NSF PR 01-03
Cheryl Dybas (703) 292-8070 email@example.com
(Harold) Rich Lane (703) 292-8551 firstname.lastname@example.org
New Predatory Dog-Sized Dinosaur Unearthed on Madagascar
Note: Images of the discovery are available at:
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
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
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
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.