Cranial Endocast of the Lambeosaurine Hadrosaurid Amurosaurus riabinini from the Amur Region, Russia

Pascaline Lauters,Martine Vercauteren,Pascal Godefroit,Yuri L Bolotsky,Richard J Butler

doi:10.1371/journal.pone.0078899

Abstract

Information on the structure of the brain of the lambeosaurine hadrosaurid dinosaur Amurosaurus riabinini, from the Late Maastrichtian of Blagoveschensk, Far Eastern Russia, is presented based on endocranial casts. The endocasts are compared with physical and digital endocasts of other dinosaurs. The olfactory tract was large. The cerebral hemispheres are enlarged and round, illustrating the important development of this part of the brain in hadrosaurids. The pituitary body is enlarged as well, perhaps prefiguring the large size attained by hadrosaurids. The EQ of Amurosaurus was similar to that of the lambeosaurine dinosaur Hypacrosaurus altispinus and was relatively larger than in most extant non-avian reptiles, including sauropod and ceratopsian dinosaurs. However, it was apparently relatively smaller than those of most theropod dinosaurs. The relatively large size of the cerebrum is consistent with the range and complexity of social behaviors inferred for lambeosaurine dinosaurs.

Highlights

Since 1902, and the first discovery of dinosaur fossils in the Amur region (Far Eastern Russia), thousands of bones were collected from this area
The purpose of this paper is to describe the endocast and the cranial nerves of Amurosaurus riabinini, and is based on the assumption that the casts provide a good insight into the general morphology of the brain [13,14,15,16,17]
The Reptile Encephalization Quotient (REQ) (2.3–3.8) estimated for Amurosaurus is higher than most extant non-avian reptiles [14], as well as sauropod (Diplodocus, 0.53–0.69; Nigersaurus, 0.4–0.8; [48,49]) and ceratopsian (Psittacosaurus, 1.7; Triceratops, 0.7; [49,50]) dinosaurs

Summary

Introduction

Since 1902, and the first discovery of dinosaur fossils in the Amur region (Far Eastern Russia), thousands of bones were collected from this area. Charonosaurus jiayinensis Godefroit, Zan, and Jin, 2000 [5,6], Sahaliyania elunchunorum Godefroit, Shulin, Tinghai, and Lauters, 2008 [7] and Wulagasaurus dongi Godefroit, Shulin, Tinghai, and Lauters, 2008 [7] were found in the adjacent region of China (Heilongjiang Province) Among this material, some braincases of Amurosaurus were found. In some cases this method is impractical; the specimen may be too small or too large to be CT scanned, or researchers cannot access the machine or the cost to use it is too high It is possible in some cases to make an endocast without damaging the specimen, using materials such as silicone or latex rubber [11,12]

Objectives

Results

Conclusion