These are the fossilised remains of an extinct mammal known as Wynyardia bassiana that, until recently, was identified as Australia’s oldest known marsupial. Found in the mid-1800s by an anonymous beachcomber at Fossil Bluff, near Wynyard on Tasmania’s north-west, it is dated to the early Miocene period – making it about 23 million years old.
Originally, the fossil was found in a block of sandstone that had come loose from the cliff face and tumbled down to the cliff’s base. This fall not only exposed the fossil but is also believed to have broken off a lower portion of the animal’s skull, consequently making it difficult to determine exactly which genus of marsupial it may have been related to.
Other damage to the lower jaw and the pelvis – that apparently occurred before the animal became embedded – as well as the impact of weathering after its exposure have also made conclusive research difficult. Studies have indicated, however, that the marsupial was similar to that of a phalanger – a genus of possum – but it is of a larger and stouter build than any known living animal of this type today.