- Researchers have described a new species of pocket shark, a small shark measuring just 14 centimeters (5.5 inches) long, that possibly glows in the dark.
- The shark has been named the American pocket shark, or Mollisquama mississippiensis, in recognition of the biologically rich region in which it was discovered.
- Only two pocket sharks have ever been caught from the ocean. The previous specimen, M. parini, was collected from the eastern Pacific Ocean in 1979.
- The discovery of a new pocket shark species shows there is much more to learn about the Gulf of Mexico, researchers say.
In 2010, researchers surveying the eastern Gulf of Mexico to study what sperm whales eat, collected numerous animals from the ocean’s depths. While examining the collection in 2013, Mark Grace of the National Oceanic and Atmospheric Administration (NOAA) discovered a small shark among the specimens, measuring just 14 centimeters (5.5 inches) in length.
Now, Grace and his colleagues have identified that shark as a new-to-science species, one that possibly glows in the dark. The newly described animal is a species of pocket shark, researchers say in a new study published in Zootaxa.
The pocket shark gets its names not for its small size but because of small pocket-like openings or glands found behind each of its pectoral fins. Grace and his team have named the new species the American pocket shark, or Mollisquama mississippiensis, “in recognition of the vast North American Mississippi River Basin; a biologically and geographically rich region that nurtures Gulf of Mexico fauna and unites diverse cultures,” they write in the paper. The proposed common name recognizes the “extraordinary Americas of the Western Hemisphere.”
Pocket sharks are incredibly rare. Before the discovery of the American pocket shark, the only other specimen of pocket shark, archived at the Zoological Museum in St. Petersburg, Russia, was collected from the eastern Pacific Ocean in 1979. The species was named M. parini after the Russian ichthyologist Nikolai Vasilevich Parin.
The American pocket shark is the second species of pocket shark to be described. While the shark resembles M. parini in general shape and placement of fins and pocket glands, there are several notable differences, the researchers say. The American pocket shark has 10 fewer vertebrae than M. parini, for example, different teeth, a likely pit organ located near its lower jaw, and numerous light-producing organs or photophores covering much of the body, which possibly help the shark luminesce in the deep sea.
“In the history of fisheries science, only two pocket sharks have ever been captured or reported,” Grace said in a statement. “Both are separate species, each from separate oceans. Both are exceedingly rare.”
Henry Bart, a co-author of the study and director and curator of fishes at Tulane University’s Museum of Natural History, said the discovery of a new pocket shark species showed there was much more to learn about the Gulf of Mexico.
“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,” he said in the statement.
Grace, M. A., Doosey, M. H., Denton, J. S., Naylor, G. J., Bart, H. L., & Maisey, J. G. (2019). A new Western North Atlantic Ocean kitefin shark (Squaliformes: Dalatiidae) from the Gulf of Mexico. Zootaxa, 4619(1), 109-120. doi:10.11646/zootaxa.4619.1.4