Bolivosteus chacomensis is a rhenanid placoderm from the Eifelian of Bolivia, and is the only placoderm known from the “Malvinokaffric” invertebrate faunas. The Malvinokaffric faunas represent a series of cold-water ecosystems near or at the South Pole during the Middle Devonian, and apparently lacked the presence of ammonoids, bryozoa, or colonial corals.[1] B. chacomensis is known from skull fragments and scales.