''Bolivosteus chacomensis'' is a rhenanid placoderm from the

Eifelian The Eifelian is the first of two faunal stages in the Middle Devonian Epoch. It lasted from 393.3 ± 1.2 million years ago to 387.7 ± 0.8 million years ago. It was preceded by the Emsian Stage and followed by the Givetian Stage. North American ...

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

, 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 The South Pole, also known as the Geographic South Pole, Terrestrial South Pole or 90th Parallel South, is one of the two points where Earth's axis of rotation intersects its surface. It is the southernmost point on Earth and lies antipod ...

during the Middle Devonian, and apparently lacked the presence of ammonoids,

bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a ...

, or colonial corals. ''B. chacomensis'' is known from skull fragments and scales.

References

Rhenanida Placoderm genera Placoderms of South America Devonian Bolivia Fossils of Bolivia Fossil taxa described in 1986 {{placoderm-stub