The new species
of nototheniid fish, Cryothenia amphitreta, is detailed in the
December issue of the quarterly journal Copeia. Paul A. Cziko, a
research specialist who had graduated with bachelor's degrees in
animal biology
and biochemistry
from Illinois six months earlier, and research diver Kevin Hoefling,
discovered it in McMurdo Sound in the Ross Sea region of Antarctica
in November 2004.
They were diving in the area in search of eggs laid by naked
dragonfish (Gymnodraco acuticeps) for a study, published earlier
this year, about levels of antifreeze proteins in newly hatched
notothenioids in the salty, icy waters, where the temperature is
rarely above the freezing point of seawater. [Related
article]"We just came across this fish," Cziko recalled. "It
was just sitting on the bottom, like most other fish in the area.
There are only about a dozen species that swim in the area, with
four to five easily distinguishable species. This one jumped out at
us. First of all it was pretty big, and it looked quite different
than the others."
Cziko and Hoefling guided the egg-laden fish into a mesh bag and
surfaced.
"It was about twice as big as what you normally see swimming
around," said Arthur L. DeVries, a professor of animal biology who
many years earlier had discovered antifreeze proteins in
notothenioids. "Its profile was much different than other common
local notothenioids. Its center part is much higher. Most of the
other species in the area have big heads and have bodies that taper
back narrowly."
Cziko and co-author Chi-Hing "Christina" Cheng, professor of
animal biology, studied the purple-gold-colored fish, comparing its
measurements and perchlike appearance with all known species of fish
that inhabit the icy waters of Antarctica. X-ray radiographs of bone
structures were taken at the U of I
College of Veterinary Medicine.
The new fish, which DeVries theorizes may have been looking for a
place to lay its eggs in a flat, clear area near an intake pipe that
feeds water into the McMurdo Station, was placed into the genus
Cryothenia because of its overall similarity to the notothenioid
Cryothenia peninsulae, which has been found only near the Antarctica
Peninsula.
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 Although bigger in pelvic fin length and body size, as well as
having more vertebrae, what sets C. amphitreta apart from C.
peninsulae is head morphology, specifically in the area between the
eyes.
The new fish has a "wide, well-defined, two-holed interorbital
pit divided by a raised medial ridge, scales anterior to this
depression in the interorbital region, and a dark pigmentation of
the mouth, gill and body cavity linings," Cziko and Cheng wrote.
The species name was chosen to help researchers easily
distinguish the two species in the genus Cryothenia, which
translates from Greek as "from the cold," while amphitreta literally
means "an orifice with two openings."
"Even though we know a lot about Antarctica," Cziko said, "we
still don't know everything about the ecosystems and the animals in
them. There's probably a lot more to be learned about how these fish
evolved and survived."
The area where C. amphitreta was found is the most-frequented
location in McMurdo Sound, explored by divers and fished with hand
lines. DeVries has been going to the site for more than 40 years.
The new fish was located on a large, flat rock in water that was
minus 1.91 degrees Celsius and 20 meters deep.
"Art has been swimming there for more than 40 years," Cziko said.
"You'd think he would have caught everything." DeVries does have an
Antarctic fish named after him: Paraliparis devriesii.
National Science Foundation grants to Cheng and DeVries funded
the research.
Note: The original draft of this news release was written by Jim
Barlow, who has since become the director of science communications
for the University of Oregon.
[Diana Yates, life sciences editor,
University
of Illinois at Urbana-Champaign News Bureau]
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