Scientists say a newly identified prehistoric shark discovered near Darwin, northern Australia, is now the earliest known mega-predator of the modern shark lineage, rewriting what researchers thought they knew about the evolution of giant sharks. The findings, published in Communications Biology, reveal that enormous sharks were roaming Earth’s oceans far earlier than previously believed.
The ancient shark lived around 115 million years ago during the Cretaceous period, predating other known giant sharks by roughly 15 million years.
What Happened
Researchers re-examined several massive shark vertebrae found along the coastline near Darwin, fossils that were originally unearthed in the late 1980s and 1990s but largely overlooked for decades.
Using advanced tools such as CT scans, fisheries data, and mathematical modeling, an international research team determined the vertebrae belonged to a gigantic cardabiodontid shark, an extinct group of mega-predatory sharks.
Based on the size of the vertebrae—each measuring about 12 centimeters (4.7 inches) across—scientists estimate the shark was approximately 8 meters (26 feet) long, significantly larger than today’s great white sharks.
Background: Who Were These Ancient Sharks?
Sharks have existed for nearly 400 million years, but modern great white sharks belong to a lineage known as lamniform sharks, which were thought to have started small. Fossil records previously suggested lamniforms appeared around 135 million years ago and were only about 1 meter long at the time.
This new discovery dramatically changes that understanding.
“These sharks had already become enormous by 115 million years ago, which was completely unexpected,” said Benjamin Kear, senior curator of paleobiology at the Swedish Museum of Natural History and one of the study’s authors.
Discovery Details and Scientific Significance
The vertebrae were found in sediment that was once part of an ancient ocean connecting Gondwana (modern Australia) to Laurasia (modern Europe). The region is already known for fossils of prehistoric marine reptiles such as plesiosaurs and ichthyosaurs.
Shark vertebrae are particularly rare in the fossil record because shark skeletons are made of cartilage, not bone. Most shark fossils are teeth, which makes estimating body size difficult.
“Vertebrae give us real clues about size,” Kear explained. “Teeth alone don’t tell us whether a shark had a massive body or just big teeth.”
What the Shark Looked Like
According to researchers, the ancient mega-shark likely resembled a modern giant shark, similar in body shape to today’s great white.
“This is a body model that has worked for 115 million years,” Kear said. “It’s an evolutionary success story.”
The study suggests that modern-style sharks rose to the top of prehistoric food chains much earlier than scientists previously believed.
Broader Impact and Future Research
Researchers believe this discovery opens the door to finding even older mega-sharks in similar environments around the world.
“They must have been around before,” Kear said. “This thing had ancestors.”
Studying ancient marine ecosystems could also help scientists better understand how today’s species may respond to climate change and environmental shifts.
“This is where our modern world begins,” Kear added. “By looking at past changes in climate and biodiversity, we can better understand what might come next.”
What Happens Next
Scientists plan to continue searching for similar fossils in ancient marine environments worldwide, hoping to uncover more clues about the early evolution of giant sharks and the ecosystems they dominated.
The discovery near Darwin stands as a major breakthrough in paleontology, reshaping the timeline of shark evolution and confirming that giant ocean predators emerged far earlier than once thought.
This story may be updated with more information as it becomes available.
