The (truly) first fossil freshwater molluscs from Antarctica

Abstract

New collection work in Mount Flora, Hope Bay, Antarctic Peninsula, has confirmed the presence of bivalve moulds in the Jurassic Mount Flora Formation. In contrast to a twenty-first century article claiming to report the first discovery of fossil freshwater molluscs in Antarctica, evidence of these molluscs was first reported for Antarctica more than 110 years ago by J. Gunnar Andersson. The bivalve was formally described and named some 50 years later, by Camacho, as Antediplodon esperanzaensis. The species was subsequently transferred to the genus Diplodon for unknown reasons. Here, we illustrate specimens from the same locality for the first time with photographs, considering them Unionida incertae saedis, in view of the absence of diagnostic characters. In fact, two morphotypes are present, one elongated, very similar to the nominal species A. esperanzaensis, and another one subelliptical in shape.