Hayashibara Museum of Natural Sciences Research Bulletin, vol. 3, pp. 11–18, March 31, 2010 © 2010 by the Hayashibara Museum of Natural Sciences, Okayama, Japan Report of the HMNS-MPC Joint Paleontological Expedition in 2006 Mahito WATABE 1 , Shigeru SUZUKI 1 , Khishigjav TSOGTBAATAR 2 , Takehisa TSUBAMOTO 1 , and Mototaka SANEYOSHI 1 1 Center for Paleobiological Research, Hayashibara Biochemical Laboratories, Inc., Okayama 700-0907, Japan 2 Mongolian Paleontological Center, Mongolian Academy of Sciences, Ulaanbaatar 210351, Mongolia Watabe, M., Suzuki, S., Tsogtbaatar, Kh., Tsubamoto, T., and Saneyoshi, M., 2010. Report of the HMNS-MPC Joint Paleon- tological Expedition in 2006. Hayashibara Mus. Nat. Sci. Res. Bull. 3: 11–18. Abstract. Procedures and results of the joint expedition between Japan and Mongolia in 2006 were briefly reported. The expedition was carried out in the western part of the Gobi desert mainly on Nemegt and Ba- rungoyot dinosaur fossil localities and Paleocene and Eocene mammalian localities. 11 Introduction The joint expedition in 2006 was carried out in the western area of the Gobi desert (Ingeni Khoovur and Nemegt basins). The geological age of the localities sur- veyed is late Cretaceous and Paleogene (Paleocene and Eocene). The joint expedition was planned for the follow- ing purposes. 1. Prospecting vertebrate fossils on dinosaur localities in the western region of the Gobi desert, especially of the Nemegt age. 2. Geological survey on those localities for sedimento- logical interpretation of their paleoenvironments. 3. Prospecting vertebrate fossils on mammalian locali- ties in the western region of the Gobi desert, especially of Paleogene (Paleocene and Eocene) age. 4. Geological survey on those localities for interpreta- tion of their paleoenvironment. Members of the Joint Expedition Party in 2006 The members of the joint expedition party from the Japanese side are as follows: SUZUKI, Shigeru (researcher, HMNS); WATABE, Mahito (researcher, HMNS); TSUBAMOTO, Takehisa (researcher, HMNS); SANEYOSHI, Mototaka (researcher, HMNS); TSUIHIJI, Takanobu (researcher: University of Ohio, USA); KAWAHARA, Yasuhiro (preparator, HMNS); Total number of Japanese participants is six. *Hayashibara Museum of Natural Sciences is abbreviated as HMNS. The members of the party from the Mongolian side are as follows: TSOGTBAATAR, Khishigjav (researcher, MPC); GERELTSETSEG, Lkhagva (researcher, MPC); CHINZORIG, Tsogtbaatar (researcher, MPC); OTGONJARGAL, Chultem (preparator, MPC); BAT-ORKHON, Namjaa (preparator, MPC); BAYARDORJ, Chagnaa (preparator, MPC); MAINBAYAR, Buurei (student of Ulaanbaatar Univer- sity); KHATANBAATAR, Purevdorj (student of Ulaanbaatar University); GAN-ULZII, Davgadulam (driver of new GAZ truck); DAMDINKHUU, Tolya (driver of old GAZ truck); TSOLMONBAATAR, Davaasuren (driver of ZIL truck); DUGERLKHAM, Alik (cook). Total number of Mongolian participants is twelve. *Mongolian Paleontological Center is abbreviated as MPC. Schedule of fieldwork and localities surveyed The expedition was performed from July 31 to Sep- tember 12, 2006, a total of 44 days. In the following section, name of the localities are shown. The geological formation and age of each locality (estimated) are shown in parenthesis. The geographical distribution of these localities and the expedition route are shown in Figure 1. Detailed location map of these locali- ties are shown in Figure 2. Bugin Tsav and Bugin Tsav II (Upper Cretaceous, Nemegt Formation) Gurilin Tsav (Upper Cretaceous, Nemegt Formation) Eastern badlands of Gurilin Tsav (Upper Cretaceous?) Khaichin Ula I (Upper Cretaceous, Nemegt Formation) Altan Ula II, III, and IV (Upper Cretaceous, Nemegt Formation) Tsagaan Khushuu (northern area) (Upper Cretaceous, Nemegt Formation)