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lite.cnn.com - on gopher - inofficial
ARTICLE VIEW:
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Long-lost ocean worms photobomb tiny seahorses, surprising scientists
By Mindy Weisberger, CNN
Updated:
3:24 PM EST, Fri November 15, 2024
Source: CNN
A species of marine worm that scientists lost sight of for almost 70
years has finally resurfaced, thanks to some eagle-eyed sleuthing and a
seahorse less than an inch long. When researchers analyzed images of
tiny seahorses taken by scuba divers, they found evidence of
photobombing worms in the hundreds, living alongside the seahorses in
coral colonies from Japan to Australia.
The long-lost worm is Haplosyllis anthogorgicola, a species of bristle
worm, or polychaete. It typically measures no more than 0.24 inches (6
millimeters), and it burrows inside branching gorgonian corals at a
density of up to 15 worms per cubic centimeter. But the creature
hasn’t been directly observed in the wild since 1956, when Kyoto
University marine biologist Huzio Utinomo first identified it,
scientists reported Wednesday in the journal .
Finding these worms is extremely challenging because their small size
and near transparency make them almost impossible to see underwater,
said lead study author, a doctoral student in the Molecular
Invertebrate Systematics and Ecology, or MISE, Laboratory at the
University of the Ryukyus in Okinawa, Japan.
“I love that this paper crowdsources imaging from the public to learn
more about where and how these animals occur and what they are
doing,” said , a researcher and curator in the department of
invertebrate zoology at the Smithsonian National Museum of Natural
History in Washington, DC.
With about 10,000 named species of bristle worms and perhaps twice that
number yet to be discovered, there are many open questions about
polychaete biology, interactions with other species, “and the impacts
they have on the areas they inhabit,” said Osborn, who was not
involved in the study, in an email. “This paper beautifully shows how
they are just below our noses, but virtually unnoticed.”
‘She noticed some worms’
Study coauthor Ai Takahata, an undergraduate student at MISE and
Forreau’s lab partner, was researching the camouflage of pygmy
seahorses (Hippocampus bargibanti) when she unexpectedly found several
H. anthogorgicola worms in coral samples collected in waters near
Japan.
“When she cut a branch of the coral, she noticed some worms came out
of it,” Forreau said. “She gave them to me as she knew I was
interested in polychaetes, but prior to looking at the worms, I
didn’t even know about this species.”
Forreau suspected that pygmy seahorses’ gorgonian coral colonies
might yield more of the worms, she told CNN. In 2023, during an
unrelated survey in southern Sukumo Bay in Kochi, Japan, she asked the
boat captain to make a detour to sample corals, and she found H.
anthogorgicola bristle worms inside them.
But as Forreau was sorting her underwater photos of seahorses and
corals, she made another unexpected discovery: The worms’ coral
burrows were visible in the images. Perhaps, she thought, that might
also be the case in other photos of pygmy seahorses. She and her study
coauthors turned to iNaturalist, a website where people share nature
images and information on biodiversity, to find photos of pygmy
seahorses (and possibly of their worm neighbors, too).
Because pygmy seahorses are so small — about 1 inch (2.5 centimeters)
long — divers tend to photograph them in extreme close-ups, which
include detailed views of nearby corals. On iNaturalist, 489 photos of
the seahorses also included evidence of worms, the researchers
reported.
Images of pygmy seahorses taken by scuba divers were crawling with worm
photobombs. Worms’ limbs, heads and tails poked out of coral burrows
in the hundreds; the scientists even counted seven examples of worms
crawling on seahorses’ bodies. Worms’ tunnels snaked through coral
branches and into polyps, and approximately 84 percent of the
photographed corals were hosting worm infestations, the researchers
estimated.
Wider distribution of bristle worms
Prior to this study, very little was known about H. anthogorgicola’s
range and habits; piecing together the lifestyles of hard-to-find
animals is especially challenging when published research about them is
nearly nonexistent, Forreau said.
“But our paper shows that we can repurpose the large information
available on better known species to learn about understudied ones like
worms,” Forreau added in an email.
GPS coordinates on the iNaturalist photos expand the worms’ potential
distribution much farther to the south than previously thought,
encompassing Australia, East Timor, Indonesia, Japan, Malaysia, New
Caledonia, Papua New Guinea, the Philippines and Taiwan, according to
the study.
Utinomo’s 1956 paper linked the worms to just one coral species —
Anthogorgia bocki — but analysis of the photos suggests that these
worms inhabit other corals in the genus. The images also provided the
first evidence of the worms interacting directly with seahorses.
Polychaetes live in diverse habitats “including polar ice, methane
seeps and deep-sea hydrothermal vents, the spaces between corals, and
the vast open ocean,” Osborn said. “They are critical to food webs
and build habitat for other animals.”
The iNaturalist photos answered some long-standing questions about H.
anthogorgicola’s lifestyle and habits, Forreau added.
“They confirm that the worms are highly reliant on their burrows;
most of their time is spent inside,” she said. In many of the images,
the only visible part of a worm was its antennae and other trailing
appendages poking out of the tunnel. “This position suggests that
worms spend a lot of time sensing their environment around them,
perhaps waiting for something to eat in the water, or to detect the
coral polyp’s movement to steal its food.”
However, many of the burrows were not close to polyps, hinting that the
worms could be coral cleaners rather than food thieves.
“There is still much to be learned about the relationship between the
worms and the corals where they live,” Forreau said.
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