The recently formally named and categorized Arenaerpeton supinatus, a giant lizard-like creature from 240 million years ago, is rewriting history after being recognized by scientists from the University of New South Wales and the Australian Museum.

Discovered in the 1990s by a chicken farmer in a quarry, the fossil provides a unique example of temnospondyls, an extinct group of animals that lived before and during the time of dinosaurs.

The fossil is a significant discovery because it includes the entire skeleton with preserved skin outlines. Arenaerpeton supinatus, translating to ‘supine sand creeper,’ measured up to 1.2 meters (4 feet) from head to tail. The creature inhabited fresh waters in what is now the Sydney Basin during the Triassic period.

Lachlan Hart, a paleontologist from the Australian Museum, highlighted the rarity of finding skeletons with both the head and body intact, and the even rarer occurrence of soft tissue preservation.

The fossil reveals features such as heavyset build, gnarly teeth, and fang-like tusks on the roof of its mouth. While superficially resembling the modern Chinese Giant Salamander, the Arenaerpeton was considerably more robust.

The fossil sheds light on temnospondyls, an ancient group that existed 120 million years before the last temnospondyls in Australia. Some temnospondyls grew to massive sizes, and their evolutionary trend toward increased size might have contributed to their longevity across two mass extinction events.

Described as one of the most important fossils found in New South Wales in the past 30 years, Arenaerpeton supinatus adds a key chapter to Australia’s fossil heritage.