Showing posts tagged mollusc
Why Most Snails Do Coil to the Right? by Jennifer Carpenter When plucking a snail from the beach you’d be lucky to snag a left-coiling shell.That’s because only 5% of all snails are “lefties,” new research shows. Shell enthusiasts have long marveled at the lack of sinistral (left-coiling) snails among their collections, especially when other shelled mollusks, such as clams and the now-extinct ammonites—nautiluslike creatures that sported dozens of tentacles inside spiraled shells—are just as likely to be left- as right-coiling. Now, in the largest survey of its kind, researchers inspected more than 55,000 snail species—representing two-thirds of all gastropods—to reveal that left-coiling has arisen more than 100 times, and yet few of the species that have made the switch have been particularly successful. In the rare cases where left-coiling took off, it was almost always on land, the team reported here in a presentation last week at the annual meeting of the Canadian Society of Zoologists. The researchers don’t know why sinistrality is so rare underwater, but the most likely explanation, they say, is that unlike land snails that tend to hang around where they hatch out, the microscopic young of sea snails are carried on ocean currents that make the chance of meeting and reproducing with another left-coiling nest-mate slim. Without such a meeting, the left-coiling lineage goes extinct. (via: Science NEWS/AAAS)                            (photo: Yang Hao) View high resolution

Why Most Snails Do Coil to the Right?

by Jennifer Carpenter

When plucking a snail from the beach you’d be lucky to snag a left-coiling shell.That’s because only 5% of all snails are “lefties,” new research shows. Shell enthusiasts have long marveled at the lack of sinistral (left-coiling) snails among their collections, especially when other shelled mollusks, such as clams and the now-extinct ammonites—nautiluslike creatures that sported dozens of tentacles inside spiraled shells—are just as likely to be left- as right-coiling.

Now, in the largest survey of its kind, researchers inspected more than 55,000 snail species—representing two-thirds of all gastropods—to reveal that left-coiling has arisen more than 100 times, and yet few of the species that have made the switch have been particularly successful. In the rare cases where left-coiling took off, it was almost always on land, the team reported here in a presentation last week at the annual meeting of the Canadian Society of Zoologists.

The researchers don’t know why sinistrality is so rare underwater, but the most likely explanation, they say, is that unlike land snails that tend to hang around where they hatch out, the microscopic young of sea snails are carried on ocean currents that make the chance of meeting and reproducing with another left-coiling nest-mate slim. Without such a meeting, the left-coiling lineage goes extinct.

(via: Science NEWS/AAAS)                            (photo: Yang Hao)

astronomy-to-zoology:

Geography Cone (Conus geographus)

…is a species of cone snail found throughout the Indo-Pacific, Red Sea, Indian Ocean, and parts of Africa and Madagascar. Like other cone snail species the geography cone is a piscivore (fish eater) and dispatches its prey with a venomous barb that is shot like a harpoon. It is one of the most venomous cone snails known to science and is responsible for several human deaths, its venom has no known antivenom and treatment is limited to keeping the victim alive until the toxin wears off. Have fun swimming….

Phylogeny

Animalia-Mollusca-Gastropoda-Neogastropoda-Conoidea-Conidae-Coninae-Conus-geographus

Image Source(s)

(Reblogged from astronomy-to-zoology)

Endangered Ocean Creatures Beyond the Cute and Cuddly

by Emily Frost

Our oceans are taking a beating from overfishing, pollution, acidification and warming, putting at risk the many creatures who make their home in seawater. But when most people think of struggling ocean species, the first animals that come to mind are probably whales, seals or sea turtles.

Sure, many of these large (and adorable) animals play an important part in the marine ecosystem and are threatened with extinction due to human activities, but in fact, of the 94 marine species listed under the Endangered Species Act (ESA), only 45 are marine mammals and sea turtles. As such, these don’t paint the whole picture of what happens under the sea. What about the remaining 49 that form a myriad of other important parts of the underwater web?

These less charismatic members of the list include corals, sea birds, mollusks and, of course, fish. They fall under two categories: endangered or threatened. According to NOAA’s National Marine Fisheries Service (pdf), one of the groups responsible for implementing the ESA, a species is considered endangered if it faces imminent extinction, and and a species is considered threatened if it is likely to become endangered in the future. A cross section of these less-known members of the ESA’s list are described in detail here…

(read more: Smithsonian Magazine)

(photos: T - Atlantic Salmon by E. Peter Steenstra/USFWS; ML - Short-tailed albatross by USFWS; MR - White abalone by John Butler, NOAA; B - Staghorn Coral by Albert Kok)

astronomy-to-zoology:

Hummingbird Bobtail Squid (Euprymna berryi)

Also known as Berry’s bobtail squid, the hummingbird bobtail squid is a species of bobtail squid found throughout the warm waters of eastern Asia. Like most bobtail squid, berry’s bobtail squid has a light organ in its gill cavity which emits light to help it hide its silhouette from predators. During the day the hummingbird bobtail squid can be found buried in the sediment, at night they will emerge to feed on small invertebrates like shrimp and other crustaceans.

Phylogeny

Animalia-Mollusca-Cephalopoda-Sepiolida-Sepiolidae-Sepiolinae-Euprymna-berryi

Image Source(s)

(Reblogged from astronomy-to-zoology)

oceanportal:

Sea butterflies, a group of swimming sea snails, are canaries in the coal mine for the ocean.

Delicately beautiful and highly sensitive to the changing oceans, these tiny creatures—most smaller than a pinky nail!—present a unique way to gauge climate. One-quarter of the carbon dioxide we release into the atmosphere dissolves into the ocean, which makes the water more acidic and makes it more difficult for these animals to build their own shells.

Scientists at the Smithsonian’s National Museum of Natural History are studying them to learn how ocean acidification will affect a wide array of ocean animals. Read our article at Smithsonian Magazine about the animals and scientists studying them—with stunning photos.

All photos © Karen Osborn (Smithsonian biologist)

(Reblogged from oceanportal)
An octopus, sea star, bivalves, and cup corals all share the same overhang… During the Deepwater Canyons 2013 expedition, U.S. Geological Survey (USGS) scientists are collecting samples of coral and invertebrates for later DNA analyses, to determine the numbers of different types of species in an area. Why would they want this info? Well, preserving biodiversity is a central tenet in conservation biology, but before we can ascertain if we are doing a good job in protecting the biodiversity of a region, we need to know what’s there. Learn more about molecular tools for taxonomy. (via: NOAA Office of Ocean Exploration and Research) View high resolution

An octopus, sea star, bivalves, and cup corals all share the same overhang…

During the Deepwater Canyons 2013 expedition, U.S. Geological Survey (USGS) scientists are collecting samples of coral and invertebrates for later DNA analyses, to determine the numbers of different types of species in an area.

Why would they want this info? Well, preserving biodiversity is a central tenet in conservation biology, but before we can ascertain if we are doing a good job in protecting the biodiversity of a region, we need to know what’s there.

Learn more about molecular tools for taxonomy.

(via: NOAA Office of Ocean Exploration and Research)

Pink Coryphella (Flabellina pedata) This nudibranch is easily recognised by the overall pink-purple coloration of the body and processes. Opaque white pigment is present on the extremities and as white rings at the tips of the cerata. The digestive gland is usually red in colour, partly masked by the purple hue. Typically about 20mm in length. Structurally similar to other Flabellinids, but distinguished by its purple hue. Flabellina affinis shares this coloration, but has lamellate rhinophores and more pedunculate cerata and is found in the Mediterranean Sea, but not further north. (read more: Encyclopedia of Life) (photo: BioImages - the Virtual Fieldguide (UK),  Ian Smith) View high resolution

Pink Coryphella (Flabellina pedata)

This nudibranch is easily recognised by the overall pink-purple coloration of the body and processes. Opaque white pigment is present on the extremities and as white rings at the tips of the cerata. The digestive gland is usually red in colour, partly masked by the purple hue. Typically about 20mm in length. Structurally similar to other Flabellinids, but distinguished by its purple hue. Flabellina affinis shares this coloration, but has lamellate rhinophores and more pedunculate cerata and is found in the Mediterranean Sea, but not further north.

(read more: Encyclopedia of Life)

(photo: BioImages - the Virtual Fieldguide (UK),  Ian Smith)

Nice defensive coloring, little nudibranch! When you’re four centimeters long and soft-bodied, you have to protect yourself somehow. Nudibranchs or sea slugs, like many soft marine animals, employ a lot of visual and chemical defenses. Bright colors can work a couple of different ways: if they are the same color as the coral or whatever you are sitting on, they help you blend in and avoid detection. In other cases, bright, visible coloring warns predators that you contain noxious or toxic chemicals. Which is often the case if, like this individual, you feed on hydroids.Check out the other colors in our Nudibranch gallery.Photo: Facelina auriculata, by Ian Smith via Bioimages- The Virtual Fieldguide (via: Encyclopedia of Life) View high resolution

Nice defensive coloring, little nudibranch!

When you’re four centimeters long and soft-bodied, you have to protect yourself somehow. Nudibranchs or sea slugs, like many soft marine animals, employ a lot of visual and chemical defenses. Bright colors can work a couple of different ways: if they are the same color as the coral or whatever you are sitting on, they help you blend in and avoid detection. In other cases, bright, visible coloring warns predators that you contain noxious or toxic chemicals. Which is often the case if, like this individual, you feed on hydroids.

Check out the other colors in our Nudibranch gallery.

Photo: Facelina auriculata, by Ian Smith via Bioimages- The Virtual Fieldguide

(via: Encyclopedia of Life)

A Case of Mistaken Snail Identity Leads to Irrational Freak Out in Houston, TX… Thanks Corporate News!

Big snail is beneficial, not bad.

By Kathy Huber

A case of mistaken identity sparked a false alarm this week when word spread that the giant African snail - a voracious mollusk that poses a potential health threat to humans - had come to town.

Turns out the big snail found in a Houston garden is beneficial, not bad. It was a rosy wolf snail, a predator of snails that devour garden plants, said Michael Warriner, invertebrate biologist with Texas Parks and Wildlife Department.

The good snail’s story, like that of the bad snail’s, seems like science fiction. But it comes with a happy ending.

Photos of the suspicious snail tipped Warriner to its identity. Both the rosy wolf snail and the giant African snail have appendices for seeing and smelling. But the rosy wolf snail has a third set, oral lappets, that help it locate other snails’ slime. It then grabs its prey and rasps it with its radula, which works like a rough tongue, Warriner explained

In addition to its extra appendices, the rosy wolf snail matures to 2 or 3 inches, considerably smaller than the potentially 8-inch giant African snail, Warriner said…

(read more: Houston Chronicle)

(photos: T - Rosy Wolf Snail; B - African Giant Snail)

biomedicalephemera: Humboldt Squid/Jumbo Squid Loligo gigas [now Dosidas gigas]  The Humboldt squid is among the largest of the squid, despite their lifespan of just under one year. Other giant squids have a lifespan estimated to be around five years at a minimum, and don’t reach their maximum size until near the end of their life. One of the major sources of food for Humboldt squid is other Humboldt squids, which is believed to contribute significantly to their fast growth. All of the suckers of the Humboldt are ringed with sharp, flesh-tearing teeth, and when squid are feeding, they’ve been known to be very aggressive towards scuba divers. Outside of feeding time (generally dusk to dawn), the squid are generally non-aggressive creatures. Like many squid, the Humboldt has chromatophores in its skin, allowing for rapid color changes. When they feed or are in distress (such as when they’re caught by fishers), they flash bright red. This led to one of their first colloquial names - El diablo rojo - the Red Devil. Voyage dans l’Amerique Meridionale: Tome Neuvieme. Alcide d’Orbigny, 1847. View high resolution

biomedicalephemera:


Humboldt Squid/Jumbo Squid

Loligo gigas [now Dosidas gigas] 

The Humboldt squid is among the largest of the squid, despite their lifespan of just under one year. Other giant squids have a lifespan estimated to be around five years at a minimum, and don’t reach their maximum size until near the end of their life. One of the major sources of food for Humboldt squid is other Humboldt squids, which is believed to contribute significantly to their fast growth.

All of the suckers of the Humboldt are ringed with sharp, flesh-tearing teeth, and when squid are feeding, they’ve been known to be very aggressive towards scuba divers. Outside of feeding time (generally dusk to dawn), the squid are generally non-aggressive creatures.

Like many squid, the Humboldt has chromatophores in its skin, allowing for rapid color changes. When they feed or are in distress (such as when they’re caught by fishers), they flash bright red. This led to one of their first colloquial names - El diablo rojo - the Red Devil.

Voyage dans l’Amerique Meridionale: Tome Neuvieme. Alcide d’Orbigny, 1847.

(Reblogged from biomedicalephemera)

alex—stein:

Kings of Camouflage - PBS Nova (by Civil Digital)

So, there’s an entire NOVA episode on cuttlefish I felt you guys would enjoy!

(Reblogged from awrrex-stein)

Discovery of a New Deep Chemosynthetic Community

Deepwater Canyons Project Science Team

After several days of lost dives due to bad weather and making dives under difficult conditions, we are today in calm seas exploring an area that was discovered last year during a NOAA mapping cruise.  While conducting a seafloor survey, NOAA Ship Okeanos Explorer found bubbles coming from the seafloor at a site south and offshore of Norfolk Canyon; they thought these bubbles may indicate a new methane seep site, but they had no way of verifying this idea.  

Today, we deployed the Jason remotely operated vehicle (ROV) from the NOAA Ship Ron Brown to 1,600 meters (nearly a mile deep—our deepest dive yet!) to explore the area around those bubbles. After transecting over soft sediment for a short time, we saw some indications that we were getting close to a probable methane seep. These indications included white patches of bacteria on the sediment surface that feed on the methane and sulfides, plus shells of dead mussels, which are the dominant animals of methane seep communities…

(via: NOAA Ocean Explorer)

(photos: Deepwater Canyons 2013 - Pathways to the Abyss, NOAA-OER/BOEM/USGS)

Science in Action: What lives in deep-sea mud and how do all of these little critters interact?

U.S. Geological Survey (USGS) scientist Amanda Demopoulos and her team are hoping to find out.

The deep sea is rich with life, from fish to invertebrates to microbes. Hidden within the mud and rocks are numerous small animals (less than 1 millimeter) that are almost invisible to the naked eye. While small, they represent a major component of deep-sea diversity.

My research focuses on understanding and identifying the communities found within deep-sea sediments, called infauna, and characterizing their role in deep-sea food-webs. The basic questions that I’m addressing include: How many animals are in the sediment? What is the community composed of and who are the rare or most abundant species? What interactions occur among these species, including who is eating what or whom?

Basic patterns in species composition, abundance, and diversity can all be a function of the environment in which they live…

(read more: NOAA Ocean Explorer)

Blanket octopuses (Tremoctopus violaceus) are immune to the venomous Portuguese man o’ war, whose tentacles the small male (pictured top with man-o-war tentacle) and immature females rip off and use for defensive purposes. Also, unlike many other octopuses, the blanket octopus does not use ink to intimidate potential predators. When threatened, the female (pictured bttm) unfurls her large net-like membranes that spread out and billow in the water, greatly increasing her apparent size.

(via: Encyclopedia of Life)

(photos: T - Dhugal Lindsay/JAMSTEC/CMarZ, B - via Mission Blue)

Fish Use ‘Sign Language’ to Help Out Hunting Buddies by Douglas Main Two types of fish have been shown to use gestures, or sign language, to help one another hunt. This is the first time these types of gestures have been found to occur in animals other than primates and ravens. Both types of fish, grouper and coral trout, are known for hunting cooperatively with other kinds of animals. Whereas the grouper hunts with giant moray eels and a fish called the Napoleon wrasse, coral trout partner up with octopuses to snag prey. A study published last week in the journal Nature Communications found that the fish are able to “point” their heads toward prey, to help out their hunting buddies. After observing the fish in the wild for many hours, the researchers found that when a prey fish escaped its hunting party, a grouper occasionally moved over the place where the fugitive prey was hiding. The grouper would then rotate its body so that its head faced downward, and it would shake its head back and forth in the direction of the potential meal, in what researchers call a “headstand” signal. Coral trout make a similar sign, the researchers found… (read more: http://www.livescience.com/29120-fish-use-sign-language-to-hunt.html?cmpid=514627) (photo: Klaus Jost., Univ. of Mich. - ADW) View high resolution

Fish Use ‘Sign Language’ to Help Out Hunting Buddies

by Douglas Main

Two types of fish have been shown to use gestures, or sign language, to help one another hunt. This is the first time these types of gestures have been found to occur in animals other than primates and ravens.

Both types of fish, grouper and coral trout, are known for hunting cooperatively with other kinds of animals. Whereas the grouper hunts with giant moray eels and a fish called the Napoleon wrasse, coral trout partner up with octopuses to snag prey. A study published last week in the journal Nature Communications found that the fish are able to “point” their heads toward prey, to help out their hunting buddies.

After observing the fish in the wild for many hours, the researchers found that when a prey fish escaped its hunting party, a grouper occasionally moved over the place where the fugitive prey was hiding. The grouper would then rotate its body so that its head faced downward, and it would shake its head back and forth in the direction of the potential meal, in what researchers call a “headstand” signal. Coral trout make a similar sign, the researchers found…

(read more: http://www.livescience.com/29120-fish-use-sign-language-to-hunt.html?cmpid=514627)

(photo: Klaus Jost., Univ. of Mich. - ADW)