Common Name
FAT-WHORLED PONDSNAIL

Scientific Name
STAGNICOLA BONNEVILLENSIS

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Utah Taxonomy

Chamberlin and Jones (1929), who knew this species only as a fossil form, used for it the common name the Bonneville snail. Clarke (1991) called it the banded Bonneville stagnicola.

No subspecies are recognized in this species.

Status in Utah

This species is known to be extant at only 3 very closely associated sites (Clarke 1991). Clarke (1991) wrote: "A relict species, previously correctly reported only from Pleistocene Lake Bonneville deposits and until recently thought to be extinct ...."

The three sites inhabited by this species are "located in an area about 3 miles long close to Utah Highway 83, between mileposts 14 and 17 (measured from Corinne, Box Elder Co.)" (Clarke 1991), in northeastern Box Elder County, Utah.

Clarke (1991) estimated a combined total population of more than 3 million individuals; however, Clarke appears to be inclined to liberal estimation of gastropod populations (see, for example, account of Oreohelix eurekensis for discussion of another of Clarke's population estimates). Even if Clarke's estimate is not exaggerated, since the species survives at only 3 sites, its overall population must still be considered small relative to other similar organisms.

Continued searches for other populations in northwestern Utah may be of value.

Habitats Utilized in Utah

Clarke (1991) wrote: "The pools which contain S. bonnevillensis are all spring-fed, occupy areas of between 1/4 and 1 acre, have diverse substrates (mud, gravel, and/or rocks) and are well-vegetated. When first searched in 1990 (on June 15) water quality measurements were: pH, 7.2-8.2; temperature, 16-18 degrees C; conductivity, 4,500-10,000 micromhos [/cm]; and oxygen values varied from low (2.8 ppm in the mouth of the underwater spring at [one station]) to supersaturated (14.8 among algae at [another station]), but were intermediate elsewhere. The whole region has extensive lacustrine deposits. At [one station] S. bonnevillensis also occurred in a narrow outlet ditch."

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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