A giant 280m-year-old salamander-like creature that was an apex predator before the age of the dinosaurs has been found by fossil hunters in Namibia.
the creature, Gaiasia jennyae, was about 2.5 meters tall, had an enormous toilet seat shaped head and terrifying interlocking fangs. It peered into cold swampy waters and lakes with its mouth wide open, preparing to clamp its powerful jaws on any prey unwise enough to swim past.
“When we found this enormous specimen just lying on the outcrop as a giant concretion, it was really shocking,” says Prof. Claudia Marsicano of the University of Buenos Aires, who excavated the fossil with colleagues. “I just knew from the moment I saw it that it was something completely different. We were all very excited.”
Gaiasia would have been the top predator of its ecosystem and among the largest land predators of the period.
“It has a large, flat, toilet seat-shaped head that allows it to open its mouth and suck in prey. It has these huge tusks, the whole front of the mouth is just giant teeth,” said Jason Pardo, of the Field Museum in Chicago and the co-lead author of a paper describing the fossils. “It is a large predator, but possibly also a relatively slow ambush predator.”
The fossil is named after the Gai-As Formation in Namibia where it was found, and for Jenny Clack, a paleontologist who specialized in the evolution of early tetrapods, four-legged vertebrates that gave rise to amphibians, reptiles, birds and mammals.
At least four incomplete fossil specimens have been discovered, including skull fragments and a nearly complete spine. The of Gaiasia skull was about 60 cm long and its jaw structure suggests it had a powerful bite capable of capturing large prey.
“After examining the skull, the structure of the front of the skull caught my attention,” Marsicano said. “It was the only clearly visible part at the time, and it showed very unusually large interlocking tusks, creating a unique bite for early tetrapods.”
The location of the discovery is significant because until now most insights into the early evolution of land animals have come from fossils discovered at ancient equatorial wetlands in what is now Europe and North America. By the time the creature lived, present-day Namibia would have been positioned much further south, almost level with the northernmost tip of Antarctica, and part of the large southern supercontinent Gondwana. While the land near the equator was drying out and becoming forested, the swamps remained closer to the poles, possibly next to patches of ice and glaciers.
The latest discovery shows that despite the unforgiving climate, large predators thrived in these icy swamps. The fossils have greater similarities to more ancient vertebrates, while in warmer, drier parts of the world, animals seem to have branched off into new forms to one day become mammals, reptiles and amphibians.
“This tells us that what happened in the far south was very different from what happened at the equator,” Pardo said. “And this is very important because there were many groups of animals that appeared during this time that we don’t really know where they came from. The more we look, we may get more answers about these large animal groups that we care about, such as the ancestors of mammals and modern reptiles.”
