Lepidomeda aliciae

The generic allocation of leatherside chubs has been unstable. The original name was Squalus copei; subsequently the species was placed in six other genera. Uyeno (1960, Ph.D. diss., Univ. Michigan) restudied taxonomy and placed it in genus Gila, subgenus Snyderichthys (Lee et al. 1980). Starnes (1995) treated Snyderichthys as a full genus and referred to this species as S. copei; he noted that the populations in separate subbasins of the Bonneville Basin system should be investigated for polytypy.

Simons and Mayden (1997) presented reasons for recognizing Snyderichthys as a genus rather than as a subgenus of Gila.

Dowling et al. (2002) studied cytochrome b gene sequences and found that Snyderichthys from the Snake and Bear River drainages is part of a clade that includes Lepidomeda mollispinus and L. albivallis, casting doubt on the validity of morphologically diagnosed Snyderichthys. Based on the molecular data and a possible biogeographic scenario, Dowling et al. (2002) indicated that Snyderichthys may become a synonym of Lepidomeda, and that Snyderichthys from the central and southern Bonneville basin may warrant recognition as a distinct species, possibly L. aliciae (Jouy, 1881). However, Dowling et al. (2002) noted that further study is needed.

Nelson et al. (2004) cited Simons and Mayden (1997) as a basis for listing Snyderichthys as a valid genus. They did not mention the work of Dowling et al. (2002).

Johnson et al. (2004) found that the leatherside chub is composed of two reciprocally monophyletic clades characterized by numerous fixed genetic differences for both mitochondrial and nuclear DNA markers. The clades also showed significant differences in cranial shape, and controlled growth and foraging experiments show that the clades appear to be locally adapted to the thermal environments where they now occur. Combined, these three lines of evidence support the hypothesis that leatherside chub is composed of two species. Moreover, all lines of evidence place these two species within the genus Lepidomeda. Johnson et al. (2004) therefore recognized the two clades of leatherside chub as two distinct species (Lepidomeda copei in the north and L. aliciae in the south), and they argued that each warrants independent conservation and recovery action.

This species has a very limited range in highly fragmented habitat in Utah. The population has declined due to habitat degradation caused by human activities. Invasive brown trout diminish populations and force individuals to seek suboptimal habitat, limiting populations.

This species is endemic to central and southern Utah, United States. The range includes the southeastern margins of the Bonneville Basin; historical range included the American Fork, Provo River, and Spanish Fork drainages of the Utah Lake Basin and the San Pitch River, East Fork Sevier River, Beaver River, and the lower, middle, and upper Sevier River drainages of the Sevier River Basin (Utah Division of Wildlife 2010). Using Global Biodiversity Information Facility (GBIF) (2025) records from 2000-2025, range extent is estimated to be 19,007 km² (RARECAT 2025).

This species is apparently extirpated from the Provo River at Utah Lake, and from the Beaver River (Johnson et al. 2004). Introduced populations of leatherside chubs (species uncertain) occur in the Strawberry, Green, and Fremont rivers within the Upper Colorado River Basin (Utah Division of Wildlife 2010).

The species has been found in three 4th level HUCs in the Utah Lake drainage and six 4th level HUCs in the Sevier River drainage (Johnson et al. 2004, Utah Division of Wildlife 2010).

Irrigation projects have fragmented and modified most of this species' habitat (Johnson et al. 2004, Utah Division of Wildlife 2010). Much of the current population fragmentation and habitat degradation is caused by human activities including irrigation projects, dams and water diversion, culverts, stream channelization, habitat degradation, dewatering, urbanization, poor grazing practices, and the introduction of non-native fish predators (Utah Division of Wildlife 2010). Intentionally introduced non-native game fishes, such as brown trout (Salmo trutta), prey upon leatherside chub and displace individuals to marginal habitats (Walser et al. 1999, Olsen and Belk 2005, Billman et al. 2010). Natural climatic events such as flood, fire, and drought may threaten fragmented populations (Utah Division of Wildlife 2010).