四川自贡大山铺中侏罗世蜀龙和峨眉龙长骨骨组织结构的初步研究

PRELIMINARY HISTOLOGICAL STUDY ON THE LONG BONES OF MIDDLE JURASSIC SHUNOSAURUS AND OMEISAURUS FROM DASHANPU, ZIGONG, SICHUAN

通过对四川自贡大山铺恐龙动物群中两种主要蜥脚类恐龙—李氏蜀龙和天府峨眉龙肱骨和尺骨的骨组织结构观察,并与我国晚白垩世的几种恐龙长骨进行对比,结果发现:1)恐龙的长骨都具有快速的后生生长速率;2)恐龙的生长方式属于非限定生长,即在成年后并不停止生长;3)不同类型的恐龙到了成年以后,其骨沉积速率可能有较大差异;4)不同类型的恐龙在长骨的生长改建过程中,骨组织内部的重吸收作用有较大差异;5)生长轮结构在不同部位的骨骼中或在骨骼的生长发育过程中可能也有较大差异。

The present paper describes the histological features of the long bones of Shunosaurus lii and Omeisaurus tianfuensis from the Dashanpu Dinosaur Fauna in Zigong. There are some similar features in these two dinosaurs as follows： The long bones of the two dinosaurs are composed of the compact bone and cancellous bone. The cortex of the compact bone of the two dinosaurs are fibrolamellar tissues which are composed of primary woven-fibroid and lamellar bone tissues. The cancellous trabeeulae are composed of the lamellar bone and with secondary Haversian bones in the lamellar bones. There is an obviously broken cancellous area in the center of the cancellous bone in humerus of the two dinosaurs. The restlines are not found in the long bones of the two dinosaurs. On the other hand, there are some differences in these two dinosaurs as follows： There are no laminar structures in the fibrolamellar bones of the humerus of Shunosaurus lii, but the laminar structures are present in those of Omeisaurus tianfuensis. There is no obvious Haversian bone in the adult humerus of Shunosaurus lii, but it is very obvious in Omeisaurus tianfuensis and its thickness is about the ninety percent of the compact bone. The broken cancellous area in the center of the cancellous bone in humerus of Omeisaurus tianfuensis is much smaller than that of Shunosaurus lii. Through the comparative histological study on the long bones of these two sauropods and other several dinosaurs from the Upper Cretaceous in China, the following results are obtained： The fibrolamellar tissues typical in the compact bones indicate that its long bones had a rapid postnatal growth rate. The growth styles of the dinosaurs belong to the indeterminate growth, it means that the growth is not ceased after they reached adult stage. The rates of deposition are obviouly different in adult dinosaurs. The resorption in the inner part of the bone has more differences in the growth process of the long bones in different dinosaurs. The growth lines have some obvious differences between the different bones or in the growth process of the bones. All the features as mentioned above reveal that the histological features of dinosaurs are very complicated, in which there are some obvious differences between the different dinosaurs or in the adult and juvenile materials of the same dinosaur or the different bones of one individual or the different parts of one bone.