Gulf of Mexico
Photos courtesy of Tulane University and NOAA/NMFS.

New shark species identified -- rarest of all

An “exceedingly rare” pocket shark—originally collected in a trawl survey in the Gulf of Mexico in 2010 and stored in a giant freezer for three years before anyone identified the species—has been officially identified as a new species and given a name.

Mollisquama mississippiensis: A new species of Kitefin Shark from the Gulf of Mexico.

Kitefin Sharks, Dalatiidae, are small Sharks with robust lower jaws, which lack spines in their dorsal fins and have no anal fins. They show heterodont dentition (the teeth are not all the same, in this case with the upper and lower teeth being distinct, and some species are bioluminescent. The group includes the distinctive Cookiecutter Sharks, Isistius spp., which feed by taking a circular (or cookie shaped) bite of flesh from prey animals much larger than themselves.

In a paper published in the journal Zootaxa on 18 June 2019, Mark Grace of the Mississippi Laboratories of the National Oceanic and Atmospheric Administration, Michael Doosey of the Tulane University Biodiversity Research Institute, John Denton of the Florida Program for Shark Research at the University of Florida, and the Department of Ichthyology at the American Museum of Natural History, Gavin Naylor also of the Florida Program for Shark Research at the University of Florida, Henry Bart, also of the Tulane University Biodiversity Research Institute, and John Maisey of the Department of Vertebrate Paleontology at the American Museum of Natural History, describe a new species of Kitefin Shark from the Gulf of Mexico.

The new species is placed in the Pocket Shark genus Mollisquama (so called because some species reach less than 40 cm in length, and the presence of a distinctive pocket-shaped gland above the pectoral fin), and given the specific name mississippiensis, meaning 'from Mississippi'. The species is described from an immature male specimen 142 mm in length and weighing 14.6 g. The specimen was caught in February 2010 during survey by the NOAA Ship Pisces at a depth of between 5 and 580 m, in an area where the seafloor is slightly over 3000 m deep.

Presenting the American Pocket Shark, whose scientific name is Mollisquama mississippiensis, partly in recognition of the NOAA/National Marine Fisheries Service Laboratory where the specimen was stored and first discovered.

The findings were published in the animal taxonomy journal Zootaxa by authors Mark Grace of NMFS Mississippi Laboratories and NOAA, and Henry Bart and Michael Doosey of Tulane University Biodiversity Research, Tulane University announced Thursday.

“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,” Bart told Tulane University.

Added Grace, “In the history of fisheries science, only two pocket sharks have ever been captured or reported. Both are separate species, each from separate oceans. Both are exceedingly rare.”

In fact, the pocket shark is the rarest of all sharks.

The newly named pocket shark, which seems to resemble a mini-whale, has five features not seen in the only other known specimen that was captured in the Eastern Pacific Ocean in 1979 and is housed at the Zoological Museum in St. Petersburg, Russia.

“We’ve now shown that in addition to being a new species, indeed this is a luminous shark that has numerous photophores and it can produce a luminous cloud from its pockets [behind the gills],” Grace told USA Today/For The Win.

From Tulane University:

Researchers said there were notable differences between the original Pacific Ocean specimen and the newer specimen from the Gulf of Mexico. Those differences include fewer vertebrae and numerous light-producing photophores that cover much of the body. The two species both have two small pockets that produce luminous fluid (one on each side near the gills).

“Anytime a new species is described it is significant, especially for something from the deep ocean that has as many unique features as the American Pocket Shark,” Grace told For The Win Outdoors. “Imagine that shark alive and in its environment; glowing, stalking, a predator. This is an earthly creature and not science fiction.”

Also on FTW Outdoors: Angler defies odds, lands truly enormous halibut

The American Pocket Shark was collected during a 2010 mid-water trawl survey 190 miles south of Louisiana by NOAA/NMFS Southeast Fisheries Science Center while studying prey of sperm whales.

The dead specimen measuring 5 1/2 inches was collected with other sea creatures, bagged up and stored in a giant freezer at NOAA’s lab until they could be identified.

Grace has spent more than 30 years going through bags of fish and identifying them and it took him three years before coming across the pocket shark, which made headlines in 2015.

“Naming a new species was a new experience for me,” Grace told For The Win Outdoors. “Of course having Mississippi in the name is in recognition of the location of my NOAA/NMFS Laboratory in Pascagoula, Mississippi, and the state of Mississippi which has been my home state for many years.

“The name also unites my birthplace and the location of Tulane University (New Orleans) where the specimen is archived in.”

Photos courtesy of Tulane University and NOAA/NMFS.

See For the Win article . . .

See also Sciency Thoughts article . . .