 |
| Liaoningotitan sinensis Zhou, Wu, Sekiya & Dong, 2018 in Shan, 2025. |
Abstract
Liaoningotitan sinensis is one of three sauropod species found in the Jehol Biota. Liaoningotitan sinensis is from the Lower Cretaceous Yixian Formation in Liaoning, China. The discovery of Liaoningotitan sinensis was an important breakthrough for researching the diversity of giant herbivorous animals in the Jehol Biota. However, the research and analysis of Liaoningotitan sinensis are not yet complete. This study presents a comprehensive research and analysis of Liaoningotitan sinensis holotype. First, the skull, vertebrae, pelvic girdle, and appendicular elements of Liaoningotitan sinensis holotype were carefully reexamined, leading to the discovery of mosaic evolution occurring in the skull and the identification of one new autapomorphy of humerus of Liaoningotitan sinensis: the attachment point of coracobrachialis muscle on the anterior surface of the proximal end of the humerus is flat. Second, the characteristics of the Liaoningotitan sinensis holotype and other well-preserved sauropod dinosaurs were used to reconstruct the skull of Liaoningotitan sinensis. Next, Euhelopus zdanskyi was used to reconstruct the body type of Liaoningotitan sinensis holotype, the result indicating that Liaoningotitan sinensis was approximately 10 m in length. Finally, TNT software was utilized to analyze the phylogenetic position of Liaoningotitan sinensis, with the result indicating that Liaoningotitan sinensis can be classified into the Euhelopodidae.
 |
Skull of Liaoningotitan sinensis holotype PMOL-AD00112. Preserved elements of Liaoningotitan sinensis holotype PMOL-AD00112. Edited from Euhelopus zdanskyi, a preserved complete Titanosauriform dinosaur. Painted by Gallipus (a net ID of helper https://www.deviantart.com/yty2000) Scale bar: 1 m. |
Conclusion:
The Liaoningotitan sinensis holotype is a partial skeleton from the Lower Cretaceous Yixian Formation, a formation famous for Jehol Biota. It displays some characteristics that suggest Liaoningotitan sinensis is a valid species that can be distinguished from other Titanosauriformes dinosaurs. This analysis classifies Liaoningotitan sinensis into Euhelopodidae, indicating that members of Euhelopodidae family inhabited this biota, which increases the known diversity of sauropod dinosaurs in the Jehol Biota. The research on the skull of Liaoningotitan sinensis holotype indicated that mosaic evolution is present in the Liaoningotitan, and it is in the transitional phase from early-diverging Titanosauriformes to late-diverging Titanosauriformes. The body type reconstruction of Liaoningotitan, which is referred to Euhelopus zdanskyi, shows that the Liaoningotitan sinensis holotype is more than 10 m long. Therefore, it is a medium-sized sauropod dinosaur. However, the unfused sacral vertebrae indicated the holotype is an immature specimen. In the end, we concluded the skull type of the Titanosauriformes. We got four types, indicating that the evolution of the Titanosauriformes may be more complex than we considered in the past.
Bingqing Shan. 2025. The Re-description of Liaoningotitan sinensis Zhou et al., 2018. PeerJ. 13:e19154. DOI: doi.org/10.7717/peerj.19154
