Ellen Phiddian
Cosmos science journalist
Palaeontologists have uncovered a massive salamander-like creature that loitered in swamps about 280 million years ago, 40 million years prior to the emergence of dinosaurs.
The archaic salamander, named Gaiasia jennyae, is described in a paper in Nature.
“Gaiasia jennyae was considerably larger than a person, and it probably hung out near the bottom of swamps and lakes,” says co-lead author Dr Jason Pardo, a postdoctoral fellow at the Field Museum in Chicago, US.
“It’s got a big, flat, toilet seat-shaped head, which allows it to open its mouth and suck in prey. It has huge fangs, the whole front of the mouth is just giant teeth.
“It’s a big predator, but potentially also a relatively slow ambush predator.”
The fossil was found in the Gai-as Formation in Namibia. It was named Gaiasia for the formation, and jennyae for the late palaeontologist Jenny Clack.
“When we found this enormous specimen just lying on the outcrop as a giant concretion, it was really shocking. I knew just from seeing it that it was something completely different. We were all very excited,” says co-lead author Professor Claudia Marsicano, a palaeontologist at the University of Buenos Aires, Argentina.
“After examining the skull, the structure of the front of the skull caught my attention. It was the only clearly visible part at that time, and it showed very unusually interlocking large fangs, creating a unique bite for early tetrapods.”
The researchers found several specimens at the site.
“We had some really fantastic material, including a complete skull, that we could then use to compare with other animals from this age and get a sense of what this animal was and what makes it unique,” says Pardo.
Gaiasia would have inhabited a much colder world than its current resting place. Modern-day Namibia was close to the 60th parallel south, and filled with icy swamps.
It was also a relic in its own time: it belongs to a group of four-legged animals called stem tetrapods, which eventually became modern mammals, reptiles, amphibians, and birds.
By 280 million years ago, a newer phase of tetrapods, called crown tetrapods, was reigning supreme.
“It’s really, really surprising that Gaiasia is so archaic. It was related to organisms that went extinct probably 40 million years prior,” says Pardo.
“There are some other more archaic animals still hanging on 300 million years ago, but they were rare, they were small, and they were doing their own thing.
“Gaiasia is big, and it is abundant, and it seems to be the primary predator in its ecosystem.”
The creature’s existence can be used to learn more about the world during the Permian period, when it lived.
“It tells us that what was happening in the far south was very different from what was happening at the Equator,” says Pardo.
“The fact that we found Gaiasia in the far south tells us that there was a flourishing ecosystem that could support these very large predators.”
