Two million years ago bizarre creatures roamed the Australian continent—the flesh-eating giant rat-kangaroo, the thunder bird, the marsupial wolf, and a giant monitor lizard. But these animals have never taken center stage in the public's imagination or even the scientific community like the large prehistoric creatures of other continents—in part, because a poor fossil record revealed few specimens that looked either large or ferocious. Now a recent study suggests that one creature—with a bite that may rival that of most predatory mammals—may have been sorely misjudged. Until it died out about 30,000 years ago, Thylacoleo carnifex—or "pouched lion executioner"—was Australia's reigning mammalian predator. According to a recent study, Thylacoleo was not only a much larger predator than previously believed but also the most specialized mammalian carnivore of all time. A team of Australian scientists led by Stephen Wroe, a specialist in marsupial carnivore evolution at the University of Sydney, used a new method to estimate the size of this long-extinct predator. A subsequent series of experiments explored its "bite force"—essentially measuring how much pressure its jaws could exert on the head or neck of another creature during a kill. Results suggest few creatures would have survived its bite. Using about a dozen fossilized skulls from T. carnifex, Wroe and his colleagues determined the species's brain volume, which was used to calculate overall body size. The "lion" was determined to be about 215 pounds (98 kilograms).

While that's not as big as a saber-toothed cat or even a living lion or tiger—it is twice as large as previous estimates that pegged T. carnifex as being the size of a leopard. The work was published late last year in the journal Paleobiology. "Body weight is one of the most significant aspects of an animal's biology—it radically alters how we perceive its role and its impact on the ecology," Wroe said.

View: Full Article | Source: National Geographic