Lissomus cacique Johnson, new species from Costa Rica and Panama is described and discriminated from its morphologically most similar and geographically disjunct congener, Lissomus flavipennis Guérin-Méneville from Guatemala and southern Mexico. These two species form a unique pair in Lissomus Dalman distinguished by their relatively large and robust body form, yellow-brown to orange-red elytra not concolorous with the body, and the presence of a complete arcuate postcoxal carina partially delimiting the meso-metaventral crural impression. This new species is the largest of the genus and is only known from premontane cloud forests in Costa Rica and adjacent Panama. Lissomus flavipennis is known only from comparable premontane cloud forests in Guatemala and Mexico. The habitats of both species are now remnants of formerly more extensive forests and are threatened by anthropogenic activities.