Western Australian Museum discovers fossil bone of ‘fish lizard’ dating back millions of years

The WA Museum has discovered the fossil bone of a “fish lizard” dating back between 94 and 97 million years.

The museum discovered a flipper bone three decades ago and it has now been confirmed as coming from the youngest “fish lizard”, or ichthyosaur, in the southern hemisphere.

“We’ve now confirmed the youngest occurrence of an ichthyosaur in the southern hemisphere and our study offers unprecedented insight into the final stages of these marine reptiles’ existence before their global extinction,” head of earth and planetary sciences Mikael Siversson said.

“Ichthyosaurs were remarkable marine reptiles and looked like a long-snouted dolphin with a shark tail, perfectly adapted for hunting fish and squid-like cephalopods.”

The discovery of the phalanx bone fossil was made at Murchison House station in 1995 but its significance was not realised until years later.

Dr Siversson and his team returned to the original location of the fossil in 2018 and continued to the Giralia Range in 2022-24, where they collected Cretaceous shark teeth critical to pinpointing the fossil’s age.

The museum said the discovery was a significant milestone in ichthyosaur research because it contributed to the understanding of the timing of the animal’s extinction and gave an insight into the geographic distribution of the group in the last stages of existence.