A new caenagnathid dinosaur from the Upper Cretaceous Wangshi Group of Shandong, China, with comments on size variation among oviraptorosaurs

Yilun Yu,Peiye Wang,Xing Xu,Shuqing Chen,Shuo Wang,Kebai Wang,Corwin Sullivan

doi:10.1038/s41598-018-23252-2

Abstract

The bone-beds of the Upper Cretaceous Wangshi Group in Zhucheng, Shandong, China are rich in fossil remains of the gigantic hadrosaurid Shantungosaurus. Here we report a new oviraptorosaur, Anomalipes zhaoi gen. et sp. nov., based on a recently collected specimen comprising a partial left hindlimb from the Kugou Locality in Zhucheng. This specimen’s systematic position was assessed by three numerical cladistic analyses based on recently published theropod phylogenetic datasets, with the inclusion of several new characters. Anomalipes zhaoi differs from other known caenagnathids in having a unique combination of features: femoral head anteroposteriorly narrow and with significant posterior orientation; accessory trochanter low and confluent with lesser trochanter; lateral ridge present on femoral lateral surface; weak fourth trochanter present; metatarsal III with triangular proximal articular surface, prominent anterior flange near proximal end, highly asymmetrical hemicondyles, and longitudinal groove on distal articular surface; and ungual of pedal digit II with lateral collateral groove deeper and more dorsally located than medial groove. The holotype of Anomalipes zhaoi is smaller than is typical for Caenagnathidae but larger than is typical for the other major oviraptorosaurian subclade, Oviraptoridae. Size comparisons among oviraptorisaurians show that the Caenagnathidae vary much more widely in size than the Oviraptoridae.

Highlights

Oviraptorosauria is a clade of maniraptoran theropod dinosaurs characterized by a short, high skull, long neck and short tail
ZCDM V0020 (Zhucheng Dinosaur Museum, Zhucheng, Shandong, China), an incomplete left hindlimb, including the left femur missing the distal end, the left tibia missing the proximal end, the left fibula missing the distal and proximal ends, a complete metatarsal III and two pedal phalanges. These bones are disarticulated, they are inferred to be derived from a single theropod individual given that 1) they were preserved in a small area of less than 0.3 square metres within a Shantungosaurus bonebed; and 2) no other theropod skeletal elements are preserved nearby
In order to determine the systematic position of Anomalipes zhaoi, we conducted a phylogenetic analysis of a matrix derived from a recently published comprehensive dataset for coelurosaurian theropod phylogeny[32], but with the addition of Anomalipes zhaoi and 13 new characters

Summary

Introduction

Oviraptorosauria is a clade of maniraptoran theropod dinosaurs characterized by a short, high skull, long neck and short tail. Over the last decade we have organized several major excavations in the Upper Cretaceous Wangshi Group at the Zangjiazhuang, Longgujian, and Kugou localities, Zhucheng, Shandong Province, China, which are in close geographic and stratigraphic proximity to each other, and produce similar dinosaur assemblages dominated by colossal hadrosaurid specimens. These excavations have yielded at least four new dinosaur taxa, including a tyrannosaurid, two leptoceratopsids, and a ceratopsid[9,10,11,12,13]. This new discovery, along with previously reported fossil remains, provides strong evidence supporting a close biogeographical relationship between the Zhucheng dinosaurian fauna and contemporary North American ones

Methods

Results

Conclusion