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

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

pocket shark The pocket shark (''Mollisquama parini'') is a species of kitefin shark in the family Dalatiidae. The species is found in deep water off Chile in the southeastern Pacific Ocean. It was the only member of the genus ''Mollisquama'', until another ...

native to the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

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

Discovery

The shark was first discovered by scientists from

Tulane University Tulane University, officially the Tulane University of Louisiana, is a private university, private research university in New Orleans, Louisiana. Founded as the Medical College of Louisiana in 1834 by seven young medical doctors, it turned into ...

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 ''Physeter'' and one of three extant species in the sperm whale famil ...

s in 2010. In 2013, the

National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...

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 the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

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

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

e and numerous light-producing

photophore A photophore is a glandular organ that appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors, ...

Description

The head is bulbous, resembling that of a

whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

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

gill A gill () is a respiratory organ that many 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 respiration on land provided they are ...

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