Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news about fascinating discoveries, scientific breakthroughs and more.
A huge creature with fangs and a head shaped like a toilet seat lurked in swamps near the end of the world 280 million years ago, long before the first dinosaurs appeared, new research has found.
Now the scientists who made the surprising discovery of its fossils in Namibia and Brazil want to know why the archaic, salamander-like predator seemed to flourish millions of years after its relatives near the equator went extinct.
They reported the findings of their study, the result of work begun in 2018, on Wednesday in the journal Nature.
“Gaiasia jennyae was considerably larger than a person and likely lived near the bottoms of swamps and lakes,” said study co-lead author Jason Pardo, a National Science Foundation postdoctoral fellow at the Field Museum of Natural History in Chicago, in an affirmation. “It has a large, flat head shaped like a toilet seat, which allows it to open its mouth and suck in its prey. He has huge fangs, the entire front of his mouth is just giant teeth. It is a large predator, but potentially also a relatively slow ambush predator.”
So far, paleontologists have discovered a well-preserved skull and spine, some partial skulls, vertebrae and pieces of jaw after carrying out two seasons of fieldwork. The largest skull is more than 0.6 meters long.
“When we found this huge specimen in the outcrop like a giant concretion, it was really shocking,” said Claudia Marsicano, researcher and professor in the geology department at the University of Buenos Aires, co-author of the study. declaration. “Just seeing it, I knew it was something completely different.”
Ancient polar creatures
Together, the fossil pieces tell the story of a creature that defied all expectations based on the evolutionary paths of better-known animals of the time, which mostly lived closer to the equator.
Creatures that live in the far south have been more difficult to identify, and less is known about animals that lived closer to the poles.
Gaiasia lived in the middle of the Permian period, which lasted 298.9 million years until 251.9 million years ago. It thrived as a top predator 40 million years before dinosaurs evolved to roam the Earth, according to the study.
At the time, the planet was dominated by a supercontinent called Pangea, which included a large land mass known as Gondwana. The landmass included what is now South America, Africa, Antarctica, Australia, New Zealand, and the Indian subcontinent.
Today, Namibia is north of South Africa. But 300 million years ago, what is now Namibia was much further south and was located near the northernmost point of today’s Antarctica.
At the beginning of the Permian period, the planet was warming after the end of an ice age. While wetlands near the equator dried up and turned into forests, cold swamps closer to the poles remained and were framed by glaciers and ice.
New animals appeared in the hotter, drier regions near the equator as quadrupedal vertebrates, called stem tetrapods, evolved and divided into groups that formed the basis of modern animals. But that doesn’t appear to be the case at the poles, where ancient creatures did their own thing, Pardo said.
“Gaiasia is a stem tetrapod – it’s a remnant of that earlier group, before they evolved and split into the groups that would become mammals, birds, reptiles and amphibians, which are called crown tetrapods,” Pardo said. “It is truly surprising that Gaiasia is so archaic. It was related to organisms that went extinct probably 40 million years earlier.”
An incomparable predator
Part of the reason Gaiasia is so surprising to researchers is because it was so large and dominant.
“There are some other more archaic animals that were still around 300 million years ago, but they were rare, they were small and they did their own thing,” Pardo said. “Gaiasia is large and abundant and appears to be the top predator in its ecosystem.”
Although the creature’s contemporaries were the size of modern eels or snakes, Gaiasia probably reached about 3 meters in length. But it could be twice that long, Pardo said.
Fossils of Gaiasia’s limbs, if it had any, or its tail, have not yet been found, but researchers know where the creature fits on the tree of life, and Gaiasia’s ancestors and distant relatives did have limbs. Discovering more fossils during future fieldwork could help researchers improve body size estimates, Pardo said.
What they’ve found so far paints a picture of a terrifying creature you wouldn’t want to encounter, he said.
Gaiasia’s wide, flat skull was like placing two huge plates on top of each other. As the creature opened its mouth, a natural suction occurred, pulling in fish, sharks or any other nearby prey. Inside, tusks measuring 7.6 centimeters long waited to pierce the prey so Gaiasia could swallow its meal whole, Pardo said.
“After examining the skull, the structure of the front part of the skull caught my attention,” Marsicano said. “It was the only part clearly visible at that time and showed large tusks intertwined in an unusual way, creating a bite unique to early tetrapods.”
The research team suspects that Gaiasia went extinct around 268 million years ago, but it is unclear what caused the tetrapod’s disappearance.
A Mystery in the Deep South
The discovery of Gaiasia is forcing scientists to ask new questions, such as how it persisted for so long in such a cold environment. Normally, this animal would adapt to become an endotherm, a warm-blooded animal capable of regulating its body temperature by producing its own heat.
But Gaiasia was an ectotherm, which depended on the external environment to regulate its body temperature.
“It is a large aquatic animal, essentially something between a fish and an amphibian, and it reaches very large body sizes,” Pardo said. “If you are cold-blooded, this is very difficult because you have to eat a lot of food and survive for a long period of time to grow.”
It’s possible that Gaiasia lived between 20 and 40 years to reach such large sizes, but researchers can’t be sure, Pardo said.
In addition to looking for more fossil specimens of the species, researchers are also curious to find other animals that lived in this extreme southern ecosystem.
“This tells us that what was happening in the far south was very different from what was happening at the equator. And this is very important because many groups of animals emerged at this time that we don’t really know where they came from,” said Pardo.
“The fact that we found Gaiasia in the far south tells us that there was a thriving ecosystem that could support these large predators,” he added. “The more we look, the more we may find answers about these large groups of animals we care about, like the ancestors of modern mammals and reptiles.”
For more news and newsletters from CNN, create an account at CNN.com
