The first tyrannosauroid tooth from Korea

摘要

A tyrannosauroid premaxillary tooth has been discovered for the first time in the Hasandong Formation (Lower Cretaceous) in South Korea. Carinae on the tooth form both the mesial and distal edges of the lingual face, producing a “D-shaped” cross section typical of tyrannosauroids. The Korean premaxillary tooth is different from those of other known Early Cretaceous tyrannosauroids (Dilong, Eotyrannus, and a Japanese tooth) in having a distinct lingual ridge on the lingual surface. This discovery probably indicates a subsequent Asian diversification of this group (Korea, China and Japan) after the origination of tyrannosauroids in the early Late Jurassic (e.g., Guanlong) in China.