Therian mammals have two families of postcanine teethpremolars and molars, which primitively are morphologi-cally distinct, but within each family, structure of thecrowns changes in an evenly graded series from mesial todistal loci. Here we report a new M Therian mammals have two families of postcanine teethpremolars and molars, which primitively are morphologi-cally distinct, but within each family, structure of thecrowns changes in an evenly graded series from mesial todistal loci. Here we report a new M