In this work we present a revision of the genus Ommatoiulus Latzel, 1884 in Portugal. Based
on recently collected material and older museum samples, including type specimens, we describe six
new species to science, viz. Ommatoiulus alacygni sp. nov., O. camurus sp. nov., O. denticulatus sp. nov.,
O. litoralis sp. nov., O. staglae sp. nov. and O. stellaris sp. nov. The species O. alacygni sp. nov.,
O. denticulatus sp. nov. and O. staglae sp. nov. described from the Algarve are outstanding by their
extremely reduced mesomerital process. The species O. porathi (Verhoeff, 1893) and O. andalusius
(Attems, 1927) are recorded and redescribed for the first time after their original description. The finding
of O. andalusius – originally described from Andalusia in Spain – constitutes a new record for Portugal
together with two species, viz. O. fuentei (Brolemann, 1920) and O. martensi Mauriès, 1969. The
taxonomic status of several species is revised. Thus Archiulus (Schistocoxitus) cingulatus Attems, 1927
is here considered as a junior synonym of Ommatoiulus lusitanus (Verhoeff, 1895) while Schizophyllum
cervinum Verhoeff, 1910 is synonymized with Ommatoiulus moreleti (Lucas, 1860). An identification
key to all hitherto known Portuguese species of Ommatoiulus is presented as well as a distribution map
illustrating the various species occurrences in the country.