A new genus and species belonging to the Macrosemiidae is described. This is the first record of a macrosemiid in the New World. The material was collected from the Early Cretaceous (Albian) Tlayúa Quarries, in Tepexi de Rodríguez, central México. The new taxon is a small, elongated fish that bears a combination of apomorphic and plesiomorphic characters including a divided dorsal fin with an area devoid of scales on either side, prearticular and coronoid bones with small pointed teeth, and strongly ornamented body scales. Phylogenetic analysis using PAUP revealed a close relationship of this new genus to Macrosemius and Legnonotus. The occurrence of macrosemiids in the Tlayúa beds indicates a wider distribution of the group within the Tethys Ocean, and represents the westernmost record of this group of neopterygians.