This species was formerly known as Sterictopsis argyraspis. According to Moths of Victoria Part 4, Oxyphanes and Sterictopsis have been included as part of the genus Rhuma (Pitkin et al 2007). The AFD recognises R. argyraspis but not S. argyraspis and that Rhuma and Sterictopsis are synonyms. MoV regards the taxonomy as uncertain and further research is required. Darker forms (i.e. brown not grey) of R. argryaspis, as in this specimen, are recognised. I think there is a good match with this specimen and the darker forms of R. argyraspis labelled as such on Bold Sytems 4, but there is no underwing pattern illustrated there for that species. However, Moths of Victoria does show an underwing pattern for R. argyraspis and there is a good match with this specimen, see the second image.