Abstract: Teeth of saurischian tyrannosaurid and squamate mosasaurid are studied mainly by scanning electron microscopy. The teeth of both diapsids are cone —shaped homodontic teeth mediolaterally compressed and curved posteriorly. The sharp cutting edges at both anterior' and posterior aspects of tyrannosaurid tooth are serrated with invagination of a quite thin aprismatic enamel layer. Fissures and pits of the invaginations are packed with what is possibly a layer of fossilized organic substance. In contrast, similar serrated cutting edges are only observed at the basal portion or lepidosaurian mosasaurid teeth. The present scanning electron microscopy (SENI) observes a. similar intermediate type orthodentine (tubular dentine) with ill —developed peritubular dentine of both extinct reptiles. SEM reveals that dentinal tubules are regularly branched only in the vicinity of the flat dentino —enamel junction in tyrannosaurid tubular dentine, bul are complicatedly branched in the rnid and superficial —layer of mosasaurid dentine. The ryesent study also shows a few dentinal tubules invaded the enamel layer, with a similar configuration and an evident distribution of interglobular dentine beneath the thin enamel layer of both reptiles. Based on the present fine structure study, we elucidates some histological similarities and dissimilarities of the enamer and dentine in the reptilian tyrannosaurid and mosasaurid of different infraclasses.

摘要： 本文是利用扫描电子显微镜对陆栖恐龙tyrannosaurid与海栖蜥蜴mosasaurid牙齿结构进行的比较解剖学研究。化石采自加拿大Red Deer River Valley上白垩统Horseshoe Canyon组。通过研究地层中出现的生物化石，特别是动物牙齿的组织结构，可以了解动物为了适应生活环境而发生的进化过程，也可以推测它们的系统发育关系。 tyrannosaurid与mosasaurid都拥有锥状的同形齿，牙齿侧向扁平，且略向后弯曲。研究结果确认了tyrannosaurid的牙齿由于薄