Common Name

Scientific Name

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Utah Taxonomy

Several authors (e.g., Chamberlin and Jones 1929, Jones 1940b, Woolstenhulme 1942a, and Chamberlin and Roscoe 1948) discussing this taxon in Utah have treated it as a race of Fossaria modicella: "Fossaria modicella rustica". Turgeon et al. (1988, 1998) listed this taxon as a full species but seemingly with reservations, for they consider its classification to be uncertain.

No subspecies are recognized in this species.

Status in Utah

There are 12 known occurrences of this species in Utah, all being historical. It has been reported in Utah mainly from the north-central part of the state, where it is known from extreme western Summit County (Jones 1935), extreme southern Morgan County (Jones 1935), extreme northeastern Tooele County (Jones 1940b, Woolstenhulme 1942a), and northern Utah County (Jones 1940a). It has also been reported from northeastern Utah in Uintah County (Woolstenhulme 1942a). There is one record from extreme southern Utah in Kane County (Daniels and Ferriss in Chamberlin and Jones 1929).

No meaningful abundance data have been reported for this species in Utah. Jones (1940b) did mention "three living specimens", which indicates that the species has been found alive in this state. Jones (1940a) reported "two", and Woolstenhulme (1942a) listed "4" and "4" from two localities, but there was no indication by either author whether any of these were living.

Threats to this species in Utah have not been reported. Since almost any aquatic site in Utah may be subject to dewatering, alteration, and degradation, and since most of the known localities for this species in Utah are in areas that have experienced and currently are experiencing serious impacts from development, threats to this species in Utah, if it is extant here, are likely great. Population trend of this species in Utah is not known.

Inventory is needed to ascertain whether this species is extant in Utah and, if so, to determine its distribution and abundance.

Habitats Utilized in Utah

No habitat data have been reported for this species in Utah. The known Utah localities range greatly in elevation.


  • 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.