A second species in the spider genus Magnopholcomma Wunderlich, 2008 (family Theridiidae Sundevall, 1833) is described based on a male found at Fortescue Bay in Tasman National Park (Tasmania, Australia). The genus differs from all other genera in the family by somatic characters, specifically the large globular clypeal outgrowth. Magnopholcomma adelphus sp. n. differs from M. globulus Wunderlich, 2008 by somatic and genitalic characters, especially the larger clypeal outgrowth, an inconspicuous fovea, pedipalp with longer tibia, median apophysis strongly basally projected and apical lobe of theridiid tegular apophysis undivided. The genus genital morphology and its systematic position in Pholcommatinae are also discussed, stabilizing the inconsistent nomenclature of sclerites of the male pedipalp (e.g., the interpretation of the theridiid terminal apophysis) of members of the subfamily.