二连浩特恐龙肩胛骨显微结构分析

Microstructure Analysis of the Dinosaur Scapula in Erenhot

晚白垩世的二连盆地是恐龙的理想栖息地。通过手标本观察、铸体薄片分析、扫描电镜分析、X射线衍射分析、能谱分析等方法,对取自于二连盐池北部二连达布苏组的一块骨骼化石进行了系统研究。结果表明:①该骨骼化石为恐龙的肩胛骨;②肩胛骨由骨密质(包括腹侧面骨板和背侧面骨板)和骨松质组成,基本单位为骨单位;③骨单位结构和形态随肩胛骨部位的不同而具有明显差异,腹侧面骨板中的骨单位呈现扁长状-板状紧密排列,而骨松质中的骨单位呈浑圆状或椭圆状且脉管通道直径粗大,背侧面骨板的骨单位介于前两者之间;④在骨单位内部,生长较晚的骨细胞核部饱满且通常位于脉管通道附近,而生长较早的骨细胞则远离脉管通道,细胞核部干瘪,但骨小管异常发育;⑤依据骨单位的相互蚕食现象、骨密质与骨松质中骨单位生长纹的差别,以及骨单位中新老骨细胞的排列规律,推测恐龙肩胛骨的骨生长方式属于膜内成骨模式;⑥成分分析发现,恐龙肩胛骨化石的成分为氟磷灰石,其与现有生物差别不大,表明其进化已接近完善。

The Eren basin was the ideal habitation of dinosaurs in the Late Cretaceous. The study system- atically analyzes the osteolith sample collected from the Eren Dabasu Formation in the northern Erlian Yanchi by using macroscopic sample observation, cast thin-sections analysis, SEM analysis, X-ray diffrac- tion analysis, and energy spectrum analysis methods. The results showed that the osteolith is a dinosaur scapula composed of compact bone including ventral and dorsal osseous lamella and spongy bone, and the osteon is the basic unit of the scapula. According to the observations, the structure and appearance of the ostean are closely related to its position in the scapula, the osteons in the ventral side of osseous lamella are arranged in narrow strip, .the spongy bone are in almost roundness with large diameter vascular canals, and the feature of osteons in the dorsal side are between the first two types. In the interior osteon, the new- born osteocyte is generally located beside the vascular canal with plump main part, on the contrary, the old one is far from the vascular canal with wizened main part and well-developed bone canalicules. Based on the phenomenon of erosion between osteons, the difference of growth-line between compact bone and spongy bone, and the arrangement of both old and young osteocytes, this paper conjectures that the growth pat- tern of the dinosaur scapula is intramembranous ossification. The X-ray diffraction analysis showed that the composition of the fossil is fluorapatite which is not much divergent from animals nowadays. As a re- sult, it is speculated that the dinosaur is almost evolved into a modern creature-like animal.