''Assiminea pecos'' is a rare

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 ...

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 ...

in the family

Assimineidae Assimineidae is a family of minute snails, also known as palmleaf snails, with an operculum, gastropod mollusks or micromollusks in the superfamily Rissoidae. Many of these very small snails live in intermediate habitats, being amphibious betwee ...

known by the common name Pecos assiminea. It is native to

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

and

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 ...

in the United States. Specimens known from Mexico are now treated as members of a separate species, ''

Assiminea cienegensis ''Assiminea'' is a genus of minute, salt-tolerant snails with an operculum, aquatic gastropod mollusks, or micromollusks, in the family Assimineidae.Bouchet, P.; Gofas, S. (2015). Assiminea Fleming, 1828. Accessed through: World Register of ...

''.Hershler, R., et al. (2007)
Genetic and morphologic variation of the Pecos assiminea, an endangered mollusk of the Rio Grande region, United States and Mexico (Caenogastropoda: Rissooidea: Assimineidae).
''Hydrobiologia'' 579 317-35. The Pecos assiminea was federally listed as an

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 in 2005.USFWS
Listing Roswell springsnail, Koster's springsnail, Noel's amphipod, and Pecos assiminea as endangered with critical habitat; Final rule.
''Federal Register'' August 9, 2005. This snail was first described in 1987.Taylor, D. W. (1987). Fresh-water molluscs from New Mexico and vicinity. ''New Mexico Bureau of Mines and Mineral Resources Bulletin'' 116: 1-50. It is generally between 1 and 2 millimeters long. Little is known about its life history.USFWS
''Assiminea pecos'' Five-year Review.
December 2010. This tiny snail lives in the

Pecos River The Pecos River ( es, Río Pecos) originates in north-central New Mexico and flows into Texas, emptying into the Rio Grande. Its headwaters are on the eastern slope of the Sangre de Cristo mountain range in Mora County north of Pecos, New Mexico ...

basin in eastern New Mexico and western Texas. It inhabits

karst Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...

topography, such as caves, caverns, and springs. It lives in mud and mats of saturated vegetation with small amounts of running water. The snail can be found at six sites: four in the

Bitter Lake National Wildlife Refuge Bitter Lake National Wildlife Refuge is a United States National Wildlife Refuge located in two separate sections in central Chaves County, New Mexico, United States, a few miles northeast of the city of Roswell, New Mexico, Roswell. Both sectio ...

in New Mexico, one site at Diamond Y Spring and its drainage in Pecos County, Texas, and one site at East Sandia Spring in

Reeves County, Texas Reeves County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 14,748. Its county seat and most populous city is Pecos. The county was created in 1883 and organized the next year. It is named for George ...

. Threats to this species and to other invertebrates living in the same habitat include the loss of the water sources that feed the karst cave network. This has been caused by the tapping of the

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...

beneath it; some areas have been drained dry. Diamond Y Spring and East Sandia Spring are in danger of being drained. The springs are also located in active oil and gas extraction regions, and pollution of the water is a threat. Fire is also a destructive force in the wildlife refuge habitat. The

introduction Introduction, The Introduction, Intro, or The Intro may refer to: General use * Introduction (music), an opening section of a piece of music * Introduction (writing), a beginning section to a book, article or essay which states its purpose and g ...

of the

decollate snail The decollate snail, scientific name ''Rumina decollata'', is a medium-sized predatory land snail, a species of terrestrial pulmonate gastropod mollusk in the family Achatinidae. It is a European species that has been introduced in a number o ...

(''Rumina decollata'') is a potential threat, as it could be a predator upon the assiminea.

References

{{Taxonbar, from=Q309193 Assimineidae Endemic fauna of New Mexico Endemic fauna of Texas Gastropods described in 1987 Taxonomy articles created by Polbot ESA endangered species