The vernal pool fairy shrimp, ''Branchinecta lynchi'', is a species of freshwater

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 can ...

in the family Branchinectidae. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sove ...

s of

Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...

and

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

, living in

vernal pool Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the safe ...

s as well as non-vernal pool habitat. They range in size from long. Vernal pool fairy shrimp are listed as a

vulnerable species A vulnerable species is a species which has been categorized by the International Union for Conservation of Nature as being threatened with extinction unless the circumstances that are threatening its survival and reproduction improve. Vulnera ...

on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

, and has been listed as Federally Threatened species since 1994.

Description

Vernal pool fairy shrimp are usually

translucent In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable scattering of light. On a macroscopic scale (one in which the dimensions ...

, however some have been observed to be white or orange. They feature stalked

compound eye A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which disti ...

s, no carapace, and eleven pairs of legs. The fairy shrimp swim by moving their legs from front to back in a wave-like motion. They eat algae,

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

, protozoa, rotifers, and detritus, and are eaten by

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s and other animals, notably by the

tadpole A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found ...

s of spadefoot toads. Vernal pool fairy shrimp have a lifetime of about two months. They usually hatch in early January, and die in early March. The female fairy shrimp lay

drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...

-resistant

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...

s shortly before they die. The eggs sink to the bottom of the vernal pools, embedding into the soil when they dry. When the vernal pool refills the next winter, the eggs hatch, starting the process over.

Habitat

Vernal pool fairy shrimp have been found in vernal pools in

southern Oregon Southern Oregon is a region of the U.S. state of Oregon south of Lane County and generally west of the Cascade Range, excluding the southern Oregon Coast. Counties include Douglas, Jackson Jackson may refer to: People and fictional charac ...

, and parts of

. They can survive if the pool's temperature is between and . In Oregon, they have been discovered in the

Agate Desert The Agate Desert is a prairie located near White City, Oregon, of which is protected as the Agate Desert Preserve. The area is not in fact a desert as its name suggests; it is so named because of the abundance of agate, petrified wood, jasper, and ...

, around

Agate Lake Agate Lake is a reservoir located above sea level in Jackson County, Oregon, United States. It is northeast of Medford, just north of Roxy Ann Peak. The lake is formed by the tall Agate Dam, which impounds Dry Creek, in the Rogue River wate ...

, and on the

Upper and Lower Table Rock Upper Table Rock and Lower Table Rock are two prominent volcanic plateaus located just north of the Rogue River in Jackson County, Oregon, U.S. Created by an andesitic lava flow approximately seven million years ago and shaped by erosion, they ...

s. In California, fairy shrimp have been found in 32 locations in the Central Valley from

Shasta County Shasta County (), officially the County of Shasta, is a county in the northern portion of the U.S. state of California. Its population is 182,155 as of the 2020 census, up from 177,223 from the 2010 census. The county seat is Redding. Shasta ...

Tulare County Tulare County ( ) is a county located in the U.S. state of California. As of the 2020 census, the population was 473,117. The county seat is Visalia. The county is named for Tulare Lake, once the largest freshwater lake west of the Great Lakes. ...

, and in the Coast Range from

Solano County Solano County () is a county located in the U.S. state of California. As of the 2020 census, the population was 453,491. The county seat is Fairfield. Solano County comprises the Vallejo–Fairfield, CA Metropolitan Statistical Area, which i ...

San Benito County San Benito County (; ''San Benito'', Spanish for " St. Benedict"), officially the County of San Benito, is a county located in the Coast Range Mountains of the U.S. state of California. As of the 2020 census, the population was 64,209. The co ...

. They have also been found near

Soda Lake A soda lake or alkaline lake is a lake on the strongly alkaline side of neutrality, typically with a pH value between 9 and 12. They are characterized by high concentrations of carbonate salts, typically sodium carbonate (and related salt complex ...

Santa Barbara County Santa Barbara County, California, officially the County of Santa Barbara, is located in Southern California. As of the 2020 census, the population was 448,229. The county seat is Santa Barbara, and the largest city is Santa Maria. Santa Barba ...

, the

Santa Rosa Plateau The Santa Rosa Plateau is an upland plateau and southeastern extension of the Santa Ana Mountains in Riverside County, southern California. It is bounded by the rapidly urbanizing Inland Empire cities of Murrieta and Temecula to the northeast an ...

, and

Riverside County Riverside County is a county located in the southern portion of the U.S. state of California. As of the 2020 census, the population was 2,418,185, making it the fourth-most populous county in California and the 10th-most populous in the Uni ...

References

{{Taxonbar, from=Q4021102 Branchiopoda Crustaceans of the United States Endangered fauna of California Freshwater crustaceans of North America Natural history of Oregon Taxonomy articles created by Polbot ESA threatened species Crustaceans described in 1990