The fossil, identified as the flipper bone of an ichthyosaur, a marine reptile, holds the distinction of being the youngest “fish lizard” ever found in the southern hemisphere.

This remarkable find, meticulously studied by researchers in recent years, provides crucial insights into the species’ existence and extinction.

Dr Mikael Siversson, the paleontologist who discovered the fossil in 1995, describes ichthyosaurs as air-breathing reptiles, “a mix between a shark and a dolphin”.

Through extensive research, scientists have determined that this particular ichthyosaur dates back 94 to 97 million years, pushing the species’ extinction timeline further back than previously believed.

Siversson said ichthyosaurs were experiencing a steep decline during this period, but they likely did not survive until the major extinction event that wiped out numerous species, about 100 million years ago.

This extinction event was triggered by extreme global warming, with carbon dioxide levels reaching 1500 to 2000 parts per million, significantly higher than today’s levels.

Further analysis of a fossil shark tooth discovered in the same geological layer as the ichthyosaur fossil has aided scientists in accurately determining the age of the remains. 

This discovery contributes to a broader research project aimed at comprehensively documenting all marine reptiles that existed during the age of dinosaurs in WA.

“There’s a lot of exciting new discoveries, new species, so there’s lots to look forward to,” Siversson said.