''Branchinecta longiantenna'' is a rare species of crustacean in the family

Branchinectidae Branchinectidae is a family (biology), family in the order Anostraca (fairy shrimp), containing two genera – ''Branchinecta'' and ''Archaebranchinecta''. The majority of the species are in the genus ''Branchinecta'', with only ''Archaebranchine ...

and the order Anostraca, the fairy shrimp. Its common name is longhorn fairy shrimp. It is endemic to California in the United States, where there are only four known populations. It is a federally listed

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

of the United States.USFWS
Longhorn Fairy Shrimp Five-year Review.
September 28, 2007. Retrieved 23 April 2023. This fairy shrimp is between one and two centimeters in length and differs from other fairy shrimp in the shape of its

antenna Antenna ( antennas or antennae) may refer to: Science and engineering * Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves * Antennae Galaxies, the name of two collid ...

e. The animal lives in vernal pools on grasslands as well as pools on sandstone substrates. The fairy shrimp takes at least 23 days to reach maturity, and about 43 days on average. There are four populations in California, all well separated from each other. In San Luis Obispo County the fairy shrimp occurs in vernal pools on the

Carrizo Plain The Carrizo Plain ( Obispeño: ''tšɨłkukunɨtš'', "Place of the rabbits") is a large enclosed grassland plain, approximately long and up to across, in southeastern San Luis Obispo County, California, about northwest of Los Angeles. It con ...

. Several are protected, and some are unprotected on private property. In Merced County in the Central Valley, the species can be found within the

San Luis National Wildlife Refuge The San Luis National Wildlife Refuge in the San Joaquin Valley of central California is one of the great remnants of a historically bountiful wintering grounds for migratory waterfowl on the Pacific Flyway. Located in the Bear Creek, Salt Slough, ...

, where it is protected. In

Contra Costa County ) of the San Francisco Bay , subdivision_type = Country , subdivision_name = United States , subdivision_type1 = State , subdivision_name1 = California , subdivision_type2 ...

the species is present in several vernal pools and can be found in scattered water-filled rock indentations. This population is protected in a preserve. In Alameda County the fairy shrimp occurs in vernal pools in a preserve, where it is protected. In addition to these four populations, one individual fairy shrimp was located near Los Banos in 2003, but it probably does not indicate the presence of a new population. This species is at risk for extinction because it has few small populations and the extirpation of any one could greatly reduce the total population.

References

{{Taxonbar, from=Q4021790 Branchiopoda Endemic fauna of California Endemic crustaceans of the United States Freshwater crustaceans of North America Crustaceans described in 1990 Taxonomy articles created by Polbot