A new species of the endemic pseudoscorpion genus Protoneobisium Curcic, 1988, P basilice sp. n. from Croatia has been found, described and diagnosed. From its phenetically close congener, R biocovense (Muller, 1931), the new taxon differs in many respects of both qualitative and quantitative nature, Both species of Protoneobisium have a limited distribution; they inhabit Mt. Biokovo, Croatia, and are probably the remnants of some ancient Maditerranean fauna of pre-Tertiary origin.