A New Hyolithid Australolithes troffsensis gen. et sp. nov. from an Early Devonian (Lochkovian) Limestone in Central New South Wales

Abstract

Hyoliths have a sparse fossil record worldwide in the Devonian, with only one Devonian hyolith from Australia – the orthothecid Costulatotheca schleigeri  – treated systematically to date. The material described here, from the Connemarra Formation of central New South Wales, comprises disarticulated conches and opercula showing a range of sizes. Since all have the same proportions and structural features, they are considered a growth series from a single species Australolithes troffsensis gen. et sp. nov., characterized by a smooth external surface on the conch and operculum, as well as a pair of smooth straight hollow clavicles with a circular crosssection on the operculum. The specimens described here are unusual in being completely replaced by goethite (iron oxide-hydroxide), allowing their preservation in residues from acetic acid etching of a limestone sample.