The genus Nurhachius comprises istiodactylid pterodactyloid pterosaurs that originated in the Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China, between the Barremian to Aptian ages. Its fossilized remnants show an approximate age of 120 million years.
Discovery
In 2005, Wang Xiaolin, Diogenes de Almeida Campos, Zhou Zhonghe, and Alexander Kellner named the genus. The Nurhachius ignaciobritoi is the type species. The first emperor of the Qing Dynasty, Nurhaci, whose initial domain included the area where the fossil was discovered, is referenced in the genus name. The particular name is a tribute to the late Ignácio Aureliano Machado Brito, a Brazilian paleontologist who led the way in pterosaur research in his nation. Initial descriptions of Nurhachius were based on the incomplete skeleton and skull found in its holotype fossil, IVPP V-13288. Later on, LPM 00023, a second specimen, was assigned to the species. Nurhachius luei, a second species, was given a name in 2019. The late Lü Junchang is honored with the particular name. It is based on the lower Jiufotang Foramation holotype BPMC-0204, which has seven neck vertebrae and a skull with lower jaws. The oldest known record of the genus in terms of geology was found in 2023 when a specimen measuring 1.6 meters in wingspan was identified and attributed to Nurhachius sp. from the Jingangshan Member of the upper Yixian Formation.
Description
Nurhachius's wingspan was estimated to be between 2.4 and 2.5 meters (7.87–8.20 feet). Witton calculated the wingspan and weight in 2008 to be 228 centimeters (7.48 feet) and 4 kilograms (8.8 lb), respectively. The front tip of the palate has a small upward tilt, which is the only apomorphy, or distinctive characteristic of the genus that has been identified for 2019. The holotype of the elongated skull is 315 millimeters (12.4 in) in length, with an estimated total length of 330 millimeters (13 in). At 58% of the length of the skull, the nasoantorbital fenestra, or great skull opening, is comparatively long. 290 millimeters (11 in) is the length of the lower jaws. Particularly in the long fenestra and the compressed teeth from side to side, the cranium resembles that of Istiodactylus, who lived in what is now England, about the same period. It is distinct from Istiodactylus in a few ways, though, such as having a somewhat smaller skull, a different jugal, and a little curvature to the top edge of the lower jaw. The teeth are strong, have three roots, and are bent to the rear. They are restricted to the anterior ends of the jaws, where there are a total of 54 teeth—28 in the upper jaw and 26 in the lower jaw. With the exception of a few cervical vertebrae, the ribs, the tail, and the two most extreme phalanges of the wing finger, the majority of the postcranial skeleton is known.
Classification
The humerus's twisted deltopectoral crest, which is exclusive to the clade Istiodactylus + Anhangueridae, was one of the similarities noted by the describers with the Pteranodontoidea. According to a cladistic study done by Wang and associates, Nurhachius belonged to the Istiodactylidae family. A 2008 research by Lü Junchang confirmed that it is closely linked to Istiodactylus. Lü also proposed in 2008 that Nurhachius was a junior synonym of Liaoxipterus, another istiodactylid belonging to the same habitat. But according to a 2012 study by Mark Witton, these two istiodactylids were not similar to one another and—more significantly—did not form a single evolutionary tree. Witton added that in Lü's research, they likewise did not truly form a group. Zhou and associates validated the Istiodactylidae's inclusion in 2019. Both of the Nurhachius species (N. ignaciobritoi and N. luei) were found to be sister taxa and basal members of the Istiodactylidae family in their phylogenetic study. Their topology is followed in the cladogram below.
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Reconstruction of N. ignaciobritoi near water by Nobu Tamara.
Skull of N. ignaciobritoi at a Brazilian museum.
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