octopus

Four New Octopus Species Discovered in the Deep Sea

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Enigmatic octopuses that have been newly discovered in the waters off Costa Rica add to a growing registry of deep-sea dwellers

A pink female octopus curls her tentacles around her body

A mother octopus broods her eggs near a small outcrop of rock unofficially called El Dorado Hill. When a female octopus broods (which can be a time span of multiple years), she does not eat and dies around the same time that her eggs hatch.

Last month a team of scientists visited an ethereal nursery on the seafloor off Costa Rica, where they watched in awe as a new generation of deep-sea octopuses gently emerged from a quivering cluster of oblong, semitranslucent eggs.

Now the researchers have confirmed these deep-sea dwellers are members of an entirely new, yet-to-be-named species, nicknamed the “Dorado octopus.” And they have announced they’ve discovered three more new deep-sea octopus species on top of that.

“Finding four new species of octopuses on just two expeditions is exciting, revealing some of the rich biodiversity of the deep sea and hinting at how much more waits to be discovered,” says Jim Barry, a deep-sea ecologist at the Monterey Bay Aquarium Research Institute, who was not involved in the expeditions.

The nursery visit last December was part two of a Schmidt Ocean Institute expedition that took place six months earlier. Then, too, researchers witnessed baby deep-sea octopuses emerge from eggs that their respective mothers were brooding near hydrothermal vents on the same underwater rock formation, called the Dorado Outcrop (hence the new species’ nickname). The octopuses’ proximity to the vents suggests these creatures may have evolved to use warmth from the seeping hydrothermal fluid to accelerate the incubation process—which is notoriously long for many deep-sea creatures, leaving their offspring vulnerable to predators for extended periods.

An octopus hatchling emerges from a group of eggs at a new nursery, first discovered by the same team in June, at Tengosed Seamount off Costa Rica.
An octopus hatchling emerges from a group of eggs at a new nursery, first discovered by the same team in June, at Tengosed Seamount off Costa Rica.

The team collected some octopus specimens near the vents and others farther away and brought them to the Zoology Museum at the University of Costa Rica. Fiorella Vásquez, a research assistant at the Zoology Museum, and Janet Voight, associate curator of invertebrate zoology at the Field Museum of Natural History in Chicago, then set out to classify the creatures.

The Dorado octopus is remarkably similar to the pearl octopus (Muusoctopus robustus), which a separate team of researchers previously found brooding eggs near hydrothermal vents off central California. To distinguish the Dorado octopus as a separate species in the recent investigation, the scientists made careful observations and descriptions of the different octopuses, such as measuring their arms and enumerating their suckers. “The two species share an unusual morphology, having smallish eyes, a robust body and fairly short arms,” Voight explains. “It’s the details that separate them.”

Of the three additional species the team identified farther from the hydrothermal vents, two are also members of the genus Muusoctopus. They have double rows of suckers on their arms and lack an ink sac––other traits that are characteristic of the genus.

“But they look really different,” Voight says of these two species. For both, large eyes are the most obvious difference from the Dorado octopus. And one of the species is reddish, with long arms, while the other has a lighter shade on its top side and a darker one underneath.

Multiple octopuses clinging to a rock in the ocean.
Brooding mother octopuses often curl themselves up, with tentacles and suckers facing out. Researchers believe this to be a defensive position that warns off predators. When a female octopus broods (which can involve a time span of multiple years), she does not eat and dies around the same time that her eggs hatch.

The fourth species is an oddball. “It was just so unlike anything I had seen; I didn’t know where to assign it,” Voight says. But she and Vásquez observed a single row of suckers on each of the animal’s arms and strange bumps on its skin, which they say could place this species in the genus Graneledone. Voight notes, however, that “its bumps aren’t quite like what I expected to see, and it’s really pale-colored, so it’s a bit of an enigma.”

These three other newfound species are also officially nameless so far. The researchers collected additional specimens that they’re still poring over to determine the best classifications. Subsequently they’ll have to meticulously describe and illustrate each species, run that information through peer review and then, if accepted, the species names will enter the scientific literature.

“We have so much to explore in the deep ocean, and part of that exploration is to find new species,” Vásquez says. “Every step we take to learn a little more about what is at the bottom of our ocean will help us to conserve it.”

The expedition also identified a rare deep-sea skate nursery—which the scientists are calling Skate Park—and three new hydrothermal springs. Expedition co-leader Jorge Cortés-Núñez, a professor emeritus of biology at the University of Costa Rica, says “we have samples and data for many years to come, motivation to continue along that line of research, and powerful information and images to justify the protection and conservation of the deep sea, not only of Costa Rica but of all the ocean.”

Octopus Intelligence Sheds Light on Evolution of Complex Brains

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Octopuses have both a central brain and a peripheral nervous system–one that is capable of acting independently.

Meeting an octopus is, in many respects, the closest we can come to meeting interplanetary aliens. Yet, new research shows their brains have some startling commonalities to those of humans—perhaps most notably in terms of microRNA (miRNA) and the role it plays in brain development. miRNA may be crucial for the development of complex brains.

“Complex brains with higher cognitive features have only evolved in vertebrates…with one exception: soft body cephalopods, for example octopuses,” notes Nikolaus Rajewsky, PhD, scientific director of the Berlin Institute for Medical Systems Biology of the Max Delbrück Center (MDC-BIMSB), and head of the systems biology of gene regulatory elements lab. “This is important because the octopus brain has evolved completely independently from the complex mammalian brain.”

Rajewsky began his research after reading scientific literature noting that octopuses are adept at RNA editing. He hypothesized that perhaps the octopus is therefore an “RNA-artist” and has evolved other RNA-based mechanisms. “Those mechanisms would be interesting to identify—not only to understand octopus evolution better but also to potentially harness new tools for RNA applications in humans,” Rajewsky says.

He profiled messenger RNAs, noncoding RNAs and, specifically, small RNAs in18 different tissue types from deceased octopuses. While RNA editing turned out to be less interesting because editing sites did not map to important sites, the researchers discovered 42 novel miRNA families in neural tissue—primarily in the brain.

Octopuses have complex “camera” eyes, as seen here in a juvenile animal. [Nir Friedman]

“This is the third-largest expansion of microRNA families in the animal world, and the largest outside of vertebrates,” Grygoriy Zolotarov, MD, lead author of a paper in Science Advances, said when the announcement was made. Therefore, miRNA appears to be closely linked to the evolution of complex animal brains.

The 42 miRNA families Rajewsky and his team identified are not shared with humans. In fact, the most recent common ancestor of octopuses and humans was a primitive flatworm that lived approximately 750 million years ago. These genes were conserved during the evolution of the octopus, so they are likely to be beneficial. Now the question is exactly what benefits they provide.

Another style of intelligence

Octopuses are curious creatures possessing an inventive mindset exemplified by their ability to disguise and protect themselves using opened shells for protection or as projectiles and to gather and store them for later use, as well as their well-known camouflage abilities. They also remember people and things and have distinct preferences. A team of Brazilian researchers thinks they may even dream.

Some researchers have reported they aren’t motivated by snacks (like other animals). As Rajewsky points out, “They do have personalities, so—just maybe—they realize you’re trying to reward them with food and don’t like to be manipulated. I’m not a behavioral scientist. I’m just speculating,” he stresses, “but it does account for the fact that there’s intelligence there that you cannot right away compare with our concepts.

“The octopus is a special invertebrate. By studying how the brain functions in octopuses, we can maybe learn new tools to interfere with our nervous systems or to understand our nervous system better,” Rajewsky tells GEN. While researchers are clearly interested in studying this animal, it’s not in danger of becoming the next lab rat. Its brain is “the most distant brain of all other animal brains.”

Octopuses also are difficult to study, needing aquariums. Rajewsky is a systems biologist working in molecular biology to understand the functioning of cells in tissues, as well as diseases, by studying molecular interactions. “To do this in the octopus, I can only do descriptive studies. I cannot do molecular experiments in octopuses because I don’t have tanks with animals.” It also would require adjusting the existing tools to octopus biochemistry. Therefore, he says, “I’m not intending to experiment on octopuses.” Instead, he analyzes frozen tissue samples collected from a marine station in Naples.

Finding the evolutionary departure

Rajewsky and his team began by quantifying major modes of posttranscriptional regulation across the 18 octopus tissues. They found that A-to-I editing was separate from the miRNA function, and therefore did not modulate it in any functionally important regard. Specifically, “…most of that editing occurred in the introns and 3 prime UTRs of mRNAs,” they wrote, with alternative splicing highest in neural tissues, as expected. Editing rarely altered the splice sites. The transcriptome, in fact, generally resembled that of other invertebrates.

The major evolutionary departure of the octopus from other invertebrates became evident when the researchers investigated miRNAs, they knew bound to the 3’ untranslated regions (3’UTRs).

The octopus genome has 138 miRNA families. When miRNA from Octopus vulgaris was compared with that of another species, O. bimaculoides, which last shared a common ancestor approximately 50 million years ago, the researchers found 43 novel miRNA families were shared among the two octopus species and squid. (Research also shows that 12 miRNAs are shared between squid and nautilus, and another 35 miRNAs are restricted to the octopus lineage.)

The research team is now planning to apply a technique, which will make the cells in octopus tissue visible at a molecular level. [Nir Friedman]

Of the 43 miRNAs unique to the octopus tissue, 34 were expressed in greatest quantity in neural tissues—typically at rates 13 times higher than when expressed in non-neuronal tissue. Levels were particularly high in the visceral ganglion, vertical lobe, and optic gland. Notably, these novel miRNAs were present in late-stage embryos and in just-hatched octopuses as well as in adult tissue, thus underscoring their likely involvement in brain development.

The paper notes that these miRNA sites are conserved throughout evolution and the researchers suggest conservation is the result of functional interaction between the miRNA and miRNA response elements in specific tissues.

Next research goals

There are three things Rajewsky says he wants to learn from this research:

  • In which specific cell types the newly discovered miRNAs are active. To do this, “We’ve developed a method to quantify miRNAs’ single cells,” he says, making them visible at a molecular level.
  • How the various type of neurons and other cells in the brain communicate with each other at a molecular level and how they’re organized. “For this we will perform spatial transcriptomics.”
  • How organism-specific miRNAs relate to brain evolution and either differ or correlate function between the octopi and human brains. “We can do experiments in human organoids to study human-specific miRNAs,” to determine this, he says.

Going further, Rajewsky plans to form a network of other octopus scientists to exchange insights.

Rajewsky became fascinated with octopuses after a trip to California’s Monterey Bay Aquarium, becoming “mesmerized” by an octopus in one of the tanks. “I have the feeling that this is a special and intelligent mind…so I read about octopuses as a hobby. Then, three years ago, I read a paper saying octopuses have elevated levels of RNA editing—a mechanism exists in humans in which RNA molecules can be reprogrammed, thus changing the nucleotide sequence in the RNA.

“Suddenly, I thought, maybe the octopus is an RNA extremophile. If they do this editing, maybe they do other things at the nuclear RNA level, as well.” He then embarked on a project to better understand how “this amazing animal has evolved, maybe learn something fundamental about how complex brains evolve and also something cool about RNA.”

What he has learned opens the door to a deeper understanding of miRNA’s role in the development of complex brains. “That is something that has been hypothesized for a long time,” Rajewsky says, and now it is becoming clearer. “It probably says, also, that miRNA is doing something in the brain that we still don’t understand.”

Octopus And Squid Evolution Is Officially Weirder Than We Could Have Ever Imagined

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Just when we thought octopuses couldn’t be any weirder, it turns out that they and their cephalopod brethren evolve differently from nearly every other organism on the planet.

In a surprising twist, in April last year scientists discovered that octopuses, along with some squid and cuttlefish species, routinely edit their RNA (ribonucleic acid) sequences to adapt to their environment.

main article image

This is weird because that’s really not how adaptations usually happen in multicellular animals. When an organism changes in some fundamental way, it typically starts with a genetic mutation – a change to the DNA.

Those genetic changes are then translated into action by DNA’s molecular sidekick, RNA. You can think of DNA instructions as a recipe, while RNA is the chef that orchestrates the cooking in the kitchen of each cell, producing necessary proteins that keep the whole organism going.

But RNA doesn’t just blindly execute instructions – occasionally it improvises with some of the ingredients, changing which proteins are produced in the cell in a rare process called RNA editing.

When such an edit happens, it can change how the proteins work, allowing the organism to fine-tune its genetic information without actually undergoing any genetic mutations. But most organisms don’t really bother with this method, as it’s messy and causes problems more often that solving them.

“The consensus among folks who study such things is Mother Nature gave RNA editing a try, found it wanting, and largely abandoned it,” Anna Vlasits reported for Wired.

But it looks like cephalopods didn’t get the memo.

In 2015, researchers discovered that the common squid has edited more than 60 percent of RNA in its nervous system. Those edits essentially changed its brain physiology, presumably to adapt to various temperature conditions in the ocean.

The team returned in 2017 with an even more startling finding – at least two species of octopus and one cuttlefish do the same thing on a regular basis. To draw evolutionary comparisons, they also looked at a nautilus and a gastropod slug, and found their RNA-editing prowess to be lacking.

“This shows that high levels of RNA editing is not generally a molluscan thing; it’s an invention of the coleoid cephalopods,” said co-lead researcher, Joshua Rosenthal of the US Marine Biological Laboratory.

The researchers analysed hundreds of thousands of RNA recording sites in these animals, who belong to the coleoid subclass of cephalopods. They found that clever RNA editing was especially common in the coleoid nervous system.

“I wonder if it has to do with their extremely developed brains,” geneticist Kazuko Nishikura from the US Wistar Institute, who wasn’t involved in the study, told Ed Yong at The Atlantic.

It’s true that coleoid cephalopods are exceptionally intelligent. There are countless riveting octopus escape artist stories out there, not to mention evidence of tool use, and that one eight-armed guy at a New Zealand aquarium who learned to photograph people. (Yes, really.)

So it’s certainly a compelling hypothesis that octopus smarts might come from their unconventionally high reliance on RNA edits to keep the brain going.

“There is something fundamentally different going on in these cephalopods,” said Rosenthal.

But it’s not just that these animals are adept at fixing up their RNA as needed – the team found that this ability came with a distinct evolutionary tradeoff, which sets them apart from the rest of the animal world.

In terms of run-of-the-mill genomic evolution (the one that uses genetic mutations, as mentioned above), coleoids have been evolving really, really slowly. The researchers claimed that this has been a necessary sacrifice – if you find a mechanism that helps you survive, just keep using it.

“The conclusion here is that in order to maintain this flexibility to edit RNA, the coleoids have had to give up the ability to evolve in the surrounding regions – a lot,” said Rosenthal.

As the next step, the team will be developing genetic models of cephalopods so they can trace how and when this RNA editing kicks in.

“It could be something as simple as temperature changes or as complicated as experience, a form of memory,” said Rosenthal.

How octopuses coordinate their arms

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Octopus (c) Science Photo Library
The study is the first to examine how octopuses co-ordinate their eight, flexible limbs as they crawl

With the aid of high-speed cameras, scientists have revealed how octopuses co-ordinate their arms to crawl.

Researchers from the Hebrew University of Jerusalem filmed crawling octopuses to work out exactly how the animals used their almost limitlessly flexible arms when they move.

This revealed the surprising simplicity of their motion; they just choose which arm to use to push themselves along.

The findings are published in the journal Current Biology.

 The study is the first detailed analysis of exactly how octopuses manages to move without a rigid skeleton.

How octopuses control and move their soft bodies is of interest to engineers who aim to design biologically inspired robots.

“People want to build soft robots for medical purposes and rescue operations,” said Dr Guy Levy, one of the researchers involved in the project.

Such soft-bodied, octopus-inspired arms would not be limited by fixed joints, he explained. This could be useful to access narrow, difficult to reach spaces – perhaps getting help to people trapped at the scene of a collapsed building.

Pick a leg

To find out the secrets of the octopus’s remarkably efficient movement, Dr Levy and his colleague Prof Benny Hochner videoed the animals from underneath as they crawled, and analysed their motion frame by frame.

This detailed study showed that, by shortening and lengthening, each arm pushed the body in only one direction.

“So the octopus only has to decide which arm to use for the pushing – it doesn’t need to decide which direction this arm will push,” explained Dr Levy.

“[It has] found a very simple solution to a potentially complicated problem – it just has to pick which arm to recruit.”

And because the creatures are able to push off any of their eight legs, they are able to crawl in any direction – no matter which way their body is facing. And, uniquely, there is no rhythm or pattern to their undulating limb movements

The scientists’ next step is to delve into the internal circuitry of the octopus nervous system, to find out exactly how this co-ordinated crawling is controlled.

Dr Levy added: “Every time we try to understand something new about the octopus, there are new surprises.”

Antarctic Octopus’s ‘Blue Blood’ Helps It Survive in Frigid Waters

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Octopuses in Antarctica survive subzero temperatures because of blue pigment in their blood, a new study finds.

The ice-cold temperatures in the Southern Ocean surrounding Antarctica range between 28.8 degrees Fahrenheit (minus 1.8 degrees Celsius) to 35.6 degrees F (2 degrees C). In such frigid conditions, animals have a harder time transporting oxygen throughout their bodies and therefore delivering it to tissues.

To cope, Antarctic octopuses use a copper-based protein called haemocyanin. It makes their blood run blue and is much more efficient at keeping their bodies properly oxygenated at freezing temperatures. [8 Crazy Facts About Octopuses]
“This is the first study providing clear evidence that the octopods’ blue blood pigment, haemocyanin, undergoes functional changes to improve the supply of oxygen to tissue at subzero temperature,” lead study author Michael Oellermann, a biologist at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in Germany, said in a statement.

To find out what keeps an octopus’s body oxygenated, Oellermann and his colleagues compared haemocyanin levels in an Antarctic octopus species (Paraledone charcoti) and in two species that live in warmer climates (Octopus pallidus in southeast Australia and Eledone moschata in the Mediterranean).

The Antarctic octopus had the highest concentration of haemocyanin in its blood compared with other species. At 50 degrees F (10 degrees C), the Antarctic octopus could release far more oxygen (76.7 percent), than the two warm-water octopuses (at 33 percent for the Octopus pallidus and 29.8 percent for the Eledone moschata).

Although the Antarctic octopus is far more adept at producing oxygen in cold waters than its warm-water counterparts, these animals actually thrive when the water is a balmy 50 degrees F (10 degrees C), rather than at 32 degrees F (0 degrees C), which is typical in the Southern Ocean’s lowest latitudes.

“This is important because it highlights a very different response compared to Antarctic fish to the cold conditions in the Southern Ocean,” Oellermann said. “The results also imply that due to improved oxygen supply by haemocyanin at higher temperatures, this octopod may be physiologically better-equipped than Antarctic fishes to cope with global warming,” he said.

The Antarctic octopus’s ability to adjust its blood oxygen supply to suit variable temperatures could help it cope with warming temperatures as a result of climate change. But, this “blue blood” also helps explain why different species of octopuses live in such diverse environments, ranging from the freezing waters around Antarctica to the warm equatorial tropics.