Scientists discover tiny ‘pocket shark’ that glows in the dark

It's only the second pocket shark specimen ever discovered.

Scientists discover tiny ‘pocket shark’ that glows in the dark
MARK DOOSEY
  • The pocket shark is an extremely rare deepwater fish about which little is known.
  • This new specimen, first discovered in 2010, measures just 5.5 inches long and has pocket glands thought to emit a bioluminescent fluid.
  • The finding "underscores how little we know about the Gulf [of Mexico]," wrote one researcher involved with the recent study.


Scientists have identified a new species of tiny shark that secretes a glow-in-the-dark liquid.

The 5.5-inch specimen — dubbed the American Pocket Shark, or Mollisquama mississippiensis — was first discovered in 2010 in the Gulf of Mexico during a NOAA mission to study sperm whale feeding. In a recent study, researchers identified its species by using a dissecting microscope and studying radiographic (x-ray) images and high resolution CT scans.

The findings are published in a paper in the animal taxonomy journal Zootaxa.

"In the history of fisheries science, only two pocket sharks have ever been captured or reported," Mark Grace of the NMFS Mississippi Laboratories of NOAA said in a press release. "Both are separate species, each from separate oceans. Both are exceedingly rare."

The first pocket shark was discovered in 1979 in the East Pacific Ocean, but the new study confirmed that the shark found in 2010 was a separate species. Although "pocket" can refer to these sharks' small size, the term actually describes two pocket glands that scientists believe can produce a bioluminescent fluid that helps attract prey.

Still, little is known about these deepwater fish.

Henry Bart, director of the Tulane Biodiversity Research Institute, added: "The fact that only one pocket shark has ever been reported from the Gulf of Mexico, and that it is a new species, underscores how little we know about the Gulf — especially its deeper waters — and how many additional new species from these waters await discovery."

​How many undiscovered species probably exist in the ocean?

Not only is it hard to answer this question, but it's even hard to tell exactly how many marine species have already been discovered. Finding that number would require sifting through thousands of scientific papers and reports, and cataloguing the results in one central database – like the World Register of Marine Species (WoRMS), which currently contains more than 240,000 marine species.

As for estimating the number of undiscovered species, scientists generally take one of two approaches, as described by Andy Solow, director of the Marine Policy Center and a Senior Scientist at Woods Hole Oceanographic Institution:

"One approach is based on the species-area curve, which summarizes how the number of species in a region increases with the area of the region," Solow wrote for Smithsonian Ocean. "By seeing how species accumulate as the area covered by taxonomic surveys increases, biologists can make estimates about how many species are in a region with an area as large as the ocean. A big problem with this approach is that the total area covered by taxonomic surveys is a miniscule part of the ocean, and thus different prediction methods can give vastly different answers.

"Another popular approach uses the way in which species discoveries accumulate with time to estimate future discoveries. For some groups, like marine mammals, the discovery rate has fallen off rapidly and perhaps not that many more species remain undiscovered. However, for other groups, such as invertebrates, the discovery rate has actually increased steadily over time, so an estimate based on this ever-increasing rate is essentially infinite. But this method has a more fundamental problem: the discovery record on which this approach is based is the product of human activity, not some natural process."

U.S. Navy controls inventions that claim to change "fabric of reality"

Inventions with revolutionary potential made by a mysterious aerospace engineer for the U.S. Navy come to light.

U.S. Navy ships

Credit: Getty Images
Surprising Science
  • U.S. Navy holds patents for enigmatic inventions by aerospace engineer Dr. Salvatore Pais.
  • Pais came up with technology that can "engineer" reality, devising an ultrafast craft, a fusion reactor, and more.
  • While mostly theoretical at this point, the inventions could transform energy, space, and military sectors.
Keep reading Show less

Do you worry too much? Stoicism can help

How imagining the worst case scenario can help calm anxiety.

Stoicism can help overcome anxiety

Credit: OLIVIER DOULIERY via Getty Images
Personal Growth
  • Stoicism is the philosophy that nothing about the world is good or bad in itself, and that we have control over both our judgments and our reactions to things.
  • It is hardest to control our reactions to the things that come unexpectedly.
  • By meditating every day on the "worst case scenario," we can take the sting out of the worst that life can throw our way.
Keep reading Show less

Study: People will donate more to charity if they think something’s in it for them

A study on charity finds that reminding people how nice it feels to give yields better results than appealing to altruism.

How to get people to want to give you money, literal balls of cash not gaurenteed.

Photo by Pixabay from Pexels
Personal Growth
  • A study finds asking for donations by appealing to the donor's self-interest may result in more money than appealing to their better nature.
  • Those who received an appeal to self-interest were both more likely to give and gave more than those in the control group.
  • The effect was most pronounced for those who hadn't given before.
Keep reading Show less
Surprising Science

160-million-year-old ‘Monkeydactyl’ was the first animal to develop opposable thumbs

The 'Monkeydactyl' was a flying reptile that evolved highly specialized adaptations in the Mesozoic Era.

Quantcast