The amazing eyes found on the mantis shrimp may inspire a new generation of CD:s and DVD:s, according to a new study from the University of Bristol.

Odontodactylus scyllarus, a species of mantis shrimp living on Australia’s Great Barrier Reef, has the most complex vision system known to science and can see in twelve colours as opposed to the human eye which only sees in three. As if this wasn’t enough, Odontodactylus scyllarus can also distinguish between different forms of polarized light.

The eyes of this mantis shrimp are equipped with special light-sensitive cells that work like the quarter-wave plates found in CD and DVD players; they can rotate the plane of the oscillations of a light wave as it travels through. Thanks to this feature, the mantis shrimp is capable of converting linearly polarized light to circularly polarized light and vice versa.

The design and mechanism of the quarter-wave plate in the mantis shrimp’s eye outperforms anything manmade. While the quarter-wave plates found in CD and DVD players tend to work well for one colour of light only, the mantis shrimp can convert light across the whole visible spectrum, i.e. from infra-red to nearly ultra-violet.

“What’s particularly exciting is how beautifully simple it is,” said Dr Roberts, lead author of the article. “This natural mechanism, comprised of cell membranes rolled into tubes, completely outperforms synthetic designs. It could help us make better optical devices in the future using liquid crystals that have been chemically engineered to mimic the properties of the cells in the mantis shrimp’s eye.”

How the mantis shrimp benefits from having this ability remains unknown, but polarization vision is sometimes used by animals to secretly communicate within their own species without catching the attention of predators. Also, it might make it easier for the mantis shrimp to see under water, which would come in handy when hunting for prey.

The research was carried out at the University of Bristol’s School of Biological Sciences in the UK in collaboration with researchers at the University of Queensland, Australia and the University of Maryland, Baltimore County, USA.

The paper was published in Nature Photonics on October 25.

http://www.nature.com/nphoton/

http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2009.189.html

Scientists say they are baffled by the large number of whale shark sightings reported this summer in the northern Gulf of Mexico. Reports have been pouring in from all over; from Clearwater to the Florida Panhandle and along the Alabama, Mississippi and Louisiana coasts.

“The sheer number of anecdotal reports from the public is amazing. There’s obviously something going on,” says shark scientist Bob Hueter who heads the Shark Research Center at Mote Marine Laboratory.

It is common for Whale sharks to gather in the plankton-rich waters off the Yucatan Peninsula during the summer, but this year numerous whale shark sightings have been reported from the eastern and northern parts of the Gulf as well. The concentrations spotted off the Yucatan Peninsula are also higher than before with hundreds of Whale sharks being seen in a single location.

According to Mote Marine Laboratory records, there were just three Whale shark sightings in the Florida Gulf in 2005, two in 2006, five in 2007, and three in 2008. This year, there have been 12 sightings just from July to mid-August.

According to Heuter, the large Whale sharks may have been attracted by a change in the massive “loop current” in the Gulf that took place this year, and there is also a stronger than usual upwelling of cold, nutrient-rich water off the Yucatan that may play a role.

“That changed the oceanography a bit, and it could have driven some of these animals up into the northern Gulf,” Hueter explained.

Eric Hoffmayer, a biologist with the Gulf Coast Research Laboratory on the Mississippi coast, said his lab has gotten reports of 30 sightings in just the last two weeks. On Aug. 1, there was a reported sighting of more than 100 whale sharks congregating about 60 miles off the Louisiana coast.

“We don’t know what’s going on,” said a baffled Hoffmayer.

Many of the sightings have occurred when there was a full moon.

As mentioned above, record sightings are being reported from the waters off Yucatan as well. An aerial survey last week did for instance reveal over 400 whale sharks in a relatively small area near the Isla Mujeres. The Yucatan aggregation is an annual phenomenon, but it usually takes place near Isla Holbox and the group tends to be much smaller.

The Top 10 list of new species from 2008 has now been compiled by the ASU institute and an international committee of taxonomists. Last year, thousands of new species were described by science, many of them native to hard-to-access regions of our planet, such as remote tropical areas or deep sea habitats, but two of the species on the list actually hail from much less exotic locations: Cardiff and a bottle of hairspray.

“Most people do not realize just how incomplete our knowledge of Earth’s species is,” said Quentin Wheeler, director of the International Institute for Species Exploration at Arizona State University, which announced the top 10 new species list. “We are surrounded by such an exuberance of species diversity that we too often take it for granted“.

These are the selected few that made it all the way to the ASU Top 10:

1.) A palm with no close relatives in the neighbourhood

Name: Tahina spectabilis
Common Name: Tahina Palm

This plant produces truly spectacular inflorescence with numerous flowers. After fruiting, the palm dies and collapses. Strangely enough, the genus Tahina is not closely related to any of the other 170+ palm species found on Madagascar. Its closest relatives are instead found in Afghanistan, Thailand, Vietnam and China.

Soon after the publication of the species, seeds were disseminated throughout the palm grower community, raising money for its conservation by the local villagers.

2.) The world’s longest known living insect

Name: Phobaeticus chani
Common Name: This insect has no common name in English. Perhaps Chani’s stick insect would be a suitable English common name? Do any of the readers of this blog know if this species has a common name in Malaysia?

With a body length of 35.6 cm (14 inches) and an overall length of 56.7 cm (22.3 inches), Phobaeticus chani is the world’s longest known now living insect. Once upon a time, insects grew much larger than this, but none of those gigantic insects have survived into our time.

3.) The world’s smallest seahorse

Name: Hippocampus satomiae
Common Name: Satomi’s Pygmy Seahorse

This is the smallest known seahorse in the world. It has a standard length of no more than 13.8mm (0.54 inches) and an approximate height of 11.5mm (0.45 inches).

4.) The world’s smallest snake

Name: Leptotyphlops carlae
Common Name: Barbados Threadsnake

This is the world’s smallest snake with a total length of 104 mm (4.1 inches).

5.) A Welsh ghost slug

Name: Selenochlamys ysbryda
Common Name: Ghost Slug

The word ysbryda is a Latinized version of the Welsh word ysbryd which means ghost or spirit. The name alludes to the species’ ghostly appearance, nocturnal, predatory behaviour and the element of mystery surrounding its origin. Strangely enough, this new species was discovered in Cardiff, UK, a well-collected and densely populated part of the world. (For all the Torchwood fans out there, this mesmerizing find naturally comes as no surprise.)

6.) A snail with a surprising twist

Name: Opisthostoma vermiculum
Common Name: This species has no common name in English. Do any of the readers of this blog know it has a common name in Malaysia?

Most gastropod shells tightly coil according to a logarithmic spiral and have an upper limit of three coiling axes, but the shell of Opisthostoma vermiculum consists of four different coiling axes which is the highest number ever seen in gastropods. As if this wasn’t enough, the shell whorls detach three times and reattach twice to preceding whorls in a fairly consistent manner, which suggests that the coiling strategy is under some form of strict developmental-gene control.

7.) Deep-blue deep-dweller

Name: Chromis abyssus
Common Name: Deep Blue Chromis

Compared to other members of its genus, the deep blue Chromis abyssus lives pretty far from the surface but it is certainly not found at abyssal depths. The name is instead a reference to the BBC documentary Pacific Abyss, since the type specimen was collected during the making of this show. This species was also the first one to have its description registered in the newly launched taxonomic database Zoobank.

8.) A 380 million year old delivery

Name: Materpiscis attenboroughi
Common Name: Mother Fish

This is the oldest known live bearing (viviparous) vertebrate and we know of it from fossil record only. Amazingly, the fossil shows a female fish in the process of giving birth some 380 million years ago. It was found at Gogo Station in Western Australia. The name of the genus, Materpiscis, means “mother fish” in Latin, while the species itself is named in honour of Sir David Attenborough who first drew attention to the Gogo fish sites in his 1979 series Life on Earth.

9.) African decaf

Name: Coffea charrieriana
Common Name: Charrier Coffee

This is a true member of the genus Coffea, but it is completely void of caffeine. Coffea charrieriana is the first known caffeine-free Coffea species from Central Africa and coffee makers are now pondering the idea of using it to make natural decaf coffee.

10.) Hair spray bacteria

Name: Microbacterium hatanonis
Common Name: None

This new species wasn’t found in some remote rainforest or deep down in blue; it was isolated as contaminant of hairspray.

The Top 10 New Species were selected from the thousands of species fully described and published in 2008. The public could nominate species through the IISE Web site and nominations were also generated by IISE staff and committee members themselves. The Committee had complete freedom in making its choices and developing its own criteria to provide a breadth of species attributes and importance.

I am sorry that we don’t have pictures of all species. To see pictures of all species you can here.

If you would like to nominate a species for the 2010 Top 10 New Species please click here.

The first-ever comprehensive global report on the state of shellfish has been released by The Nature Conservancy at the International Marine Conservation Congress in Washington, DC.

This one of its kind report is a collaborative work carried out by scientists from five different continents employed by academic and research institutions as well as by conservation organizations.

The report, which focuses primarily on the distribution and condition of native oyster reefs, show that 85 percent of oyster reefs have been completely destroyed worldwide and that this type of environment is the most severely impacted of all marine habitats.

In a majority of individual bays around the globe, the loss exceeds 90 percent and in some areas the loss of oyster reef habitat is over 99 percent. The situation is especially dire in Europe, North America and Australia where oyster reefs are functionally extinct in many areas.

“We’re seeing an unprecedented and alarming

decline in the condition of oyster reefs, a critically

important habitat in the world’s bays and estuaries,”

says Mike Beck, senior marine scientist at The Nature

Conservancy and lead author of the report.

Many of us see oysters as a culinary delight only, but oyster reefs provide us humans with a long row of valuable favours that we rarely think about. Did you for instance known that oyster reefs function as buffers that protect shorelines and prevent coastal marshes from disappearing, which in turn guard people from the consequences of hurricanes and other severe storm surges? Being filter feeders, oysters also help keep the water quality up in the ocean and they also provide food and habitat for many different types of birds, fish and shellfish.

Even though the situation is dismal, there is still time to save the remaining populations and aid the recuperation of damaged oyster reefs. In the United States, millions of young Olympia oysters have been reintroduced to the mudflats surrounding Netarts Bay in Oregon, in an effort to re-create a self-sustaining population of this native species. The project is a joint effort by government and university scientists, conservation groups, industry representatives, and local volunteers.

“With support from the local community and other partners, we’re demonstrating that shellfish restoration really works”, says Dick Vander Schaaf, Oregon director of coast and marine conservation for the Conservancy. “Expanding the effort to other bays and estuaries will help to ensure that the ecological benefits of oyster reefs are there for future generations.”

If wish to learn more about the global oyster reef situation, you can find the report here.

Thanks to a system of underwater hydrophones, scientists have been able to document the presence of North Atlantic Right whales in an area where they were believed to have gone extinct.

The North Atlantic Right whale (Eubalaena glacialis), where even the name is a reference to it being the “right” whale to hunt, was heavily targeted by whalers during the 19^th and 20^th century and the entire species was on the brink of extinction when the moratorium on whaling was implemented in the 1960s.

Being an important whaling area throughout the 19^th century, Cape Farewell Ground off the southern tip of Greenland was believed to have no surviving population of Right whales, but when scientists from Oregon State University (OSU) and the National Oceanic and Atmospheric Administration (NOAA) begun investigating the area using hydrophones, they recorded a total of 2,012 Right whale “calls” from July through December 2007.

“We don’t know how many right whales there were in the area,” says David Mellinger, assistant professor at OSU’s Hatfield Marine Science Center in Newport and chief scientist of the project. “They aren’t individually distinctive in their vocalizations. But we did hear right whales at three widely space sites on the same day, so the absolute minimum is three. Even that number is significant because the entire population is estimated to be only 300 to 400 whales.”

During the last 50 years no more than two Right whales have been sighted at Cape Farewell Ground, so even a figure as low as three during the same day is good news.

The project has been using five hydrophones engineered by Haru Matsumoto at OSU, configured to continuously record ambient sounds below 1,000 Hz over a large region of the North Atlantic. These underwater hydrophones are sensitive enough to record sounds from hundreds of miles away. The scientists used previous recordings of Atlantic and North Pacific Right whales to identify the species’ distinct sounds, including a type of vocalization known as “up” calls.

“The technology has enabled us to identify an important unstudied habitat for endangered right whales and raises the possibility that – contrary to general belief – a remnant of a central or eastern Atlantic stock of right whales still exists and might be viable,” says Mellinger.

Results of the 2007 study were presented this week at a meeting of the Acoustical Society of America in Portland, Oregon.

In addition to Mellinger and Clapham, scientists involved in the project include Sharon Nieukirk, Karolin Klinck, Holger Klinck and Bob Dziak of the Cooperative Institute for Marine Resources Studies – a joint venture between OSU and NOAA; Phillip Clapham, a right whale expert with NOAA’s National Marine Mammal Laboratory, and Bryndís Brandsdóttir of the University of Iceland.

The release of sediment and algae-boosting fertilizers into Lake Victoria can cause cichlid species to interbreed in the murky water, according to Ole Seehausen, evolutionary biologist at the University of Bern in Switzerland and the Swiss Federal Institute of Aquatic Science and Technology in Kastanienbaum.

In a recent article published in Nature, Seehausen and his colleagues are shedding some light on the question of how closely related species of cichlids living adjacent to each other in Lake Victoria manages to avoid interbreeding. According to Seehausen et al, species may develop and stay distinct because of how the members of each species see colours.

Seehausen and his research team have studied closely related species of Lake Victoria cichlids where the males are either blue or red. It has since long been known that females of these species prefer to mate with the male displaying the brightest colours, but the new research suggests that both sexes have evolved to preferentially see only red or blue. This means that if a brightly coloured red male swims by a blue-seeing female, she will not be able to appreciate his sexy brightness since see can not see the colour red.

“Reds and blues live in the exact same spot,” says Seehausen,. “Colour is very important in mate choice.”

In order to fully understand the role of vision in underwater evolution, we must be aware of how light acts when it penetrates the water. Blue colours shine much brighter than red ones in the shallows, while red pigmentation trumps blue as we proceed farther down. As you probably have guessed already, red cichlid species tend to be found near the surface in Lake Victoria, while the blue ones inhabit greater depths.

To learn more about what happens to cichlids in the transition between red and blue zones in the lake, Seehausen and his team studied species inhabiting the shores of five different islands. The cloudiness of the surrounding waters varies from island to island due to variations in sedimentation, giving the researchers a great opportunity to study the effects of varying water clearness.

In comparatively clear waters, the colour that appears brighter slowly and gradually changes from red to blue with depth. This makes each species stay within its own zone and prevents interbreeding. In more clouded waters, the change from red to blue occurs much more suddenly, causing a higher prevalence of interbreeding between closely related species of fish.

Further testing in laboratory aquariums showed that hybrid females, like the ones living in cloudy waters, did not favour red males over blue ones or the other way around. This distinguished them from non-hybrid females, since females belonging to a species with red-sensing eyes picked red males in the laboratory tanks while the blue-sensing females opted for blue beaus.

Seehausen is now worried that the unchecked release of sediment and algae-promoting fertilizers into Lake Victoria will cause more and more fish to interbreed, thereby greatly reducing the number of species in a lake famous for its astonishing biological diversity and degree of endemic species. “Species diversity in this lake has imploded in the last 30 years,” Seehausen says. “It is the largest human-witnessed mass extinction of vertebrates.“

You can read more in the article “Speciation through sensory drive in cichlid fish” by Seehausen et al. http://www.nature.com/nature/journal/v455/n7213/abs/nature07285.html

According to a new study from Uppsala University, the origin of fingers and toes can be traced back to a type of fish that inhabited the ocean 380 million years ago. This new finding has overturned the prevailing theory on how and when digits appeared, since it has long been assumed that the very first creatures to develop primitive fingers were the early tetrapods, air-breathing amphibians that evolved from lobed-finned fish during the Devonian period and crawled up onto land about 365 million years ago.

Lead author Catherine Boisvert[1] and co-author Per Ahlberg[2], both of Uppsala University in Sweden, used a hospital CT scanner to investigate a fish fossil still embedded in clay. “We could see the internal skeleton very clearly, and were able to model it without ever physically touching the specimen,” says Ahlberg. The scan revealed four finger-like stubby bones at the end of the fin skeleton. The bones were quite short and without joints, but it was still very clear that they were primitive fingers. “This was the key piece of the puzzle that confirms that rudimentary fingers were already present in the ancestors of tetrapods,” Catherine Boisvert explains.

The scanned fossil was that of a meter-long Panderichthys, a shallow-water fish from the Devonian period. Panderichthys is an “intermediary” species famous for exhibiting transitional features between lobe-finned fishes and early tetrapods, while still clearly being a fish and not a tetrapod. The specimen used was not a new finding; it had just never been examined with a CT scan before.

So, why have researchers for so long assumed that digits were something that evolved in tetrapods without being present in their fishy ancestors? The main reason is the Zebra fish (Danio rerio), a commonly used model organism when vertebrate development and gene function is studied. If you examine a Zebra fish, you will find that genes necessary for finger development aren’t present in this animal. Researchers therefore assumed that fingers first appeared in tetrapods and not in fish.

It should be noted that similar rudimentary fingers were found two years ago in a Tiktaalik, an extinct lobe-finned fish that lived during the same period as Panderichthys. Tiktaalik is however more similar to tetrapods than Panderichthys.

The Panderichthys study was published in Nature on September 21.