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Sea
monster
fossil
sheds light on old mystery
Posted
Sept.
23,
2004
Courtesy
the
Field
Museum
of
Chicago
and
World
Science
Staff
 |
| Copyright AAAS/Science/ Illustration: Carin L. Cain |
An
extinct
sea
monster
used
its
long
neck
to
creep
up
on
victims
with
its
head,
then
suck
them
in,
scientists
suggest
based
on
a
new
fossil
find.
The
creature
is
a
member
of
the
Protorosauria,
a
group
of predatory reptiles
and
distant
relatives
of
dinosaurs
that lived as far back as 280 million years ago.
Scientists have never been able to figure out the function of the extremely long neck that characterizes some species of this
group.
The
new
fossil
suggests the neck may have been part of a unique,
very effective method for capturing prey in
water,
according
to
researchers.
Dinocephalosaurus
orientalis, which means "terrible-headed lizard from the Orient," was recently discovered in southern China.
In
a
paper
in
the
Sept.
24
issue
of
the
research
journal
Science,
researchers
describe how the neck may have been used to capture prey.
"This is important research because we have finally explained the functional purpose of this strange, long neck," said Olivier
Rieppel, a co-author of the Science paper and chair of geology and curator of fossil amphibians and reptiles at Chicago's Field Museum. "It allowed an almost perfect strike at prey, which usually consisted of elusive fish and squid."
Prey in water is slippery, and any movement toward it not only alerts the prey of an attack but also creates a pressure wave that could push the prey away. Fish and some turtles combat these factors with suction feeding, i.e., pulling the prey into their months by rapidly expanding the mouth cavity.
Crocodiles and alligators use a different approach. They catch prey with their flat head and pincer jaws, which allow them (when feeding in water) to strike
from
the
sides, cutting through the water while minimizing the force that pushes the prey away.
Dinocephalosaurus apparently
had
yet another
tactic,
Rieppel
and
his
colleagues
say. When it thrust its head forward to capture prey, the ribs along its neck would splay outward. This would
create a suction that would
draw
in
water,
along with the prey.
In addition, the long neck allowed Dinocephalosaurus to draw near its prey stealthily so it would have less of a chance of being detected. "To a fish in murky water, Dinocephalosaurus' head would have initially looked like another animal its own size, but by the time the fish was able to see Dinocephalosaurus' body, it would already have been lunch," said Michael LaBarbera, professor of organismal biology and anatomy at the University of Chicago.
Dinocephalosaurus' neck measures 1.7 meters, while its trunk is less than 1 meter long.
Unlike most protorosaurs,
Dinocephalosaurus was fully aquatic, although it might have laid its eggs on land.
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