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| Jinchuanloong niedu N. Li, Zhang, Ren, D. Li & You, 2025 |
Abstract
Sauropod dinosaurs were gigantic quadrupedal herbivores. They range from Early Jurassic to Late Cretaceous and have been found on all continents. The rich sauropod faunas in the Middle and Late Jurassic of China are mainly from southern or western China. Here, we describe a non-neosauropod eusauropod from the Middle Jurassic Xinhe Formation of Gansu Province, northwestern China, based on an associated partial skeleton that includes a nearly complete skull with mandible, the five anteriormost cervical vertebrae appressed with the skull and the posterior 29 articulated caudal vertebrae. It can be diagnosed as a new taxon Jinchuanloong niedu gen. et sp. nov. based on several cranial and postcranial autapomorphies. In Jinchuanloong, the posterior margin of the external naris lies in front of the posterior margin of the antorbital fenestra, similar to that in basal eusauropods, and the base of the maxillary ascending process presents a foramen, similar to that in neosauropods. The finding of Jinchuanloong adds diversity and helps elucidate the evolution of the sauropods in East Asia.
Keywords: Dinosauria, Sauropoda, Eusauropoda, Jurassic, China
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| Skull of Jinchuanloong niedu (JCMF0132) in left lateral view. Abbreviations: a, aperture; an, angular; aof, antorbital fenestra; d, dentary; en, external naris; f, frontal; fo, foramen; inf, infratemporal fenestra;j, jugal; l, lacrimal; m, maxilla; n,nasal; o, orbit; p, parietal; pf, prefrontal; pm, premaxilla; po, postorbital; pop, paraoccipital process; q, quadrate; qj, quadratojugal; sa, surangular; snf, subnarial foramen; sq, squamosal. |
Jinchuanloong niedu gen. et sp. nov.
Horizon and locality: Jinchuan District, Jinchang City, Gansu Province, northwest of China; lower part of the Xinhe Formation (late Bathonian).
Diagnosis: Jinchuanloong can be diagnosed by a suite of unique character combinations (autapomorphies are marked by *): (1) in lateral view, there is a small foramen at the base of the nasal process of the maxilla *. (2) The anterodorsal surface of the prefrontal bears a small round aperture near the bifurcation (Figs. 2 and 5) *. (3) In lateral view, the postorbital is very robust. The ratio of the anteroposterior length to the dorsoventral height of the posterior process of the postorbital of Jinchuanloong is 0.9 *. (4) The posteroventral process of the jugal contributes 22% of the ventral margin of the infratemporal fenestra; The dorsal process of the jugal contacts the lacrimal and has a small contribution to the antorbital fenestra (Fig. 2).
Etymology: The genus name ‘Jinchuan’ refers to the region where the specimens were found; ‘loong’ is Mandarin Chinese for ‘dragon’. ‘Nie’, the Mandarin Chinese for ‘nickel’; ‘du’, the Mandarin Chinese for ‘city’, reflecting that Jinchuan (Jinchang) is a city famous for its rich nickel resources.
Ning Li, Xiaoqin Zhang, Xinxin Ren, Daqing Li and Hailu You. 2025. A New eusauropod (Dinosauria, Sauropodomorpha) from the Middle Jurassic of Gansu, China. Scientific Reports. 15: 17936. DOI: doi.org/10.1038/s41598-025-03210-5 [23 May 2025]