Pyrrhulina marilynae, new species, is described. The new species can be distinguished among congeners mainly by presenting a conspicuous, dark, zigzag shaped primary stripe, extending to distal end of median caudal-fin rays, reduction of the number of precaudal vertebrae, absence of postecleithrum 2, and nine principal rays on caudal-fin dorsal lobe. The putative relationship of the new species with Pyrrhulina australis, P. vittata and P. zigzag, three small-sized species of the genus, is discussed.