A new troodontid from the Upper Cretaceous Gobi Basin of inner Mongolia, China

Abstract

A new troodontid dinosaur, Papiliovenator neimengguensis gen. et sp. nov., from the Upper Cretaceous (Campanian) Wulansuhai Formation at Bayan Manduhu, Inner Mongolia, China, is described here. The holotype (BNMNH-PV030) consists of a nearly complete cranium and fragmentary postcranial bones in semi-articulation and this specimen is inferred as a subadult based on the osteohistological information and the fusion of bones. Papiliovenator neimengguensis is distinguishable from other troodontids based on a suite of features such as the lateral groove of the dentary not posteriorly expanded, a deep surangular fossa anteroventral to the glenoid fossa and hosting the surangular foramen, the ventral ridge of the surangular fossa mainly on the surangular, and a unique anterolaterally broadened and butterfly-shaped neural arch of the anteriormost dorsal vertebrae in dorsal view. Our phylogenetic analysis recovered Papiliovenator neimengguensis at the earliest-diverging branch of a clade including all other Late Cretaceous troodontids except Almas. The discovery of Papiliovenator neimengguensis allows for an improved understanding of troodontid anatomy, as well as the regional variation of troodontids from the Upper Cretaceous of the Gobi Basin.