The sand dragonet (Callionymus marleyi) is a species of dragonet native to the western Indian Ocean where it occurs at depths of from over sandy substrates. Its diet consists mostly of benthic invertebrates. This species grows to a length of TL. The specific name most likely honours Harold Walter Bell-Marley (1873-1945) soldier and the Principal Fisheries Officer in the Natal Province from 1918 to 1937.