A new species of Pterolebias from Caceres, Paraguay River Basin, State of Mato Grosso, Brazil, is described. It was found in a temporary lagoon on the Brazilian Central Cerrado and seems to have the same annual habits of the other species of the group. The new species differs from all other species but P. staeckiin the colour pattern on the sides of the body, which consists of longitudinal stripes. From P. siaecki it differs in the relative length of the pelvic-fin and of the predorsal area and by the number of scales in the longitudinal series. The similarity between P. bokermanni and P. longipinnis is discussed.