No fish story: Meet the 'Megapiranha'
By SCOTT SUNDE, SEATTLEPI.COM STAFF
More fierce, the scientists say, than prehistoric whale-eating sharks, the four-ton armored fish Dunkleosteus terrelli or the Tyrannosaurus rex.
Don't worry, the fish lived about 10 million years ago.
Scientists say the appropriately named Megapiranha paranensis just didn't bite through flesh as modern day piranhas do. It also could pierce thick shells and crack bones and armoring.
"If our calculations are correct, Megapiranha was probably a bone-crushing predator taking bites of anything and everything," said Stephanie Crofts, a University of Washington doctoral student in biology. She is co-author of "Mega-Bites: Extreme jaw forces of living and extinct piranhas," published Dec. 13 in the online journal Scientific Reports.
The findings come from the first field tests of the biting force of the largest piranha around today: The black piranha.
One 2 1/2-pound black piranha can bite with the force of 320 newtons -- a measure of force -- or 72 pounds. That's about 30 times its body weight.
The Megapiranha, which weighed about 22 pounds, could have had a bite force of 1,240 newtons to 4,750 newtons, or 280 to 1,070 pounds.
The T. rex had quite a bite: 13,400 newtons or 3,000 pounds. But scientists say its bite was not close to 30 times its body weight.
So the paper can conclude: "For its relatively diminutive size, Megapiranha paranensis' bite dwarfs other extinct mega-predators."
Measuring the bite force of a piranha -- the beast we all remember in movies as turning some poor explorer into all bone and no flesh -- seems like no fun at all.
You catch one, hold the tail with one hand, the belly with the other and get the thing to bite a force gauge.
Scientists say the black piranha was built to bite. It has huge jaw muscles and tendons like ropes. Those two assets account for 2 percent of the fish's weight.
The jaw has evolved into a level that the scientists describe as "one of the highest jaw-closing mechanical advantages ever identified in fishes."
To borrow a phrase, it's not the size of the fish in the fight but the size of the fight in the fish.
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