''Americamysis almyra'' is a

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are refer ...

-like

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

in the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Mysida Mysida is an order (biology), order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a Brood pouch (Peracarida), brood pouch or "marsupium" in females. The ...

, the opossum shrimps. It is native to

estuarine An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...

waters in the western Atlantic Ocean and Gulf of Mexico. It is often referred to in the literature as ''Mysidopsis almyra''.

Distribution and habitat

''Americamysis almyra'' is native to shallow parts of the western Atlantic Ocean and Gulf of Mexico. Its range extends from Maryland to Florida and the whole Gulf of Mexico, and includes the brackish waters of

Lake Pontchartrain Lake Pontchartrain ( ) is an estuary located in southeastern Louisiana in the United States. It covers an area of with an average depth of . Some shipping channels are kept deeper through dredging. It is roughly oval in shape, about from west ...

, St. Andrews Bay and

Chesapeake Bay The Chesapeake Bay ( ) is the largest estuary in the United States. The Bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula (including the parts: the ...

. Its habitat is typically

seagrass meadow A seagrass meadow or seagrass bed is an underwater ecosystem formed by seagrasses. Seagrasses are marine (saltwater) plants found in shallow coastal waters and in the brackish waters of estuaries. Seagrasses are flowering plants with stems and ...

s and shallow marshy areas at depths of less than . It is tolerant of

salinities Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...

ranging from 0 to 30 psu (practical salinity units) but is usually found in areas with a salinity below 20 psu. ''Americamysis almyra'' was first described from Lake Pontchartrain from specimens collected in 1953. It was identified as being present in

St. Johns River The St. Johns River ( es, Río San Juan) is the longest river in the U.S. state of Florida and its most significant one for commercial and recreational use. At long, it flows north and winds through or borders twelve counties. The drop in eleva ...

Florida in 1977 and was first detected in the

Patapsco River The Patapsco River mainstem is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed April 1, 2011 river in central Maryland that flows into the Chesapeake Bay. The river's tidal port ...

flowing into Chesapeake Bay in 1980. It is unclear whether it had

invaded An invasion is a military offensive in which large numbers of combatants of one geopolitical entity aggressively enter territory owned by another such entity, generally with the objective of either: conquering; liberating or re-establishing con ...

these areas, perhaps in the

ballast water Ballast is used in ships to provide moment to resist the lateral forces on the hull. Insufficiently ballasted boats tend to tip or heel excessively in high winds. Too much heel may result in the vessel capsizing. If a sailing vessel needs to vo ...

of ships, or whether it had been there previously but had been misidentified as '' Americamysis bigelowi''.

Ecology

''Americamysis almyra'' is an

omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutr ...

and examination of its stomach contents showed that its diet includes 31% vascular plant debris and 11%

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

s and

diatom A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ...

s. Opossum shrimps play an important part in the estuarine

food chain A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), det ...

and are consumed in large quantities by such fish as the

striped bass The striped bass (''Morone saxatilis''), also called the Atlantic striped bass, striper, linesider, rock, or rockfish, is an anadromous perciform fish of the family Moronidae found primarily along the Atlantic coast of North America. It has al ...

inland silverside The inland silverside (''Menidia beryllina'') is a neotropical silverside native to eastern North America, and introduced into California. It is a fish of estuaries and freshwater environments. Inland silversides are quite elongate even for silv ...

whiffs ''Whiffs'' is a 1975 comedy film directed by Ted Post and starring Elliott Gould, Eddie Albert, Harry Guardino, Godfrey Cambridge, and Jennifer O'Neill. It was produced by Brut Productions and released theatrically in the U.S. by 20th Century Fox. ...

and

flounders Flounders are a group of flatfish species. They are demersal fish, found at the bottom of oceans around the world; some species will also enter estuaries. Taxonomy The name "flounder" is used for several only distantly related species, thoug ...

References

{{Taxonbar, from=Q4508877 Mysida Crustaceans described in 1964