Xenotriphleba dentistylata gen. et sp. n. is described from specimens of both sexes collected in Germany and Switzerland. The new genus resembles Triphleba in non-genitalic characters, but the male genitalia differ from Triphleba Rondani and the majority of phorid genera in possessing two freely articulated surstyli which are not fused to the epandrium. This remarkable character state represents a plesiomorphic ground-plan feature of the Phoridae which has been lost in all genera except Burmophora Beyer and Beyermyia Disney. The phylogenetic significance of selected character states is evaluated and the systematic affinities of the new genus are discussed. Xenotriphleba dentistylata cannot be classified properly in the phylogenetic system of Phoridae proposed by Brown (1992) as the character states observed in this genus are in contradiction to the hypothesized constitutive features of all recognized subfamilies. Until further progress in the classification of Phoridae has been made, X. dentistylata must be regarded as a primitive representative of a basal lineage of this family.