A new monotypic Australian genus in the orb-weaving spider family Araneidae Clerck, 1757 is described, Quokkaraneus gen. nov., with Q. necopinus (Keyserling, 1887) comb. nov. as type species. Morphologically the new genus has affinities with the Australasian clade informally termed 'backobourkiines', due to the presence of a single patellar macroseta and the median apophysis forming an arch over the radix in the male pedipalp. It distinctly differs from other genera of this clade by somatic characters, such as a unique white cephalic and/or thoracic area and abdomen. Some genitalic characters are also diagnostic amongst the backobourkiines, such as a C-shaped median apophysis with pointed tip, triangular terminal apophysis and prominent concave conductor in males, and a very broad female epigyne scape. Quokkaraneus necopinus comb. nov. occurs in southern Australia, from western Victoria to south-western Western Australia.