The above photo is of Apolemia lanosa a type of siphonophore belonging to phylum Cnidaria that also includes corals and jellies.  It’s basically the ocean’s way of celebrating Christmas all year long.  Like many other Cnidarians, siphonophores bud new individuals—exact clones themselves.  In a manner similar to Christmas elves although this is not proven by science. In the case of some Cnidarians, the clones never leave home so family never has to travel for the holidays.  

In some Cnidarians, clones in the colony will specialize but among siphonophores the specialization is unrivaled. Clones will specialize for feeding, defense, locomotion or reproduction. The feeding clones catch food by tentacles equipped with cells that shoot out poisonous harpoons stinging and stunning their prey.  In the most popular of all siphonophores, the Portuguese man o’ war, with a large gas filled buoyant bladder adapted for catching the wind and sailing.  Interestingly, all the clones are attached via a single digestive and circulatory system.  Research is still needed on which clones are adapted for drinking eggnog, singing carols, and wrapping gifts.

 The species of Apolemiidae may be record holders for the longest animals on earth. Fragments of specimens of this family with a length of over 30 meters have been reported from the French Mediterranean coast in the bay of Villefranche-sur-Mer. In most physonect siphonophores clones are arranged along a central stem, it itself the founding clone developed from a single egg.  At the front end, is a group of clones that are propulsion clones. Basically, Santa’s reindeer if Dasher, Dancer, Prancer, Vixen were all budded from and identical to Santa.  In the larger and remaining region of a physonect siphonophore, one can find the clones for engaging in the spirit of Christmas, eating and…  New clones are formed in special growth regions of the siphonophore.  As new clones are formed the old clones get pushed down the line. But Apolemia species are special.  In addition to other clones Apolemia can also add new feeding clones along the entire length of the stem. This fact might be the reason why members of this particular family of siphonophores can grow to such tremendous length.

The post The Ocean’s Gelantinous Christmas Tinsel first appeared on Deep Sea News.

A four-leaf clover represents just one kind of rareness. One might find a 4-leaf clover just about anywhere. Four-leaf clovers are not just restricted to Ireland. Four-leaf clovers are rare because at any given locality they occur in very minuscule numbers.

The idea of whether rareness imparts values has tormented philosophers, including Nietzsche. “Whatever can be common always has little value. In the end it must be as it is and always has been: great things remain for the great, abysses for the profound, nuances and shudders for the refined, and, in brief, all that is rare for the rare.” But of course, Nietzsche does not define rare. What does “all that is rare for the rare even mean?” Freakin’ Nietzsche.

We all feel we know what rare means. But contrast the case of four-leaf clovers with platinum. Platinum is special for me. For my 10th wedding anniversary, I had a custom wedding ring made of platinum for my wife. This platinum band was to replace one from our youth when I had more limited income and could afford a metal less “precious” and less “rare.” Yet, platinum represents another kind rarity, occurring in great abundance but only at a few locations. Locally abundant but geographically restricted.

In a classic 1981 paper, Dr. Deborah Rabinowitz, a professor at the University of Michigan, laid out the seven forms of rarity. What makes something rare depends on three characteristics; geographic range, habitat specificity, and local population size. First, is a species found globally or only at a single location? Two, is species seen at any given site in low numbers? Third, is the species only found in a specific type of habitat?

As Rabinowitz notes in elegant writing., “If each of these attributes is dichotomized, a 2 x 2 x 2 or eight-celled block emerges. Although creating the hazard of false reification – that is, converting an idea into an object – such a simple scheme can aid in focusing our thoughts, and this is my intention. The patina – a gloss or incrustation conferred by age – of monolithic rarity may have hindered our understanding of an exceedingly heterogeneous assemblage of organisms. Since the products of rarity are diverse, the causes of rarity and the genetic and population consequences of rarity are undoubtedly equally multiple.”

But obviously, 2x2x2 does not equal 7. One state is lost, a species found everywhere, in high numbers, and several different kinds of habitats. This species isn’t rare at all! You can think of the seven forms of rarity as three singe type cases (geographically limited/small numbers/habitat specialist), the three double type cases (geographically limited and small numbers/geographically limited and habitat specialist/small numbers and habitat specialist), and the last triple case (geographically limited and small numbers and habitat specialist).

The most uncommon form of rarity is a species found all over but in limited numbers at a single location. One such species is the exceptionally beautiful deep-sea snail Oocorys sulcata found in the eastern and western corridors fo the Atlantic and reaching will into the Indian Ocean and the western Pacific. Oocorys sulcata also show incredible depth tolerance found all the way from the shelf at 150 meters down to the deepest abyss over 5000 meters. Yet, despite this fantastic distribution, it is rarely found. A famous sampling effort off of New England did not capture a single individual in 41 samples. Another 24 samples later as part of later effort only yielded a single specimen. Indeed, based on some very rough calculations, you would probably only find about 15 every square kilometer or roughly 45 Manhattan city blocks.

Hydrothermal vents possess mollusks that are both unique and fascinating. A snail first described in 2003, the unusual snail Chrysomallon squamiferum, maybe the most exciting find thus far at a hydrothermal vent. I admit my bias here, as most of my interest lies with studying deep-sea snails. Nonetheless, the discovery of “gold-footed” snails a the Kairei vent field in the Indian Ocean is fascinating.

At this point, I should state that the foot of the snail is mineralized with pyrite and greigite. Many of you might note the misnomer here, as pyrite is only ‘Fool’s Gold,’ but in deciding on a temporary ordinary name Fool’s Gold-Footed Snail seemed a bit lengthy. I hope all will forgive the intentional misnomer for the sake of creative writing. Although other names due include the big-hearted iron snail (it also possesses an abnormally large heart for its size). And of course the scaly foot snail. So maybe the big-hearted, iron gold, scaly foot snail.

The scales, or sclerites, that cover the entire length of the snail’s foot can be up to 8mm long. The presence of mineralized scales is remarkable in itself, but the existence of iron sulfide as skeletal material is unknown from any other animal. The purity of sulfides, among other lines of evidence, suggest that the building of the scales is controlled by the gastropod itself. The sclerites are thought to have evolved recently and homologous to the operculum. It is believed they may serve as a defense against cone shells also occurring at the vent.

Chrysomallon squamiferum is rare, not only for the oddity of its features amongst the animal kingdom but because the snail is known from only three hydrothermal vents in the Indian Ocean. While abundant at any of these vents it is geographically restricted, like platinum. The scaly foot is actually a “double rare” case both geographically restricted and a habitat specialist. Given this potential habitat of only a few square meters, some of which endangered by deep mining interests, led a new paper by Dr. Sigwart and colleagues establishing Chrysomallon squamiferum as endangered on the IUCN RedList. This listing places the big-hearted, iron gold, scaly foot snail with 25 species all either bony fish, cartilaginous fish, or cephalopods all assessed to be either endangered or critically endangered.

Helen Macdonald writes in H is for Hawk “The rarer they get, the fewer meanings animals can have. Eventually rarity is all they are made of. The condor is an icon of extinction. There’s little else to it now but being the last of its kind. And in this lies the diminution of the world. How can you love something, how can you fight to protect it, if all it means is loss?”

I am hoping for future where Chrysomallon squamiferum I remember this elegant mollusk for the rarity of beauty, adaptation, and morphological marvel not the rarity of its existence.

Sigwart, J. D., Chen, C., Thomas, E. A., Allcock, A. L., Böhm, M., & Seddon, M. (2019). Red Listing can protect deep-sea biodiversity. Nature Ecology & Evolution, 1.

Rex, M.A., Stuart, C.T., Etter, R.J., & McClain, C.R. (2010). Biogeography of the deep-sea gastropod Oocorys sulcata Fischer 1884. Journal of Conchology, 40, 287.

Rabinowitz, Deborah. (1986). Seven forms of rarity and their frequency in the flora of the British Isles. Conservation Biology: The Science of Scarcity and Diversity 

Rabinowitz, Deborah. (1981) Seven forms of rarity. Biological Aspects of Rare Plant Conservation

The post The Beauty of Rarity first appeared on Deep Sea News.

Because my other post today is just a wee bit ranty, here a tranquil set of awe-inspiring videos for your consumption.  The ribbon eel is the only species in its genus, meanings it is pretty unique, in the larger family of Moray eels.  The ribbon eel, Rhinomuraena quaesita, is found among the lagoons and reefs throughout the Indo-Pacific oceans.  If you note the snout on these critters, you will see the flared nostrils.  This is usually the only part sticking out from burrows.  Apparently, the ribbon ells use these to attract small prey, clamping down on the unsuspecting food with their strong jaws and retreating into their burrows.  In addittion, all ribbon eels begin life as males and then ultimately become females.  This is called sequential hermaphroditism.

The post Ribbon Eel Video Roundup first appeared on Deep Sea News.

Far below the surface of the Pacific Ocean, three quarters of a mile deep, lies the peak of an underwater mountain.  Rising 1.4 miles off the abyssal plains, Davidson Seamount, nearly 26 miles long and 8 miles wide, is one of the largest known seamounts in U.S. waters. Davidson contains an abundance of life including massive groves of large bubblegum corals and reefs of glass sponges.  Life is so abundant at the seamount, we proposed nearly a decade ago that Davidson Seamount with its dense aggregations of invertebrates may serve as source of many species to nearby canyons and rocky outcrops off the California coast.  Davidson may be a perfect habitat for many species allowing their populations to explode.  This Davidson Seamount cradle then may serve as source of migrating individuals into other less perfect habitats nearby.  This idea of Davidson as a biodiversity source was instrumental in getting Davidson added to the Monterey Bay National Marine Sanctuary (MBNMS) in 2009.

A recent expedition by NOAA, MBNMS, and Nautilus, returned to Davidson Seamount.  And is typical of Davidson delivered with a spectacular display of life.   Over 1,000 individuals of the small sized octopus Muusoctopus robustus were caught on video hugging the rocks in a brooding position.  It is unclear why these octopuses are using the seamount as a nursery.  Higher currents around seamounts may bring more oxygenated waters.  The dense aggregations of other animals may provide abundant prey.  The crevasse, cracks, and rocky rubble of this old volcano may provide shelter from predators.

The post An Octopus Nursery Discovered on a Deep Underwater Mountain first appeared on Deep Sea News.

For more updates on my research, follow along at jellybiologist.com, or on twitter @RebeccaRHelm

As a scientist, I love jellyfish, and I suffer for it. Up until a few years ago, I had no way of knowing exactly where or when the jellyfish I study would appear. So I traveled to Washington and France and Florida looking for them, and more often than not, came up empty handed. The most frustrating part of all this travel was that I had all the species I needed right at home, but couldn’t use them. That’s because jellyfish, like butterflies, are the last stage in a complicated life cycle. Jellyfish have a stage that’s analogous to a caterpillar, termed a ‘polyp’, which lives happily in the lab. So imagine studying butterflies, and having all the caterpillar you need, expect none of them will metamorphose. No matter how hard you try to convince them, they just sit there eating leaves, and so you travel all around the world to find and study the actual butterflies. That is the exact position researchers and aquarists have been in with jellyfish.

This is why I’m so excited to share with you a paper I just published in PLOS ONE on a simple method for triggering metamorphosis in a huge variety of jellyfish species. Now, rather than traveling halfway around the globe, scientists can add a couple drops of a special compound to their polyp tank, and have jellyfish to study in under a week! I hope this work will be helpful to many different kinds of jelly-lovers, form biologists to aquarists and beyond.

This research started out of frustration. I’d been traveling for over two years looking for the best species to study, and was consistently coming up short. I wanted to better understand the process of metamorphosis, called ‘strobilation’, but I needed to find a species that would easily strobilate in captivity. No luck. And so one day, rather than going out to look for jellies,  I decided it was time to spend a couple months indoors, to test out a hair-brained idea that was all together different.

Throughout the decades, a handful of scientist have recorded that this-or-that chemical, when added to water with this-or-that polyps species, will trigger strobilation. Most of these papers stretch back to the 70’s and earlier, and most have been largely forgotten. But I decided it was time to revisit those old studies, and test out different chemicals. The experiments were messy and quirky–I had a bunch of chemicals, jars, and polyps all soaking in different substances for different lengths of time–but I remember the exact moment when I got my first breakthrough.

I carried a small dish of polyps, which had been soaking in a type of chemical called an ‘indole’, to the microscope. I was working alone in the lab, and I was feeling pretty discouraged. It’d been two weeks of stirring up different chemical solutions, doling them out in precise proportions, and checking every single day for signs that the little polyps had begun metamorphosis. Nothing. But when I looked down at the polyps soaking in indoles…well, I think my lab notebook can express it better than I can (there was, um…some language):

Each polyp had formed a small ring below the tentacles. This ring was the first sign of metamorphosis. Each ring would eventually grow to be a tiny jellyfish (the pictures at the top of this post are the same animals I saw that day!) This species is the Pacific sea nettle, but the same compound also worked for species from the Atlantic and Indian oceans. Almost every species I tried would dutifully metamorphose into a tiny jellyfish.

Not only did this open up a whole new research avenue for me, it has become the foundation for my career. Now we can have tiny jellyfish of almost any species in under a week. Even box jellies!

But here’s a result that’s got me head scratching: one type of polyp, from a crown jellyfish, didn’t strobilate with the indoles. I tried all sorts of different combinations of conditions, nothing worked. But there are a couple really cool things about crown jellies that may explain why they didn’t respond. First, the polyp lives in a small tube, unlike any other species. So it’s possible the compound didn’t work because the polyp is mostly tucked away behind a barrier. But the second cool thing about this species is that it’s a very distant cousin of most of the species that I studied. So it is possible that over evolutionary time it evolved a slightly different biochemistry, which makes it insensitive to indoles. Similar to the way catnip gets cats high, but doesn’t have the same impact on people. Indoles works well on many related species of jellies, but not so well on a distant relative.

I’m now working on figuring out the reason why indoles works so well for some species. What genes might this compound help turn on and off? By studying metamorphosis in jellyfish, I hope to better understand how metamorphosis evolved over long time scales. For example, are there genetic similarities of metamorphosis between frogs, butterflies, and jellies?

Those results are still pending. For now, I’m enjoying all the new jellies we have growing in the lab. And I hope these results can be helpful to all those seeking to learn more about jellyfish in this coming new year!

Paper:

Rebecca R. Helm & Casey W. Dunn (2017). Indoles induce metamorphosis in a broad diversity of jellyfish, but not in a crown jelly (Coronatae). PLOS ONE 12(12): e0188601. doi:10.1371/journal.pone.0188601

The post New Research Reveals How to Easily Grow Jellyfish In Captivity first appeared on Deep Sea News.

Which is why those visiting the California coast for summer vacation might be slightly confused on who dropped the Ramen in the ocean? Why would anyone waste their 10 for $10 special in the briny blue? It’s preposterous.

Well my friends, that’s because only one of these is Ramen noodles. Can you tell which?

Just in case you need a close up…
Yes, only one is Ramen…the other, Sea Hare egg masses. You heard me right.

Now put away your flavor packets and listen up cause we are gonna have “the talk.” When one mommy sea hare loves a daddy sea hare…just kidding they are hermaphrodites so we can throw all of that basically out the window. During their breeding season, sea hares form large aggregations in which they chain together to make the cutest sea hare babies you ever saw. Being hermaphrodites, the adult hares have both lady bits and man bits too and can choose which to use depending on who is where in the love chain.

Once the deed is did, they lay long “Ramen-like” ribbons of about 80 million eggs that attach to the benthos, turn a pinkish-brown, and take about 10-12 days to hatch. Sea Hares live in the plankton for roughly 30 days till they make their way back to the ocean floor and begin to chow down and start the cycle all over again.

So there you have it, no Ramen wasted here. Keep Calm and Noodle on.

The post Only One of These is Ramen Noodles first appeared on Deep Sea News.

While this misconception or inaccuracy may seem harmless, it could pose problems for future conservation efforts, as people are more likely to support conservation of cute rather than creepy-looking animals. While the angler fish is easily turned into a scary monster, the similar-sized tiny Pac-Man looking octopus is cute and popular with the public…If images are posted on social media by laypeople in a way that appears sensational and even heartless, and without any accurate information about the animals, then there is no resulting respect for these sea creatures or educational value. Simply viewing these creatures as freaks, ignores the importance of their role in keeping our oceans healthy.

More recently, DSN republished a very tongue-and-cheek rant about the uselessness of ocean sunfish.  This drew criticism in the comments. “We are in no position to dis other species.” “Agree with…other pelagic researchers…molas are awesome, fast, predators that given their numbers and chosen prey must play an integral role in the open ocean ecosystem. Please stop spreading this rant.”  Let’s not also forget the post where we railed against the cute, cuddly view of dolphins and received a backlash of comments.

So first thing is for everybody to take a breath and stop taking yourselves so damn seriously.

Nobody is going to protect and conserve what they do not know or understand.  These pieces use a whimsical and creative writing style and informal tone to draw the audiences in.  Quite simply these posts draw views, far more than other kinds of posts here at DSN.  The reason?  Because we tap into the human curiosity of the natural world and instill a sense of awe. Or maybe because most people have a sense of humor and like science with a helping of laughter. Humor, ick factor, bizarreness, oddities, and challenging the way we think about species allows us to deliver knowledge.  How many people actually knew about ocean sunfish before the viral rant?

More than once over the years DSN has been criticized for being “too informal”, “not being serious enough about science”, and by far my favorite to date “tarting up science.”

This “oh-so-hip” presentation of a very interesting phenomenon is regrettable. I stopped reading halway [sic] through it as I couldn’t take any more. Just present the science. Tarting it up for people to read is pointless. Such readers have no value. Too bad, I would have liked to learn the real scinece [sic] presented here.

I CAN NOT DISAGREE MORE WITH THESE COMMENTERS.  Our “tarting it up” is and will remain a core value for DSN.  We will continue to work diligently to make science accessible, relevant, current, and of course fun.  Now more than ever.  You know what happens to science writing that is not engaging?  Nobody engages with it.   Quite frankly, the old way of dry science communication and being serious about science did not work.  Science communication occurred within echo chamber and we all patted ourselves on the back for a job well done.  Now, look where we are at. We need new methods engaging new audiences—those audiences that some think have no value.  For Pete’s sake, let’s lighten up and get sense of humor.

More than once here at DSN, we have referred to ocean organisms as monsters.  From parasitic crustaceans to colossal squids, we have playfully applied the monster moniker.  Quite frankly, I believe it is completely acceptable to call deep-sea species monsters, freaks, and oddities.  Anything else would not acknowledge how other worldly, bizarre, fascinating, unique, and, indeed, special these deep-sea species actually are.  That otherness reflects a fascinating evolutionary trajectory these organisms to adapt to the environmental extremes of the deep sea.  They are nothing short of beautiful monsters full of adaptive solutions to the most unique place on earth.  If Monster’s Inc., Where the Wild Things Are, and Cookie Monster taught us anything is that monster’s are lovable and beautiful.

By the way did you know the spinal column of M. mola contains fewer vertebrae and is shorter in relation to the body than that of any other fish.  That’s weird.  Why and how did that happen?  Which brings me to my next point.  When we acknowledge oddity, everyone’s natural next questions are why and how? That’s a good thing…opening the door for some amazing science communication.  To borrow from the ever articulate Jamie Vernon, “Curiosity expands our worldview.”   This weirdness inspires awe and instead of harming them may ultimately lead to their protection.

There is also nothing wrong with acknowledging that some animals suck.  Evolution does not create perfect animals.  Evolution creates just good enough animals.  Anything changes—environment, competitors, predators—those species become not so good.  The history of life on Earth is riddled with story of story of species that just could not cut it; over five billion in fact or more than 99% of all species are now extinct.  The Mola mola, or the ocean sunfish, in many regards is a ridiculous animal with some very peculiar behaviors and evolutionarily good enough.  Of course, I love ocean sunfish because of these.  Also take pandas.  They kind of suck at being a species.

Female pandas can expect a solid 16 years of fertility, but they only ovulate once a year, and can only handle one set of offspring every two years. There’s no clearer recipe for extinction.

In 1940, geneticist Richard Goldschmidt suggested that new species may arise not by gradual change but by macromutations.  Of course, these major mutational changes may be disastrous and fatal.  He called these monsters.  But in very rare circumstances, one of these macromutations, by shear dumb luck, may produce a very well adapted animal ready to exploit a completely new way of life.  His term of these?  Hopeful monsters.

I choose to embrace those hopeful monsters for their oddity, their differences, and sometimes even their suckiness.

The post So yeah ocean sunfish are ridiculous, dolphins are @#$@&, and deep-sea anglerfish are monsters first appeared on Deep Sea News.

It isn’t the first time DSN gets it’s underwater rave on, whether we are showing you the fluorescent corals of coral reefs, Red Sea underwater disco, or fluo raving diving on the Great Barrier Reef, we’ve always been keen to show you how to have a great time underwater and look stylish (or at least bright) while doing so. A returning theme besides how awesome it looks, is why? Why would there be an entire world of dazzling colours underwater that us puny humans can only see by using specials tools? While I don’t pretend to know the answers, I might offer a few suggestions that could make you look at it in a different light…either that or confuse you even more while showing pictures of pretty glowing fish.

As a short recap, biofluorescence is not the same as bioluminescence. In the latter, fish produce their own light, the former (which this blog is about) reflects colours from an external light source at a different wavelength. You can find the technical details here. While diving, we can only observe biofluorescence using a few aids: a blue dive torch to stimulate fluorescence and a yellow filter in front of the mask to block the excess blue light and only see the reflected colours. Originally the blue torches used were UV-lights, but increasingly we are finding that normal, high intensity blue light actually works better. It also has the added benefit that it doesn’t make you go blind if you stare at it for too long.

So there we are, blue light in hand, yellow filter on, ready to marvel at all things fluo. The question remains why? Looking at what happens on land might give a few clues, because biofluorescence is not limited to the ocean. Birds, scorpions, butterflies, flowers, etc. all show biofluorescence. It has been suggested to play a role in attracting pollinators, mates, or even detecting light levels. One of the few functions that has been proven, is that it is used as a sexual signal in parrots.

Now that we’ve ended up at sex, it’s time to get back in the ocean.

• The beautiful fairy wrasses seem to use biofluorescence in a similar way as parrots. Males of the Red-eyed wrasse (Cirrhilabrus solorensis) show stronger aggression to other males that are fluorescent than to those who are not. So potentially fluorescence could be a way to see potential sexual competitors.
• A second suggestion is that small fish might use it as a secret way of signalling to each other. Red light does not travel far underwater, which would allow fish of the same species that are close (such as potential mates) to see the signals, but predators that swim by at a further distance would not see the reflected light.
• Predators could use biofluorescence to their benefit as well. Recently frogfish with fluorescent lures have been documented. Their orange fluo lures are the same colour as biofluorescent free-swimming worm found nearby. So these frogfish might be using fluorescence to attract prey.

Of course, all these explanations depend on whether or not fish can actually see fluorescence, which is still an important point of discussion. The fact that many species that are fluorescent also possess yellow filters in their eyes similar to what we use for diving hints at the fact that they might. But simultaneously, the low light levels found in the ocean might be too weak to stimulate the reaction. So alternatively, marine biofluorescence could just be a quirky side-effect of evolution that serves no real purpose. Even if that would be the case, we can still marvel at just how beautiful the hidden quirks of the ocean can be.

Want more from Maarten ? Check him out online!

Instagram: crittersresearch

Blog: crittersresearch.com

Twitter: DeBrauwerM

His website: https://crittersresearch.com/

References:

De Brauwer, M., & Hobbs, J. P. A. (2016). Stars and stripes: biofluorescent lures in the striated frogfish indicate role in aggressive mimicry. Coral Reefs, 35(4).

Gerlach, T., Sprenger, D., & Michiels, N. K. (2014). Fairy wrasses perceive and respond to their deep red fluorescent coloration. Proc. R. Soc. B, 281(1787).

Heinermann, P. H. (1983). Yellow intraocular filters in fishes. Exp. Biol., 43(2).

Michiels, N. K., Anthes, N., Hart, N. S., Herler, J., Meixner, A. J., Schleifenbaum, F., Schulte, G., Siebeck U. E., Sprenger, D. & Wucherer, M. F. (2008). Red fluorescence in reef fish: a novel signalling mechanism? BMC ecology, 8(1).

The post Reef raving revisited: 4 good reasons for fish to glow in the dark first appeared on Deep Sea News.

*alternative titles include “Looking a gift seahorse (genome) in the mouth”, “My kingdom for a seahorse genome”, “Hold your seahorses“, and “The galloping evolution of seahorses“.

Let’s face it, seahorses, pipefishes, and seadragons are messed up. That’s not a subjective opinion but an evolutionary fact.  It’s like all the approximately 300 species in Syngnathidae (the family of fish that contains all these critters) held a meeting and decided unanimously “Nah, screw it, we’ll do things however we damn well please.”  The Syngnathids are revolutionaries of the fish world.  ¡Viva la Evolución Revolución!

Seriously, almost everything in these species is different.  There is the elongated snouts and small mouths and jaws.  The pelvic and caudal fins are often gone.  The scales are replaced with an armor of bony plates.  Let’s not forget about the whole “male pregnancy” thing where the males nourish the developing embryos in a pouch.  Seahorses take it all to a whole other level with the prehensile tail and the vertical body axis.

So ultimately, one is left wondering what’s up with those genes?  Well, thanks to an intrepid group of geneticist, the complete genome of the tiger tail seahorse, Hippocampus comes, is complete.  With the full genome comes great power, the ability to compare this genome to the other sequenced fish.

Part of the story regarding the bizarreness of seahorses is gene loss.   Secretory calcium-binding phosphoprotein (SCPP) genes code for matrix proteins that are important in the formation of bone and teeth.  These genes are completely missing in Hippocampus comes and may explain why seahorses do not have teeth.  Did I forget to mention that?  Yeah seahorses and seadragons are toothless. The tbx4 gene, conserved in jawed vertebrates, acts as a regulator of hindlimb formation.  The gene is completely absent in the seahorse genome and explains the absence of those pesky pelvic fins.

What about that whole “male pregnancy” thing?   The H. comes genome contains six pastn genes, part of a family of genes that regulate the hatching of embryos.  The researchers conducted extra work, like the genome was not enough, suggesting a role for these pastn genes in brood pouch development and/or hatching of embryos within the brood pouch prior to birth.

Seahorses have also apparently lost many conserved noncoding genes (CNEs) that function as enhancers, repressors, and insulators of other genes.  1,612 CNEs have been lost in seahorses.  Compare this to the 281 in the Nile perch.  It is unclear how the loss of the CNEs may be related to some of the oddities of the seahorse, but loss of CNEs is tied to moderate short stature and shortened limbs in humans.

How I imagine the scientists of the study acted once they finished the genome

The awesomeness of this kind of work cannot even be articulated.  The researchers have done an amazing job of unpacking the genome of a seahorse and showing how genome evolution directly leads to all the uniqueness of seahorses.  Admittedly, I am little disappointed in not seeing a discussion of the prehensile tails genes and armored plating discussed. I guess I’ll need to wait a bit to build my army of aquatic minions to take over the world.

The post In the evolution of fishes, this is a one seahorse race* first appeared on Deep Sea News.

For fiddler crab males, size is everything.  Well over 60 different species of fiddler crabs, genus Uca, exist across the globe.  You are probably familiar with the crabs.  The males have one ridiculously large claw.  You might think I’m being unfair to fiddler crabs, but the claw of male fiddler crabs is one of the most exaggerated, sexually-selected structures of animals.  That ginormous claw can exceed 1/3 of total body size in large males.  For perspective, that is the equivalent of a 200-pound human male having a hand that weighs 66 pounds.  The average weight of human male hand is 1.25 pounds.  So yeah I think ridiculously large is an apt description.

So why gargantuan claws?  To attract the ladies of course.   Male fiddler crab wave their claws about, held high above their head to attract females into breeding burrows. Each species as unique claw wave.  Uca longisignalis, the fiddler crabs right aside my window here at the marine lab in southern Louisiana, stands outs because of numerous small jerks, sometimes reaching more than 30, that occur before the raising of the claw.  Uca musica, a fiddler crab from the tropical Pacific, conducts a prominent circular motion with its claw during a display. In my Louisiana fiddler crab, Uca longisignalis, the circular motion is weak at best, clearly needing some practice.

Why are the claws so important to the fiddler crab ladies?  In part males with larger claws are more likely to win contests, much more a ritual than an actual fight.  To the winner goes the spoils.  In this case the spoils are prime burrows in the mud flat, important both as bunkers during hide tides and nurseries.  Wandering pregnant females actually choose males partly on the basis of the respectability of the burrow.   Of course bigger claws are quite frankly just more visible to females. Interestingly, despite the large claw primarily being just for show, the equivalent biological bling, the claws are still functional and quite capable of generating enough Newtons of force to successfully cut the author’s index finger.

In a great 1996 study by Jennions and Blackwell, males of Uca annulipes were removed from their burrows and released back into the colony.  The two researchers then monitored the fighting success between the residents of the burrows and the released intruders.  Intruders with relatively large claws for their body size won more fights.  However, not just claw size that mattered.  Released intruders initiated encounters more frequently with burrow resident males smaller than themselves.   When the intruder was larger than the residents, the intruder was more likely to win.  The bigger the loser or winner in any fight the longer the battle goes.  Another study by Blackwell and Passmore, found females not only are particular for larger claws but larger males as well.  At the beginning of a mating period, females selectively go for the larger males in the population.  Toward the end of the mating period, when females feel the pressure of mating in time to release young to coincide with the following nocturnal spring tide, they become a little less choosy for big males.

The ladies love big claws and big males.

The post My What A Big Claw You Have! All the Better to Love You With. first appeared on Deep Sea News.