Pocket-sized, glow-in-the-dark shark species discovered by scientists
A pocket-sized pocket shark found in the Gulf of Mexico has turned out to be a new species. And the mysterious pouches that it’s named for, up near its front fins? Scientists say they squirt little glowing clouds into the ocean. Researchers from around the Gulf and in New York have named the species the American pocket shark, or Mollisquama (mah-lihs-KWAH-muh) mississippiensis (MISS-ih-sip-ee-EHN-sis).
It’s only the third out of more than 500 known shark species that may squirt luminous liquid, said R. Dean Grubbs, a Florida State University scientist who was not involved in the research. He said the other two are the previously known pocket shark and the taillight shark, which has a similar gland near its tail.
“You have this tiny little bulbous luminescent shark cruising around in the world’s oceans and we know nothing about them,” said Grubbs, the immediate past president of the American Elasmobranch Society — scientists who study sharks, skates and rays. “It shows us how little we actually know.”
Like the only other pocket shark known to science — a 16-inch (400-millimeter) adult female found in the Pacific Ocean off Peru — this 5.6-inch (142-millimeter) newborn male fished out of the Gulf has a pouch next to each front fin. But with this one, scientists figured out what they’re for.
The muscular glands are lined with pigment-covered fluorescent projections, indicating they squirt luminous liquid, National Oceanic and Atmospheric Administration ichthyologist Mark Grace and his collaborators wrote in the journal “Zootaxa.” The shark also has clusters of light-emitting cells dotted on its belly. The luminescence might conceal the shark from prey or from predators, he added.