Fossils dating back 240 million years have finally been officially identified after being hidden inside a retaining wall for decades. Researchers from UNSW Sydney and the Australian Museum have named and described this ancient amphibian, drawing new attention to a rare discovery that began in the 1990s.
This specimen was first discovered by a retired poultry farmer who was sourcing stone from a nearby quarry to build a retaining wall for his garden. Some of the stones contained fossils and were later donated to the Australian Museum in Sydney.
Rare fossil preserves skeleton and skin
Paleontologist Lachlan Hart, who works for both UNSW Science and the Australian Museum, said the fossil, now named, Arena Elpeton SpinatusIt means “supine sand vine” and is very well preserved. It contains almost the entire skeleton of the animal and even the faint outline of its skin.
“This fossil is a unique example of a group of extinct animals known as temnospondyls that lived before and during the time of the dinosaurs,” said Hart, a PhD candidate in UNSW’s School of Biological, Earth and Environmental Sciences (BEES).
“It’s rare to find a skeleton with the head and torso still attached, and even more rare to have soft tissue preserved.”
Triassic river predators
Alena Elpeton lived in a freshwater environment in what is now the Sydney Basin during the Triassic period, about 240 million years ago. Hart said it’s likely that they preyed on ancient fish such as Claislolepis. Beyond that, evidence about other species with which it shared its habitat is limited.
Externally, this creature may remind you of the modern Chinese giant salamander, especially if you look at the shape of its head.
“On the surface, Alena Elpeton closely resembles the modern Chinese giant salamander, especially in the shape of its head,” Hart said.
“However, the size of the ribs and soft tissue outlines preserved in the fossil indicate that it was considerably heavier than its living descendants. It also had some rather dangerous teeth, including a pair of fang-like fangs on the roof of its mouth.”
Size may have contributed to survival
One of the most notable aspects of Arena El Peton is its size. Hart estimated it was about 1.2 meters long from head to tail, making it unusually large compared to many of its contemporaneous relatives.
He points out that subsequent temnospondyls continued to exist in Australia for another 120 million years, with some species reaching even larger sizes. This long history spans two major mass extinction events, suggesting that increased body size may have played a role in their survival.
Massive fossil discovery in Australia
Dr Matthew McCurry, Senior Lecturer at the New South Wales Bee School and Curator of Paleontology at the Australian Museum, emphasizes the importance of this discovery.
“This is one of the most important fossils discovered in New South Wales in the past 30 years, so we’re excited to formally describe it,” said Dr McCurry, who is also a co-author of the study. “This represents an important part of Australia’s fossil heritage.”
This study Journal of Vertebrate Paleontology.
