The Neotropical genus LucernutaLaporte, 1833 comprises a mixed assembly of taxa, whose diagnoses currently overlaps with some species listed under CratomorphusMotschulsky, 1853. Here, we review, provide new biological data, and update the geographic range of the species currently listed under Lucernuta in McDermott 1966. We propose the following nomenclatural decisions: Lucernuta fenestrataGermar, 1824 is considered a junior synonym of L. savigniiKirby, 1818; Lucernuta minutaPic, 1930 is transferred to Cratomorphus, therefore generating the new combination C. minutusPic, 1930; L. hammariMcDermott, 1959 is considered a junior synonym of Platylampis diversithoraxPic, 1943; Lucernuta paraguayensisMcDermott, 1960 is considered a junior synonym of Cratomorphus besckeiOlivier, 1895. Therefore, Lucernuta is regarded as monotypic, with L. savignii as the sole species in this genus, which is endemic to the Brazilian Atlantic Rainforest. Moreover, we designate a lectotype and describe for the first time the female of C. minutus. We also provide a key to Lamprocerini genera, in addition to new diagnoses, distribution maps, and illustrations of diagnostic features for the four species studied here: L. savignii, P. diversithorax. C. besckei and C. minutus, and highlight issues that should be addressed in the future towards a revised classification of Cratomorphus.