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This 5,000-pound behemoth is the world’s heaviest bony fish

(Credit: Fit News)

The heaviest bony fish ever caught weighs in at a whopping 5,070 lbs. (2,300 kg). Now, scientists know her name.

The fish is a Mola alexandrini sunfish, researchers reported Dec. 5 in the journal Ichthyological Research. Originally it was the fish, which was caught in 1996, was incorrectly identified as a Mola mola, a better-known species of sunfish. But recent research has upended the entire Mola gender and led to the reidentification of some species. M. alexandrini is recognizable by the distinctive shape of the head, borrow the common name of the “bump-headed sunfish.”

“For the same reason we take the already proposed Japanese common name Ushi-manbo,” said study leader Etsuro Sawai, a sunfish expert at Hiroshima University. “‘Ushi” means “cow,” and refers to the head of the profile of the fish.” [Photos: The world’s Largest Bony Fish]

Big fish

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Ocean sunfish are the largest bony fish in the sea. Unlike sharks and rays they have skeletons made of bone rather than cartilage. They are also very strange to watch. Their bodies are large and round, in the form of a wheel or pancakes. They can grow to about 10 feet (3 meters) long.

The Mola genus was not well understood until in the last few years, because the study of such massive instances is not easy. They are difficult to collect and even more difficult to carry out a thorough anatomical investigations. Genetic studies have opened up the case, which suggests that once the fish classified as Mola mola were in fact very different from each other, and that certain gene sequences do not fit nicely into pre-existing types of categories. In July 2017, researchers with the name of a new species of john dory with these sequences, Mola tecta, after finding a handful of specimens washed ashore on a New zealand beach.

M. tecta has a round snout and a distinctive stripe that divides the body of the rudder-type fin on the fish, which is known as the clavus.

The redefining of the ocean sunfish

In the new study, researchers studied 30 specimens of Mola who do not belong to the M. tecta species. They also hunted by the historical photos, looking for anatomical features that could contribute to distinguish the species from each other. Eventually, they used this information to redescribe M. alexandrini and to distinguish it from M. tecta and M. mola.

The realization that M. alexandrini wins the heavy price for bony fish grew out of this newly clarified classification. Guinness World Records lists M. mola the world’s heaviest bony fish, but Sawai and his team discovered that the largest catch on record was actually a M. alexandrini caught in 1996 in Kamogawa, Japan. That fish was 8.9 feet (2.72 meters long, raising the question of whether a number of individuals of this species are even heavier. In 2004, anglers recorded the capture of a 10.9 metre (3.32 m) M. alexandrini in the vicinity of Aji Island, Japan, but they were not the roads that behemoth.

Original article on Live Science.

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