All authors who have commented on this species in Utah (e.g., Pilsbry 1899, Henderson and Daniels 1917, Chamberlin and Jones 1929, Jones 1940a, 1940b; Woolstenhulme 1942a, Chamberlin and Roscoe 1948) have referred to it as Amnicola limosa, the specific epithet containing a gender error that has since been corrected.
The race of this species that occurs in Utah is the type race, Amnicola limosus limosus (see Burch 1989).
Status in Utah
Five historical occurrences of this species in Utah are known. (Prehistoric occurrences, based on subfossil material, have been excluded.) These localities are in the central or north-central part of the state. Reports that are thought to represent historical occurrences (and not merely prehistoric material) are from Utah County (Pilsbry 1899, Henderson and Daniels 1917, Chamberlin and Jones 1929, Jones 1940a), Salt Lake County (Woolstenhulme 1942a), Tooele County (Jones 1940b), and Juab County (Chamberlin and Jones 1929); however, populations at some of these historical localities are now known to be extirpated. It should be noted that many of the reports of this species from Utah are based upon subfossil or fossil material; for example, the species is well known from Box Elder County as fossils.
Abundance of this species at most reported localities in Utah is not well known, even historically. The question of its historical abundance in Utah is clouded by the fact that many authors did not explicitly distinguish dead shells from living individuals in their reports, and a few did not distinguish prehistoric (i.e., subfossil and fossil) material from fresh specimens. Jones (1940b) reported "several, alive" from one locality in Utah. Jones (1940a) reported from another Utah locality collections of 4, 2, and "several", and from still another locality 3 specimens; he seemed to be referring to fresh material as opposed to fossils or subfossils. Although Chamberlin and Jones (1929) wrote that "Amnicola limosa is a common form in Utah Lake", this is no longer true, the species seemingly having completely disappeared from this locality since the time of their publication. Chamberlin and Jones (1929) mentioned 1 specimen at another locality, and Woolstenhulme (1942a) reported 3, both of these reports possibly representing fresh, if not living, examples of the species. The apparent extirpation of this species from Utah Lake and the small numbers reported from other localities suggest that the species is now rare in Utah.
Threats to this species in Utah have included and almost certainly continue to include alteration and degradation of aquatic sites, especially in the heavily populated region along the Wasatch Front. Draining of wetlands and development of these former wetlands for agricultural, industrial, and commercial and residential purposes has resulted in widespread loss of habitat for this species. Dewatering for agricultural irrigation may also be a threat. Pollution from agricultural chemical use, industrial effluent, sewage, and mosquito abatement activities are other likely threats to the species.
This species is known to have declined precipitously in abundance and distribution in Utah during this century. It no longer survives at many of the localities where it was formerly found as a living species (e.g., Utah Lake and surrounding localities). Some of the aquatic sites from which it was formerly collected have, in fact, been destroyed (e.g., Beck's Hot Springs near Salt Lake City).
It is very important to distinguish between prehistoric (i.e., subfossil and fossil), fresh (dead), and living specimens of this species in Utah when examining pertinent literature, museum specimens, and examples encountered in the field.
Habitats Utilized in Utah
Although Chamberlin and Jones (1929) stated that "[t]his species occurs ... in streams, rivers and more quiet bodies of water ... on muddy bottoms and aquatic plants", it appears that they were writing in general terms concerning the species rangewide rather than of the particular habitats that it utilizes in Utah; for example, no information has been found that suggests that the species has ever been identified from streams or rivers in Utah. The species formerly occurred in Utah Lake, a large, shallow, slightly saline, freshwater lake where Chamberlin and Jones (1929) clearly were familiar with it, but several reported Utah localities are springs (see, for example, Jones 1940a) or salt springs (see, for example Woolstenhulme 1942a), habitats that Chamberlin and Jones (1929) did not mention, though they were aware of spring localities.