One new genus and two new species of Graphidaceae are described from tropical dry forests of Mexico, based on morphological and molecular data of the mtSSU, nuLSU and ITS markers. The new genus Jocatoa in subfamily Graphidoideae is described to accommodate the species Graphis agminalis (syn.: Medusulina texana), previously known from Colombia and North America. The new genus resembles Diorygma but differs by having simple paraphyses tips that do not form an epithecium. Jocatoa agminalis is similar to Diorygma monophorum but differs by having larger ascospores, hypostictic and stictic acids and by the type of paraphysis tips. In subfamily Redonographoideae, the two new species Gymnographopsis corticicola and Redonographa parvispora are described, representing the first corticolous species in the subfamily. Gymnographopsis corticicola is characterized by the smallest spores in the genus, the presence of norstictic acid, and a rectangular perispore that appears to be a newly recognized character state in fungi. Redonographa parvispora is characterized by warty periphysoids, small ascospores with 3 transverse septa, and norstictic acid. It also frequently develops a rectangular perispore. We present a phylogenetic analysis, based on the markers mtSSU, nuLSU and RPB2, that includes all the genera in the family Graphidaceae, with available sequences, to accommodate the new genus and to validate for the first time the position of Gymnographopsis. Diagnostic anatomical and ecological characters are discussed for Redonographoideae. Gymnographopsis is newly reported to the Northern Hemisphere.