Tag Archives: seahorse

Arque tail.

Robotic, seahorse-inspired tail can help people maintain balance through sickness or hard work

Three graduates from Keio University’s (Japan) graduate school of media design have created a bio-inspire robotic tail — that you can wear.

Arque tail.

Arque, the new robotic tail.
Image via Youtube / yamen saraiji.

If you’ve ever envied your pet‘s tail, Junichi Nabeshima, Yamen Saraij, and Kouta Minamizawa have got you covered. The trio designed an “anthropomorphic” robotic tail based on the seahorse’s tail that they chirstened ‘Arque’. The device could help extend body functions or help individuals who need support to maintain balance.

Tail-ored for success

Most animals rely on their tails for mobility and balance. While our bodies lack the same ability, the team hopes that Arque can help provide it. The authors explain in their paper that “the force generated by swinging the tail” can change the position of a person’s center of gravity. “A wearable body tracker mounted on the upper body of the user estimates the center of gravity, and accordingly actuates the tail.”

The tail is constructed out of several individual artificial vertebrae around a set of four pneumatic muscles. The team notes that they looked at the tail of seahorses for inspiration when designing the tail’s structure.

“In this prototype, the tail unit consists of a variant number of joint units to produce,” the trio told The Telegraph. “Each joint consists of four protective plates and one weight-adjustable vertebrae.”

“At each joint, the plates are linked together using elastic cords, while the vertebrae are attached to them using a spring mechanism to mimic the resistance to transverse deformation and compressibility of a seahorse skeleton, and also to support the tangential and shearing forces generated when the tail actuates.”

Arque’s modular design means that its length and weight can be adjusted to accommodate the wearer’s body. Apart from helping patients with impaired mobility, the tail could also be used in other applications, such as helping to support workers when they’re moving heavy loads.

The team also has high hopes for Arque to be used for “full-body haptic feedback”. Just as the tail can be used to change the center of mass and rebalance a user’s posture, it can be employed to generate full body forces (depending on where it’s attached to the body) and throw them off balance — which would help provide more realism to virtual reality interactions.

Arque’s intended use is to be worn, but one has to take into account personal experience and social interactions when predicting whether this will work or not. How likely would it be for people to feel comfortable putting one on, or wearing them outside? Most people definitely enjoy gadgets but, as the smart-glasses episode showed us, they need to perceive it as ‘cool’ or they won’t ever succeed. Whether or not a robotic tail will ever be as socially acceptable as a cane remains to be seen but.

In the meantime, it definitely does look like a fun tail to try on.

The tail was presented at the SIGGRAPH ’19 conference in Los Angeles. A paper describing the work “Arque: Artificial Biomimicry-Inspired Tail for Extending Innate Body Functions” has been published in the ACM SIGGRAPH 2019 Emerging Technologies journal.

A small seahorse holds a cotton swab tightly in Indonesia. Credit: Justin Hofman via Natural History Museum.

The devastating state of ocean pollution in one depressing photo

Justin Hofman, a California-based nature photographer, was marveling at the beauty of a reef near Sumbawa Island, Indonesia, when a sight he wished he’d unsee came before his camera lens. It was at that moment that the 33-year-old snapped this depressing photo of a tiny seahorse, no bigger than a shot glass, hopping a ride on a pink cotton swab.

A small seahorse holds a cotton swab tightly in Indonesia. Credit: Justin Hofman via Natural History Museum.

A small seahorse holds a cotton swab tightly in Indonesia. Credit: Justin Hofman via Natural History Museum.

Hofman says he wishes the picture ‘didn’t exist’ but since it does the photographer thought he might as well share it with the world. The emotional shot impressed a lot of people, becoming one of the finalists of the London Natural History Museum’s Wildlife Photographer of Year. A note on the contest entry’s page has the backstory.

“Seahorses hitch rides on the currents by grabbing floating objects such as seaweed with their delicate prehensile tails. Justin watched with delight as this tiny estuary seahorse ‘almost hopped’ from one bit of bouncing natural debris to the next, bobbing around near the surface on a reef near Sumbawa Island, Indonesia.”

“But as the tide started to come in, the mood changed. The water contained more and more decidedly unnatural objects—mainly bits of plastic—and a film of sewage sludge covered the surface, all sluicing towards the shore. The seahorse let go of a piece of seagrass and seized a long, wispy piece of clear plastic. As a brisk wind at the surface picked up, making conditions bumpier, the seahorse took advantage of something that offered a more stable raft: a waterlogged plastic cottonbud.”

The powerful photo serves as an allegory for the rather wretched state of plastic pollution and debris humans have forced upon oceans. The waters around Indonesia and its many islands are among the most polluted in the world. Local government has taken note, pledging $1 billion over eight years for cleanup. The trash keeps piling up, though, putting into question the efficacy of such measures absent complementary policy that might curb pollution at the source. One recent study estimates there are at least 5.25 trillion pieces, weighing an estimated 269,000 tonnes in total, contaminating the world’s oceans. In 2010 alone, 8 million metric tons of plastic were dumped by humans into the waters.

plastic pollution chart

Seahorses have the fastest evolving genome

Seahorses have a highly specialized morphology, with several characteristics unique in the animal kingdom. Now, researchers have found another remarkable trait of seahorses – their genome evolves extremely fast.

A different species of seahorse. Image credits: Maëlick Seahorse.

The genome project, comprises six evolutionary biologists from Professor Axel Meyer’s research team from Konstanz and researchers from China and Singapore. They chose the tiger tail seahorse Hippocampus comes. The assembled genome is 502Mb or about 1/6th the size of the human genome. The reason why they chose this species is pretty straightforward – just look at it.

It doesn’t look like any other fish – or any other creature for that matter – nor does it behave like any other creature. We don’t know if its features are adaptive or not, but we do know its evolutionary history to some extent. So scientists looked at 4,122 orthologous genes (segments of DNA with shared ancestry because of a speciation event) and calculated mutation rates, finding that the rate of change is extremely high.

Figure 1 of the paper. Adaptations and evolutionary rate of H. comes.

Researchers believe that their study may partly explain why seahorses evolved the way they did.

“Our genome-wide analysis highlights several aspects that may have contributed to the highly specialized body plan and male pregnancy of seahorses,” they write in the study. “These include a higher protein and nucleotide evolutionary rate, loss of genes and expansion of gene families, with duplicated genes exhibiting new expression patterns, and loss of a selection of potential cis-regulatory elements.”

Seahorses possess one of the most highly specialized morphologies and reproductive behaviours. Their bodies include a toothless tubular mouth, a body covered with bony plates, a male brood pouch, and the absence of caudal and pelvic fins. Another surprising evolutive feature is male pregnancy. When mating, the female seahorse deposits up to 1,500 eggs in the male’s pouch. The male carries the eggs for 9 to 45 days until the seahorses emerge fully developed, but very small. After that, the male’s role is done but even so, it is a truly spectacular and almost unique trait (another type of fish does it – pipefishes).

Particularly noteworthy is the loss of the pelvic fins. Evolutionarily, you can consider them as analogous to human legs. The gene responsible for this feature (tbx4) is present in nearly all vertebrates, but is missing from the seahorse’s genome. Also, while some genes were absent, some genes were duplicated. When a gene is duplicated, it can fulfill a completely different role. In the seahorse, this is probably how a part of the newly created gene makes male pregnancy possible.

But not everyone is convinced. Writing on his website, Larry Moran, a Professor in the Department of Biochemistry at the University of Toronto, says that the accuracy of the study can’t be assessed without going deep into the big data algorithm they used.

“They looked at a set of 4,122 orthologous genes and calculated mutation rates. The results are shown in Figure 1 in the paper. The differences in distance are quite small, ranging from 94% tp 99% of the seahorse value (0.463) in the major clade. Nevertheless, the authors claim the difference is statistically significant. They also looked specifically at neutral changes and found the same thing—faster in seahorses. The implication is that the strange morphological differences between seahorses and other species of fish can be explained by a faster mutation rate.”

“Here’s the problem. I have no idea how they came up with these numbers. I can’t possibly evaluate the quality of their data to know whether it’s believable or not. Clearly the Nature referees thought it was good enough to publish. Those referees must be experts in this kind of analysis. Can someone out there help me understand the quality of this analysis?”

This indicates an issue with many modern studies. Even experts in respective fields can’t assess the validity of certain papers, because of the reliance on complex algorithms and big data. In other words, if you want to really understand the study, you often have to go through hundreds of lines of code (which are not readily accessible), in a language you are perhaps not familiar with – that’s simply not doable. Hopefully, reviewers are doing their job.

Journal Reference: Qiang Lin et al. The seahorse genome and the evolution of its specialized morphology. Nature, 2016; 540 (7633): 395 DOI: 10.1038/nature20595

seahorse

Genes show how the seahorse got its cute snout and became such a great father

 

seahorse

Credit: Pixabay

Seahorses remain an enigma. These mysterious-looking creatures appear to float around coastal seas with a grace and level of perfection that sucks in observers and admirers from all quarters of society. In ancient Greek and Roman times, seahorses were revered. They were once seen as symbols of power and of authority. Even the Latin taxonomic family name stirs the imagination, as Hippocampus translates as the “horse sea monster”.

The reality is that seahorses are part of the teleost group – the most common type of fish – and so are far more closely related to an Atlantic cod than to any horses, monsters or imaginary creatures. But seahorses also have some very unusual features, from their equine appearance and body armour to the fact that it is the males that carry and give birth to offspring. Now a new analysis of all the genes in the seahorse’s DNA (known as its genome) could for the first time help us fully understand these rare characteristics and uncover some of the creature’s mysteries.

Seahorses belong to the syngnathids family of fish, which includes approximately 300 species. Analysing the seahorse’s genes confirmed that it is in a sister group of fishes to that of the stickleback. What makes the particular group, which includes seahorses, unique among vertebrates, however, is their “male pregnancy”. The males nourish developing embryos in a brood pouch until hatching and parturition occurs. The male provides all the parental care and so have adaptations to provide the embryos with the right balance of fluids, oxygen and nourishment.

We think this oddity of evolution came about as a way for male seahorses to ensure they were the fathers of their mate’s children. In some species of seahorse, this phenomenon of male “pregnancy” reverses the usual roles of attracting a mate, with females competing for the males’ attention and evolving their own secondary sexual characteristics to do so.

The new research, from the ASTAR institute in Singapore and published in the journal Nature, shows that this unique feature of seahorses is clearly coded into the male genome. The researchers found that five of the genes responsible for hatching embryos that are usually active in most female fishes are very active in male seahorses and may be involved in male pregnancy.

Beacons of hope

Of course, it is not just the paternal role of seahorses that attracts the attention of observers. Seahorses also have a distinct snout structure that leads many to compare them with other larger animals. This snout in fact evolved through the loss of mineralised teeth that led the seahorse’s jaws to fuse into a tube-like structure with a small mouth.

This unique tube is extremely efficient in sucking small food items that are abundant in the water above the seabed. The adaptation is critical in ensuring seahorses maximise their opportunities to catch and gather food. The new research sheds light on the genetic origins of this fusion of the teeth. In particular, the analysis suggests the fused jaw may be due to the loss of the genes responsible for the proteins in tooth enamel.

While this kind of research helps confirm our fascination with seahorses, they are sadly threatened by our over-exploitation of the ocean. As the seas become increasingly altered by human activities, we need unique and novel animal life such as seahorses more than ever to help communicate to the world the importance and value of this watery environment.

In particular, many seahorse species live in seagrass meadows, which are threatened the world over. Communicating the value of these habitats for other less enigmatic species, such as Atlantic Cod, is difficult at best, so seahorses provide a beacon of hope for explaining to the world why we need seagrasses. Being able to truly understand the genetic basis for many of the interesting characteristics of seahorses can only help us explain more fully the seahorse story.

Richard K.F. Unsworth, Research Officer (Marine Ecology), Swansea University

This article was originally published on The Conversation. Read the original article.

Seahorses may inspire new generation of armored robots

Seemingly small and delicate, seahorses are actually much more resilient than they look. Engineers have demonstrated that the seahorses’ prism-like tails are mechanically superior to the cylindrical ones; the discovery could lead to the development of more resilient robots.

Models of the cylindrical tail, left, and the square-prism tail. (Michael M Porter, Clemson University)

There are 54 species of seahorses, and while they may be significantly different one from the other, all feature a segmented bony armour, an upright posture and a curled prehensile tail. The tail, which is used for grasping objects, consists of 36 squarish segments with a boxy cross section rather than the more common cylindrical form like a tree branch, a tail or a human arm. Researchers had a hunch there might be a good reason for this.

“When living organisms deviate from the norm, there’s usually a good biomechanical reason: a clue to some specific problem that needs to be solved,” Miriam Ashley-Ross of Wake Forest University in North Carolina, who was not involved in the paper, pointed out in a commentary.

While there are several other animals (like monkeys or chameleons) that have prehensile tails, the seahorse tail is particularly strong. It’s covered in strong, rigid plates, but despite all of this, it’s really flexible. The team wanted to learn exactly what makes it so strong and resilient.

Seahorses use their tails to grab things.

Seahorses use their tails to grab things.

“Nature makes things just strong enough not to break, and then flexible enough to do a wide range or tasks,” paper co-author Ross Hatton, an assistant professor of robotics at Oregon State University, says in a statement. “That’s why we can learn a lot from animals that will inspire the next generation of robots.”

They were particularly interested in how they could make “hard” (mechanical) robots safely operate around humans. So after they thoroughly studied the seahorse tail, they moved on to the next step: they 3D printed their own tail to see how it works. They also created the round equivalent, to have a point of comparison. They found that the round version gets smooshed if enough pressure is applied, while the square one was much more resilient, especially to compression. If great pressure is applied, the seahorse tail simply flattens out by allowing its bony plates to slide past each other, deflecting damage away from the vertebral column and giving it the ability to absorb much more damage.

“The square one just felt better. It felt like it basically fit together better and just performed more robustly, whereas the round one just didn’t really hold its shape well and just didn’t seem to fit together as well,” said Porter, who is now a mechanical engineer at Clemson University in South Carolina. “So that’s what led to this idea of ‘Huh, I wonder if the square actually had some advantages over the circle, and how can we actually prove that it has those advantages?’ “

Models demonstrate that a seahorse’s tail (with its flexible and square structure) can outperform some cylindrical types of tails.
Credit: Courtesy of Oregon State University

Since lead author Michael Porter was already working with a steerable catheter, he also tried to design it with a square cross section and again, the results were better. This means that technologies based on seahorses could also lead to better robotic performance in the operating room. However, while extremely exciting, this technology is likely years away from becoming a reality.

New Seadragon Species Discovered After 150 Years – Ruby Seadragon Uses Color as Camouflage

Until now, only two species of seadragon had been reported, with the last one being discovered 150 years ago! Now, biologists have discovered a new species off the coast of Australia: a red hot sea dragon.

The three known seadragon species. Image credits: Stiller et al.

“All this time we thought that there were only two species,” marine biologist Nerida Wilson of the Western Australia Museum said in a press release. “Suddenly, there is a third species! If we can overlook such a charismatic new species for so long, we definitely have many more exciting discoveries awaiting us in the oceans.”

It may be only 15 cm long (6 inches), but Phyllopteryx dewysea is definitely a beauty. It’s basically a longer, larger version of a seahorse. There are significant differences between the two though.

“Sea dragons have very long, thin snouts; slender trunks covered in bony rings; and thin tails which, unlike their seahorse cousins, cannot be used for gripping. They have small, transparent dorsal and pectoral fins that propel and steer them awkwardly through the water, but they seem quite content to tumble and drift in the current like seaweed. … Sea dragons survive on tiny crustaceans such as mysids, or sea lice. It is not known if they are preyed upon by other animals.”

Model of the Ruby Seadragon. Image credits: Stiller et al.

 

Scientists were excited to make the find offshore Australia, and actually believe that there may be other seadragons waiting to be discovered. The other two known species of seadragon are the Leafy Seadragon and the Weedy Seadragon – now we get a Ruby Seadragon.

“That such large charismatic marine species are still being found is evidence that there is still much to be done,” Rouse added. “This latest finding provides further proof of the value of scientific collections and museum holdings.”Advanced imaging allowed scientists to study the anatomy of the red seadragon and confirm their genetic findings.

The team discovered three specimens, including one which was lying around in a museum collection since 1919. Thanks to new developments in technology, they were confidently able to say it is indeed a new species.

“We’re now in a golden age of taxonomy and these powerful DNA tools are making it possible for more new species than ever to be discovered,” Greg Rouse of Scripps Oceanography, one of the study’s authors, said in a press release.

Scripps graduate student Josefin Stiller first identified this new species, a male carrying several dozen babies – because like seahorses, seadragon daddies take care of the babies. She studies migration patterns and genetic diversity to help bolster seadragon conservation efforts.

(a) On-deck shortly after being trawled; (b) preserved, with tip of tail and eggs removed for DNA extraction; pa pectoral area; ds facing dorsal spine; (c–f) three-dimensional scan generated by μCT; (c) outer bony plates, arrows pointing to different enlarged spines; (d) left half of the plates removed to reveal parts of the skull, pectoral girdle and spine (in white); (e) ventral view of the enlarged pectoral area; (f) detail of the trunk region. Scale bars, 1 cm. Image credits: Stiller et al.

“A CT (computer tomography) scan gave us 5,000 X-ray slices that we were able to assemble into a rotating 3-D model of the new seadragon,” said Stiller. “We could then see several features of the skeleton that were distinct from the other two species, corroborating the genetic evidence.”

Comparison of the skeleton of the three species of seadragons. X-ray radiographs of (a) the leafy seadragon Phycodurus eques, SIO 04-28; (b) the common seadragon Phyllopteryx taeniolatus, SIO 84-300; (c) Phyllopteryx dewysea n. sp., holotype WAM P33223.002. Scale bars, 1 cm.

The team believes there’s a reason why this species is so red – it inhabits the deeper waters, where red hues are absorbed more efficiently (the same reason why water is blue) and being red colored can help camouflage.

Journal Reference (you can read the full article for free): Josefin Stiller , Nerida G. Wilson , Greg W. Rouse. A spectacular new species of seadragon (Syngnathidae). DOI: 10.1098/rsos.140458.

Extremely rare baby seahorse sighting

Seahorses are just as elusive as they are cute, so diver Neil Garrick-Maidment, the executive director of the Seahorse Trust was absolutely thrilled when he spotted a 1.5 inch long baby female seahorse “clinging onto a piece of seagrass”. This trule remarkable sighting was made in the waters of Great Britain, in the Dorset waters, a region well known as a breeding area for seahorses.

“These babies are so small they have never been seen before in Britain, and as far as I know in Europe either,” Garrick-Maidment said. “The species is literally hanging on by its fingertips so it’s heartening to see them breeding here. I can’t overestimate how rare it is to see something like this. It’s absolutely, mind-blowingly fantastic.”

If we were to take a look at these little guys, the odds aren’t good for them at all. Of the 3-500 baby seahorses born during each breeding cycle, just 2 or 3 make it to adulthood. Think about that whenever you’re having a rough day.