Abstract: A mammalian lower jaw with the last two premolars and four molars was discovered from the late Early Cretaceous ( Aptian-Albian) Shahai Formation in Heishan County , Liaoning Province , China. It represents the first record of " eupantotherian" in China. It is characterized by submolarized last premolar , relatively large but unbasined talonid and lacking facet 5 on molars , enlarged m4 and elevated angular process. A new genus and species, Mozomus shihamai gen. et sp. nov. , is named based on the specimen. Morphologically , the new taxon is similar to the Mongolian KielanLherium of ? Aptian or ? Albian in general ( Dashzeveg and Kielan-Jaworowska, 1984) , but differs from the latter, probably primitively, in lacking facet 5 on molars. Kielantheriids were regarded as plesiomorphic in molar structure among mammals with tribosphenic pattern " and possess " a putative phylogenetic position as a stem boreosphenidan" (Luo et al. , 2002 : 11 ) . Reexamination of the specimen of Kielantherium gobiensis ( GI PST 10-16) brings into question of the shearing facet, and a comparison between Kielantherium and Mozomus is given in the present paper.