Latest news with #KenshuShimada
CNN
11-03-2025
- Science
- CNN
The largest shark that ever lived just got larger, scientists say
Paleobiologist Dr. Kenshu Shimada has been fascinated by fossil sharks, including the giant Otodus megalodon, since childhood — he found his first megalodon tooth at 13 years old. So when he saw the 2018 blockbuster 'The Meg,' he thought something was fishy. Not only did the movie depict the long-extinct megalodon surviving to modern times, but the 75-foot-long (23-meter-long) Hollywood version of the predator seemed way too big. Exactly how large megalodon was in real life is a long-standing mystery — no complete fossils have ever been discovered. But now, to Shimada's own surprise, his most recent research suggests megalodon could have reached a whopping length of 80 feet (24 meters). What's more, he and his coauthors posit that megalodon was slenderer than previously thought, closer in build to a sleek lemon shark than a chunky great white, according to the study published Sunday in the journal Palaeontologia Electronica. 'Megalodon is not a simple, gigantic version of great white shark. I think that we really have to move away from that concept,' said Shimada, a professor of biological and environmental sciences at DePaul University in Chicago who served as lead author. The findings could help reshape how scientists and popular science fiction depict the enormous creature — and has possibly shed light on what lets some marine vertebrates evolve extraordinarily huge proportions, according to Shimada. Megalodon fossil record: Plenty of teeth but not much else Unlike in 'The Meg,' the prehistoric megalodon never coexisted with humans, but between 15 million and 3.6 million years ago, the apex predator dominated oceans around the world, according to various megalodon fossils scientists have unearthed. As a shark, megalodon is part of the family of cartilaginous fishes. 'They have a very poorly mineralized skeleton. There are no true bones that make the skeleton hard,' Shimada said. 'On the other hand, teeth are very hard, so they're durable.' Megalodon produced new teeth throughout its life, helping make these fossils a fairly common find. Along with teeth, the existing fossil record includes parts of giant shark skeletons from the same period, including a 36-foot-long (11-meter-long) section of a fossilized spinal column from Belgium, a news release stated. The vertebrae of this shark are up to 6 inches (15 centimeters) in diameter; another fossil shark specimen from Denmark has vertebrae that are 9 inches (23 centimeters) across. For context, adult human vertebrae are roughly 1 inch (2.5 centimeters) in diameter. Neither shark backbone specimens were found with the massive, serrated teeth associated with megalodon, but scientists have presumed they belong to the same species. Megalodon's teeth resemble those of a modern great white shark, so some scientists previously concluded that the two sharks had a similar stout body shape. Shimada followed this hypothesis when he published a paper in September 2019, arguing that the maximum size for megalodon was 'just' 50 feet (15.3 meters) long. However, several years ago, Shimada and some of his colleagues began to question the underlying assumption that megalodon looked like a huge great white shark. In reviewing a August 2022 paper, in which scientists built a digital 3D model of megalodon, Shimada found some of the math behind the shark's proportions didn't seem to add up. 'We kind of realized — click— that (the) great white shark is not a good model,' Shimada said. So, he began searching for a better match for megalodon's modern analogue. Megalodon may have had a long, sleek body Shimada and his team compared 145 species of living sharks and 20 species of extinct sharks and built a database of the proportions of their heads, bodies and tails. The researchers then compared these proportions with the parts of megalodon's body that have been found. 'We have a vertebral column that's known, and if we assume that that's the complete trunk length, then why can't we estimate the head length and a tail length based on modern day?' Shimada said. The researchers calculated that the likeliest body plan for megalodon wouldn't have been that of a stout, tanklike great white but rather a more streamlined fish, such as a lemon shark. In this discovery, Shimada said, his team also stumbled upon a larger pattern in marine biology. 'Inadvertently, we discovered the mystery of why some vertebrates can get large, but some cannot,' Shimada said. Great white sharks, with their thick bodies that grow to about 20 feet long (6 meters), seem to be about as big as a stocky animal can be and still move efficiently through the water. Meanwhile, sleeker animals such as blue whales, which can grow up to about 100 feet (30 meters) long, can attain enormous lengths while still swimming well. 'If you stay in a skinnier body, there is a better chance of being able to grow larger,' Shimada said. This principle applies to megalodon, which according to Shimada's new study could have been up to 80 feet (24 meters) long, but thinner than previous models. Dr. Stephen Godfrey, the curator of paleontology at the Calvert Marine Museum in Solomons, Maryland, who was not involved with the study, said he was surprised by both megalodon's proposed similarity to a lemon shark and by the giant size proposed by Shimada and his team. 'The argument that they make, that a long, slender animal that size is more hydrodynamically efficient than if they're really kind of fat and chunky, like if you scale up a living great white — that argument is a good one,' he said. 'But still, I'm not saying it gets stuck in my craw, but wow. I mean, that's twice the size,' Godfrey said, referring to the estimated megalodon length increasing from 50 to 80 feet. Ultimately, there's just one way to know for certain how long megalodon was and what it looked like. 'What we really need is the discovery of the complete skeleton,' Shimada said. 'The real test comes when we really have the complete skeleton, and then it will support or refute whether it was really skinny or stocky.'
Yahoo
11-03-2025
- Science
- Yahoo
The largest shark that ever lived just got larger, scientists say
Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Paleobiologist Dr. Kenshu Shimada has been fascinated by fossil sharks, including the giant Otodus megalodon, since childhood — he found his first megalodon tooth at 13 years old. So when he saw the 2018 blockbuster 'The Meg,' he thought something was fishy. Not only did the movie depict the long-extinct megalodon surviving to modern times, but the 75-foot-long (23-meter-long) Hollywood version of the predator seemed way too big. Exactly how large megalodon was in real life is a long-standing mystery — no complete fossils have ever been discovered. But now, to Shimada's own surprise, his most recent research suggests megalodon could have reached a whopping length of 80 feet (24 meters). What's more, he and his coauthors posit that megalodon was slenderer than previously thought, closer in build to a sleek lemon shark than a chunky great white, according to the study published Sunday in the journal Palaeontologia Electronica. 'Megalodon is not a simple, gigantic version of great white shark. I think that we really have to move away from that concept,' said Shimada, a professor of biological and environmental sciences at DePaul University in Chicago who served as lead author. The findings could help reshape how scientists and popular science fiction depict the enormous creature — and has possibly shed light on what lets some marine vertebrates evolve extraordinarily huge proportions, according to Shimada. Unlike in 'The Meg,' the prehistoric megalodon never coexisted with humans, but between 15 million and 3.6 million years ago, the apex predator dominated oceans around the world, according to various megalodon fossils scientists have unearthed. As a shark, megalodon is part of the family of cartilaginous fishes. 'They have a very poorly mineralized skeleton. There are no true bones that make the skeleton hard,' Shimada said. 'On the other hand, teeth are very hard, so they're durable.' Megalodon produced new teeth throughout its life, helping make these fossils a fairly common find. Along with teeth, the existing fossil record includes parts of giant shark skeletons from the same period, including a 36-foot-long (11-meter-long) section of a fossilized spinal column from Belgium, a news release stated. The vertebrae of this shark are up to 6 inches (15 centimeters) in diameter; another fossil shark specimen from Denmark has vertebrae that are 9 inches (23 centimeters) across. For context, adult human vertebrae are roughly 1 inch (2.5 centimeters) in diameter. Neither shark backbone specimens were found with the massive, serrated teeth associated with megalodon, but scientists have presumed they belong to the same species. Megalodon's teeth resemble those of a modern great white shark, so some scientists previously concluded that the two sharks had a similar stout body shape. Shimada followed this hypothesis when he published a paper in September 2019, arguing that the maximum size for megalodon was 'just' 50 feet (15.3 meters) long. However, several years ago, Shimada and some of his colleagues began to question the underlying assumption that megalodon looked like a huge great white shark. In reviewing a August 2022 paper, in which scientists built a digital 3D model of megalodon, Shimada found some of the math behind the shark's proportions didn't seem to add up. 'We kind of realized — click— that (the) great white shark is not a good model,' Shimada said. So, he began searching for a better match for megalodon's modern analogue. Shimada and his team compared 145 species of living sharks and 20 species of extinct sharks and built a database of the proportions of their heads, bodies and tails. The researchers then compared these proportions with the parts of megalodon's body that have been found. 'We have a vertebral column that's known, and if we assume that that's the complete trunk length, then why can't we estimate the head length and a tail length based on modern day?' Shimada said. The researchers calculated that the likeliest body plan for megalodon wouldn't have been that of a stout, tanklike great white but rather a more streamlined fish, such as a lemon shark. In this discovery, Shimada said, his team also stumbled upon a larger pattern in marine biology. 'Inadvertently, we discovered the mystery of why some vertebrates can get large, but some cannot,' Shimada said. Great white sharks, with their thick bodies that grow to about 20 feet long (6 meters), seem to be about as big as a stocky animal can be and still move efficiently through the water. Meanwhile, sleeker animals such as blue whales, which can grow up to about 100 feet (30 meters) long, can attain enormous lengths while still swimming well. 'If you stay in a skinnier body, there is a better chance of being able to grow larger,' Shimada said. This principle applies to megalodon, which according to Shimada's new study could have been up to 80 feet (24 meters) long, but thinner than previous models. Dr. Stephen Godfrey, the curator of paleontology at the Calvert Marine Museum in Solomons, Maryland, who was not involved with the study, said he was surprised by both megalodon's proposed similarity to a lemon shark and by the giant size proposed by Shimada and his team. 'The argument that they make, that a long, slender animal that size is more hydrodynamically efficient than if they're really kind of fat and chunky, like if you scale up a living great white — that argument is a good one,' he said. 'But still, I'm not saying it gets stuck in my craw, but wow. I mean, that's twice the size,' Godfrey said, referring to the estimated megalodon length increasing from 50 to 80 feet. Ultimately, there's just one way to know for certain how long megalodon was and what it looked like. 'What we really need is the discovery of the complete skeleton,' Shimada said. 'The real test comes when we really have the complete skeleton, and then it will support or refute whether it was really skinny or stocky.' Kate Golembiewski is a freelance science writer based in Chicago who geeks out about zoology, thermodynamics and death.
CNN
11-03-2025
- Science
- CNN
The largest shark that ever lived just got larger, scientists say
Paleobiologist Dr. Kenshu Shimada has been fascinated by fossil sharks, including the giant Otodus megalodon, since childhood — he found his first megalodon tooth at 13 years old. So when he saw the 2018 blockbuster 'The Meg,' he thought something was fishy. Not only did the movie depict the long-extinct megalodon surviving to modern times, but the 75-foot-long (23-meter-long) Hollywood version of the predator seemed way too big. Exactly how large megalodon was in real life is a long-standing mystery — no complete fossils have ever been discovered. But now, to Shimada's own surprise, his most recent research suggests megalodon could have reached a whopping length of 80 feet (24 meters). What's more, he and his coauthors posit that megalodon was slenderer than previously thought, closer in build to a sleek lemon shark than a chunky great white, according to the study published Sunday in the journal Palaeontologia Electronica. 'Megalodon is not a simple, gigantic version of great white shark. I think that we really have to move away from that concept,' said Shimada, a professor of biological and environmental sciences at DePaul University in Chicago who served as lead author. The findings could help reshape how scientists and popular science fiction depict the enormous creature — and has possibly shed light on what lets some marine vertebrates evolve extraordinarily huge proportions, according to Shimada. Megalodon fossil record: Plenty of teeth but not much else Unlike in 'The Meg,' the prehistoric megalodon never coexisted with humans, but between 15 million and 3.6 million years ago, the apex predator dominated oceans around the world, according to various megalodon fossils scientists have unearthed. As a shark, megalodon is part of the family of cartilaginous fishes. 'They have a very poorly mineralized skeleton. There are no true bones that make the skeleton hard,' Shimada said. 'On the other hand, teeth are very hard, so they're durable.' Megalodon produced new teeth throughout its life, helping make these fossils a fairly common find. Along with teeth, the existing fossil record includes parts of giant shark skeletons from the same period, including a 36-foot-long (11-meter-long) section of a fossilized spinal column from Belgium, a news release stated. The vertebrae of this shark are up to 6 inches (15 centimeters) in diameter; another fossil shark specimen from Denmark has vertebrae that are 9 inches (23 centimeters) across. For context, adult human vertebrae are roughly 1 inch (2.5 centimeters) in diameter. Neither shark backbone specimens were found with the massive, serrated teeth associated with megalodon, but scientists have presumed they belong to the same species. Megalodon's teeth resemble those of a modern great white shark, so some scientists previously concluded that the two sharks had a similar stout body shape. Shimada followed this hypothesis when he published a paper in September 2019, arguing that the maximum size for megalodon was 'just' 50 feet (15.3 meters) long. However, several years ago, Shimada and some of his colleagues began to question the underlying assumption that megalodon looked like a huge great white shark. In reviewing a August 2022 paper, in which scientists built a digital 3D model of megalodon, Shimada found some of the math behind the shark's proportions didn't seem to add up. 'We kind of realized — click— that (the) great white shark is not a good model,' Shimada said. So, he began searching for a better match for megalodon's modern analogue. Megalodon may have had a long, sleek body Shimada and his team compared 145 species of living sharks and 20 species of extinct sharks and built a database of the proportions of their heads, bodies and tails. The researchers then compared these proportions with the parts of megalodon's body that have been found. 'We have a vertebral column that's known, and if we assume that that's the complete trunk length, then why can't we estimate the head length and a tail length based on modern day?' Shimada said. The researchers calculated that the likeliest body plan for megalodon wouldn't have been that of a stout, tanklike great white but rather a more streamlined fish, such as a lemon shark. In this discovery, Shimada said, his team also stumbled upon a larger pattern in marine biology. 'Inadvertently, we discovered the mystery of why some vertebrates can get large, but some cannot,' Shimada said. Great white sharks, with their thick bodies that grow to about 20 feet long (6 meters), seem to be about as big as a stocky animal can be and still move efficiently through the water. Meanwhile, sleeker animals such as blue whales, which can grow up to about 100 feet (30 meters) long, can attain enormous lengths while still swimming well. 'If you stay in a skinnier body, there is a better chance of being able to grow larger,' Shimada said. This principle applies to megalodon, which according to Shimada's new study could have been up to 80 feet (24 meters) long, but thinner than previous models. Dr. Stephen Godfrey, the curator of paleontology at the Calvert Marine Museum in Solomons, Maryland, who was not involved with the study, said he was surprised by both megalodon's proposed similarity to a lemon shark and by the giant size proposed by Shimada and his team. 'The argument that they make, that a long, slender animal that size is more hydrodynamically efficient than if they're really kind of fat and chunky, like if you scale up a living great white — that argument is a good one,' he said. 'But still, I'm not saying it gets stuck in my craw, but wow. I mean, that's twice the size,' Godfrey said, referring to the estimated megalodon length increasing from 50 to 80 feet. Ultimately, there's just one way to know for certain how long megalodon was and what it looked like. 'What we really need is the discovery of the complete skeleton,' Shimada said. 'The real test comes when we really have the complete skeleton, and then it will support or refute whether it was really skinny or stocky.'
BBC News
10-03-2025
- Science
- BBC News
Megalodons were larger than previously thought, scientists say
You might have to forget what you think you know about the are ancient fish, thought to be the largest to ever to a new study, the ancient predator which became extinct nearly four million years ago, could be even larger than previously thought. Scientists now think they could grow to nearly 25 metres (around 80 feet) in length - that's more than twice as long as a double decker bus! What did scientists discover? The megalodon was a type of ancient giant shark which lived a long time ago. The ocean predator roamed the world's seas between four million and 20 million years international team of scientists, led Professor Kenshu Shimada of DePaul University in US city of Chicago, decided to take a closer look at the fearsome studied the teeth and vertebrae of previously found megalodon fossils and came to some interesting discovered that they could reached 24.3 metres (80ft) in length - ten metres longer than previously thought. Scientists had also thought the creature was barrel-chested like the great white shark. This new research, published in the journal Palaeontologia Electronica, argues its body was more slender and elongated - closer to that of a lemon think that meant that the megalodon was more efficient at moving through water.
Yahoo
10-03-2025
- Science
- Yahoo
Megalodon: Scientists Reveal a Crucial Surprise About The Mega-Shark
It remains a sad fact of this world that we will never know for certain what the long-lost megalodon truly looked like – but a new study gives us what may be the most accurate reconstruction yet. An international team led by paleontologist Kenshu Shimada of DePaul University in the US has determined that the megalodon (Odontus megalodon) was probably longer and sleeker than previous interpretations of its scant, mysterious remains. "This study provides the most robust analysis yet of megalodon's body size and shape," says marine biologist Phillip Sternes, formerly of the University of California Riverside, now at SeaWorld. "Rather than resembling an oversized great white shark, it was actually more like an enormous lemon shark, with a more slender, elongated body. That shape makes a lot more sense for moving efficiently through water." The megalodon is one of the most captivating mysteries on the fossil record. It lived from around 23 million to around 3.6 million years ago, during which time it occupied a prime position at the top of the food web, before being driven to extinction. We know it was huge, compared to modern sharks, but learning more about what it looked like is extremely difficult. That's because, like those of today's sharks, megalodon's skeleton was mostly cartilage. Only its teeth and vertebrae have been preserved as fossils on the seafloor, indicating a monster of a shark that could have been anywhere between around 11 meters to over 40 meters (36 to 131 feet) in length. Most estimates settle between around 13 to 18 meters, with the white shark (Carcharodon carcharias) as the basis for their model, using one of the most complete megalodon fossils we have: an almost complete spine found near Belgium measuring 11 meters in length. The white shark is a true powerhouse, one of the fiercest predators in the ocean, so it's easy to see why scientists might turn to it to understand the megalodon. Not all sharks are built alike, though. Rather than examining the megalodon spine in the context of just a handful of species, Shimada and his colleagues compared it against a huge catalog of 145 living and 20 extinct shark species. In particular, they were looking to calculate the length of the body parts not represented by the fossilized vertebral column; that is, the head and the tail of the shark. Their new approach found that if the megalodon's body plan was consistent with most of the other sharks evolution has so elegantly crafted, the extinct predator's head and tail could have represented 16.6 and 32.6 percent of the total body length, respectively, with a sleeker, slimmer body more like that of the lemon shark (Negaprion brevirostris) than the white shark. This means that, for the Belgian individual, the head would have measured 1.8 meters in length and the tail 3.6 meters, making that specific megalodon a total of 16.4 meters wide. Although the Belgian spinal column gives scientists a bunch of related bones to work with, they are not the only megalodon vertebrae paleontologists have found; nor are they the largest. The largest vertebra in the assemblage is 15.5 centimeters (6.5 inches) long. Other vertebrae found near Denmark are reported to be significantly larger, up to 23 centimeters across. Assuming that this represents the largest possible size a megalodon vertebra can reach, the researchers calculated a new top size for the shark. "The length of 24.3 meters is currently the largest possible reasonable estimate for O. megalodon that can be justified based on science and the present fossil record," Shimada says. That length is comparable to two school buses, end-to-end, much larger than most sharks that swim the oceans today, although filter-feeding whale sharks (Rhincodon typus) can reach lengths of 20 meters or so, and actual whales can be significantly larger. The interesting thing about all these large marine animals is that their bodies, also, are long and sleek. The shorter, stockier shape of the white shark is built for short bursts of speed; the longer, sleeker bodies of lemon sharks, whale sharks, and whales are better for more energy-efficient swimming, and minimal drag. A longer, sleeker, more hydrodynamic body would have allowed megalodon to grow much larger than the white shark, whose maximum body size is less than 6 meters, limited by the energy demands of its swimming and hunting style. At 23.4 meters in length, a megalodon would have cruised the oceans at speeds around 2.1 to 3.5 kilometers (1.3 to 2.2 miles) per hour, using sparing speed bursts only when necessary. "This research not only refines our understanding of what megalodon looked like, but it also provides a framework for studying how size influences movement in marine animals," Sternes says. "Gigantism isn't just about getting bigger – it's about evolving the right body to survive at that scale. And megalodon may have been one of the most extreme examples of that." The research has been published in Palaeontologia Electronica. Dead Bacteria Dissolve Their Own Corpses as a Parting Gift For Relatives Stick From a Dead Shrub Reveals Surprising Truth About Its Record Lifespan Scientists Discover Thousands of New Microbes Lurking in The Ocean's Deepest Zone
