Fossilized Teeth Help Determine Biggest Shark Ever

A great white shark in Southern Australia in 2015.NiCK / Getty Images file
A great white shark in Southern Australia in 2015.NiCK / Getty Images file
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Fossilized Teeth Help Determine Biggest Shark Ever

A great white shark in Southern Australia in 2015.NiCK / Getty Images file
A great white shark in Southern Australia in 2015.NiCK / Getty Images file

US researchers have found that Megalodon was the most massive shark that ever lived, even among living sharks.

Most Megalodon fossils date to around 15 million years ago, however, little is known about its anatomy; since shark skeletons are made of cartilage rather than bone, they are extremely scarce in the fossil record, save for their plentiful fossilized teeth, which were used by a research group led study author Kenshu Shimada, a professor of paleobiology at DePaul University in Chicago, to estimate the size of the animal.

In the study published Monday in the journal Historical Biology, Shimada and his colleagues generated a new tool for calculating body length: an equation representing the actual quantitative relationship between body length and tooth size in lamniform. They based it on the teeth and known body lengths from 32 specimens of living, predatory lamniform sharks, representing all shark species including Megalodon.

The researchers found that many extinct lamniform sharks were quite large, and the Megalodon was the biggest among them, estimated to have measured up to 50 feet (15 meters) in length, about as long as a bowling lane. It was also substantially bigger than the next-biggest extinct shark in the Lamniformes order by at least 23 feet (7 meters).

While the Megalodon picture is now a little clearer than it was before, many fundamental questions about the size of the massive super-shark are still unanswered. Why Megalodon became extinct is another big fundamental question that remains unsettled, Shimada said.

Speaking about the value of the new findings, Shimada said understanding body sizes of extinct organisms is important in the context of ecology and evolution. "Lamniform sharks have represented major carnivores in oceans since the age of dinosaurs, so it is reasonable to assert that they must have played an important role in shaping the marine ecosystems we know today. This is why we need further information about them," he added.



Acropolis to Close in the Afternoon Due to Heatwave

People stand in a shade while visiting the Acropolis, at the start of a 3-days heatwave with temperatures expected to overpass 40 Celsius degrees, in Athens, Greece, July 7, 2025. REUTERS/Louisa Gouliamaki
People stand in a shade while visiting the Acropolis, at the start of a 3-days heatwave with temperatures expected to overpass 40 Celsius degrees, in Athens, Greece, July 7, 2025. REUTERS/Louisa Gouliamaki
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Acropolis to Close in the Afternoon Due to Heatwave

People stand in a shade while visiting the Acropolis, at the start of a 3-days heatwave with temperatures expected to overpass 40 Celsius degrees, in Athens, Greece, July 7, 2025. REUTERS/Louisa Gouliamaki
People stand in a shade while visiting the Acropolis, at the start of a 3-days heatwave with temperatures expected to overpass 40 Celsius degrees, in Athens, Greece, July 7, 2025. REUTERS/Louisa Gouliamaki

Greece's culture ministry on Tuesday ordered a partial closure of the Acropolis, the country's top monument, to protect visitors amid heatwave conditions.

The ministry in a statement said the site would be closed from 1:00 to 5:00 pm (1000 to 1400 GMT) "for the safety of workers and visitors, owing to high temperatures."

The four-day heatwave that began Sunday is the second to grip Greece since late June.

Temperatures in the country are expected to reach 42 Celsius (107.6 Fahrenheit) on Tuesday, with a maximum of 38 Celsius in Athens.

Similar temperatures are expected Wednesday.

The 2,500-year-old Acropolis, built on a rock overlooking the capital that offers little shade, draws tens of thousands of visitors daily.

Last year it recorded some 4.5 million visitors, an increase of over 15 percent compared to 2023.