Massive fossil find in Namibia uncovers secrets of early land-dwellers

Paleontologists have unearthed a giant fossil in Namibia that sheds new light on the early evolution of land-dwelling animals in a groundbreaking discovery.

Researchers have unearthed a giant basal tetrapod fossil in Namibia, shedding light on early land animal evolution and emphasizing the significance of southern continents in the study of these ancient species, Caliber.Az reports citing the foreign media.

An international team of paleontologists discovered the nearly complete three-metre-long skeleton in the Ugab River valley, Damaraland, identifying it as a new species named Gaiasia jennyae.

Basal tetrapods, early four-legged vertebrates with fingers and toes, lived around 280 million years ago during the crucial transition from aquatic to terrestrial life. This discovery challenges the previously held belief that early tetrapods were confined to the northern hemisphere and provides fresh insights into the origins of land-dwelling animals.

Unearthing a New Species

In their recent study published in Nature, researchers embarked on a quest to find evidence of the earliest four-legged animals to walk on land in the ancient supercontinent Gondwana. Gondwana, which existed from around 550 to 180 million years ago, encompassed present-day South America, Africa, Antarctica, Australia, and India.

While conducting fieldwork in Namibia, the team made a significant discovery. “The nearly complete skeleton was preserved in mudstone from an ancient freshwater lake,” explains Prof. Roger Smith, a Distinguished Professor at the Evolutionary Studies Institute at Wits and Emeritus Research Associate at Iziko Museums in Cape Town. He further details how the decomposition of soft tissue led to the formation of gases, causing calcium carbonate to crystallize around the bones and create a protective crust that prevented them from being crushed as they were buried deeper.

Sibusiso Mtungata, a skilled fossil technician from the Iziko Museum, recalls the moment of discovery: “We had been finding isolated vertebrae of something big and were searching for a more complete skeleton. I discovered two round cylinders of rock with bone in the middle that fit together – and then a third. I called Roger over, and as we walked upslope, he spotted a large flat rock, which he recognized as the head. When we looked along the edge and saw rows of teeth, we knew we had finally found what we were searching for – a nearly complete skull and skeleton!”

The Significance of Gaiasia

Prof. Claudia Marsicano from the University of Buenos Aires, Argentina, highlights the significance of this discovery. “As soon as I saw this enormous animal, I knew it was a different species. There is no record of giant basal tetrapods during the Carboniferous-Permian transition (approximately 299 million years ago) anywhere in the world, and certainly none from the southern continents that made up Gondwana. What caught my attention next was the structure of the front part of the skull, which was sticking out of the ground. It showed unusually interlocking large fangs,” she noted. This creature was an ambush predator, preying on the fish that lived in the same ancient lake.

Collecting the fossil was a meticulous process. “The skeleton had already weathered out of the rock, so there was no need for excavation, but the whole team spent hours searching for fragments that had fallen off the skull block and moved downslope,” says Mtungata. The skeleton was then transported to the Iziko South African Museum in Cape Town, where it underwent painstaking preparation in the Karoo Fossil Laboratory, a process that spanned two years. “Mechanical preparation was challenging because the fossil was too large to CT scan, so I didn’t know what to expect – especially in the palate, where teeth of all different sizes were scattered everywhere. There was also up to 10 cm of rock around the vertebrae that needed to be carefully drilled away, creating so much red dust that we had to bring in a special extractor,” Mtungata explains.

Analysis and Exhibition

The fossil preparation revealed that the large, flattened skull of the discovered tetrapod had intricate patterns and a distinctive palate structure, featuring enormous, backward-curved fangs in both the upper and lower jaws—an anatomical design unlike anything seen before. Initially thought to be a large amphibian, further analysis revealed that the skull possessed characteristics of much older, less evolved tetrapods, previously only found in older northern hemisphere rocks.

“We named the new species Gaiasia jennyae,” explains Prof. Smith. “‘Gaiasia’ is inspired by Gaias, a nearby desert spring where the fossil was discovered, while ‘jennyae’ honors Professor Jennifer Clack, a world-renowned expert in early tetrapod evolution who passed away in 2020.”

The discovery strongly indicates that early tetrapods were well-established in the cold-temperate regions of Gondwana as early as the Carboniferous-Permian transition. “This finding challenges previous beliefs about early tetrapod distribution and evolution, which were predominantly based on fossils from the northern hemisphere,” says Prof. Marsicano. “Our research uncovers a well-established early Permian fauna in high-latitude Gondwana, with Gaiasia as the apex predator in rocks now located in central Namibia. This not only challenges previous ideas but also reveals that the early history of tetrapods in Pangea during the Palaeozoic was far more complex than previously understood.”

The specimen has been returned to Windhoek, where it will soon be displayed at the Geological Museum of Namibia.