Specimens originally reported as Fluminicola hindsi and Fluminicola fusca have been referred by Hershler and Frest (1996) to this species, which they called "Fluminicola coloradensis [sic]". They noted that, though Morrison (1940), who described this species, included, in his concept of the species, snails from the Great Basin, significant morphological differences between the Green River and the Great Basin populations suggest that the Great Basin populations may represent one or more undescribed species. Hershler and Frest (1996), thus "have decided to restrict F. coloradensis [sic] to populations from the Green River."
No subspecies have been proposed in this species.
Status in Utah
Although Hershler and Frest (1996) stated the distribution of this species as "Upper Green River drainage, Wyoming" and mapped its range only in Wyoming, they examined 4 collections supposedly from Utah; there are questions concerning the locality data of all 4. It is questionable whether 2 of these collections are actually from Utah, the locality for both being "Head of Green River", which is far to the north of Utah in Wyoming. Perhaps the term was used loosely and what was meant was "upper Green River". Another Utah collection was from Emery County, but Hershler and Frest (1996) were "unable to confirm the Emery County, Utah, record, which is well downflow from other Green River sites for the species and may represent drift material (shells in this lot are worn and were collected empty)." The only other Utah record bears the ambiguous and perhaps indefinite locality "Green River" (Hershler and Frest 1996). Conceivably it could refer to the town of Green River and thus may be somewhat precise (and would corroborate the other Emery County record). However, it could equally well refer to the river itself, most of which is in Utah, where its course is hundreds of miles in length. Thus, while it seems that this species has been collected in the Green River drainage in Utah, there are no occurrences that can be precisely located.
Abundance of this species in Utah is unknown. Only 4 specimen lots from Utah have been reported (Hershler and Frest 1996), but the numbers of specimens in these lots were not provided.
Threats to this species in Utah are unknown. Alterations of the flow or degradation of the water quality of the Green River may be considered potential threats. Population trend in this species in Utah is unknown.
Surveys for this species in the Green River are needed in order to evaluate the status of this species in Utah.
Habitats Utilized in Utah
No habitat information for this species is available. Two of the Wyoming localities reported by Hershler and Frest (1996) are at bridges where highways cross the Green River.