A new species of Diastoleus is described from the Atacama desert. Both morphological and genetic evidence support distinction of the Diastoleus reticulatus sp. nov. This new taxon is morphologically close to D. costalenis but genetically closer to D. bicarinatus. Probably all these species belong to the same lineage together with D. arrigadai. The newly discovered species constitutes the first record of this species group in the Andes Cordillera.