Palaeontologists have unveiled the oldest skink fossil ever found in Australia, a 25-million-year-old specimen that is the ancestor of the bluetongue lizard.
The fossil has been confirmed as a new species called Proegernia mikebulli.
"I'm pretty excited," said palaeo-herpetologist Dr Kailah Thorn, who conducted the research.
"It takes a long time for these things to happen, paleontology is a slow science, as it should be," she said.
Dr Thorn says researchers found the specimen while they were digging through clay sediment on a 45 degree day, at a large inland salt lake north of Adelaide.
Lake Pinpa on the Frome Downs station is a rich site for fossil hunters.
Thylacine fragments, the remains of prehistoric dolphins and crocodiles, and fossils of koala ancestors have all been found nearby.
Scientists found the skink fossil in 2017, but Dr Thorn says it took her almost a year to realise that she'd dug up a new species.
"It was very different to anything we had seen before," she said.
Unlike other skinks, Proegernia mikebulli has 27 teeth on its lower jaw, and its nerve system enters its skeleton in unusual places.
The skink is an early member of the skink subfamily Egerniinae, which includes bluetongues and shinglebacks.
It's been named after the renowned Flinders University biology professor, Mike Bull, who died in 2016.
The new species has been established with the publication of Dr Thorn's paper in the Royal Society's Open Science.