The soils east of the Darling Scarp are generally too heavy for this species, with the exception of some isolated pockets of deep alluvial or aeolian yellow sand. "B. prionotes" thus has a very patchy distribution east of the scarp. This area nonetheless accounts for around half of its geographic range, with the species extending well to the south and south-east of the scarp. In total, the species occurs over a north–south distance of about , and an east–west distance of about .