Swarms of up to a thousand giant trilobites—extinct marine arthropods such as this 35-inch-long (90-centimeter-long) fossil specimen—roamed shallow prehistoric seas, new fossils show.
The 465-million-year-old fossils, found recently in northern Portugal, are of the largest trilobites ever discovered.
The trilobites may have clustered to mate and molt—shedding old exoskeletons as new ones grew in—as well as avoid predators, scientists say.
The benefits of swarming may explain why these distant relatives of horseshoe crabs were among the most widespread arthropods of the Paleozoic era (542 to 251 million years ago).
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September 26th, 2009
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Megapiranha was up to 3 feet long (1 meter) — a fish-beast four times as big as piranhas living today, studies of its jawbones indicate. It lived about 8 million to 10 million years ago and might have been quite comfortable stalking cartoon animals in an “Ice Age” movie.
Another close relative of the piranha, called pacu (singular and plural), is not so scary. Pacu have squared-off stumps of teeth used for munching veggies. (For the record, tales of carnivorous piranhas eating humans are fictional.)
Now a newly uncovered jawbone of a transition species ties all these teeth together. Named Megapiranha paranensis, this previously unknown fossil fish bridges the evolutionary gap between flesh-eating piranhas and their plant-eating cousins.
The new fossil shows an intermediate pattern: teeth in a zig-zag row. This suggests that the two rows in pacu were compressed to form a single row in piranhas. “It almost looks like the teeth are migrating from the second row into the first row,” said John Lundberg, curator at the Academy of Natural Sciences in Philadelphia and a co-author of a study of the jawbone.
If this is so, Megapiranha may be an intermediate step in the long process that produced the piranha’s distinctive bite. To find out where Megapiranha falls in the evolutionary tree for these fishes, Dahdul examined hundreds of specimens of modern piranhas and their relatives.
The Megapiranha fossil was originally collected in a riverside cliff in northeastern Argentina in the early 1900s, but remained unstudied until paleontologist Alberto Cione of Argentina’s La Plata Museum rediscovered the startling specimen — an upper jaw with three unusually large and pointed teeth — in the 1980s in a museum drawer.
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September 21st, 2009
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It’s hard enough to find fossils of hard things like dinosaur bones. Now scientists have found evidence of 95 million-year-old octopuses, among the rarest and unlikeliest of fossils, complete with ink and suckers.
The body of an octopus is composed almost entirely of muscle and skin. When an octopus dies, it quickly decays and liquefies into a slimy blob. After just a few days there will be nothing left at all. And that assumes that the fresh carcass is not consumed almost immediately by scavengers.
Fuchs and his colleagues now have identified three new species of octopuses (Styletoctopus annae, Keuppia hyperbolaris and Keuppia levante) based on five specimens discovered in Cretaceous Period rocks in Lebanon. The specimens, described in the January 2009 issue of the journal Palaeontology, preserve the octopuses’ eight arms with traces of muscles and rows of suckers. Even traces of the ink and internal gills are present in some specimens.
Unlike vertebrate animals, octopuses lack a well-developed skeleton, which allows them to squeeze into spaces that a more robust animal could not.
“The more primitive relatives of octopuses had fleshy fins along their bodies. The new fossils are so well preserved that they show, like living octopus, that they didn’t have these structures,” Fuchs said.
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September 20th, 2009
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Giant fossil sea monster found in the Arctic and known as “Predator X” had a bite that would make T-Rex look feeble, scientists said Monday.
The 50 ft (15 meter) long Jurassic era marine reptile had a crushing 33,000 lbs (15 tonnes) per square inch bite force, the Natural History Museum of Oslo University said of the new find on the Norwegian Arctic archipelago of Svalbard.
“With a skull that’s more than 10 feet long you’d expect the bite to be powerful but this is off the scale,” said Joern Hurum, an associate professor of vertebrate paleontology at the museum who led the international excavation in 2008.
“It’s much more powerful than T-Rex,” he said of the pliosaur reptile that would have been a top marine predator. Tyrannosaurus Rex was a top land carnivore among dinosaurs.
The scientists reconstructed the predator’s head and estimated the force by comparing it with the similarly-shaped jaws of alligators in a park in Florida.
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