NEW DINO WITH WACKY DENTITION A dog-sized, predatory dinosaur discovered in Madagascar has scientists shaking their heads over its mouthful of unruly teeth. The theropod dinosaur, new to science, dates to the late Cretaceous period (65-70 million years ago) and was named Masiakasaurus knopfleri,according to a paper in the recent issue of the journal Nature.
No complete example of the creature were found, rather researchers unearthed fossil jaws and bones from many indviduals in a single site in Madagascar. "When we dug up the first lower jaw bone, we weren’t even sure it belonged to a dinosaur!" says University of Utah paleontologist Scott Sampson, leader of the research team. "It was only after we compared it with the lower jaws of other carnivorous dinosaurs that we became convinced...Certain features at the back of the jaw are unmistakably theropod."
The bizarre aspect of this theropod dinosaur is its extremely specialized teeth and jaws. The first tooth of the lower jaw is oriented almost horizontally, projecting forward instead of upward. Subsequent teeth angle increasingly upward until the sixth tooth; from this point backward, all the teeth point straight up.
The teeth themselves are also unique. The teeth at the back of the jaw are typical of theropods-being flattened and serrated, those at the front are longer and almost conical, with hooked tips and only tiny serrations. These features are otherwise unknown among theropod dinosaurs, which tend to have teeth of the same type front and back.
There are a few species of living mammals, including various shrews, as well as a group of South American marsupials known as caenolestids, that possess a similar dental set up, with elongate, conical, forward-projecting teeth up front. In virtually all cases, the front teeth are used for grasping and piercing rather than tearing and slicing, and the prey generally consists of insects.
The jaws of Masiakasaurus suggest a similar feeding strategy, with the front teeth used to capture and manipulate animal prey, and the blade-like rear teeth then slicing the victim into bite-sized chunks. The scientists guess the preferred prey of this little dinosaurian carnivore includes insects, fish, lizards, snakes, and small mammals.
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Story with pictures National Science Foundation
MARSUPIAL FOUND TO SPREAD SEEDS, TOO Not only birds disburse seeds critical to the survival of plant species. Scientists working in the temperate rainforest of sounthern Chile have identified a nocturnal creature, Dromiciops australis, that plays a vital role in propagating the sticky seeds of the parasitic South American mistletoe.
Gillermo Amico and Marcelo A. Aizen of the Universidad Nacional del Comahue in Rio Negra, Argentina, staked out the mistletoe plant, Tristerix corymbossus for 500 hours, hoping to observe birds eating mistletoe seeds. No birds ate the seeds, but a 20-inch long, big-nosed marsupial did.
This area of the world contains threatened species of flora and fauna that can trace their lineage back some 70 million years, to the time of the continent of Gondwanaland. The newly discovered relationship of the mistletoe plant and its seed-eating marsupial may be a profoundly ancient one. The researchers say in their article in the 21/28 December 2000 Nature say that fossils found in the tropical Andes Mountains indicate that the marsupial-mistletoe bond may have been much more widespread as well.
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