In a groundbreaking discovery, Australian scientists have unearthed evidence of an ‘Age of Monotremes’ in Lightning Ridge, NSW. Led by Honorary Associate Professor Tim Flannery and Professor Kris Helgen, the team discovered opalised jaws dating back to the Cenomanian Age of the Cretaceous Period, between 102 million to 96.6 million years ago. The findings reveal that 100 million years ago, Australia was home to a diversity of monotremes, ancestors of the modern platypus and echidna. This discovery sheds light on Australia’s prehistoric past as a land of furry egg-layers, challenging the perception of the country as primarily inhabited by marsupials.
The study identified three new species of monotremes exhibiting unique combinations of features not seen in other living or fossil monotremes. One of the species, Opalios splendens, shows characteristics of both the earliest known monotremes and their modern descendants. This indicates that Australia was host to a variety of evolutionary paths for monotremes over 100 million years ago. The evolutionary history of these egg-laying mammals is traced from the oldest monotreme, Teinolophos trusleri, with five molars, to the toothless echidnas and platypuses of today. The fossil record at Lightning Ridge presents a snapshot of six different egg-laying mammals coexisting over 100 million years ago, highlighting the potential evolutionary destinies that branched out from this diverse group.
Dr. Matthew McCurry, Curator of Palaeontology at the Australian Museum, emphasized the significance of the discovery of the three new genera of monotremes in piecing together their evolutionary story. The diversity of monotremes found at Lightning Ridge suggests that their family tree is more complex than previously thought. This discovery has added over 20% to the known diversity of monotremes, shedding light on their habitat, appearance, and evolutionary adaptations to environmental changes. The rarity of monotreme fossils underscores the importance of each new discovery in understanding the evolutionary journey of these unique Australian mammals.
Collaborators from Museums Victoria Research Institute, Dr. Thomas Rich and Honorary Associate Professor Patricia Vickers-Rich, highlighted the importance of the discovery of new species in expanding our understanding of the ancient fauna of Australia. The presence of multiple new species in a small area suggests a more intricate family tree for monotremes than previously assumed. As research continues in the Mesozoic era of Australia, scientists hope to gain further insights into the evolution of life over time. The ongoing exploration of Australian paleontology provides exciting opportunities to uncover new evidence and unravel the mysteries of prehistoric fauna.
The fossils were discovered by Elizabeth Smith and her daughter Clytie of the Australian Opal Centre in Lightning Ridge, who have dedicated decades to searching for opalised fossils in the region. Opalised monotreme fossils are exceptionally rare, with only one specimen found amidst a million other pieces. Elizabeth Smith emphasized the uniqueness of the specimens, offering a window into Australia’s prehistoric past as a land of furry egg-layers. The abundance of monotreme fossils at Lightning Ridge suggests that this region was home to a diverse array of these ancient mammals 100 million years ago, unlike anywhere else on earth.
The discovery of the ‘Age of Monotremes’ at Lightning Ridge provides valuable insights into Australia’s prehistoric biodiversity and the evolutionary history of egg-laying mammals. The findings challenge conventional notions of Australia as a land dominated by marsupials, revealing a rich diversity of monotremes that once inhabited the continent. This research sheds light on the complex evolutionary paths and adaptations of these unique Australian mammals, offering a glimpse into their past and enriching our understanding of the natural history of the region. As further research is conducted and new discoveries are made, the story of Australia’s ancient fauna continues to evolve, deepening our appreciation for the diverse and fascinating organisms that once roamed the land.