January's image, "This is a mystery!", was taken by Michael Frese from the University of Canberra.
This is an SEM image of an an acritarch microfossil and was captured using the FEI Quanta QEMSCAN®. The fossil was found at McGraths Flat, a recently discovered fossil Lagerstätte near Gulgong, New South Wales.
In the mid-Miocene (about 15 million years ago), McGraths Flat was a small oxbow lake in which organisms were rapidly encased in and replaced by goethite. This mode of preservation did not only produce fossils with exquisite details, it also allows SEM imaging of uncoated samples.
Arcritarchs are microfossils of uncertain origin. While many are believed to be algae or dinoflagelates, the exact taxonomic affiliation of the depicted fossil remains a mystery. Whatever it is, this specimen nicely showcases the high-fidelity preservation of fossils from McGraths Flat.
Creative support, Mike Cheeseman
Taxonomic advice, Mary Dettman
Technical support, Hua Chen and Frank Brink
Financial support, University of Canberra and Australian Museum