Conservation of Anthracotherium magnum fossils from Chiuppano, Italy

Lignite deposits are characterized by a high probability of fossil preservation along with a high concentration of pyrite minerals. When fossils are discovered, exposure to the humidity and oxygen in the air begins a destabilization of the minerals and activation of chemical oxidation. In the last century, it was common practice to protect fossils by covering them with unspecified commercial varnish, but today it is clear this method is useless for long-term preservation. Moreover, varnish obliterates the precise features of teeth and bones, usually preventing researchers from correctly analysing and describing these specimens. In this paper, we describe the methodology applied for conserving fossils identified as Anthracotherium magnum, discovered in lignite deposits of Chiuppano (Vicenza, Italy) in the mid-twentieth century. We pre-prepared the specimens, removing varnish from the fossil surfaces, and we exposed them to an aerosol solution of PEG400 and concentrated ammonia. We discuss the colour shift of bones and the rediscovery of anatomical characteristics to underline the importance of prompt action in the preservation of fragile specimens for future exhibition.