Date of this Version
Woodman in Systematics, Historical Ecology, and North American Fresh Water Fishes (1992), edited by R.L. Mayden.
As presently understood the genus Rhinichthys consists of seven species: R. atratulus, R. bowersi, R. cataractae, R. deaconi, R. evennanni, R. falcatus, and R. osculus (Lee et al., 1980; Matthews et al., 1982; Miller, 1984; Goodfellow et al., 1984). The genus is mostly western in distribution but R. atratulus is restricted to the eastern portion of North America. Rhinichthys cataractae is the only other species found in eastern North America, but substantial populations also exist west of the Continental Divide. Rhinichthys falcatus is restricted to the Fraser and Columbia River system and R. osculus is native to all major western drainages from the Columbia and Colorado rivers south to Sonora, Mexico (Lee et al., 1980) with disjunct populations showing high degrees of endemism. Rhinichthys evennanni is restricted to the Umpqua River system in Oregon.
The monotypic western genera Agosia and Tiaroga have also been viewed by some writers (Lee et al., 1980) as derivatives of Rhinichthys or a Rhinichthys-like stock. Agosia has long been associated with a subset of what we now recognize as Rhinichthys, specifically the subgenus Apocope (Jordan and Evermann, 1896; Jordan et al., 1930). Agosia is common in the Bill Williams and the Gila rivers but its southern limits are not well defined (Lee at al., 1980). Tiaroga is restricted to the upper Gila River basin in Arizona and New Mexico. As a result of a phylogenetic analysis inferring genealogical relationship, I present arguments in support of including the nominal genera Agosia and Tiaroga within Rhinichthys. Consequently, I will refer to these species as Rhinichthys chrysogaster and Rhinichthys cobitis, respectively.