterus belongs, includes the largest flying animals, with the most famous being Quetzalcoatlus northropi, which had a wingspan of 10–11 meters. Their elongated cervical vertebrae characterize Azhdarchids with neural spines reduced to a neural ridge. They were a diverse and widely distributed group of pterosaurs during the Late Cretaceous. Nipponopterus differs from other azhdarchids by being less constricted and by the morphology of the postzygapophyses.
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