''Mollisquama mississippiensis'' or the American pocket shark is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of pocket shark native to the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

. It is the second species of pocket shark to be described.

Discovery

The shark was first discovered by scientists from

Tulane University The Tulane University of Louisiana (commonly referred to as Tulane University) is a private research university in New Orleans, Louisiana, United States. Founded as the Medical College of Louisiana in 1834 by a cohort of medical doctors, it b ...

that were conducting a study on

sperm whale The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the Genus (biology), genus ''Physeter'' and one of three extant species in the s ...

s in 2010. In 2013, the

National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with Weather forecasting, forecasting weather, monitoring oceanic and atmospheric conditions, Hydrography, charting the seas, ...

identified it as a pocket shark, the first to be found in its region. A previously found specimen of a different pocket shark species was caught off the coast of

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

in 1979 and was used to identify the two different species due to their differences in size,

vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

e and numerous light-producing

photophore A photophore is a specialized anatomical structure found in a variety of organisms that emits light through the process of boluminescence. This light may be produced endogenously by the organism itself (symbiotic) or generated through a mut ...

Description

The head is bulbous, resembling that of a

whale Whales are a widely distributed and diverse group of fully Aquatic animal, aquatic placental mammal, placental marine mammals. As an informal and Colloquialism, colloquial grouping, they correspond to large members of the infraorder Cetacea ...

. The shark is very small, at only . Near the

gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow r ...

s are two "pockets" that secrete a luminous fluid which may enable the shark to hunt. The body is grey with the fins being darker. The areas around the gills are cream colored. There are clusters of photophores around the body, which are able to produce light.

References

{{Taxonbar, from=Q65938991 Fish described in 2019 Fish of the Gulf of Mexico Dalatiidae Species known from a single specimen