Pterophyllum Brongniart 1825 is one of the most abundant morphogenus of bennettitalean foliage with at least 157 species documented in China. Among the numerous Pterophyllum species, P. crassinervum Huang et Chow was originally established solely based on insufficiently macromorphological features with limited fossil records. Here, we re-investigate this species for detailed descriptions and interspecific comparisons, and firstly show its epidermal structure based on new fossil collections from the Rhaetian of Upper Triassic strata in the northeastern Sichuan Basin, South China. The thoroughly re-examination of Pterophyllum crassinervum confirms its taxonomic validity and define the standard criteria for distinctive segregation of this species from its analogues. A neotype and an emended specific diagnosis with supplementary microstructures of Pterophyllum crassinervum are formally proposed. Based on a comprehensive interspecific comparison of Pterophyllum species, we confirm that the occurrence of mucronate teeth on pinnae apices is a rare character among this plant group. Considering the predominant position of Bennettitales (especially Pterophyllum) and active herbivories (especially marginal/ apical feeding) during the latest Triassic in northeastern Sichuan Basin, the appearance of mucronate teeth may represents the plant-insect co-evolutionary results.