Laiyangosaurus youngi was erected as a saurolophine hadrosaurid on the basis of several cranial elements from the Jingangkou Formation, Wangshi Group, Upper Cretaceous of Laiyang, Shandong, China. The postcranial elements of this taxon are described in detail here, providing additional postcranial characteristics to L. youngi. The phylogenetic analysis included postcranial elements of L. youngi, indicating that L. youngi still lies in the Edmontosaurini clade and no more supplement of postcranial autapomorphy. However, three new postcranial autapomorphies can help distinguish L. youngi from other members of Edmontosaurini: a poorly expanded deltopectoral crest of the humerus, a brevis shelf at the base of the postacetabular process of the ilium, and a well-defined medioventral ridge on the medial side of the postacetabular process. This study is to increase our knowledge on the anatomy and phylogeny of hadrosaurids of Edmontosaurini and provide new valuable evidence for discussing on the taxonomic position and validity of hadrosauroids in the Laiyang Hadrosauroid Fauna.
Keywords: Laiyang; Laiyangosaurus youngi; Saurolophinae; Wangshi group; postcranial anatomy.
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