A team of researchers has found traces of a new particular species of prehistoric sharks called the “megalolamna paradoxodon,” which dates back to 20 million years and resembles modern white sharks.

The new discovery shows a never-before-seen species of sharks that lived during the Miocene period and belongs to a family group of sharks called ‘Lamniformes,” in which modern sharks are featured. Researchers discovered the megalolamna paradoxodon thanks to a series of teeth that measured almost 1.77 inches, found in both eastern and western U.S regions, Japan and Peru.

Megalolamna Paradoxodon/Shark
Discoverers named the recently-found species “paradoxodon” due to its sudden emerge in oceanic history. Image credit: Kenshu Shimada.

“The fact that such a large shark with such a wide geographic distribution had evaded recognition until now indicates just how little we still know about the Earth’s ancient marine ecosystem,” said Kenshu Shimada, a paleobiologist from DePaul University in Chicago and the study’s first author.

Can researchers calculate the size of a shark by measuring its teeth?

Sharks are dangerous predators that live somewhere in the ocean’s deep structures, located at the top of the marine food chains. They represent an imminent threat to those who share space with them.

Researchers discovered the first trace of an ancient shark when analyzing the fossils of a “spiny shark” that dated back to over 420 million years. Since then, over 500 different species of sharks have been found in the deepest oceans, living in depths of up to 6561.68 feet.

Megalolamna Paradoxodon/Shark
“The idea that megalodon and its close allies should be placed in Otodus is not new, but our study is the first of its kind that logically demonstrates the taxonomic proposition,” Shimada noted. Image credit: Kenshu Shimada.

Sharks are measured in different species depending on their size. For example, the smallest shark is called the dwarf lantern shark and measures only 6.6 inches, while the title the of the world’s largest shark goes to the whale shark that measures up to 39 feet long.

The team of researchers led by Professor Shimada first thought that the megalolamna paradoxodon belonged to a genus of sharks called “Lamna”  in which today’s salmon shark is featured, due to its large teeth.

However, after analyzing the ancient teeth and comparing them to modern-day sharks, researchers noted that this genus didn’t fit the fossils’ measures.  According to Shimada’s report, the found-teeth were too robust and they fit better with the “Otodus” type.

Researchers noted that the Megalolamna actually was the Otodus’ closest relative with a 45-million-year gap between the two cousins. This discovery was made when researchers compared the fossils with evidence belonging to the Carcharocles Megalodon, the species that features history’s largest shark.

The Carcharocles Megalodon species grows up to be almost 60 feet long and according to studies its bite could be even harder than a T-Rex’s bite. The Megalodon, as well as the newly discovered Paradoxodon, belong to the Otodontidae family.

Shark researchers have debated whether the Megalodon should be placed in the Otodus family due to its large size, and now thanks to the comparison with the Megalolamma, researchers have proof.

Otodus Obliquus Shark Tooth
Otodus Obliquus Shark Tooth found in Morocco. Image credit: http://www.foreshorefossils.com/.

Researchers note that the M. Paradoxodon had large teeth that allowed the predator to seize and slice prey thanks to its front and back teeth that worked as sharp knives.

Initial studies affirm the newly-discovered species lived in coastal and shallow waters with midlatitudes such as where the team of researchers found the fossils in North Carolina, California, Japan, and Peru.

Shimada’s team of researchers has concluded that the recently-found shark measured up to 12 feet long and could be a few inches smaller than its modern competitor the great “white shark.” However, some scientists don’t agree with this position.

John-Paul Hodnett, a shark specialist at Philadelphia’s Saint Joseph’s University, said that calculating the size of a shark only by its teeth could result in a mistake, Live Science informed.

Professor Shimada’s findings have been published in the Journal of Historical Biology and hope to shed some light on the oceanic history of these long-studied predators.

“For teeth, you should always be cautious of the fact that it is possible to have very large or small teeth in a shark’s jaw, which do not represent the true aspect of the shark’s body,” informed Hodnett, who compared the modern whale shark’s small teeth to the animal’s size (12 meters).

Source: DePaul University