Gaiasia jennyae: Giant salamander-like predator roamed Namibia 280 million years ago

A giant, salamander-like predator that sucked its prey into its mouth, then held it in place with huge fangs, was roaming cold swamps 280 million years ago in what is now the Namib desert.

The fossil creature was first discovered in 2015 in Namibia. In total, researchers have found four incomplete specimens and estimate that the animal was 2.5-metres long with a 60-centimetre-long skull, making it the biggest of its kind ever found.

Claudia Marsicano at the University of Buenos Aires, Argentina, and her colleagues have now described these fossils in detail, naming the species Gaiasia jennyae after the Gai-As formation in Namibia and the palaeontologist Jennifer Clack.

Although G. jennyae may have resembled a dangerous, drastically scaled-up salamander, like an enormous axolotl, it wasn’t a true amphibian. Instead, the animal belongs to an archaic group of four-legged vertebrates, or tetrapods, which eventually gave rise to amphibians, as well as reptiles, birds and mammals.

Marsicano says it would have probably hunted like a crocodile, lying in wait for prey to pass nearby. “Gaiasia was an aquatic animal with a very elongated body that most probably swam like an eel, with very reduced limbs, making it very difficult for it to move on dry land,” she says.

The discovery recontextualises our understanding of early tetrapod distribution. Most tetrapod fossils have been found in the northern hemisphere, a region that was centred on the equator 280 million years ago and had a tropical climate.

But at that time, what is now Namibia would have been at a much higher latitude, around 55° south, says Marsicano. “The region where the Gaiasia fossils were found was dominated by glaciations, and [at the time] harsh, cold-temperate climatic conditions prevailed.”

Despite the chill, fish fossils found alongside Gaiasia suggest that the region was relatively well populated. “A rich vertebrate community was flourishing,” says Marsicano.