The Thylacoleo is an extinct giant marsupial lion that was part of a range of megafaunal creatures, which inhabited Australia during the Pleistocene period. The coin’s reverse depicts a Thylacoleo and its young, set against a coloured background. The inscription THYLACOLEO and The Perth Mint’s ‘P’ mintmark are also incorporated into the design. The obverse depicts the Ian Rank-Broadley effigy of Her Majesty Queen Elizabeth II.