'T. Rex' Of The Seas

An artist's illustration of the giant ichthyosaur ruled the oceans some 244 million years ago. (Image: Raul Martin/National Geographic Magazine)

The researchers say the 28-foot long predator probably could have tackled victims as large as itself or larger.

Newfound fossils of a giant dolphin-shaped reptilian predator are now shedding light on how the world recovered after the most devastating mass extinction in history, researchers say.

 

This prehistoric sea monster could provide information on how the planet might deal with the mass extinction humans are causing now, scientists added.

 

The giant marine predator was at least 28 feet (8.6 meters) long, fossils showed. The carnivore was recovered over a course of three weeks in 2008 from what is today a mountain range in central Nevada, and is now kept at the Field Museum in Chicago.

 

This new species, formally named Thalattoarchon saurophagis — which means "lizard-eating ruler of the sea" — was an early member of the ichthyosaurs, marine reptiles that evolved from land reptiles just as modern whales did from land mammals. Ichthyosaurs cruised the oceans for 160 million years, apparently going extinct about 90 million years ago, some 25 million years before the age of dinosaurs ended.

 

"They were the most highly adapted of all marine reptiles, acquiring a fishlike shape and giving birth to live young," said researcher Martin Sander, an evolutionary biologist at the University of Bonn in Germany.

Thalattoarchon possessed a massive skull and jaws armed with large teeth with cutting edges used to seize and slice prey. The researchers say it probably could have tackled victims as large as itself or larger. [See Images of the Prehistoric Sea Monster]

 

"Our new carnivorous ichthyosaur was a top predator, meaning that it had the same role as killer whales in the sea and Tyrannosaurus or the big cats of today on land," Sander said. "This is the first predator in a long row of predators down to this day. The players have changed, but not the game."

 

Most of the animal was preserved, including the skull — except the front of the snout — parts of the fins, and the complete vertebral column up to the tip of the tail. The fossil was christened "Jim" after its discoverer, Jim Holstein, of the Field Museum.

 

The newfound carnivore apparently lived 244 million years ago, just 8 million years before the greatest mass extinction in Earth's history, a die-off at the end of the Permian period that killed as many as 80 to 96 percent of all ocean species. Relatively small species were the main survivors.

 

"Our 'Jim' was thus the first in a long row of T. rexes of the sea, which is why we named him Thalattoarchon, 'ruler of the seas,'" Sander said.

 

The fact that a giant predator capable of tackling similarly large prey arose so soon after the end-Permian mass extinction reveals that ecosystems recovered rapidly after the die-off.

 

"A top predator is a very good indicator that the ecosystem was complete, because if the highest level in the food web is there, the lower levels must have been there as well. Otherwise it won't work," Sander said.

Ichthyosaurs diversified very rapidly. "We hope that by studying this group we can better understand the processes of evolution at the grand scale," researcher Lars Schmitz, an evolutionary biologist at Claremont McKenna College, told LiveScience.

 

"Ecosystem recovery has been a big topic of research for a while, partially because we as humans are causing one of the biggest extinctions right now," Sander said. "People thus have a keen interest in knowing how long it takes to rebuild things once you have destroyed them."

Via: "Mother Nature Network"

Introducing: MegaPiranha

Skeleton of today’s black piranha. In the wild, one 2 ½ pound black piranha delivered a bite with a force 30 times its body weight.

Piranha Kin Wielded Dental Weaponry Even T. Rex Would Have Admired

The bite force of Megapiranha, which lived 10 million years ago, was extrapolated from the first field measurements of the biting force of Earth’s largest piranha today, Serrasalmus rhombeus or black piranha. One 2 ½ pound fish delivered a bite with a force of 320 newtons, or about 72 pounds, which is 30 times its body weight. The force is nearly three times greater than the bite force of an equivalent size American alligator.

Based on the 2 ½ pound piranha and other specimens tested in the wild,  the scientists calculate that Megapiranha paranensis, which weighed approximately 22 pounds, could have had a bite force anywhere from 1,240 to 4,750 newtons  – or 280 to 1,070 pounds – and possibly more.

Other scientists have previously estimated that T. rex slammed its jaws shut with 13,400 newtons, or 3,000 pounds of force, but that’s nowhere near 30 times its body weight.

Pound for pound, Megapiranha and black piranha have the most powerful bites among carnivorous fishes, living or extinct, the paper said. “For its relatively diminutive size, Megapiranha paranensis’ bite dwarfs other extinct mega-predators” including the enormous whale-eating Carcharodon megalodon and the monstrous Dunkleosteus terrelli, a four-ton armored fish.

Justin Grubich, et al/Scientific Reports

Bite force quotients – considering both bite force and body size – compare the powerful bites of black piranha (S. rhombeus) and now-extinct Megapiranha (M. paranensis) with barracuda, blacktip shark (C. limbatus), bull shark (C. leucas), hammerhead shark (S. mokarran), the extinct 4-ton Dunkleosteus terrelli, great white shark (C caracharias) and the extinct whale-eating Carcharodon megalodon.

The same was true when the scientists corrected for body size and made comparisons with today’s barracudas, hammerhead sharks and great white sharks.

“We were surprised that in spite of their long history and infamous reputations that no one had ever measured their bite forces,” said Justin Grubich, with the American University in Cairo, Egypt, and lead author of the paper. “When we finally started to get the data, we were blown away at how tremendously strong the bites were for these relatively little fish.”

As the paper says, “While anecdotes of piranha-infested waters skeletonizing hapless victims are generally hyperbole, the effectiveness of their bite is not.”

Just how does one measure the bite force of a piranha living in the wild? Well, you get out your rod and reel and go fishing. Land a specimen, then hang tight to the tail with one hand and use your other hand to support its belly while offering the fish a chance to bite the plates of a customized force gauge.

“Piranhas are ornery little fish so they bit down as hard as they could,” Crofts said based on what she was told by those on the fishing expedition along tributaries of the Amazon River.

The black piranha’s bite is so powerful in part because of its massive jaw muscles and rope-like tendons that together account for 2 percent of the fish’s overall weight, the scientists found. Further the shape of their jaw has evolved into a powerful lever, “one of the highest jaw-closing mechanical advantages ever identified in fishes,” the paper said.

Crofts’ main contribution involved analysis of how Megapiranha teeth handled stresses and how breakable the teeth might have been. The scientists were particularly interested because Megapiranha’s unusual teeth appear to do two things at the same time, one the piranha-like ability to shear soft tissues and the other an ability to bite like the nut-crushing pacu, piranha’s close relative.

Based on a fossilized jaw and three teeth, Crofts conducted a computer generated “finite element analysis” for the team.

“We found the Megapiranha teeth had the same maximum strength like you saw in regular piranha, but then the patterns of stress distribution within the tooth was also similar to fish able to eat hard-prey,” she said.

The actual diet remains a mystery, but during the time when Megapiranha lived a lot of potential prey species were gigantic.

“Thus it is reasonable to assume the food resources available to Megapiranha would likely have required jaw forces and dental weaponry capable of capturing and processing very large prey,” the paper says.

Other co-authors on the paper are Steve Huskey with Western Kentucky University, Guillermo Orti with George Washington University and Jorge Porto with the Instituto Nacional de Pesquisas da Amazônia.

Funding came from the National Geographic and the Field Museum of Natural History.

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For more information:
Crofts, croftss@uw.edu, phone: Contact Sandra Hines, shines@uw.edu, 206-543-2580

National Geographic video (natgeotv.com) of Justin Grubich and others fishing for piranha and testing bite force in the wild.

Piranha Bite Force:



Via: "The University Of Washington"