Fun Animals Wiki, Videos, Pictures, Stories: Snail

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Monday, October 13, 2014

Hermaphrodite snail named after marriage equality

Biologists christened the species Aegista diversifamilia, referring to a diversity of family types, because it "represents the diversity of sex orientation in the animal kingdom".

The snail is widespread throughout eastern Taiwan, but was previously mistaken for a closely related species.

A new species of hermaphrodite land snail found in Taiwan has been named in support of marriage equality.

Its discovery is reported in the journal.

"When we were preparing the manuscript, it was a period when Taiwan and many other countries and states were struggling for the recognition of same-sex marriage rights," said Dr Yen-Chang Lee, who first suggested the snail might entail its own species.

"It reminded us that Pulmonata land snails are hermaphrodite animals, which means they have both male and female reproductive organs in a single individual.

"We decided that maybe this is a good occasion to name the snail to remember the struggle for the recognition of same-sex marriage rights."

Dr Lee, from Academia Sinica in Taipei, noticed in 2003 that land snails of the established species Aegista subchinensis seemed to be markedly different on the eastern side of Taiwan's Central Mountain Range.

Together with researchers from the National Taiwan Normal University, Dr Lee then conducted a detailed study of the shape of the animals as well as molecular markers.

The new diversifamilia species, from the east of the mountains, has a larger, flatter shell and is in fact more closely related to a land snail from Ishigaki Island in Japan.

Source: Here

Wednesday, September 10, 2014

Seychelles Snail, Thought Extinct, Found Alive

A snail once thought to have been among the first species to go extinct because of climate change has reappeared in the wild.

The Aldabra banded snail, declared extinct seven years ago, was rediscovered on Aug. 23 in the Indian Ocean island nation of Seychelles. The mollusk, which is endemic to the Aldabra coral atoll — a UNESCO World Heritage Site — had not been seen on the islands since 1997, said the Seychelles Islands Foundation.

Conservationists are celebrating the banded snail's reemergence.

"Could we live without this little snail? Almost certainly," said Stuart Pimm, a conservation ecology professor at Duke University. "But we simply do not know what species are going to do for us in an economic sense. Probably from the time that somebody baked the first loaf of bread, a housewife said, 'I hate bread mold and I wish it would disappear forever.' And of course we know the scientific name of bread mold is penicillin."

A research team from the Seychelles Islands Foundation found seven of the purple-and-pink striped snails on Aldabra atoll's Malabar Island last week. Shane Brice, a junior skipper on the voyage, made the initial discovery.

"I was so surprised; no one (on the expedition) had ever seen the snail before," Brice said. "It's quite amazing."

Catherina Onezia, a senior ranger and assistant training officer for the foundation, said the team was "going crazy" with excitement over the finding.

"It shows that Aldabra has a lot of secrets still, and hopefully (we) will continue to find interesting things," Onezia said.

Mollusk experts Vincent Florens and Pat Matyot confirmed the discovery after analyzing the discovery team's photos. Florens, an associate professor of ecology at the University of Mauritius, told The Associated Press the Aldabra banded snail was "the only possible identification," citing the snail's distinctive shell pattern and locality.

The snail faces many pressures in Aldabra atoll. The coral islands grew atop an extinct volcano in the Indian Ocean. The isolated atoll, which also is home to the largest population of giant tortoises in the world, provides opportunities to study evolution and biodiversity. Conservationists are unsure how a terrestrial snail like the Aldabra banded snail initially reached these hot, dry islands surrounded by saltwater without drying out.

Onezia said her team will increase expedition efforts on Malabar Island to study the snails.

The snail's apparent demise was linked to declining rainfall on Aldabra, and was widely considered to be among the first species whose extinction could be directly tied to global warming, said biologist Justin Gerlach, a scientific coordinator for the Nature Protection Trust of Seychelles.

The once-plentiful snail's population declined exponentially between 1970 and 1990, and the last juvenile snail was found in 1976. The Seychelles Islands Foundation said the discovery of some juvenile snails is encouraging, as they are believed to be particularly vulnerable to desiccation because of reduced rainfall.

"Only time will tell if they can survive the threats of climate change and sea level rise," Gerlach said.

Source: Here

Tuesday, May 6, 2014

Snails Are Dissolving in Pacific Ocean

An increasingly acidified Pacific Ocean is dissolving the shells of tiny marine snails that live along North America’s western coast. The broad finding, which has surprised some researchers, suggests that sea life is already being affected by changes in the ocean’s chemistry caused by rising carbon dioxide levels in the atmosphere.

“It really changes the game” by demonstrating that acidification is having a noticeable impact, says biological oceanographer Jan Newton, co-director of the Washington Ocean Acidification Center at the University of Washington, Seattle. Newton was not involved in the study.

The researchers studied one kind of pteropod, common planktonic snails known as sea butterflies for the winglike body parts that help them glide through the water. Like other shellfish, pteropods use dissolved carbonate in seawater to build their shells. But laboratory studies have shown that the process can be disrupted, and shells can dissolve, as seawater becomes more acidic, or lower in pH. (Temperature has an impact, too.) As its concentration rises in the atmosphere, carbon enters the ocean through chemical reactions, causing its pH at the surface to drop by 0.1 units since the preindustrial era. That’s raised fears that marine ecosystems could be affected.

Outside the laboratory, however, just a handful of studies have linked falling pH levels to damaged shells. In 2012, researchers documented damage to oysters in hatchery tanks in Oregon fed with seawater that had become more acidic as a result of offshore upwelling patterns. The same year, researchers reported that pteropods collected at one site in the Southern Ocean around Antarctica showed signs of shell damage.

To gauge how acidification might be affecting the Pacific, biological oceanographer Nina Bednaršek of the National Oceanic and Atmospheric Administration (NOAA) in Seattle and colleagues collected pteropods at 13 sites during a 2011 research cruise between Washington and southern California. Back at the lab, they used a scanning electron microscope to examine the fragile shells, which are 1 cm in size or smaller. Normally, healthy pteropods have smooth shells. But more than one-half of these shells showed signs of dissolution, they report in the Proceedings of the Royal Society B. The pitted textures made them look like “cauliflower” or “sandpaper,” Bednaršek says.

“I was surprised by the sheer spacial extent of the dissolution,” she says. “This is something we have not predicted before -- the extent of the population that’s already affected.”

What’s not clear from this study is how such damage might be affecting pteropod populations or the broader ecosystem. Previous work has suggested that shell damage can make it harder for the invertebrates to fight infection, maintain metabolic chemistry, defend themselves against predators, and control buoyancy. And while the snails are one of the most abundant organisms on Earth, “their role in ecosystems is generally not all that well known,” writes biological oceanographer Gareth Lawson of the Woods Hole Oceanographic Institution in Massachusetts in an e-mail. But “they can be important prey items at some times and places” for fish and other creatures. For example, the pteropod examined in this study, Limacina helicina, is a key food for fish eaten by pink salmon, an important North Pacific fishery.

If the pteropod shells “are dissolving as fast as the authors claim, the effects on individual physiology, behavior, and fitness, and hence on populations and food webs, are not easy to predict,” Lawson says. But they “could be profound.”

The waters probed during this study, known as the California Current, are a hot spot of ocean acidification because of coastal upwelling, which brings naturally acidic waters to the surface, where they are made even more acidic by greenhouse gas pollution. But Richard Feely of NOAA, a co-author on the study, says that the site serves as a “harbinger” for what global seas will be experiencing decades hence.

Source: Here