A New Titanosaurian Sauropod from the Upper Cretaceous of Jiangxi Province, Southern China

• Published in: Historical biology 2024-11, Vol.36 (11), p.2443-2457
• Main Authors: Mo, Jin-You, Fu, Qiong-Yao, Yu, Yi-Lun, Xu, Xing
• Format: Article
• Language: English
• Subjects: Cretaceous; Jiangxi Province; Jiangxititan ganzhouensis; Laminates; Nanxiong Formation; New species; Phylogeny; Sympatric populations; Titanosauria; Upper Cretaceous; Vertebrae
• ISSN: 0891-2963; 1029-2381
• DOI: 10.1080/08912963.2023.2259413

Jiangxititan ganzhouensis gen. et sp. nov. is a new titanosaurian sauropod recovered from the Upper Cretaceous (Maastrichtian) Nanxiong Formation of Jiangxi Province, southern China. It is characterised by: (1) posterior cervical and anterior dorsal centra strongly compressed dorsoventrally; (2) accessory horizontal laminae present within the anterior dorsal pleurocoels; (3) posterior cervical and anterior dorsal neural arches low; (4) posterior cervical and anterior dorsal neural spines deeply bifurcated and widely separated; (5) inverted 'V' lamina formed by the left and right medial spinoprezygapophyseal laminae present at the anterior margin of the bifid point in posteriormost cervical and anteriormost dorsal neural spines; (6) triangular fossa formed by the metapophysis, medial and lateral spinoprezygapophyseal laminae present at the anterior margins of the posteriormost cervical and anteriormost dorsal neural spines; (7) postzygapophyses in the posterior cervical vertebrae fan-shaped; (8) medial and lateral spinopostzygapophyseal laminae present in the anterior dorsal vertebrae; and (9) anterior dorsal rib short and gracil. Our phylogenetic analysis places Jiangxititan within the deeply-nested titanosauriform clade Lognkosauria and the sympatric Gannansaurus in a much earlier-diverging lineage. This new discovery thus demonstrates the presence of both early-diverging and late-diverging titanosauriform sauropods in the Late Cretaceous Ganzhou dinosaur fauna.