A second hadrosauroid dinosaur from the early Late Cretaceous of Zuoyun, Shanxi Province, China

Abstract

A second basal hadrosauroid dinosaur, Zuoyunlong huangi gen. et sp. nov., is reported from the early Late Cretaceous Zhumapu Formation in Zuoyun County, Shanxi Province, northern China. Zuoyunlong preserves a partial right ilium and ischium and is unique in having a very short postacetabular process 50% as long as the iliac central plate. Our cladistic analysis recovers Zuoyunlong as the most basal Late Cretaceous hadrosauroid, with a sister taxon relationship with Probactrosaurus from the late Early Cretaceous of Inner Mongolia. Including Zuoyunlong, four Cenomanian basal hadrosauroids have been recorded, and the two taxa in North America (Eolambia and Protohadros) represent the earliest known hadrosauroids outside of Asia. In the light of the proposed phylogenetic topology and biogeographic data, the discovery of Zuoyunlong indicates that the first dispersal of hadrosauroids from Asia to North America probably happened around the boundary between the Early and Late Cretaceous.

Keywords:

• Dinosauria
• Hadrosauroidea
• Shanxi
• Zuoyun
• Late Cretaceous
• Cenomanian

Acknowledgements

We are very grateful to Mr Zhi-Lu Tang for arranging this study and to the crew of the Shanxi Museum of Geology for discovering, excavating and preparing the specimen. Hai Xing sincerely thanks the following people for access to specimens under their care: Don Brinkman, Kieran Shepherd, Mark Norell, Michael Brett-Surman, Vladimir Alifanov, Paul Barrett and David Evans. Finally, we also thank the academic editor Gareth Dyke and two anonymous reviewers for improving the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.