Early animal evolution: evidence from the Ediacaran & Cambrian

Study early animal evolution

The broad focus of our research group is the evolution of the earliest animals on Earth. The oldest macroorganisms known in Earth, are the Ediacara Biota (575–545 Ma), named after the Ediacaran Hills in the Flinders Ranges (South Australia). 

Most of these organisms show no mineralization and they reveal very diverse morphologies, making their phylogenetic relationships controversial. 

Shortly afterwards came the Cambrian ‘explosion’, the event that gave rise to most phyla –highest-rank groups within animals– some 540 Ma. 

Some exceptional outcrops preserve not only shells or bones but also complete soft-bodied organisms and even their internal organs (digestive tubes, blood vessels, nervous system) and other delicate structures (such as eyes or gills). 

One of the few such localities in the Cambrian, and the only one known in the Southern Hemisphere, is the Emu Bay Shale (515 Ma) in Kangaroo Island, which contains fossils of more than 50 different species: sponges, worms, brachiopods, molluscs, arthropods... 

The study of the fossils found in these South Australian localities is shedding light into the taxonomical diversity, phylogenetic relationships, functional morphology and palaeoecology of the earliest metazoans.