Lepidomeda mollispinis

This species formerly was referred to as L. vittata. Two subspecies are recognized: L. m. mollispinis and L. m. pratensis.

This species has a very limited range in the Virgin River system of Arizona, Utah, and Nevada. The population suffered a historical decline of approximately 40% but has now been restored to approximately 95% of the historical range. The species still faces threats from habitat fragmentation, the continued presence of non-native fishes, shoreline destabilization, and continued dewatering associated with agriculture, mining, and urbanization.

This species is endemic to the Virgin River system in the western United States in Arizona, Nevada, and Utah (Page and Burr 2011). Using Global Biodiversity Information Facility (GBIF) (2025) records from 2000-2025, range extent is estimated to be 10,361 km² (RARECAT 2025).

Subspecies mollispinis: Currently, almost all of the occupied habitat is in Utah: mainstem Virgin River above Quail Creek diversion, three reaches in Beaver Dam Wash, Santa Clara River between Veyo springs and Gunlock Reservoir, isolated reaches in Moody Wash and Mogatsu Creek, and a 6.3 km reach in the lower Santa Clara River; also found in the lower reaches of La Verkin, Ash, North, and Shunes creeks, and in the lower reaches of both the North and East forks of the Virgin River; occasionally collected in the mainstem Virgin River between Pah Tempe Springs and Littlefield, Arizona (USFWS 1994).

Subspecies pratensis: This subspecies is found in a single population within an approximate 8 km section of the Condor Canyon, Meadow Valley Wash, Lincoln County, Nevada (USFWS 1994, USFWS 2021a). Originally known from 1938 collections in the spring outflow and marsh below Big Spring (= Panaca Spring), about 2 km northeast of the town of Panaca (Miller and Hubbs 1960). The area is in a basin off the east side of Meadow Valley Wash, which follows the ancient course of the Pluvial Carpenter River, the main eastern tributary of the Pluvial White River. The Pluvial White River emptied into the Virgin River, which joined the Colorado River at what is presently the Virgin Basin or Overton Arm of Lake Mead. The Big Spring population is thought to have become extinct when the marsh dried up as a result of water diversion. In 1977, a population was discovered in Condor Canyon of Meadow Valley Wash, several kilometers upstream from the type locality (Allan 1983). In 1980, an unknown number of juveniles were collected from the pool below the falls in Condor Canyon and transplanted to the stream above the falls (Allan 1985). It is unknown if any occurred historically above the waterfall. An introduced refugium population, established in 1987 in a pond within the BLM's Shoshone Pond Resource Area in White Pine County is extirpated.

Subspecies mollispinis: There are approximately seven occurrences (USFWS 2021b).

Subspecies pratensis: There is one occurrence (USFWS 2021a).

Subspecies mollispinis:
This subspecies continues to be threatened by the ongoing effects of past habitat fragmentation, the continued presence of non-native fishes, shoreline destabilization, and continued dewatering associated with agriculture, mining, and urbanization (USFWS 2021b). Ongoing conservation action under the Virgin Spinedace Conservation Agreement and Strategy has resulted in this subspecies currently occupying 95% of its historical range, as opposed to only 60% in 1994 (USFWS 1994, Lentsch et al. 2002, Wiley et al. 2008, USFWS 2021a).

Subspecies pratensis:
The sole occurrence is vulnerable to a number of threats, including drought, dewatering, erosion and pollution from excess livestock grazing, non-native fishes, and human activities (USFWS 2021a). All of these factors either directly deplete the population or destroy the habitat. Due to being on private land and the main source of water for agriculture in the area, the type locality Panaca Spring will likely not be restored or the habitat formally protected (USFWS 2021a).