Common Name
GREAT BASIN RAMS-HORN

Scientific Name
HELISOMA NEWBERRYI

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Utah Taxonomy

Although this species had originally been placed in the genus Planorbis when it was originally described, most authors referring to its occurrence in Utah (e.g., Call 1884, Henderson and Daniels 1917, Chamberlin and Jones 1929, Jones 1940a, and Chamberlin and Roscoe 1948) have placed the species in the genus Carinifex. Chamberlin and Jones (1929) called this species Newberry's snail.

The subspecies that occurred in Utah is the type (or nominate) race Helisoma newberryi newberryi. (The species is highly variable, even within local populations, and some of the subspecies and "forms" or "varieties" that have been named are no longer considered to be valid taxa, although 3 races, including the type race, are currently recognized.)

Status in Utah

There are no known extant occurrences of this species in Utah. Call (1884), regarding this species, reported: "In the Bonneville area [i.e., western Utah] it was discovered living in Utah Lake." Call's (1884) report apparently is the only record of this species having been found alive in Utah. Henderson and Daniels (1917) noted that Call (1884) had found the species living in Utah Lake and reported that they found dead shells of this species on "the shore of Utah Lake and adjacent slough, two miles south of Lehi, Utah." Chamberlin and Jones (1929) wrote of this species: "No living specimens were taken during our studies. In previous records it has been recorded living at Utah Lake [an obvious allusion to Call (1884)]." Thus, it appears that this species disappeared from the extant fauna of Utah sometime between 1884 (or earlier, Call [1884] having provided no dates for the Utah Lake observations) and 1916, when Henderson and Daniels (1917) collected in the state, and that historically it was extant only in Utah Lake, Utah County. (It should be noted that the species is very well known in Utah from fossil material, not discussed here.)

Henderson and Daniels (1917) noted: "... [T]he water [in Utah Lake] is not so free from salts as formerly, owing to the extensive use of water for irrigation. Cameron ... reports that the mineral content, chiefly sodium chloride, of the lake water increased from 300 parts of total solids per million parts of solution in 1883 [coincidentally about the time that Call had found this species alive in the lake] to 1,400 parts per million in 1903--a period of twenty years." Surprisingly, in view of the fact that they found no truly aquatic mollusks still living in the lake itself, they continued with the speculation: "It is not likely that the salinity will increase so much as to be fatal to fresh-water mollusks ...." It is quite possible that, if accurate, a nearly fivefold increase in salinity in the 20-year period that ended 13 years before they collected at Utah Lake would have negatively impacted the aquatic mollusks of Utah Lake. Furthermore, if the salinity of Utah Lake continued, during the 13 years following the determination in 1903, to increase at the rate that it had increased in the previous 20 years, then the salinity of the lake in 1916, when Henderson and Daniels searched for mollusks there, would have been 2,180 ppm total solids.

It is extremely doubtful that inventory for this species in Utah would produce more than fossil or sub-fossil material, which is abundant at some sites.

Habitats Utilized in Utah

Call (1884), the only author who reported finding this species living in Utah, found it "in Utah Lake" but did not provide any information regarding its habitat. Utah Lake is a large, shallow, somewhat saline freshwater lake.

Sources:

  • Text modified from: Oliver, George V. and William R. Bosworth III. 1999. Rare, imperiled, and recently extinct or extirpated mollusks of Utah[:] a literature review. Publication number 99-29. Utah Division of Wildlife Resources, Salt Lake City. 230 pp.

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