ABSTRACTTenebrionoids are not uncommon in late Mesozoic ambers, but their paleodiversity remains poorly explored, partly due to the insufficiently defined families of the extant fauna. Here, we describe and illustrate a new tenebrionoid beetle from mid‐Cretaceous Kachin amber, Glyphonotum hsiaoi gen. et sp. nov., which exhibits an unusual form of pronotal sulcus and tarsi. Based on morphological comparison and phylogenetic analyses, we tentatively place Glyphonotum in the extant family Pythidae, representing the first Mesozoic fossil of this family.