About 240 million years ago, a 15-foot amphibian with a nasty bite ruled the Antarctic plains, say paleontologists who have described the creature for the first time. Fossils show that the predator, newly named Kryostega collinsoni, had an extra set of teeth protruding from the roof of its mouth, which helped it shred flesh and hold struggling prey still in its mouth.
The animal, which researchers called Antarctica’s top predator in the Triassic Period, resembled a modern crocodile but was actually a temnospondyl, a prehistoric amphibian that was an early relative of salamanders and frogs. Because of their odd mixture of characteristics, members of this group are sometimes nicknamed “crocamanders” or “frogodiles” [Discovery News]. The new species will be described in the forthcoming issue of the Journal of Vertebrate Paleontology.
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Viruses infect a wide range of plants and animals, and a new study in Nature [subscription required] shows that they can even infect one another. If that seems surprising, no wonder: until a team of French researchers watched one virus invade another, hijacking its genetic machinery and making copies of its victim’s DNA, scientists didn’t even know this was possible [Wired].
The French team dubbed the virus’s virus Sputnik and called it a “virophage” to parallel “bacteriophage,” which is the name for a virus that infects bacteria [Science]. Sputnik is tiny, with only 18,000 genetic bases in its chromosome. Its victim, by contrast, is a large mamavirus that the scientists found in a Paris cooling tower, and contains about 1.2 million genetic bases. An infection by Sputnik sickens the mamavirus by interfering with its replication.
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An extinct ancestor of the great white shark had a powerful bite that wouldn’t just put Jaws to shame, according to a new fossil analysis by Australian researchers. The colossal force of Carcharodon megalodon – also known as Big Tooth – made even Tyrannosaurus rex look puny [Telegraph].
In the study, to be published in an upcoming issue of the Journal of Zoology [subscription required], researchers took CT scans of both the skulls of great white sharks and those of the prehistoric megalodon, who swam the oceans about a million and a half years ago. They made computer models of the skulls, and then ran an analysis on the models that engineers use to determine how machinery holds up under stress.
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Researchers say they have found the world’s smallest snake on the Caribbean island of Barbados. Evolutionary biologist Blair Hedges says that the tiny reptile, which can comfortably curl up on a quarter and which is barely as wide as a spaghetti noodle, may also be at the evolutionary limit for the smallest size possible for snakes.
Most snakes produce clusters of eggs, but the newly discovered species lays only one egg, which hatches a youngster who is one-half the length of the adult. That would be like humans giving birth to a 60-pound (27kg) baby. Dr Hedges added that the snake’s size might limit the size of its clutch. “If a tiny snake were to have more than one offspring, each egg would have to share the same space occupied by the one egg and so the two hatchlings would be half the normal size.” The hatchlings might then be too small to find anything small enough to eat [BBC News].
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In the primeval forests of Europe, scaly lizards leaped from the treetops and glided safely to the ground, according to a new study. Paleontologists investigated the fossilized remains of two kinds of kuehneosaurs, which were first found in the 1950s in an ancient cave system near Bristol [The Press Association]. They say that the prehistoric reptiles used extraordinary extensions of their ribs to form large gliding surfaces on the side of the body [LiveScience], which were surprisingly effective for the larger of the two species.
Researcher Koen Stein says: “We didn’t think kuehneosaurs would have been very efficient in the air, but all the work up to now had been speculation, so we decided to build models and test them in the wind tunnel in the Department of Aerospace Engineering at Bristol. Surprisingly, we found that Kuehneosuchus was aerodynamically very stable” [Telegraph]. Researchers said the Kuehneosuchus could have glided about 30 feet before touching down on the ground, while the Kuehneosaurus, with stubbier “wings,” was more of a parachutist.
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An evolutionary puzzle that Charles Darwin mulled over has finally been solved, thanks to a re-examination of some dusty fish fossils that had been lying neglected in a museum archive. Scientists had long wondered how flatfish evolved to their present form, with both eyes on the same side of their heads; now a report in the journal Nature [subscription required] reveals that the trait evolved gradually and in stages.
All living flatfishes, which include halibut, flounder and sole, have a bizarre adaptation: both eyes are on one side of their head [Telegraph]. This allows them to lie flat on the ocean floor while using both eyes to watch for passing prey. Scientists couldn’t figure out how this trait could evolve gradually over time, and wondered whether a fish in the intermediate evolutionary stage would garner any advantage from having one eyeball that was near the top of its head. This caused people to argue that flatfish might be the product of a large and sudden evolutionary leap, and the fish were used as an argument against natural selection. Googling “flatfish creationism” will also reveal that the arguments spilled out of scientific circles as well [Ars Technica].
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Researchers say a tiny chameleon in Madagascar can lay claim to a strange record: It has the shortest lifespan of all four-limbed vetebrates. The astonishing Furcifer labordi spends eight months inside its egg, hatches in November, and then spends four months reaching maturity and mating before dying in April. By then the members of the next generation are already contained inside their eggs, ready to begin the cycle again.
The chameleon’s short life coincides with the rainy season in the arid region of Madagascar, and study coauthor Christopher Raxworthy says the lifecycle may be a response to the harsh climate. Raxworthy said that at about 3 inches long, F. labordi is the smallest of the region’s chameleons and may be less able to compete for food or more prone to desiccation in the dry season. “The best payoff may be to produce larger clutches and more offspring, rather than to conserve reserves and try to make it through the dry season as an adult,” he said [The New York Times].
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Around 365 million years ago, a fishy, finned creature that resembled a small alligator clambered up on a sandbank and earned its place in evolutionary history. Researchers who recently discovered fossils of the animal, named Ventastega curonica, say it’s the most primitive four-legged creature ever found. While it wasn’t the first “fishapod” to lurch out of the water (that honor goes to the Tiktaalik, which accomplished the feat about 375 million years ago), its more primitive evolutionary stage gives researchers new information about the earliest four-legged creatures, or tetrapods.
Ventastega was first described from a few bone fragments unearthed in Latvia in 1994, but it took additional years of excavation and the discovery of remains from many more individuals before scientists had a good idea of what the creature looked like. The latest portrait to emerge, from an especially well-preserved find, reveals an animal with a part-fish, part-tetrapod skull and a full-fledged tetrapod body. It would have spent the majority of its time on water and been clumsy on land [National Geographic News].
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The first researchers who spotted Australian dragon lizards trotting along on their hind legs were amused, perplexed, and amazed. When the critters took off over the dusty plain in a high-speed dash, they lifted their front legs and ran bipedally, looking a bit like tiny dinosaurs.
Those early researchers assumed that the trick must give the lizards an advantage in speed or endurance, but they didn’t do the lizard races to prove it. They also wondered if the lizards were gradually evolving into entirely bipedal animals. Now, a new study in the Journal of Experimental Biology [subscription required] declares that the maneuver does not help the lizards put on extra speed after all, and actually decreases endurance. In a surprising twist, researchers called the lizards’ upright stance just an “evolutionary accident.”
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