A dinosaur's worst nightmare
the punishing heat of the African Sahara, paleontologist Paul
Sereno has uncovered the remains of a giant prehistoric crocodile
that dwarfs its modern counterparts.
during the Cretaceous period, Sarcosuchus imperator ("flesh
crocodile emperor") grew to a length of 40 feet and weighed
eight tons, twice as much as a full-grown elephant. In contrast,
modern crocodiles rarely exceed 14 feet and weigh no more than
half a ton.
crocodile was probably capable of pulling down just about any
dinosaur under the right circumstances," says Sereno, professor
of organismal biology & anatomy. "It would have been
a force to be reckoned with on the shoreline. It would have been
a dinosaur's nightmare."
teeth and armored plates of Sarcosuchus were first discovered
by French paleontologist Albert-Felix de Lapparent in the 1940s
and 1950s. During expeditions to the Tènèrè
Desert of Niger in 1997 and 2000, Sereno and his research team
recovered several partial skeletons of Sarcosuchus, including
vertebrae, limb bones, armor plates, jaws, and a nearly complete
six-foot skull. Working from those remains-about 50 percent of
the whole skeleton-Sereno and coauthors Hans Larsson, SM'96, PhD'00,
Christian Sidor, SM'96, PhD'00, and Niger paleontologist Boubè
Gado published a detailed description of the animal's anatomy
on the October 25 Science Web site and in print November 16.
found the remains of Sarcosuchus in the same 110-million-year-old
sediment layer where in 1997 he discovered Suchomimus,
a two-legged, fish-eating predator measuring 36 feet long and
12 feet high at the hips. But even that large beast, Sereno notes,
would have had to be on the alert for surprise attacks from the
stealthy Sarcosuchus. Sarcosuchus's jaws were studded
with more than 100 bone-crushing teeth and an enormous, bowl-shaped
snout that may have aided the animal's sense of smell or been
used to make sounds. India's modern-day gharials, for example,
are highly communicative. "They're vibrating and belching
and growling and hissing all the time, sometimes even in the water,"
certain similarities to the much smaller gharial, Sarcosuchus
is not directly related to modern crocodiles. Nevertheless, measuring
living crocodiles in India and Costa Rica helped Sereno estimate
the size of a full-grown Sarcosuchus.
also studied the growth layers in the armored plates along the
back of Sarcosuchus. Examination of thin slices under the
microscope revealed that the animals lived to be 50 to 60 years
old, about twice the life span of modern crocodiles.
on three previous expeditions to Africa, Sereno's team probed
remote areas of the continent in temperatures reaching 125 degrees
Fahrenheit for its fossil treasures. Funded by the National Geographic
Society and the David and Lucille Packard Foundation on the 2000
expedition, the team found that Sarcosuchus had plenty
of crocodilian company in the broad rivers that flowed across
lush plains. Plying the same rivers were the doglike Araripesuchus
and a newly discovered species, yet to be named, that attained
a full-grown length of only two feet. -Steve