NSF PR 99-14 - March 14, 1999
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NSF-Funded Researcher Plucks Four Unknown Fish Species
from Antarctic Waters
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Two new bottom-dwelling fish species from Antarctica's Ross Sea
The Antarctic brainbeard plunderfish (Pogonophryne
cerebropogon), a new species recently
collected at a depth of 300 m in the Ross
Sea. The long chin barbel is used as a
lure to attract prey. This species is
nearly 15 inches long.
Photo Credit: courtesy of Danette
Pratt, of the Ohio University College
of Osteopathic Medicine.
Select image for larger version
(Size: 19KB)
The Antarctic gravelbeard plunderfish
(Artedidraco glareobarbatus), collected
at a depth of 130 m near Franklin Island
in the Ross Sea. This species lives in
the vicinity of sponge beds and uses its
chin barbel as a lure to attract prey.
This species is about 6 inches long.
Photo Credit: courtesy of Danette
Pratt, of the Ohio University College
of Osteopathic Medicine.
Select image for larger version
(Size: 22KB)
Note
About Images |
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An Ohio University researcher who netted four species
of fish previously unknown to science during a National
Science Foundation (NSF) Antarctic research cruise
says the discoveries confirm his hypothesis that the
continent's frigid seas are a world-class evolutionary
laboratory.
"Antarctica is under-appreciated as an evolutionary
site," argues Joseph Eastman, an anatomist who made
his discoveries aboard the Nathaniel B. Palmer, an
icebreaker of the NSF's polar research fleet. "The
oceanic waters surrounding the continent are a natural
evolutionary laboratory comparable to the Hawaiian
Islands or Lake Baikal in Russia."
Eastman said his research indicates the waters appear
to have been the site of geologically recent "adaptive
radiation" as a single stock of fish -- known as notothenioids
-- evolved to fill ecological niches that unrelated
species would otherwise occupy. This is the only known
example of an adaptive radiation in marine fish, according
to Eastman.
Fossil evidence indicates that a variety of different
species occupied ecological niches earlier in geological
time, when Antarctic waters probably were considerably
warmer. But Eastman said that many scientists erroneously
assume that because the relatively shallow coastal
waters around the southern continent are now so cold,
they also must be relatively barren and uninteresting
in an evolutionary sense.
The variety of species in the waters of the Antarctic
shelf, which typically are no more than 500 meters
deep, differs sharply from similar, more temperate
waters, such as in the Delaware Bay. In those waters,
Eastman noted, there is a great diversity of species
on the bottom and at different levels of the water
column.
In Antarctica, 95 species of notothenioids, all derived
from bottom-dwellers without swim bladders, dominate
all habitats. Over evolutionary time, some notothenioids
have experienced an increase in body fat and are able
to live permanently in the water column, rather than
on the bottom.
Based on his 20 years of research and his new discoveries,
Eastman said that "as far as bottom habitats are concerned,
sponge beds in Antarctica are the equivalent of coral
reefs in the tropics; sites of high fish diversity."
Polly Penhale, who oversees medical and biological
research for the U.S. Antarctic Program, said that
Eastman's findings indicate that "future research
is likely to lead to a greater appreciation of biodiversity
in the polar regions."
Eastman's discoveries -- which include the first identification
of a new species in the genus Artedidraco in 80 years
-- occurred almost by chance. Eastman studies the
anatomy of buoyancy and how it evolved in Antarctic
fishes. "It wasn't my intention to look for new species,"
he noted.
During two separate research seasons, rocky bottoms
ripped nets so that only half of 20 trawls in the
Ross Sea reaped large numbers of fish. But the four
new species were discovered in those 10 successful
trawls.
Note: Drawings of two of the new species
are available in digital form. Call the media contact
listed at the top of this release
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