Genus Lissothus Vachon, 1948 represented by L. occidentalis Vachon, 1950 is reported for the first time from four localities in Morocco and the Western Sahara. We provide a revised diagnosis of L. occidentalis, fully complemented with color photos of live and preserved specimens. Hemispermatophore is also illustrated and described in detail. Furthermore, we describe aspects of the ecology of this species, and provide photos of collection sites and habitats. We also report on the reproductive biology of this species based on captive breeding and rearing. and provide the first envenomation report for the species.