Brune's tryonia (also known as Brune's Springsnail and Brune Spring Snail),

scientific name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''Tryonia brunei'', 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 ...

of very small

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastro ...

that has a

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 ...

and an operculum, an aquatic

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

s in the family

Hydrobiidae Hydrobiidae, commonly known as mud snails, is a large cosmopolitan family of very small freshwater and brackish water snails with an operculum; they are in the order Littorinimorpha. Distribution Hydrobiidae are found in much of the world, ...

. This species 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 elsew ...

to the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

(

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

). It was formerly listed as Threatened in 1993/1994 and Data Deficient since 1996 until it was changed to Critically Endangered and possibly extinct in 2012; this is because it is found only in Phantom Lake, Balmorhea Lake, has range of less than 100 km², and was last observed in 1993. A 1991 report by the

United States Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...

also listed it as Endangered and they also later noted the unknown population. It is found in firm substratum and on mud before modification. Its habitat was impounded in 1946 and still threatened by drought and longtime water abstraction since the 1970s. However, as a helpful measure, a pump was installed to maintain water level but the effects for the snail are unknown. It was last seen in 1993 and may even be extinct and has been listed as such by some publications with further searches not locating this snail. It is also listed as G1 (critically imperiled) by

NatureServe NatureServe, Inc. is a non-profit organization based in Arlington County, Virginia, US, that provides proprietary wildlife conservation-related data, tools, and services to private and government clients, partner organizations, and the public. Nat ...

. 1987 research listed it as occurring in New Mexico but there is no further and recent informationabout this. In 2014, research published in the ''Western North American Naturalist'' moved the snail to the genus '' Juturnia'' and noting it had been extinct since 1984 but the IUCN nor other organizations have changed their information.

References

Tryonia Gastropods described in 1987 Molluscs of the United States Endemic fauna of the United States Taxonomy articles created by Polbot Taxobox binomials not recognized by IUCN {{Hydrobiidae-stub