Scientists Identify Tiny “American Pocket Shark” in Gulf of Mexico — a New, Glowing Species Smaller Than a Hand
Lede: Scientists have identified Mollisquama mississippiensis, the American pocket shark, in the Gulf of Mexico — a tiny, 14-centimeter (5.5‑inch) bioluminescent species with gland-like light pockets that underscores how much of the deep sea still remains unknown.
Key takeaways
- New species: Mollisquama mississippiensis, the American pocket shark, was identified from a single 14 cm specimen.
- Unique feature: It bears a pair of glandular “pockets” near the gills that can secrete a luminous fluid and has photophores for bioluminescence.
- Rarity and discovery: Only the second pocket shark ever recorded; specimen was collected in 2010 and described in 2019.
- Conservation unknown: With a single specimen known, abundance, range, and status remain undetermined.
Discovery and identification
The tiny specimen came to scientific attention after a 2010 research cruise in the Gulf of Mexico that was studying sperm whales. The preserved animal sat in a collection until researchers at Tulane examined it and recognized features unlike any known species. The specimen’s history and identification are summarized in a Tulane University news release on identification, which documents the steps leading to the formal description.
The official description and name, Mollisquama mississippiensis, appeared in the taxonomy journal Zootaxa in 2019; modern imaging and collaborative curation made the work possible. To confirm the species, scientists performed microscopic examinations, X-rays and high-resolution CT scans at the European Synchrotron Radiation Facility — methods that revealed internal structures and vertebral details distinguishing this Gulf specimen from the only other known pocket shark.
For more on the identification and the research team’s methods, see the Tulane University news release on identification.
Physical description and biology
The known specimen measures about 14 centimeters (5.5 inches), roughly the size of an adult’s hand, and appears to have been a newborn male when collected. It has a bulbous, whale-like head, a grey body with darker fins, and cream-colored patches around its gills.
Most striking are a paired set of gland-like “pockets” located near the gill slits that appear capable of secreting a glowing fluid — a feature thought to assist in hunting or defense in the deep, dark habitat. The body also bears clusters of photophores (light-producing organs), suggesting an ability to glow or use counterillumination.
For accessible overviews and photographs of pocket sharks and their light-producing anatomy, see the IFLScience overview of pocket sharks and a focused discussion on the “glowing” pocket shark by Sophie Maycock.
Taxonomic relations and rarity
Mollisquama mississippiensis is placed within the order Squaliformes and the family Dalatiidae, which includes kitefin and cookiecutter sharks — groups noted for small body sizes and, in some members, light-producing organs. Pocket sharks are extremely rare: prior to this work only one pocket shark species, Mollisquama parini, had been recorded off Chile in 1979.
Because only one specimen of each species has been found, basic life-history traits — population size, lifespan, breeding behavior, and exact geographic range — remain unknown. The sharks’ deepwater habits and tiny size make them difficult to sample with standard fisheries gear.
Read more about the taxonomic placement and rarity via the Wikipedia entry for Mollisquama mississippiensis and the IFLScience summary.
Scientific significance
“Finding a new shark species in U.S. waters underscores how much remains unknown about the deep sea.”
This discovery highlights the value of routine surveys, careful specimen curation, and interagency and academic collaboration. NOAA Fisheries, Tulane University, the Florida Program for Shark Research, and the American Museum of Natural History all contributed to bringing the specimen to scientific attention and enabling modern analyses.
Advanced imaging — especially CT scans and X-rays — allowed researchers to compare internal anatomy and vertebrae with the Chile specimen, revealing diagnostic differences that would have been difficult to detect with older methods. These techniques, combined with museum collections, are critical tools for revealing cryptic deepwater diversity.
Conservation status
With only a single specimen known, the conservation status of Mollisquama mississippiensis is unknown. There are no population data to determine whether the species is inherently rare, declining, or simply seldom encountered because it inhabits deep water. Scientists caution against assumptions about abundance or threat without additional data.
Key contributors
The identification involved federal scientists, university researchers and museum specialists. NOAA Fisheries helped collect and preserve the specimen; Tulane University researchers led the taxonomic work; the Florida Program for Shark Research and the American Museum of Natural History provided expertise and specimen curation.
Implications for the United States
Economic and coastal communities: For Gulf coast towns reliant on fishing, shipping or offshore energy, the discovery is a reminder of the ocean’s hidden life. The tiny American pocket shark is unlikely to affect commercial fisheries or pose any threat to people, but the finding may influence how managers consider deepwater biodiversity when planning surveys and environmental reviews.
Scientific research and resource planning: The discovery underscores the value of funding routine surveys and specimen collections; data from these efforts inform fisheries management and environmental planning tied to industry projects.
Local fisheries and anglers: There is no evidence the shark poses a risk to anglers or fishers. Its small size and deep habitat make encounters extremely unlikely. Still, reporting unusual catches and preserving specimens when possible helps scientists spot rare species sooner.
Public understanding and stewardship: The story can strengthen ties between coastal communities and research institutions; local reporting and citizen science programs help detect unexpected species.
How residents can help
- Report unusual marine animals to state fish and wildlife offices or university labs.
- If permitted, preserve specimens carefully and record precise location and depth.
- Share photographs and notes with regional marine research programs to aid identification.
Further reading and sources
- Wikipedia: Mollisquama mississippiensis
- Tulane University news release on identification
- IFLScience overview of pocket sharks
- Background on the “glowing” pocket shark
Note: This report preserves the original facts and citations about the discovery of Mollisquama mississippiensis and the sources that document the identification and research.
