Muyelensaurus redescribed + hadrosaurid from Cretaceous Nenjiang Formation of China
70 views
Skip to first unread message
Ben Creisler
Jan 13, 2026, 12:09:16 PM (5 days ago) Jan 13
to DinosaurMa...@googlegroups.com
Ben Creisler
New papers:
Agustín Pérez Moreno, José L. Carballido, Alejandro Otero & Leonardo Salgado (2026)
Osteological reassessment of Muyelensaurus pecheni (Dinosauria: Sauropoda): Systematics and its phylogenetic implications for the clade Rinconsauria
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2025.2585363
https://www.tandfonline.com/doi/full/10.1080/08912963.2025.2585363
Since its definition, Rinconsauria has been considered a titanosaurian clade more deeply nested than Lognkosauria and closely related to Aeolosaurini. However, some recent analyses include Lognkosauria within Rinconsauria, with other studies suggest that its specifiers, Rinconsaurus caudamirus and Muyelensaurus pecheni, are not particularly closely related, thereby affecting its taxonomic composition. This discrepancy may be a consequence of several different factors, from insufficient description of their anatomy, missing data, or even the presence of multiple species amongst the materials referred to Muyelensaurus. Recently, Rinconsaurus caudamirus was reviewed, but Muyelensaurus pecheni still requires a thorough re-evaluation. This titanosaur from the Late Cretaceous (Plottier Formation) was discovered at the Loma del Lindero site in the northeast of the Neuquén Province. Here, we present a detailed description of its holotype, paratypes, and originally referenced remains. The presence of repeated remains with varied morphologies indicates that there is more than one taxon amongst the materials of Muyelensaurus indicating that the specie is a chimeric assemblage. Consequently, we restrict Muyelensaurus pecheni to the holotype specimen only. Our osteological study modified an autapomorphic character of its diagnosis: a braincase with the basal tuber with a divergence angle of 90°. The holotype of Muyelensaurus pecheni was included in six phylogenetic analyses using three independent datasets, under both equal weights and extended implied weights approaches. In all analyses, the instability of Muyelensaurus affected the taxonomic content of Rinconsauria. Therefore, we redefined Rinconsauria as the most inclusive clade containing Rinconsaurus caudamirus but not Mendozasaurus neguyelap or Gondwanatitan faustoi.
=====
Kaifeng Yu, Wenhao Wu, Xiangjiang Yu & Pascal Godefroit (2026)
First occurrence of hadrosaurid (Dinosauria: Ornithopoda) remains from the Nenjiang Formation (early Campanian) in the Songliao Basin, Northeast China
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2025.2605518
https://www.tandfonline.com/doi/full/10.1080/08912963.2025.2605518
We describe the first hadrosaurid fossils from the Upper Cretaceous Nenjiang Formation (early Campanian) in the Songliao Basin, Northeast China. The material comprises an isolated tooth, three dentary fragments, and several fragmentary postcranial bones consisting of dorsal, sacral, and caudal vertebrae, as well as fragments of the pubis, ischium, and fibula. Morphological analyses indicate that the postcranial material can be assigned to Lambeosaurinae. These lambeosaurine remains represent a rare record of the early divergence of this group, supporting the hypothesis of an Asian origin for lambeosaurines and their subsequent dispersal to North America. This study expands the known geographic and temporal distribution of hadrosaurids, highlights the significance of the Nenjiang Formation in documenting dinosaur diversity, and provides valuable insights into the terrestrial ecosystems of the Songliao Basin during the Late Cretaceous.
=======
Agustín Pérez Moreno, José L. Carballido, Alejandro Otero & Leonardo Salgado (2026)
Osteological reassessment of Muyelensaurus pecheni (Dinosauria: Sauropoda): Systematics and its phylogenetic implications for the clade Rinconsauria
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2025.2585363
https://www.tandfonline.com/doi/full/10.1080/08912963.2025.2585363
Since its definition, Rinconsauria has been considered a titanosaurian clade more deeply nested than Lognkosauria and closely related to Aeolosaurini. However, some recent analyses include Lognkosauria within Rinconsauria, with other studies suggest that its specifiers, Rinconsaurus caudamirus and Muyelensaurus pecheni, are not particularly closely related, thereby affecting its taxonomic composition. This discrepancy may be a consequence of several different factors, from insufficient description of their anatomy, missing data, or even the presence of multiple species amongst the materials referred to Muyelensaurus. Recently, Rinconsaurus caudamirus was reviewed, but Muyelensaurus pecheni still requires a thorough re-evaluation. This titanosaur from the Late Cretaceous (Plottier Formation) was discovered at the Loma del Lindero site in the northeast of the Neuquén Province. Here, we present a detailed description of its holotype, paratypes, and originally referenced remains. The presence of repeated remains with varied morphologies indicates that there is more than one taxon amongst the materials of Muyelensaurus indicating that the specie is a chimeric assemblage. Consequently, we restrict Muyelensaurus pecheni to the holotype specimen only. Our osteological study modified an autapomorphic character of its diagnosis: a braincase with the basal tuber with a divergence angle of 90°. The holotype of Muyelensaurus pecheni was included in six phylogenetic analyses using three independent datasets, under both equal weights and extended implied weights approaches. In all analyses, the instability of Muyelensaurus affected the taxonomic content of Rinconsauria. Therefore, we redefined Rinconsauria as the most inclusive clade containing Rinconsaurus caudamirus but not Mendozasaurus neguyelap or Gondwanatitan faustoi.
=====
Kaifeng Yu, Wenhao Wu, Xiangjiang Yu & Pascal Godefroit (2026)
First occurrence of hadrosaurid (Dinosauria: Ornithopoda) remains from the Nenjiang Formation (early Campanian) in the Songliao Basin, Northeast China
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2025.2605518
https://www.tandfonline.com/doi/full/10.1080/08912963.2025.2605518
We describe the first hadrosaurid fossils from the Upper Cretaceous Nenjiang Formation (early Campanian) in the Songliao Basin, Northeast China. The material comprises an isolated tooth, three dentary fragments, and several fragmentary postcranial bones consisting of dorsal, sacral, and caudal vertebrae, as well as fragments of the pubis, ischium, and fibula. Morphological analyses indicate that the postcranial material can be assigned to Lambeosaurinae. These lambeosaurine remains represent a rare record of the early divergence of this group, supporting the hypothesis of an Asian origin for lambeosaurines and their subsequent dispersal to North America. This study expands the known geographic and temporal distribution of hadrosaurids, highlights the significance of the Nenjiang Formation in documenting dinosaur diversity, and provides valuable insights into the terrestrial ecosystems of the Songliao Basin during the Late Cretaceous.
=======
Reply all
Reply to author
Forward
0 new messages