Except for Call (1884), who placed this and several other species of floaters in synonymy with Anodonta nuttalliana, which he reported from Utah Lake and from near Salt Lake City, all other authors who have discussed the species in Utah (e.g., Yarrow 1875, Ingersoll 1877, Chamberlin and Jones 1929, and Jones 1940a) have used its currently accepted name.
No subspecies are recognized in this species.
Status in Utah
About 3 historical occurrences of this species in Utah are known. This species is known from historical records in 3 counties in Utah: Davis, Salt Lake (probably), and Utah counties (Ingersoll 1877, Chamberlin and Jones 1929, Jones 1940a). Yarrow (1875), in the first report of the species from Utah, stated that the species was "[c]ollected from the Sevier River, Utah"; however, this is a rather imprecise locality, the Sevier River flowing through at least 6 Utah counties.
Although Ingersoll (1877) stated that this species was "[f]ound very abundantly" in Utah Lake, where there were "[m]any specimens living", the species is no longer extant in Utah Lake. Chamberlin and Jones (1929) reported 2 Utah specimens based on shells, apparently of recent origin, and mentioned as well "[l]iving specimens secured from a state fair exhibit." Jones (1940a) listed 1 Utah specimen. It is questionable whether the species still survives in Utah.
This species, if extant in Utah, is believed to be seriously threatened. Dewatering as well as alteration and degradation of aquatic habitats in north-central Utah, especially along the heavily populated and developed Wasatch Front in the very areas of its historical occurrence in Utah, are almost certainly factors that have led to its decline, if not extirpation, in this state. If this species still exists in Utah, it likely is declining rapidly.
Inventory is needed in central and north-central Utah, particularly along the Wasatch Front, to ascertain whether this species is extant in this state.
Habitats Utilized in Utah
Ingersoll (1877), reporting this species from Utah Lake wrote: "Found ... in the brackish water at the Southern extremity of Utah Lake in the soft mud." No other habitat information has been mentioned by authors discussing this species in Utah.