WASHINGTON, D.C. -- President Barack Obama has
one. Comedian Stephen Colbert has one. Elvis Presley has one. Even
computer software magnate Bill Gates has one. And now, Bob Marley--the
late popular Jamaican singer and guitarist--also has one. So what is it
that each of these luminaries has? The answer: they each have a
biological species that has been named after them.
Paul Sikkel, an assistant professor of marine
ecology and a field marine biologist at Arkansas State University,
discovered and just named after Marley a "gnathiid isopod"--a small
parasitic crustacean blood feeder that infests certain fish that inhabit
the coral reefs of the shallow eastern Caribbean. Sikkel named the
species Gnathia marleyi.
All of the life stages of Gnathia
marleyi are described by Sikkel and his research team in the June 6th
issue of Zootaxia. This research was partly funded by the National
Science Foundation (NSF).
Sikkel said, "I named this species, which is
truly a natural wonder, after Marley because of my respect and
admiration for Marley's music. Plus, this species is as uniquely
Caribbean as was Marley."
Gnathia marleyi is a new species within the
gnathiid family, and the first new species to be described in the
Caribbean in more than two decades.
By concealing themselves within coral rubble, sea sponge
or algae, juvenile Gnathia marleyi are able to launch surprise attacks
on fish and then infest them. Sikkel explained that adult gnathiids do
not feed at all. "We believe that adults subsist for two to three weeks
on the last feedings they had as juveniles and then die, hopefully after
they have reproduced."
There have been increasing numbers of reports
that the health of Caribbean coral reef communities is declining due to
diseases. "We are currently researching the relationships between the
health of coral reef communities and gnathiid populations," said Sikkel.
"Gnathiids, in general, are the most common
external parasites found on coral reefs and are ecologically similar to
land-based blood-sucking ticks or disease-carrying mosquitoes,"
Sikkel said. "Gnathiids live on the ocean floor from pole to pole, and
from shallow reefs to the abyss--and everywhere between. They are also
the most important food item for cleaner fishes and thus key to
understanding marine cleaning symbioses."
Sikkel explained that his research group is
interested in the combined ecological effects of fishing pressure and
reef degradation. "We suspect that coral degradation leads to more
available habitat for external parasites to 'launch attacks' on host
fishes," he said. "And as the number of potential host fish decreases,
each remaining host will become more heavily parasitized."
"Our current work is focused on how changes in
coral reef environments, such as coral bleaching, influences
interactions between hosts and parasites," said Sikkel. "We're including
in our studies any effects on cleaning organisms that remove parasites
from hosts."
About 80 percent of all organisms found on coral
reefs are parasites. The gnathiid isopods are among the most
ecologically important of them, according to biologists, because many
diseases afflicting desirable fish are either caused by, or are
transmitted by gnathiids. In addition, the immune system of fish also
depends on the overall health of coral reefs, which are known as the
"rainforests of the sea" because of their vast biodiversity.
At the end of the day, it comes down to simple
oceanic economics: the more parasites there are, the fewer fish there
are--at least until the parasites run out of hosts to infect. And fewer
fish in the sea can cause significant losses to the populations that
depend on them.
Studying the effects of changes in sea-bottom
communities associated with coral and sponge diseases and their
interactions among other species will advance knowledge of blood-borne
pathogens. Sikkel suspects that Gnathia marleyi may be a vector in
transmission of these diseases.
Sikkel says his team's current funding through
NSF's Ecology and Evolution of Infectious Diseases (EEID) initiative and
Biological Oceanography is enabling the team to study precisely which
species of Caribbean reef fish harbor these blood parasites. "We are
determining the role of Gnathia marleyi, which will help us understand
the impacts of changes in coral reef habitat on the transmission of a
fish disease called haemogregarines--a type of fish malaria that may
weaken their immune systems through a reduction in certain blood cells."
"Disease ecology is a rapidly maturing field in
marine science," said Michael Lesser, a program director in NSF's
Biological Oceanography Program. "To advance this field, scientists must
identify which organisms are the main players in disease transmission
in oceans."
Lesser continued: "With so much marine diversity
yet to be described, parasitic species don't always get the attention
they deserve. But Sikkell and his team have taken an important step by
helping to analyze the ecological effects of a parasite on Caribbean
coral reef fish populations by describing this previously unknown
species."
Sikkel initially discovered Gnathia marleyi
about 10 years ago in the U.S. Virgin Islands where it is relatively
common--so common, in fact, that Sikkel had assumed for years that the
species had previously been described. Nevertheless, compelled by a
hunch, Sikkel ultimately sent a specimen of the species to Nico J. Smit
of North-West University in South Africa, a member of Sikkel's research
team, who confirmed that the species had, in fact, previously been
overlooked by taxonomists. With the help of Whitney Sears, one of
Sikkel's students, the research team raised the isopod from its juvenile
stage through adulthood, a laborious task that was necessary because
most taxonomy descriptions of gnathiids are based on adult males, which
usually differ in appearance and other ways from juvenile gnathiids.
Specimens of Gnathia marleyi will be housed
indefinitely at the American Museum of Natural History in New York City.
"We are currently discussing with AMNH the possibility of creating an
exhibit featuring this species that could be viewed by the public," said
Sikkel.
Sikkel's research team includes Charon Farquharson of the University of Johannesburg in South Africa and Smit.
And by the way, if you are wondering, President
Obama has a lichen named after him; Colbert has a beetle; Gates has a
flower fly, and Elvis has a wasp.
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