A revision of the Limnius perrisi subspecies group in the Iberian Peni
nsula is presented. Limnius perrisi subcarinatus (Sharp, 1872) is a ne
w synonym of Limnius perrisi carinatus (Perez-Arcas, 1865). Morphologi
cal variability related to some elytral interstriae corresponds to a g
eographical gradation. Limnius perrisi is restricted to the headwaters
of high-slope streams with low levels of dissolved minerals.