A large-sized basal ankylopollexian from East Asia, shedding light on early biogeographic history of Iguanodontia  

作　　者：Xing Xu Qingwei Tan Yilong Gao Zhiqiang Bao Zhigang Yin Bin Guo Junyou Wang Lin Tan Yuguang Zhang Hai Xing 

机构地区：[1]Key Laboratory of Evolutionary Systernatics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China [2]Long Hao Institute of Geology and Paleontology, Hohhot 010010, China [3]Bureau of Land and Resources of Bayannur, Bayannur 015000, China [4]Inner Mongolia Museum of Natural History, Hohhot 010020, China [5]Beijing Museum of Natural History, Beijing Academy of Science and Technology, Beijing 100050, China

出　　处：《Science Bulletin》2018年第9期556-563,共8页科学通报（英文版）

基　　金：supported by the Beijing Natural Science Foundation(5174032);the National Natural Science Foundation of China(41688103,41120124002,91514302 and 41602006);the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB18030504);the Youth Backbone Training Plan(201601);Overseas Talents Attracting Program(OTP-2018-001);Innovative Team Program(IG201705N)of the Beijing Academy of Science and Technology;the Beijing Millions of Talents Project in the New Century and the Department of Land and Resources of Inner Mongolia

摘　　要：A presumably mostly quadrupedal ankylopollexian iguanodontian, Bayannurosaurus perfectus gen. et sp. nov., is reported here, and is represented by an excellently well-preserved skeleton from the Lower Cretaceous Bayingebi Formation of Inner Mongolia, China. The diagnosis of the taxon includes several autapomorphies, notably a dorsally directed, strap-like posterodorsal process of the jugal and a horizontally oriented preacetabular process of the ilium. The nearly complete caudal series retains eight posterior-most caudals with procoelous, trapezoidal centra in dorsal view, and the last three caudals are fully fused. The discovery ofB. perfectus opens a critical new window on the early evolution and intercontinental dispersal of lguanodontia. The skeleton displays a transitional morphology between nonbadrosauriform ankylopollexians and Hadrosauriformes. A phylogenetic analysis indicates that Bayannurosaurus is positioned higher on the tree than Hypselospinus, but below Ouranosaurus just outside of Hadrosauriformes. The tree topology of Iguanodontia with temporal and spatial constraints reveals a possible biogeographic scenario supported by the statistical dispersal-vicariance analysis： around the J/K boundary, non-hadrosauriform ankylopollexians experienced multiple dispersal events from Europe to Asia, accompanying the coeval fall of the global sea level.A presumably mostly quadrupedal ankylopollexian iguanodontian, Bayannurosaurus perfectus gen. et sp.nov., is reported here, and is represented by an excellently well-preserved skeleton from the Lower Cretaceous Bayingebi Formation of Inner Mongolia, China. The diagnosis of the taxon includes several autapomorphies, notably a dorsally directed, strap-like posterodorsal process of the jugal and a horizontally oriented preacetabular process of the ilium. The nearly complete caudal series retains eight posterior-most caudals with procoelous, trapezoidal centra in dorsal view, and the last three caudals are fully fused. The discovery of B. perfectus opens a critical new window on the early evolution and intercontinental dispersal of Iguanodontia. The skeleton displays a transitional morphology between nonhadrosauriform ankylopollexians and Hadrosauriformes. A phylogenetic analysis indicates that Bayannurosaurus is positioned higher on the tree than Hypselospinus, but below Ouranosaurus just outside of Hadrosauriformes. The tree topology of Iguanodontia with temporal and spatial constraints reveals a possible biogeographic scenario supported by the statistical dispersal-vicariance analysis: around the J/K boundary, non-hadrosauriform ankylopollexians experienced multiple dispersal events from Europe to Asia, accompanying the coeval fall of the global sea level.

关 键 词：Non-hadrosauriform ankylopollexian Lower Cretaceous Bayingebi Formation Inner Mongolia Intercontinental dispersal 

分 类 号：Q915[天文地球—古生物学与地层学]