Past Extinction Visiting the Present

"This fossil is a unique example of a group of extinct animals known as temnospondyls, which lived before and during the time of the dinosaurs."

"The last of the temnospondyls were in Australia 120 million years after Arenaerpeton, and some grew to massive sizes."

"The fossil record of temnospondyls spans across two mass extinction events, so perhaps this evolution of increased size aided in their longevity."

"I was obsessed with dinosaurs ... and so twelve-year-old me saw that fossil on display back in 1997. And then 25 years later it became part of my PhD., which is insane."

Paleontoloist Lachlan Hart, Australian Museum, Sydney

Arenaepeton Supinatus "supine sand creeper"

In the 1990s a retired farmer in Australia ordered a sandstone slab from a local quarry. Mihail Mihaildis meant to use the slab in the repair of his garden's broken retaining wall. After slicing through the stone, he discovered the presence of an outline that looked like a large salamander-type creature. That revelation moved him to contact the Australian Museum in Sydney and to hand it over to the museum for identification. The sandstone block with its intriguing display was displayed in 1997 at the museum.

 

The fossil, measuring 1.2 metres end to end, entirely intact from tail to head, boasts the entire skeleton of the creature. There are also outlines of its soft tissue, long gone but memorized by the sand it lay in when it died, that eventually was transformed to sandstone. While it was on display a 12-year-old boy saw it at the museum and was deeply impressed. Like most young people intrigued by impressions and remains of ancient creatures that once roamed Earth, this boy was fascinated, and his initial exposure was never forgotten.

 

And it was that very young boy, grown to become a paleontologist that finally identified the 240-million-year-old amphibian fossil that still lay in what remained of the 1.6-tonne sandstone slab. Formally named Arenaepeton supinatus, (supine sand creeper), the study identifying and describing the ancient creature was published in the Journal of Vertebrate Paleontology.

 

"Some pretty gnarly teeth"

 

The Arenaepeton supinatus most likely was hunted by ancient fish such as Cleithrolepis while inhabiting freshwater rivers during the Triassic period, waterways now known as the Sydney Basin. There are some characteristics that the modern Chinese Giant Salamander shares with the Arenaerpeton, though the latter was quite considerably larger, featuring "some pretty gnarly teeth, including a pair of fang-like tusks on the roof of its mouth", described Paleontoloist Hart.

Its size also made the Arenaerpeton stand out as much larger than other closely related animals that existed during that era. According to Hart, it was "dumb luck" he became part of the team tasked with identifying the very fossil he first saw 26 years earlier. He is pursuing and completing his PhD at the Australian Museum and at the University of New South Wales. 

24-million-year-old fossil identified, Australia Museum