 The holotype for "M. colliveri", NMV P199986 though formerly MUGD 1874, is an incomplete skull of an adult individual collected in 1932 by George Baxter Pritchard, Alan Frostick, and Frederick Stanley Colliver–to which owes the species name–in Jan Juc, Victoria in Australia; specimen NMV P17535, consisting of a lower left molar, probably also belongs to NMV P199986.NMV P173220 consists of a left periotic bone.NMV P199587 is a partial skeleton, consisting of part of the head, spine, and arm; specimen NMV P198871, an ulna, very likely also belongs to NMV P199587.