The San Bernardino springsnail (''Pyrgulopsis bernardina'') is an endangered species of

freshwater snail Freshwater snails are gastropod mollusks which live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs ...

in the family Hydrobiidae. This species is endemic to a small number of springs in the USA and northern Mexico.

Distribution and habitat

The species relies on freshwater springs and has also been collected from a springfed brook. It appears to have formerly occurred in at least eight locations on the headwaters of the

Rio Yaqui Rio or Río is the Portuguese, Spanish, Italian, and Maltese word for "river". When spoken on its own, the word often means Rio de Janeiro, a major city in Brazil. Rio or Río may also refer to: Geography Brazil * Rio de Janeiro * Rio do Sul, a ...

: in Tule Spring in the San Bernardino National Wildlife Refuge in southeast Arizona, five springs on the John Slaughter Ranch, and two springs in

Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is d ...

, Mexico. As of 2012, its presence was only confirmed in one spring on the Slaughter Ranch and the two Sonora locations. Total area of occupancy is thus likely less than 10 km².

Description

''Pyrgulopsis bernardina'' is a small snail that has a height of and a narrowly conic, small shell. Its differentiated from other ''Pyrgulopsis'' in that its penial filament has an absent lobe and elongate filament with the penial ornament consisting of centrally positioned dorsal and ventral glands.

Ecology

The San Bernardino springsnail is aquatic, breathing through gills. It feeds on

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 and possibly bacterial films and detritus. It probably prefers sand or cobble substrates to silt and organic deposits. Like many similar molluscs, the species is preyed upon by a variety of birds, amphibians and fishes.

Conservation

The San Bernardino springsnail is classified as Endangered by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

because of its extremely limited distribution and rapid loss of habitat sites. Totalp population estimates are uncertain as numbers can vary hugely over short distances (from zero to hundreds of thousands). The species appears to have suffered a range reduction of at least 75%, presumably driven by

groundwater depletion Overdrafting is the process of extracting groundwater beyond the equilibrium yield of an aquifer. Groundwater is one of the largest sources of fresh water and is found underground. Groundwater depletion is comparable to a bank account in which mor ...

and possibly pesticide contamination. The invasive

mosquitofish The western Mosquitofish (''Gambusia affinis'') is a North American freshwater fish, also known commonly, if ambiguously, as simply Mosquitofish or by its generic name, ''Gambusia'', or by the common name gambezi. Its sister species, the easte ...

is known to feed on snails in this genus, and while not found to occur in the currently known locations, it has in the past been reported from some of the springs were the snail is now absent.

References

{{Taxonbar, from=Q3141651 Pyrgulopsis Molluscs of the United States Gastropods described in 1987 Species endangered by habitat loss Taxonomy articles created by Polbot