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Press release on Masiakasaurus knopfleri



This press release just came in from the National Science Foundation, with some background on Masiakasaurus, published in today's Nature. -- Jeff Hecht
 NSF PR 01-03
 Media contact:
 Cheryl Dybas  (703) 292-8070    cdybas@nsf.gov
 Program contact:
 (Harold) Rich Lane (703) 292-8551   hlane@nsf.gov


New Predatory Dog-Sized Dinosaur Unearthed on Madagascar

  Note: Images of the discovery are available at:
  http://www.nsf.gov/od/lpa/news/press/01/pr0103.htm

  Fossilized remains of a bizarre, dog-sized predatory
  dinosaur were recently recovered on the island of
  Madagascar. The discovery, funded in part by the
  National Science Foundation (NSF), was announced
  this week in the journal Nature by a team of
  researchers led by paleontologist Scott Sampson of
  the University of Utah. Matthew Carrano and
  Catherine Forster from the State University of New
  York at Stony Brook co-authored the paper.

  These fossils, which date to the Late Cretaceous
  period (about 65-70 million years ago), represent a
  dinosaur new to science, dubbed Masiakasaurus
  knopfleri. Masiakasaurus was relatively small, as
  dinosaurs go, with a total body length of 1.6-2.0
  meters, much of which consisted of its long neck and
  tail. The total mass of this small carnivore would have
  been approximately 35 kilograms (80 lbs.), roughly
  that of a German Shepherd dog.

  "Scott Sampson and the NSF-supported team of
  U.S. scientists working in Madagascar continue to
  reveal startling new vertebrate fossils," says H.
  Richard Lane, geology and paleontology program
  director in NSF's division of earth sciences, which
  funded the research. "Masiakasaurus is one of several
  such recent discoveries by this prolific team, with, I'm
  sure, more to come."

  Masiakasaurus is based on a number of isolated
  bones from several individuals. The great majority of
  these fossils were recovered from a single site.
  Included in the collection are parts of the jaws and
  about 40 percent of the remainder of the skeleton,
  with some bones being represented by multiple
  examples.

  The most 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. Whereas
  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.

  "When we dug up the first lower jaw bone, we
  werenít even sure it belonged to a dinosaur!" says
  Sampson. It was only after we compared it with the
  lower jaws of other carnivorous dinosaurs that we
  became convinced as to the nature of the owner.
  Certain features at the back of the jaw are
  unmistakably theropod."

  Masiakasaurus shared its island home with at least
  one other carnivorous dinosaur, Majungatholus
  atopus. At 7-9 meters in length, Majungatholus was
  the top predator of the time, likely feeding on the
  massive long-necked sauropod dinosaurs also found
  there.

  The diet of the smaller cousin, Masiakasaurus, with
  its unique teeth and jaws, is much less certain. There
  are a few species of living mammals-including various
  shrews, as well as a group of South American
  marsupials known as caenolestids-that may provide
  an analogue. These mammals 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. As to
  the nature of the preferred prey of this little
  dinosaurian carnivore, potential candidates include
  insects, fish, lizards, snakes, and small mammals.

  Masiakasaurus and Majungatholus, the two known Malagasy
  theropods, are members of an enigmatic group known as
  abelisauroids, and recovered only on Southern Hemisphere
  landmasses. In particular, the fossils of Masiakasaurus
  share a number of specialized characteristics with predatory
  dinosaurs found in Argentina and India. This finding indicates that a
  previously unrecognized radiation of small-bodied
  predatory dinosaurs spread across much of the southern
  hemisphere toward the end of dinosaur times, paralleling the Late
  Cretaceous radiation's of small-bodied theropods
  (such as dromaeosaurids and ornithomimids) in the northern hemisphere.

  In addition, the broad geographic distribution of these small-bodied
  theropods parallels that of their larger-bodied cousins, the abelisaurids,
  a finding that may have implications for plate tectonics,
  the theory that landmasses shift their relative positions as they
  move slowly across the face of the earth.

  Madagascar was once part of the southern supercontinent Gondwana,
  which fragmented during the Mesozoic heyday of dinosaurs. The known
  geographic distribution of abelisauroid theropods large and small
  is consistent with a recently proposed geophysical hypothesis that Gondwanan
  landmasses retained connections well into the Late Cretaceous,
  much longer than previously thought. "If so", Sampson added, "dinosaurs
  and other land animals may have been able to travel the vast distances
  between South America and India-Madagascar because the two regions
  remained connected via intervening land masses."

  Funding for the Madagascar project has also been provided by the
  National Geographic Society, with additional support from The Dinosaur
  Society and the Field Museum of Natural History, Chicago.

-NSF-