Although Hershler (no date) considered this species to be merely a population of Pyrgulopsis kolobensis, Hershler (1998) described this as a new species, Pyrgulopsis fusca, and has suggested the common name Otter Creek pyrg for it.
The type locality of this species is "[s]pring brook, Otter Creek, ca. 1.6 km above The Narrows, Piute County, Utah, T 28S, R 1W, SW 1/4 section 17"; the holotype, USNM 883439, was collected 1 October 1993.
No subspecies have been proposed in this species.
Status in Utah
This species occurs only in 3 locations in south-central Utah: 1 in Piute County and 2 in Sevier County.
Hershler (no date) reported the abundance of this species at two of the three localities of its occurrence as "common". Since the species is restricted to three sites, its overall abundance relative to other organisms should be regarded as very low.
All three sites known to support this species were reported by Hershler (no date) to be slightly disturbed, two of them by livestock. Hershler (no date) noted that one of the sites is near a road. The restricted habitat and distribution of the species suggest that potential threats to its survival are likely very great. Population trend in this species is not known.
Inventory in the general area of the occurrence of this species may be of value.
Habitats Utilized in Utah
Hershler (1998) described the type locality as "a small brook (2 cm deep, 1 m wide), fed by numerous small springs, which enters Otter Creek." For another locality Hershler (no date) noted that "[the spring] runs about 7 m, enters creek". Hershler (no date) reported that all 3 of the localities of occurrence are rheocrenes, their elevations ranging from 6,720 to 7,250 ft, temperatures 7 to 13 degrees C, and conductivities 190 to 200 micromhos/cm.