Abstract: Some material of Protitan is discovered by the staffs of IVPP and Dinosaur Museum of Erlianhot city from Late Eocene Tukhum beds in Erden Obo (Urtpn Obo) area of Siziwangqi, Nei Mongol during the summer field season of 1991. This is the first discovery of giant mammal from Tukhum beds in Shara Murun area. The material includes a third lower molar and several isolated bones. All of them are found in one square meter, and we believe that they represent an individual (V10104—1 VPP number). At present, a total of 4 species are found in Tukhum beds: I. Teilhardia pretiosa; 2. Lophialetes expeditus?; 3. Protitan sp. (V10104); 4. a small carnivore (unpublished).

摘要： 在内蒙古四子王旗额尔登敖包相当于晚始新世的土克木层中发现了原雷兽(Protitan)化石。这是在该层位中时隔60多年(1926-1991)之后发现的第四种动物。也是首次发现的大型哺乳动物。