This paper describes the second species of sphaerotheriid millipede to be recorded from Western Australia, Epicyliosoma (Epicyliosoma) sarahae sp. nov. It is restricted to low rainfall biotopes in the southeast coastal province of Western Australia and may be under threat from climate change and fire. Epicyliosoma sarahae is more restricted within its range than the other Western Australian species, the threatened Cynotelopus notabilis Jeekel, and both species are short-range endemics.